Going from Lead to Lithium

[Pau Hana]

I remember when AGM were thought to be the total solution

Tempis Fugit…

 

[Marco Flamingo]

It appears that the Taxnele brand is not the only Brand of these dc rated circuit breakers. This would lead me to believe that none of the Brands listed on the internet sites are the actual manufacturer of this breaker.

- It is not uncommon for high amperage cheap dc breakers to have a resistance of about 4mΩ. If you are running things at 100 Amps, the voltage drop through the breaker will be 0.4 V. Are you OK with that?

From what I can find, this is a "B" rated breaker and the time delay curve is available as a percentage of total amps. So a 250A breaker is rated at about 1 second at 3x rating. 750A for a second is more than enough to handle the inrush for my starter.

Here is what one of the Chinese MCCB manufacturing facility looks like. I was surprised that there weren't any water buffalo providing power at the facility. Tempis Fugit. . .

I got my breakers today (14 days) and tested resistance. In the video linked above at #57, the resistance was 1.1 to 1.2mΩ (for a 150A breaker). My 250A breakers were 1.7 to 1.8mΩ (at ambient). Maybe larger breakers have more resistance or maybe my multimeter isn't accurate. I have a better multimeter onboard, so I'll check again on the resistance.

If I understand luna's post, if I was running things at 100 Amps, the breaker would cause a 0.18V drop. But if my shunt showed I was using 100 Amps, I'd be looking for the short in my electrical system!! Only my starter motor draws that kind of amperage on my boat. And a starter motor 0.18 voltage drop with lithium still puts me several volts ahead of what my sagging lead acid could do, so I'm okay with that.

For charging input into the LFP batteries, I assume the same voltage drop would occur. It could be that setting absorption at 14.5 would mean that only 14.32 would actually get to the batteries (my old Balmar regulator doesn't sense at the battery). Again, not really an issue and measuring actual voltage at the batteries was already part of the plan for setting regulator charge parameters.

 

[Delta Riverat]

You don't have a inverter? A hundred amps is easy with a inverter.

 

[Marco Flamingo]

I have three inverters aboard. One is dedicated for my induction stove and it is a completely separate lithium battery and solar panel.

The second inverter is a Xantrex Freedom 30. It runs a couple of 120V outlets onboard. My wife has plugged into them for laptop charging using a USB wall wart. I've never looked to see what the inverter draws to put out the USB charging. I've since put in 12V LED lights that have their own USB ports, so we cruise with that inverter turned off. I've never even looked at the shunt to see what kind of amperage that inverter draws, mainly because if we are underway the alternator is producing. I know that inverter has a dedicated 300A Class T fuse per the owner's manual. I could take some 120V stuff to the boat, plug it in, and see if I can use 100A, but I'm not sure what it would show me. If my new breaker causes the voltage from the LFP batteries to drop from 13.4V to 13.2V at the inverter, the inverter would still be fine.

The third inverter is just a little 10A one that came with one of my LFP batteries. We charge up the dinghy LFP battery when we have shore power. I guess I just don't use enough juice.

 

[Delta Riverat]

Run the microwave off the inverter and look at the draw - Or the coffee pot. Something that's over a kilowatt.

Yeah, those little usb loads are insignificant

 

[luna]

I have three inverters aboard. One is dedicated for my induction stove and it is a completely separate lithium battery and solar panel.

The second inverter is a Xantrex Freedom 30. It runs a couple of 120V outlets onboard. My wife has plugged into them for laptop charging using a USB wall wart. I've never looked to see what the inverter draws to put out the USB charging. I've since put in 12V LED lights that have their own USB ports, so we cruise with that inverter turned off. I've never even looked at the shunt to see what kind of amperage that inverter draws, mainly because if we are underway the alternator is producing. I know that inverter has a dedicated 300A Class T fuse per the owner's manual. I could take some 120V stuff to the boat, plug it in, and see if I can use 100A, but I'm not sure what it would show me. If my new breaker causes the voltage from the LFP batteries to drop from 13.4V to 13.2V at the inverter, the inverter would still be fine.

The third inverter is just a little 10A one that came with one of my LFP batteries. We charge up the dinghy LFP battery when we have shore power. I guess I just don't use enough juice.

I also have 3 inverters onboard, one of which is a Xantrex Freedom Marine 30 from 2006ish. It is a legacy unit that produces a Modified Sine Wave. I use it to run a couple of point of use 1.5 kW water heaters, a toaster. and an electric skillet, not all at the same time. All are resistive loads that don't care about wave form. The inverter can draw 230 amps (@ 12 V.) with ease. It can also put 120 Amps back into the batteries, which proves useful.
They are good devices as long as you don't ask them to swing a motor or power modern motor controllers.

Do yourself a favor. if your unit is a modified sine wave producer, keep the microwave away from it, otherwise the microwave will most likely audibly protest.

