Need more power, new batteries?

Seevee · Aug 12, 2018

All,

Have a few questions about batteries.
First, I have 4 of the West Marine 6v AGMs, wired for a 12v system. They are 190ah each so I get 380ah from the back or 190ah running them to 50% capacity. Sound right?

When I charge them, gen or alternator, the most I can charge them to is 12.5v (think I should get 12.7). The original alternator, with out a smart regulator, was used prior to my ownership for the first 2 years of these batteries and suspect they have been somewhat damaged with overcharging. They are 3 to 4 yrs old.

With my requirements, 2 fridges, coffee in morning, microwave for a minute or two, and charging of computers, I'm about out after the coffee is made. As I type, I need to start the gen, showing 10.3v. Turning off the coffee maker it jumps up to 10.7v and I really don't like to go below 11v.

I get up early and don't like to be the prick that cranks his generator at 6am and pisses off all the sail boaters around, so need to get me thru 8 am at least.

I'm thinking of upping the battery capacity and my first choice is the Lifeline 6v GPL 6CT batteries that would give me 600ah. They are 2 in higher, but fit well....easy install.

The Odysseys look good, but size is a bit too long and would require mods.

Other batteries to consider?

===
Can't think of other options...
Solar would be great, but a major mod to do it right, expensive and I just have no place to put the cells.

Thoughts?

DavidM · Aug 12, 2018

Well, I see several problems with your current set up and operation:

You say the engine alternator was over charging the batteries in the past? With an internally regulated alternator that is unlikely.

You now recharge the batteries at anchor by starting your genset at less than 11 volts on the batteries. I suspect that voltage is measured with significant load on it which really makes it worthless for diagnosis. But that is too low in any case and you are slowly killing them by doing that. BTW all of the voltages I talk about here and below are measured after killing ALL loads for at least an hour, except for the voltage measured while charging.

How does your genset recharge the batteries? I assume with a shore powered three step charger. You say you shut it off whn it reaches about 12.5 volts. That is way, way too low. A genset powering a large (50+A) charger should go to 14+ volts to get even close to fully charged. I suspect that your current batteries have gone bad and that is what is limiting charging voltage. When it gets up to 12.5 it expends all of its current on heating the batteries- feel them next time. But you may just be operating them badly- too much current draw and not enough genset running time, or not a big enough charger.

So what to do about it?

First do a load test on your current batteries. You need to put a constant load of 1/20 * 380 for ten hours, then let the batteries sit for a couple of hours and measure the voltage. Anything below 12.0 volts indicates you don't have the original capacity. Or if you are ready to scrap them and try something else, skip this step and do the following:

We don't really know what the cumulative load is between the time you shut off the genset in the morning and when you turn it on in the morning. If it is more than 190 AHs (or your current batteries have much less than 390 AHs of capacity) then you need to reduce load, improve your recharging capability or add more battery capacity.

I can't really comment on the first two without more information, but there might be an easy, if not cheap way to add capacity. First of all Lifeline batteries while good are terribly expensive. I believe that plain old FLA batteries, either golf carts or the higher capacity L16s (used in floor polishers) give more bang for the buck.

L16s will almost double your capacity. They have more or less the same footprint as your current batteries but are much taller. But you say you have space. So replace all of your current 6V AGMs with L16s. You might not even need to do any rewiring.

Then make sure you recharge to above 14V on the genset powered shorepower charger and don't draw them down below 12.0 volts (measured after you turn off the load and let them sit for an hour).

I presume you are not a full time anchored out boater. If so then you need to consider a way to fully and I mean fully at 14.5 volts or greater, recharge the batteries at least once or twice a week. Otherwise the new ones won't last long either.

David

ranger58sb · Aug 12, 2018

See, I think you've been killing your batteries. You can probably look up voltage curves from your battery manufacturer, but anything below about 12.2V isn't good.

I doubt over-charging; more likely over-depleting.

