Charging LFP - Silent Mode/Re-Bulk?

[twistedtree]

No just turning off engine key that also turns off regulator for alternator. Engine still runs on my boat.

But if you have to turn something off for 2 minutes so be it.

Or just set the regulator float voltage a bit higher so it hols the batteries at 100% rather than letting them drop down to 70% or whatever.


It's just one approach, but my alternators charge to a bulk/absorb of 27.6V (13.8V) which brings them to 95-98%. Then it switches to float at 27V (13.5V) which trickles them up to 100% and holds them there with zero net battery current. Unless I started out really low, and had a short run between anchorages, I always drop the hook with 100% SOC.

 

[Don L]

. But I expect the majority of engines on this site shut down when the key is turned off.

Well you might have to install a switch in the regulator circuit instead then

 

[Don L]

Or just set the regulator float voltage a bit higher so it hols the batteries at 100% rather than letting them drop down to 70% or whatever.

Well if you paid attention you would know I have mine set higher. But you have pick a voltage that works for YOU

 

[twistedtree]

Well if you paid attention you would know I have mine set higher. But you have pick a voltage that works for YOU

The context was a regulator float voltage that allowed batteries to drop down to 70% (give or take) by the time one arrives at an anchorage. Your advice was to stop and restart the engine (or just the regulator) to kick the alternators back into bulk to get batteries back to 100% before anchoring.


My comment was that if one left the float voltage high enough you would arrive at anchor with 100% without having to stop/start your engines or otherwise manually trick the alternators into another bulk charge.


I'm not sure what you are getting testy about.

 

[Bmarler]

This is an interesting subject. I don’t have lfp batteries, but I do have the same issue with three charging sources, inverter/charger, balmar regulator, Victron solar. By far, the balmar is the most customizable of the three.
Peter, on the magnum, is there an option for using tail current as well as voltage for absorb time? I was looking at your setting of 1-1/2 hours before switching to float. That seems excessive to me. I think you can look at the tail current when you reach your 14.1 volts. When the charger output drops off to, let’s say double the usual house loads, you should trigger float. If the charger doesn’t have the ability to use the tail current, you may need to monitor for a couple of cycles to get the average time it takes. I suspect it will be pretty darn short.
Same for the balmar, but the float setting is higher so you are at 100% soc when reaching anchorage.
I have the balmar 618 with their smart shunt, so I may have more available settings tan the 612 might have. The 612 may not be able to use tail current, so you have to use the time setting instead, and look at the alternator output to get a sense of how long it takes before switching to float.
Solar is the last piece of the puzzle. I’d think the absorb and float settings would pretty closely match the balmar.
Not sure if you can set absorb and float to the same voltage on the balmar or solar, but setting a couple of tenths apart seems appropriate, with float being at your 100% mark.

 

[mvweebles]

Bmarler - Magnum does not have a tail current adjustment. Nor does my Balmar 612. My Victron 100/50 Solar MPPTs do, but I simply do not have anough solar panel to do more than just add Bulk charge so there is no fine-tweaking of their contribution.

Maybe someday Apple will tackle charge controlling. This is all unnecessarily complicated. Reminds me of the old DOS days in PCs where you had to learn a secret language to do something useful.

This morning, my Magnum has lost a bit of ground - still says 13.2v but VIctron SmartShunt is at 13.15 so around 57% SoC. Last night I changed the <FINAL CHARGE> from "Multi" to "Float." But still lost a bit of ground. The Magnum seems to cover the average house loads but if the loads spike, doesn't adjust upwards quickly enough. At least that's my best guess.

Before leaving Ensenada, I almost replaced the Magnum with a Victron in hopes of improved interoperable communications. Not high on priority list - the SmartShunt really gives the important information and is the single most useful device in my monitoring toolbox. But it is annoying that I feel like I'm reinventing the wheel at every turn, be it Balmar, Victron, or Magnum. Ripe for a new player to "Apple-ize" the approach.

Peter

 

[Bmarler]

Bmarler - Magnum does not have a tail current adjustment. Nor does my Balmar 612. My Victron 100/50 Solar MPPTs do, but I simply do not have anough solar panel to do more than just add Bulk charge so there is no fine-tweaking of their contribution.