I agree, the 0.2 V lost due to the resistance in the breaker should not affect the running of the loads to any significant degree. I would be more concerned about the 20 W. of heat (@ 100 A load) generated at the breaker. As breakers age this will not get better.

If it was me, I would use a Class T fuse with half or less of the voltage drop.

 

[Marco Flamingo]

The microwave was the first thing that went by the boards after we bought. It "worked" with the modified sine wave, but under protest. It may have been pulling 100 amps. Sure sounded like it. I put it in my shop and it works fine. Next, I got rid of the propane stove and a propane stainless weenie roaster on the flying bridge. The stove was replaced with induction, so I needed a pure sine wave inverter. It was easiest to connect up the induction stove top, PSW inverter, dedicated LFP battery, and solar panel as a stand alone "kitchen" system. So my coffee pot goes on the induction stove which is completely separate from house/start batteries and breakers.

I've never even thought about using an inverter to run the 120V water heater. Not sure why I would with the induction stove being so fast.

Next, I got rid of the 4kW Yanmar generator. Never used it. I'm not sure what it was ever used for. My LFP battery bank is going where it used to sit. So my electrical usage is probably not the norm.

Our main use for the Freedom 30 is as a battery charger using shore power. It is what I will be using to charge the LFP batteries in port and getting full charge maybe once a month to balance the batteries. If it produced 120A when charging, that would likely be 60 amps into each bank flowing back through the 250A breakers. Other than the starter, I think that 60A will be the largest current through the 250A breakers. In the Russian video cited above, he runs them at load and shoots them with an IR gun. Warm, but nothing to get excited about. One interesting thing was, when checking resistance, he tripped the breakers several times and the resistance changed slightly. Each smacking together of the contacts could make enough difference to measure. Makes sense. Probably a good idea to record resistance or voltage drop and check once in awhile. I saw on the DIY Solar site that there are occasionally issues with fuses/breakers over time, as with crimps, clamps, etc. A voltage drop log might come in handy.

I'd use a Class T fuse if somebody convinced me that a bank of two 280Ah LFP could not produce amperage in excess of the Class T AIC of 10-20kW. If my 560Ah bank is under 20kW, why did Epoch put a 50kW AIC fuse in their 460Ah battery? My guess is that they know something I don't (because manufacturers won't tell).

 

[luna]

All of the water that comes out of the hot tap on my ride is heated by one or more ac powered water heaters. While I'm at the dock the power comes from the Grid, underway the alternators/ inverters and on the hook, the genset. It works well and we are seldom without hot water, just like home.

Induction stoves are marvelous, we have them as well. I just have yet to figure out how the hot water in the kettle is of any use when you need a shower.

I provided a link in Post #56 to a Mersen Class T fuse, specifically model No. A3T which has an I.R. rating of 50kA @ 160 VDC. I'm quite sure this fuse fits the Blue Seas holder.
If you are looking for higher performance, their A6T shows an I.R. rating of 100kA, but you will need a new holder.
Both are UL listed and CSA certified.

 

[Marco Flamingo]

All of the water that comes out of the hot tap on my ride is heated by one or more ac powered water heaters.
Induction stoves are marvelous, we have them as well. I just have yet to figure out how the hot water in the kettle is of any use when you need a shower.

Our hot water tank is 120V at the dock and engine coolant when underway. Takes about two hours of cruising to get hot (192F thermostat, so it can be really hot). Six gallon tank, so when cruising it is enough for the evening and for showers in the morning.

But we prefer showering on the back deck. Heat water in a kettle, pour in bucket, add cold, and drop this in. Ivation Portable Review

I suppose one could add the hot water to the the sink in the head and use the Ivation Portable to take a shower there, but then the head would be all wet and need to be dried. Better on the back deck. We also have a solar shower that we use on the back deck. Placed on the FB and gravity fed to the back deck. Zero amps.

 

[SteveK]

So far engine coolant underway heats the domestic hot water tank, shore or GEN can also do so. But on the back burner I have thought about changing the element to a 12v one and heat water direct to avoid inverter conversion loss. Anyone do this. what are the results pro/cons?

 

[Marco Flamingo]

I have thought about a 12v water heater. Even went so far as to buy two different sizes of 12V elements and make a mock up of a solar 12V water heater (on another boat). Turned out that our main reason for wanting bulk hot water when not underway (or having been underway in the last 12 hours and still having engine generated hot) was for a couple of showers. For that, our solar shower laid out on the FB was faster and used no battery. I still have the 12V elements, but because they would need to  replace the 120V element that we sometimes use, they remain on the workbench.

Right at the start of last year's two month cruise, we were hit with a gust of wind that blew our empty solar shower overboard. The waves were messy enough that we couldn't find it when turning back (couldn't help thinking about a MOB situation). It was sorely missed even though we bought another crappy one in BC. Time for a $20 replacement (less than a 12V element). Something like this:

Amazon.com

In the PNW, sun can be an issue, although a cloudy day can still generate shower worthy temperatures. Being remote enough so that my wife feels comfortable showering on the back deck isn't generally a problem. Might be the opposite when boating in other areas: plenty of sun but no privacy.

 

[luna]

Heating 8 gallons water to 140º F. typically takes a lot of time.
For example, in a perfect world (no losses) with a 300 Watt element (of any voltage) to raise the temperature of 8 gallons of water 90º to 140º F. takes about 6 hours.

If you incur the costs to increase the wiring to 8 Ga. and the breaker size to 50 A. (to support a 12 V. 600 W. heating element) you can cut the time in half to 3 hours. If the water in the tank in the morning is still at 80º F. you wait 2 hours to 140º F.

In addition, with a full heat cycle you will have removed about 160 Ah. from your battery (includes the energy lost due to the 10% voltage drop @ a 30' circuit length) and will likely want to charge soon. Got solar?

All too long in time and to stored energy intensive for me.

I run my tanks at 1500 and 3000 watts to get water heated relatively quickly. To do so takes 120 V. ac. The power for these water heaters only comes from the batteries if my 5 kW of alternators are running.

Here is a Water Heating Calculator so you can look at your own situation and make a decision on what serves you best.

Water Heating Calculator for Time, Energy, and Power

The calculators on this page compute how long it takes to heat water, how much energy is consumed, and how much heating power is required.

gettopics.com

What happened to "Going from Lead to Lithium"?

 

[Marco Flamingo]

What happened to "Going from Lead to Lithium"

I just got notice that my new cables were delivered to the Post Office. Unfortunately, due to President's Day, it will be closed tomorrow. I decided to upgrade the cables after reading over the ABYC table. My 2/0 150C cables in the engine room were close to max, but I found a good deal on tinned 2/0 silicone that are rated at 200C. That made enough of a difference that I thought I would upgrade and not as pricey as going to 4/0 cable. My PO had put the cables in a 3" PVC pipe, which made for a clean install, but the ABYC further derates them for being in conduit.

I also had to reconfigure the area for the LFP batteries. Unlike LA, which have to be upright and have access for watering, LFP allows many options. But it was still difficult to get away from the LA mindset and not have the bank in a perfect line with tops accessable. I should be able to install my new whizzbang doubledecker battery shelf (patent pending) and get a photo tomorrow.

As others have noted, buying the batteries is the cheap and simple part.

 

[luna]

Yep, using a conductor with insulation rated at 200º C makes the ampacity of 2/0 about equal to 4/0 rated at 105º C, as long as the wiring is in the E.R.
Single runs or bundled, the 2 sizes are rated almost the same. Hopefully the other requirements for good marine wire are found in this high temp. stuff.

Where the higher rated insulation can't help is in voltage drop. The 2/0 will have just under double the voltage drop of the 4/0.
You should have a good look at that, as under load this reduction in voltage along with the voltage drop at the breaker, it could get material.
Only you know the layout details. The calculations are not hard.

As they say in Daytona and most other tracks, there is no substitution for cubic inches.

 

[Marco Flamingo]

My lead acid battery box spanned the shaft alley so I needed to make a shelf for the LFP.
View attachment 162337
Here it is with two of the four batteries in place. The shelf is held by dowels and is removable. A strap holds it all down in the event of another rollover.

Here are the breakers for each bank. The box will be attached to the bulkhead.

My 2/0 cable came today, so I'm making new ones. After watching a YouTube video on the Sterling alternator protector, I think I'll get that one instead of the Balmar. In the video, the alternator is running at 150A and is disconnected. No fireworks and when reconnected the alternator simply starts generating again. Sounds too good to be true at $80. What isn't discussed is whether it also saves only the alternator. The voltage gauge in the video doesn't appear to register a spike, but it seems odd that the issue of protecting additional electronics isn't discussed.

The Bluetooth app wasn't working today. Not sure what's up with that. The two batteries onboard were going to be the Guinea pigs. When I got home, it didn't work on the two in the garage.

 

[Marco Flamingo]

Here is the before and after. There was a 4kw generator that I never used. It had a Group 27 lead acid start battery. All that was removed and the LFP batteries are now in the same spot (actually a little bit lower). Removal of the generator also allowed a much simpler electrical panel.

Four 280Ah LFP batteries in two banks with a breaker for each bank. The positives go to a 1-2-Both-Off switch in the cabin. Because the breakers are 250A, the "Both" setting could have 500A continuous. For that reason (and the Heart Inverter installation manual), my prior owner had a 300A Class T on the positive to the inverter/charger. The house loads also pass through a 250A Class T. The starter circuit is fused only by the two breakers (or one breaker if using only a single bank to start).