Maybe someday Apple will tackle charge controlling. This is all unnecessarily complicated. Reminds me of the old DOS days in PCs where you had to learn a secret language to do something useful.

This morning, my Magnum has lost a bit of ground - still says 13.2v but VIctron SmartShunt is at 13.15 so around 57% SoC. Last night I changed the <FINAL CHARGE> from "Multi" to "Float." But still lost a bit of ground. The Magnum seems to cover the average house loads but if the loads spike, doesn't adjust upwards quickly enough. At least that's my best guess.

Before leaving Ensenada, I almost replaced the Magnum with a Victron in hopes of improved interoperable communications. Not high on priority list - the SmartShunt really gives the important information and is the single most useful device in my monitoring toolbox. But it is annoying that I feel like I'm reinventing the wheel at every turn, be it Balmar, Victron, or Magnum. Ripe for a new player to "Apple-ize" the approach.

Peter

.05 volts difference between the magnum and smart shunt is probably within design specs. Maybe bumping up .1 volts on the magnum would be warranted. While I agree that it would be nice for all the items to communicate with each other, and that may happen eventually, the one item I don’t worry too much about is the shore charger. But then I don’t have lfp either.
My game changer was the install of the new balmar 618 and smart shunt/smart gauge. Being able to access all the parameters and make adjustments on the fly using my phone was well worth the investment.
I feel like I’m all set up to switch to lfp when the time comes, but it’s years away as my house bank is less than a year old.

 

[cafesport]

So back to the magnum issues for a sec, bmk or not these machines do not accurately sense voltage and as a result provide less than optimal charging out of the box. Add in their black box temperature sense algorithm and I discovered why my old agm batteries were never getting a full charge.

Fortunately using the custom settings you can deal with most of the issues except for the float charge. I suggest you guys take voltage readings directly from your battery terminals at the various stages of the charge cycle and use the custom battery settings to set your charging parameters.

I found mine read +.25v. I didn’t add a bmk because according to the manufacturer it’s only designed to manage one bank. What I wound up with was individual voltage and temp sense for each bank (still using agms) at the terminals in addition to the victron bmv shunt which I also discovered lies and needs more frequent recalibration.

The beauty of lithium which I think weebles has is that the bms does this already, you just need to access the data via cable or Bluetooth for programming.

Bmarler you can trick the magnum to use tail current by setting charge amps manually to a value you want it stop absorb chargeing. Mine is set to 30 amps because that’s the value my little generator is carrying a 25% load. Once it drops to this level it goes to float which triggers a two minute no load run then it shuts down. Weebles I think you would be better off using silent rather than float for shore power. Any time the voltage drops to your desired rebulk voltage level will trigger charging again.

 

[eheffa]

Sort of off-topic but…

This Magnum Silent mode / bulk works very well with Firefly Carbon Foam batteries. (They hate being kept at full SOC...)

Since switching to this mode, I have seen much better performance from the 660Ah FF Bank.

Next house bank will be LiPO4 but switching to this mode has resurrected the Fireflies & allowed me to put that off for a while.

 

[jeremy.st]

It makes sense, but begs another question - there's a decent chance that when you leave dock, your batteries will be something closer to 70% SoC vs 100%. Do you just depend on the alternator to bring them back?....

I also configure the shore charger to float at 13.2 and alternator to float at 13.5. Leaving the dock at 70% is much better than arriving at an anchorage at 70%.

I have a sailboat now so leaving the dock near 100% is also important for me. I just cycle the inverter/charger on and off an hour or two before leaving the marina to start the charge cycle. Similar to turning the engine key off and back on above.

With Victron inverters I leave the physical switch at charge only in the marina and change it to charge/invert before leaving. Pausing at off for a few seconds between these two settings is usually enough for the charge cycle to start at bulk again.

 

[cafesport]

I never did like the way magnum inverters floated batteries so we just use ours for bulk and absorb phases. When shoreside we switch over to mastervolt inverters and chargers. For equalizing a bc8000 or a victron charger have worked shoreside and on the hook.