My vintage charger was set to AGM and the battery temperature sensor was removed. According to the operator's manual, this results in an absorption of 14.4V and a float of 13.3V. I ran the batteries down a few percent before installation so that I could watch them charge using shore power. I had noticed at home that one battery wasn't balance perfectly and had shut down several times and given a "single cell overcharge" notification for cell #1. The shutdown occurred at a cell voltage of 3.75, which I thought was higher than cells were supposed to go. Once it shut itself down, the voltage quickly dropped in cell #1, while the voltage stayed the same in the other cells. Once charging started again, all the cell voltages would rise, with cell #1 again shutting down from overcharge, but the other cells had gained .02V. So it appeared that if cycled about 10 times, the cells would balance.

I didn't complete the balance process because I wanted to see how my alternator and charger would respond to a single cell overcharge. First the charger. One bank was a bit lower, so it was taking 20-30A per battery. The other two were taking about 10-12A. Never the same acceptance for any individual battery. Each battery seemed to take only what it needed. Probably was also true with my old lead acid, but Bluetooth allows one to fret over minutia that I was unaware of before. The battery with the high cell #1 again jumped ahead as the battery approached 100% SOC. Now I could see what a BMS shutdown would do! It was a big nothing burger. The acceptance amperage in the system was already quite low, but one battery shutting down did not appear to increase the amperage to the others, i.e., no acceleration of charging likely to cause overcharges elsewhere. The second battery next to the shutdown battery actually went into "standby" during this time. I assume that means it is neither charging or discharging. Shortly thereafter, both batteries in the other bank also did the same. The battery with the high cell voltage quickly dropped to 3.6V and also went to standby mode. Although I never actually saw 14.4 volts on my system shunt (13.36V was the highest), the charger apparently went to float. I had a few lights and the diesel heater on, so the batteries flickered from charging (1-2 amps), to standby, to discharge (1-2 amps).

I turned off the charger and turned on some loads and went to lunch. When I came back, I started the engine to charge the LFP using the alternator. I can only Bluetooth one battery at a time and saw 104A from a single battery for the start draw. I then shut down and restarted using a single bank (2 280A LFP). No problem. I forgot to look at a single battery discharge for that. Presumably, the millisecond discharge would be close to continuous rating of each battery (250A). The acceptance rate of the LFP banks was impressive. With the old lead batteries, we could be in the middle of a 6 hour cruise and see that the batteries were at 85% full. It was questionable if we could get the banks full in the next three hours as the acceptance amperage would drop down to almost nothing. With the LFP at 97%, my 100A Balmar alternator was still putting out 65A (its derated output based on the external regulator and temp sensor).

As with the shore power charger, I saw that one battery still had an imbalanced cell and would likely shut down with an overcharge warning. When that battery shut down, nothing weird happened with the others. They hit the absorption voltage, amperage dropped, the batteries went to "standby" and the battery with the overcharge came back on line after a few minutes.

It's a bit scary watching this because Bluetooth gives so much freaking information. Once my one unbalanced battery balances, I'll probably program the alternator to 14.3V just to be safe when cruising and wean myself from Bluetooth. For shore power, I'll keep it at 14.4 because I know that balances the LFP and even a total shutdown of both banks at the marina doesn't bother the charger.

 

[Barking Sands]

Thats great! All of your research has paid off with a good understanding of what was happening on your initial run through. Balancing will get better on each cycle. You can see how the apps are full of great details that help you see into the inner workings and processes.

 

[Marco Flamingo]

Here is a synopsis of what was done, with costs and other numbers. I removed 4 x 6v 260Ah deep cycle batteries (which, when new, gave me approximately 260 amp hours usable if taken down to 50% SOC). Plenty for one night at anchor for us and then used for starting batteries in the morning. I replaced them with 4 x 12V 280Ah LFP batteries (which gives me 1,120 amp hours usable if taken to 0% SOC). An additional 860 amp hours or about 4 days at anchor for us (with plenty left to start the engine).

My thought was to use as much of the existing infrastructure as I could while limiting additional gadgets. Many LFP installs recommend (insist?) on a DC/DC transfer from/to a traditional lead start battery and the lithium battery. Not necessary for my boat. My boat had a start battery for the generator, but it used the lead deep cycle house battery bank to start the main engine (80hp 4cyl Lehman). I removed the generator, its lead start battery, and the lead house bank and replaced all with LFP.

4 x 280Ah LFP $1,428
2 x 250A breakers $55
New cables $90
Electrical box $26
Alt Protect Module $75

So $1,674 all in, or $1.50 per amp hour. I could have simply replaced the 4 Dyno deep cycle batteries for $265 each ($1,060 or $4.00 per amp hour). The cost difference is basically a rounding error in boat ownership. Plus, I got some new upgraded cabling.

It was some work, but I no longer have to crawl down and check the electrolyte level or add water!!! I don't enjoy that anymore. Maybe in a few years I'll think that alone was worth the $1,674.

 

[Delta Riverat]

Yeah, it is already. I love not having to attend the batteries and knowing the charge by the shunt which I found to be important as the lithium bank will read 13.2 for a long range of SOC.

 

[Marco Flamingo]

I did get a chance to download an LFP app other than the Eco-Worthy. I tried the Overkill recommended by Barking Sands. Worked almost perfectly and quite an improvement. Nothing horribly wrong with the Eco-Worthy, but the Overkill offers so much more. One apparent difference was the connect time when firing up the app. Eco-Worthy was always faster to load the batteries and always kept them in the same order 1-2-3-4. Overkill takes a little longer and varies the order. Eco-worthy not only picked up my 4 batteries, but also two 300Ah batteries somewhere else in the marina (they were always at 100% SOC).

But Overkill wins. Hopefully, I can include a couple of screen shots to show the difference. I didn't take a screen shot of the Eco-Worthy app, but it shows what's flowing in and out of a battery, overall voltage, charge/discharge rate, and the individual cell voltages. Very basic. The Overkill app has tons more, including the ability to change BMS parameters. It also records event history, so one can see if there has been an overcharge/undercharge/temp etc. event. With Eco-worthy, one had to catch the event as it happens or before it clears itself by the BMS resetting.

Here is page one after pulling up the data for battery #3:

Battery #3 was the most out of balance and I was working on getting the cells balanced. From top to bottom. First the battery name and the Overkill app version. Then the left yellow arrows indicate that it is charging at 15.91 amps. Discharge is off (maybe it can do both at the same time?) The battery is at a 70% SOC* sitting at 13.62 volts and shows the remaining Ah left. Below that are two yellow slide buttons. Charging or discharging may be turned off. What this means is that, like a 1-2-Both switch, once could turn off the charging with the alternator running. If done on all 4 batteries, I assume this would have the same effect as turning the 1-2-Both switch to Off. Don't do that. Below that is alarms. It shows the alarm event until it is cleared. Below that is the temp sensor. I knew Eco-Worthy had a temp sensor, but never knew the actual temperature. Good to know. My temp got up to 53.2 while charging/discharging for several hours. Further down in the app is the ability to change from centigrade to Fahrenheit, which I already did. So the temp shown is 51.4F. Not exactly hot.

Next line is the cell voltage delta and further down is real time cell voltages. To the right is whether the cells are actively balancing. Cell number two is behind the lead cell by .026 volts so the others have some resistance added such that cell #2 might catch up. I charged and discharged several times over several hours to watch what was happening. I also looked further into the Overkill app and saw that the stock Eco-Worthy setting had the cells balancing only when charging (as per the yellow arrows on the upper left). When charging was turned off, no balancing was taking place. Using the Overkill app, I was able to change the Eco-Worthy parameter such that when charging was off, the cells continued to balance. I have no idea why one would not want balancing to continue after charging has stopped (sometimes from the fastest cell reaching overcharge). Whatever the reason, it didn't make sense for my application.

Next is session values (starting from the time the app was opened). Not a lot of value for me as I don't usually watch the app for very long. BMS info shows that it is a JBD BMS and gives the model number and manufacture date. Not too helpful as this model changed over time. One of my batteries was manufactured in August of 2024, has Firmware Version 7, and has three temperature sensors (two on the cells and one on the BMS according to JBD website).

The next tab at the bottom is for Settings. This is one of the areas completely lacking in the Eco-Worthy app. The next tab is Calibration. Completely above my pay grade and I can't see any benefit of going so far into the weeds. Toolbox is the same. But I'll show the Settings page, with all the user adjustable parameters, in the next post.

* I don't think 70% SOC is accurate right then. I had just changed some parameters and I think the BMS was searching for the right SOC, which might require a full 100% SOC in order to recalibrate. It very quickly jumped to >95% SOC.

 

[Marco Flamingo]

Here is the Settings page of the Overkill LFP app. I changed several parameters and they were accepted by the Eco-Worthy LFP. The screen shot is from the app without a battery showing (as I'm at home). I also found out that, without a BMS connect, I can't show this entire page (there's more).

The top part of the page was just calibrations that Eco-Worthy had decided to use. Not much reason to change them. The Balancer Configuration is interesting. I can tell the BMS when to start balancing and what delta to use as "unbalanced." Eco-Worthy had that set as a cell imbalance of greater than .015 volt activates the balancer. I don't remember the voltage at which the balancing starts and will probably revisit that. From what I have seen, my imbalance starts at about 3.41 volts. The Eco-Worthy setting had the Balancer Enabled, but only when charging. I changed that. The next page of Settings was where it got interesting. Unfortunately, I can't pull that up without connecting to a BMS. To be continued . . .

 

[Barking Sands]

Great info....

The arrows just show the direction of flow. They both cant be on at the same time. If you only had a discharge load, say 10 amps, and you applied a 5 amp charge to the battery, it would just reduce the load on the battery to 5 amps of discharge. if you increased the applied charge to 10 amps then the battery would be idle and the charge applied to the system would just be carrying the ships loads. If you further increased the charge to 11 amps then 10 amps for ships loads and 1 amps of charge in.