 

[motion30]

I talked to Eco-worth, the manufacture of the batteries I bought. They actually recommended that I use Magnum's custom set up and they had very specific bulk and float voltages that they wanted me to use. I asked them about silent mode. Their opinion was that while it was technically better for the battery, practically, I would see no difference.

Practically I am very likely to notice a difference between 70% SOC and a 100% SOC when I actually need the batteries. So I took their advice and programmed in the bulk and float voltages they recommended.

Would you care to share the actual voltage parameters that they gave to you?

 

[tiltrider1]

Would you care to share the actual voltage parameters that they gave to you?

Eco-worthy advised me to bulk charge at 14.5 and float at 13.8. Set equalization to never.

 

[jeremy.st]

Eco-worthy advised me to bulk charge at 14.5 and float at 13.8. Set equalization to never.

Those numbers seem high to me. I wouldn't normally question the manufacturer but their manual lists a charge voltage of 14.6. but also states the BMS will trip on over voltage at 14.5 - 14.6.

If the BMS disconnects the batteries at 14.5 at the dock it probably isn't going to cause any problems. I would not set the alternator that high because having the house bank go offline while underway could be a serious problem.

 

[tiltrider1]

Those numbers seem high to me. I wouldn't normally question the manufacturer but their manual lists a charge voltage of 14.6. but also states the BMS will trip on over voltage at 14.5 - 14.6.

If the BMS disconnects the batteries at 14.5 at the dock it probably isn't going to cause any problems. I would not set the alternator that high because having the house bank go offline while underway could be a serious problem.

I use single wire alternators that charge at 13.8. I thought the voltages sounded high but did what the manufacturer recommended and I have had no issues so far. I will know more in 4.5 years.

 

[SteveK]

Eco-worthy advised me to bulk charge at 14.5 and float at 13.8. Set equalization to never.

Had a quick look at eco-worthy and no detailed charge data found.

what about absorbtion charge? Generally found bulk until around 14.4v and then hold volts at 14.4~ absorbtion while decreasing current for a set time, then float 13.2-13.5

My guess confusion may come from many LFP is geared towards solar charge rates with lesser current than alternators or inverter chargers. Your higher volt suggestion may be from line loss of solar cables being smaller?

 

[tiltrider1]

I set absorption to count down to 20amps then switch to float. There is next to no absorption phase with LFP.

 

[jeremy.st]

The eco-worthy manual is available under learn > download on their website.

https://cdn.shopifycdn.net/s/files/...AH_12V150AH_24V100AH_48V50AH.pdf?v=1673075852

I'm using KiloVolt batteries from Alte which is primarily for solar homes. Their charge settings have changed several times over the last year and a half since I purchased them. The float recommendation was 13.2 but it's now 13.4.

 

[SteveK]

I set absorption to count down to 20amps then switch to float. There is next to no absorption phase with LFP.

OK, another difference between LFP brands, or by the controllers attached to them. Mine sets time by total Ah and the volts stay the same with amps dropping

 

[vertigopilot]

Another way to get there if it is available on your charger is to charge to 14.1 (bulk/absorb), then go to a float setting at 13.2 or so. The difference is that the charger should (will try) to pick up the loads in float and the batts will stay at 13.2, rather than re-entering the full charge mode back up to 14.1. Either will work, and the either is better than holding the battery bank at 14.1 over time.

That's the approach I use with the same charger maintaining two 410Ah LFP batteries. Silent mode cycling may be slightly better for the batteries in the long run, but it's better suited to stationary off-grid systems and not particularly convenient for boats on the move.

 

[eheffa]

For future reference, here are the settings I ended up with on my 3000W Magnum Inverter/Charger (125A charger). I used the set-points of 14.1v for ABSORB charge, and 13.2V for FLOAT charge.

First, the following is my 'lessons learned' from this thread - lessons from some great contributors. Please correct anything I got wrong, or of course fill-in any gaps where I missed something.