The two toggle are the mosfet positions. You can manually use them, but generally those are for the BMS to control in the event of some overage of temp, current, voltage. The BMS only has those two items to affect the system (besides the balance circuit). IMO its ok to use them when you are present for troublehsooting and momentary charge/discharge disconnect for a particular battery, but I would not turn them off and leave the boat for any length of time. I think in some rare curcumstances you could lock yourself out.

The balancing during charge only.....just be careful that is stops balancing with no charge applied at some point/parameter that is achieved soon after charge shutdown. Otherwise youll balance yourself all the way to a dead battery early.

And lastly, just be careful modify the BMS parameters. Take screen shots of what they are now so you can put them back if needed. Watch Andy on Off Grid Garage programming the JBD bms. Its sometimes not straigtforward to say the least..lol. In some cases the numbers are half values etc and might throw you off. It may not be that way on the latest BMS versions but just beware it might.

The approach you took IMO is probably the best/simplest. There are so many 300ah batteries out there with a quality JBD 200amp BMS and decent cells for around $450-$650. Couple that with some good equipment like a Multiplus/Quattro and Cerbo/touch 50/tablet and a smart shunt and you can have quite a system in the 600 to 1800ah ranage for not very much money IMO. And the size of many of these ~300ah batteries is very versitile.

 

[Marco Flamingo]

This first picture is the bottom of the Home page shown in post #80. My original Eco-Worthy app didn't have any "history" information on the various faults. The Overkill app has a section that shows you what has happened. It is very interesting because the most common fault when setting up is a cell overvoltage shutdown because the battery isn't balanced yet. The "Alarm" area shown in post 80 indicates (in red) that a fault has occurred. The charge current is turned off and the cell voltages drop while some balancing goes on. After maybe as short as 5 seconds, the overvoltage cell has dropped to the point that current is turned back on and, if not watching, you've missed it. I watched this type of cycling go on for +10 minutes and 30 "alarms" shown in the picture at "single cell overvoltage" times in the picture below (I had erased them before taking this picture.) Without the history provided by the Overkill app, I would not know that this battery had gone through a rather lengthy balancing act.

Here is a screenshot of the first part of the Settings page. Unlike the picture shown in post #81, this one has the data showing. It appears that I could make up my own parameters for what constitutes 100%, 80%, etc. Don't know why I would. What interested me is the next category down, Balancer Configuration.

The Overkill app allows the user to define at what point the balancing will start. I set it at 3300mV (3.3V per cell). The delta between cells is set at 15mV (.015V difference between cells). After watching my worst balanced cell, I can generalize that my cell imbalance doesn't really begin until rising above 3.4V per cell and I don't know if an "early start" on the balancing at 3.3V actually helps (nor if starting to balance at a .010V delta would do anything.)

The default setting was Balancer Enabled, but "Balance only when charging" (the second slide button). I changed that and watched what happened when a cell hit the overvoltage alarm and turned off the charging to all cells. When charging is shut off and the cells are in the 3.4-3.6V area, the voltages naturally drift down. But with "Bal. only when charging" switched off, that actually means balance while charging and while not charging. Again, this was only for a few moments and then the parameters allowed charging to resume.

As for the possibility of a cell overcharge shutting down a battery while being charged with an alternator, and thereby damaging the alternator, there are a couple of considerations. First, I only have one battery that is going through this balancing phase. The other BMSs have remained open and receiving current. Second, the overbalance occurs only at the very end of the charging cycle. Post #80 shows my "problem" battery (#3) accepting 16 amps with balancing already begun and not even close to a cell overvoltage (3.65V). At this point, all 4 batteries are basically accepting the same current (about 75 amps total). By the time battery #3 begins cycling through any overvoltage shut downs, the acceptance current is down around 5 amps, which might be below that needed to create a damaging spike. Third, none of the other batteries have shown any tendency to be out of balance or shut down. Forth, just in case, I installed a Sterling Alternator Protection Device to absorb any voltage spikes should a simultaneous shutdown of 4 BMSs occur while charging with the alternator. Most of my testing so far has been using my shore power charger which is unphased by all four batteries shutting down (I did a nervous Nelly test).

At the bottom of the page above is Function Configuration with two slide buttons. The first is "SW switch circuit enable". Near as I can tell, this disables the Charge and Discharge slide buttons on the Home page. Weird. The next button is "Display Celsius," which changes everything to Fahrenheit. I did that.

Here is page #2 in Settings.

Of note here is the setting for "cell over voltage." I have read in many different places that one shouldn't charge LFP cells in excess of 3.65V (3650mV). The stock Eco-Worthy setting was for a cell over voltage of 3.75V for a period of 2 seconds. When I first got my Eco-Worthy batteries and was charging them for the first time in the garage, I saw Battery #3 reach a single cell overcharge of 3.75V and thought that was odd. Now I know why. I dialed that back on all batteries to 3.65V. I suppose one might get a longer balancing period by letting the outlying single cell go to 3.75V, but I'm not convinced that's a good idea.

Next are the Level 2 Protections. Oddly, these settings were not uniform on the batteries. Nor did they really reflect any of the parameters given in the Owner's Manual or the online information. The same is true for the Level 3 Protections. Nowhere in the Eco-Worthy literature is an amperage rating given in milliseconds or microseconds ("us" i.e., one millionth of a second).

Following that are the temperature sensors, which on this battery, are three. Another weirdness.

In addition to the 250A breakers for each LFP bank, the only other gadget I added was the Sterling Alternator Protection Device. I already had a Balmar ARS-5 external regulator. It was fairly easy to set it to the LFP charging parameters that I wanted. So far, even with Battery #3 doing its balancing act, the entire bank easily reaches the charging parameter of 14.4V and drops down to the sustain value of 13.3V.

Mark

 

[Marco Flamingo]

Short story. Besides replacing lead with lithium, I added three components. Two 250A breakers replacing the two 250A ANL fuses. The reason being that the breakers are capable of interrupting a 50,000 amp short (whereas the ANL are rated at 6K). Those were $52. And I added a Sterling APD which, allegedly, can dissipate a voltage spike to the alternator should all four BMSs shut down at the same time. It was $75.

As is still common, using lead for a start battery requires something like a DC\DC converter, an ACR, or some other corrective item, along with the cabling and, of course, buying a lead battery or two. Is the additional cost and complexity worth it? I guess I'll find out. I'm reminded of my Grandpa's reason for keeping a draft horse on the farm until I was in high school. "What if the tractor don't start?" Old school is that you can't trust lead acid batteries. My guess is he just liked having Biggens around. Or maybe, he thought that the care and feeding of a 17 hand Percheron was easier than maintaining a lead acid start battery (no electricity in the barn because that's dangerous.)

My old Balmar ARS-5 can be set to accommodate LFP batteries. In fact, it is superior in some ways to a newer external regulator with a dedicated "lithium" setting. Why? Because with the ARS-5 is obvious that one will have to go into the regulator's semi-complex setting feature and modify one of the existing programs (Wet cell lead, AGM, Gel) instead of merely accepting a stock "lithium" setting. The same is true for my old charger, which doesn't have a "lithium" setting but can be configure to "my requirements" for lithium. It requires more understanding of the required parameters than simply pushing the "lithium" button.

A "lithium" charger may seem convenient, but is the default "lithium" setting for a household solar array in the frigid North? A golf cart in Vegas? A trolling motor in Ohio? How big is the battery bank? How often will the LFP battery, bank, or bank(s) be charged? At what C? A "lithium" setting is just a guess by somebody to suit a generic need. Worse, some of the branded lithium chargers, sold to accompany their LFP batteries, charge to the max. Why? Because then a discharge test of your new batteries will show that they meet or exceed their rated amp hours. Yeah! 100%!! Unfortunately, one likely won't need or want that every charge cycle if the battery bank is properly sized. You certainly don't want to keep it there.

One last modification that I'm thinking about is the ARS-5 "shut off switch" capability. It is relatively easy to put a switch in the brown ignition wire from the regulator. This shuts off all charging from the alternator and basically allows it to free-wheel. That provides to "advantages," neither of which I'm sure would be productive. The first is that, in the case of a total BMS shutdown, one can simply stop the charging and continue on until one has time to troubleshoot. Of course, that requires a sufficiently sized bank. The other is to shut off charging and save fuel. The several horsepower used to turn the alternator is a fuel savings and the bank can be resupplied later with cheaper shore power. Not sure either is worth the effort.

 

[Mambo42]

Did not want to start a new topic and since this fits in the Lithium section I thought I share it here.
This week I had someone onboard who was also not really familiar with the differences between LiFePO4 and Lithium Ion, but he did tell me an interesting story. I don't know if it is true or not, but perhaps anyone has heard of it.
He was talking about corrosion inside Lithium batteries which ultimately caused a fire. He claimed the internal BMS corroded in the salt air, raising the resistance, causing heat etc etc.
I know my batteries are basically sealed off well (Victron batteries), but I could see this happening with homebuilt or DIY batteries.
Has anyone heard of this ?

 

[Barking Sands]

Did not want to start a new topic and since this fits in the Lithium section I thought I share it here.
This week I had someone onboard who was also not really familiar with the differences between LiFePO4 and Lithium Ion, but he did tell me an interesting story. I don't know if it is true or not, but perhaps anyone has heard of it.
He was talking about corrosion inside Lithium batteries which ultimately caused a fire. He claimed the internal BMS corroded in the salt air, raising the resistance, causing heat etc etc.
I know my batteries are basically sealed off well (Victron batteries), but I could see this happening with homebuilt or DIY batteries.
Has anyone heard of this ?