The video in the OP suggested battery type of CC/CV. This results in the charger going dormant while the batteries decline from 14.1v down to 13.2v. At 13.2v, the charger is awakened and tops-off the battery back to 14.1V when it shuts-down ("SILENT" in Magnum-speak). This means that in CC/CV mode, the batteries are almost always carrying the house loads, not the charger.

As "Guy with a Boat" said, better than holding the batteries at constant 14.1v, but less than ideal because the batteries power the house loads. "TwistedTree" suggested finding a setting where the Charger carries the house loads, not the batteries. I believe I have done just that and wanted to capture the settings for future reference.

I changed to the <CUSTOM> battery type with the same 14.1v ABSORB/13.2v FLOAT set points. In CUSTOM, the ABSORB time needs to be set. I have six 100Ah Lion Energy batteries - I used 15-mins each so 1.5-hours in ABSORB. When the time expires, the Charger shuts-down and the batteries descend to 13.6v, their at-rest 100% charged state. House-loads cause the bank to further decline to 13.2v whereupon the Charger enters FLOAT and carries the house loads indefinitely. This means that in CUSTOM mode, the charger almost always carries the house loads, not the batteries.

For future search reference, here are the Magnum Charger settings I used for my 600Ah bank of Lion Energy LiFePO4 batteries:

Under the SETUP menu screen:

03 Absorb Time:

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04 Battery Type:

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09 Final Charge (this is the mode Charger goes to after ABSORB is complete). This is the biggest difference between "CUSTOM" and "CC/CV" because it means the Charger will carry the house loads once it hits FLOAT:

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Note in "FINAL CHARGE" selection. There is also a "MULTI" option instead of "FLOAT". Multi is supposedly for when there are other charging sources such as solar, which I have. I will tinker with going to MULTI to see what happens, but for purposes of this post, I'm going with FLOAT as the final stage.

TWO CLOSING THOUGHTS

1. 13.2v/70% FLOAT setting: While FLOAT at 13.2v means the batteries will almost always be at 70% charge which is good for the batteries, it does mean you will depart on a trip with batteries that are not topped-off to 100%. This should not be a problem if your alternator has decent output and is configured properly as it will immediately go to BULK and top-off the batteries within a couple hours. You could also increase the FLOAT setpoint to a higher value so the batteries are charged more fully (13.3v would give approx 85%).
   
2. What about Magnum's LFP battery type setting instead of CUSTOM? My charger pre-dates the inclusion of a LFP battery type so I cannot speak directly, but my guess is the LFP settings are pretty generic and probably not as well thought out as the above 14.1v/13.2v ABSORB/FLOAT set points. I'd be interested in anyone's direct experience with a newer Magnum with LFP settings.

Hope this helps someone down the line. Has been a good learning experience for me. Thanks again to all who contributed.

Peter

Thank you Peter.

This is hugely helpful.

I have 2 x 460 A/h Epoch LiFePO4 batteries heading my way and, like you I have a Magnum controller. These new batteries will demand a Custom charging protocol similar to what you have outlined.

-Evan

 

[mvweebles]

I'm jealous Evan. Those Epoch 460 AH batteries look great.

I had.hoped someone would find the settings useful and save them the head-scratching I went through.

I guess it's been almost a month and it's holds pretty steady between 66% SoC and 71% SoC. Solar carries the load during the day.

Good luck with the Epochs

Peter

 

[eheffa]

I'm jealous Evan. Those Epoch 460 AH batteries look great.

I had.hoped someone would find the settings useful and save them the head-scratching I went through.

I guess it's been almost a month and it's holds pretty steady between 66% SoC and 71% SoC. Solar carries the load during the day.

Good luck with the Epochs

Peter

Thanks Peter,

I wish the older Magnum controller allowed of the "Bulk Always" setting as when we are out & away from shore power with semi-depleted batteries, if make the mistake of starting the main engine before starting the generator, the Inverter-charger will only go into float mode.

I hope this won't happen with the higher resting / working voltages of the Epochs. I may have to toggle between the CC/CV settings and the Bulk / float settings.

We shall see I guess, but again, thank you for your very useful post.

-Evan