I have not heard of this for Lifepo4. I have seen a dozen or so waterproof versions that somehow cracked the cases (usually from bad install practices) and had water ingress that caused BMS failure. The only result I ever saw was either Bluetooth dyeing or the battery discharged and lost communication.

One was installed on an off road side by side loosely and was bouncing around going off road and fording lakes and rivers. It was full of mud..lol.

 

[Marco Flamingo]

He was talking about corrosion inside Lithium batteries which ultimately caused a fire.
Has anyone heard of this ?

I'm having difficulty imagining how this would happen with any of the batteries I've looked at. Is it possible to build a DIY system capable of self-destruction? Sure. A store-bought battery with a BMS? Not quite sure how. It seems most battery overheat/fire scenarios would require either damage to the cells or extreme overcharge/overdischarge. For LFP, if the BMS didn't catch those, then overtemp would shut things down (assuming the external fuse didn't blow first).

But for a totally internal LFP fault caused by corrosion, it seems like it would require one cell somehow suddenly shorting into another cell. Since the LFP cells are basically balanced, I don't see how there would be a sufficient cell-to-cell voltage difference. Again, like the internal corrosion in lead acid (sulfation), it would be the resistance (in charging) which causes destruction (explosion in the case of LA, which doesn't have overcharge, overdischarge, and temperature shutdown).

It could be that LFP are as dangerous as LA. That hasn't been the case so far, but time will tell.

 

[Marco Flamingo]

Just found that Andy on OGG did an extensive video explaining the Overkill LFP app for replacing whatever app came with different brands of Bluetooth LFP batteries (using the JBD BMS). He states the one shortfall is that that one would need to keep the original brand app (Eco-Worthy in my case) because of parameters that have not been addressed in the Overkill app. And, like my understanding of the EW app, these are the ones in the weeds as to what the parameters actually do. But in my app (a later version), Overkill has now added them as the "Level 2 and Level 3 Protection" parameters shown in post #83, third picture. I still no idea what they do. Seems like Andy also wasn't sure.

The video has a different take than mine on setting of the "Balance only while charging" (at 12:30). My BMS showed that when that slide button was turned "off," that meant that the BMS balanced both while charging and not charging, therefore not only while charging. A little confusing. I also saw that his balancing delta was set to 5mv while mine is set at 15mv. I guess that whatever is "turning on and off" the balancing current isn't like a regular switch that can wear out over time? Then why not go with the smaller delta?

 

[Marco Flamingo]

A little update on the BMS balancing. When charging, all of the batteries tend to go through some amount of balancing if the parameters are set low, i.e., begin balancing at a cell voltage of 3.3V and a cell delta of >5mv. One oddity is that if I set the delta at 5mv and watch that battery (say, battery #3), it will balance #3 when the cell delta is greater than 5mv. But, even if I save that parameter (by using the "BMS write" button) it won't stay there if I pull up another battery. When I return to battery #3, it will have defaulted to 10mv, apparently the smallest delta allowed to reside on the BMS.

Not a big deal as battery #3 is almost balanced. When I first begin charging my battery bank, #3 would shut down because of overvoltage 30 times while the bank charged. The last charge, it shut down from overcurrent one time, right at the end of the absorb cycle (Bottom of the Events count).

This single overcharge shutdown was right when the battery bank was reaching full charge. The rest of the bank went ahead and shifted to "float" (or "sustain") and the charge stopped (i.e., reduced) for all batteries. As the batteries settle down to float, their voltages tend to equalize and, since #3 had shut down momentarily, it tended to still register as "charging" (from the other batteries) but only less than an amp contributed from the other three.

One of the weird things about watching these batteries with a microscope is trying to figure out just what I'm watching. For instance, the reading at the top of the app is always the percentage state of charge. 100% on a 280Ah battery. That means that each percentage point is approximately 2.8 amps per battery. With four batteries in paralleled, I would need to use up approximately 11.2 amps before a battery would read 99%. That's quite a bit for me. But that percentage is calculated some way in which it shifts around a lot. The settings on my BMS show that anything above 3.4V per cell (13.6V for the battery) will show SOC at 100%. So it could be that the first 1% of my battery bank is really 20-30 amps.

Another thing I played around with might be of help to those who need redundancy or a want a special battery for starting. The button under "Discharge" can be turned off and the battery still gets a charge (if needed) but cannot discharge. With a bank of 6 LFP batteries and a fear of somehow using them up, one could turn off one battery and save it for a rainy day (or the next morning). I've watched my LFP batteries when joined with a fairly large difference between SOC. Nothing to get exited about. Andy, on the Off Grid Garage did the same thing as a test. The "reserve" battery simply bled back into the others such that they can again each put out their rated discharge which, if the bank is properly sized, is sufficient to crank the engine. No need for lead in a special distinct bank.