As I understand the math, you have two 190-Ah pairs at 12V, so 380 Ah total sounds about right. Which means 190 Ah at 50% DoD sounds about right. Except if your batteries won't get above 12.5V at full charge, you likely don't have 100% capacity any more, maybe much less... and usually 80% of original capacity is when manufacturer's consider their batteries dead.

If you can easily service your battery bank, L16s would likely be less expensive than Lifelines. OTOH, the Lifeline 6CTs would be about equivalent to the L16s, if service isn't easy. That'd be 600 Ah total (two 300 Ah pairs), 300 Ah usable to 50% DoD.

You may need to investigate whether your charger is sufficient to meet Lifeline's recommendations about charge rate.

Lifeline will tell you their recommended bulk/absorption and float voltages. Our 4CTs want 14.3V +/- .1V at 77F, and 13.3V +/-.1V at 77F. See here, p19 for details: http://2cw8eb1vmmgg3g5i7jzt6upo.wpe...12/6-0101-Rev-E-Lifeline-Technical-Manual.pdf

I've not seen where Odyssey offers a 6V equivalent.

Depending on location, you may be introducing a slight list, which may or may not be an issue.

You can solve the early morning coffee with an inverter.

You can adopt a charging regime that treats your batteries better, if you haven't already. (For example, in our case, we charge 2x/day at anchor, once in the morning but well after coffee.... and then once in the late afternoon/evening... since our cooking is electric and we have to run the genset for that anyway.)

-Chris

mahal · Aug 12, 2018

ranger42c said:
See, I think you've been killing your batteries. You can probably look up voltage curves from your battery manufacturer, but anything below about 12.2V isn't good.

Is this with load, no load, or both?

My voltage drops to 12.1V with load and goes back up to around 12.5v or better, depending on the bank's charge level, when load is removed. Is this acceptable? What should the lowest voltage be under load? Thanks.

sunchaser · Aug 12, 2018

Seevee
Nigel Calders book on electrics is your friend. As others have said, you are drawing your batteries down way too far.

Correctly install a battery monitor and use it. Until you monitor and manage your battery banks properly new ones whether AGM, FLA or LiPO4 will die too.

DavidM · Aug 12, 2018

There is little that you can determine by measuring voltage under load. One amp drops the resting voltage a little and 10 amps will drop it a lot.

Returning to 12.5 v after removing the load sounds pretty good- 70-80% full.

David

Westiculo · Aug 12, 2018

Will your voltage go over 12.5 volts when the charger is running? If not, the problem is the charger, not the batteries.

A properly-functioning charger will drive a battery to 14+ volts regardless of it's age, it's when you turn the charger off that the battery will sag voltage below full charge of 12.7 volts.

Mahal has a good point; open circuit and closed circuit battery voltages are different animals. Just because your battery voltage is dropping much below 12 volts while drawing significant current does not mean you are killing your batteries. Mahal, there is no problem with your voltage dropping to 12.1V. I've had trouble putting a number on what the lowest voltage under load should be. Hopefully somebody else can chime in. I will say that on my Magnum Charger, the low-battery cutout function (when it disconnects the inverter at a specific voltage) can be set as low as 9.0 volts, and can't be set any higher than 12.2 volts.

Irish Rambler · Aug 12, 2018

You may not have heard of the Adverc alternator controller.
The very first alternator controller was invented by a Swedish outside broadcast engineer who sold his invention as the TWR (his initials)controller for a while.
His invention and patents were bought by owner of Adverc of Walsall, England who dissected it and further improved the original design.
You can buy an Adverc controller to suit either 1 or two alternators.
Adverc design and install systems for marine, ambulances, military, tail lift trucks etc they are relatively inexpensive and the company are always ready to give friendly professional advice with wiring diagrams and all associated electrical components diode, split chargers etc for a complete installation.
Contact mark@adverc.co,uk

When I changed our boat and bought 'Snow Mouse' I had to let the admiral have a relatively free rein on electrical 'essentials' I agreed providing it was low consumption ie 800w electric kettle instead of 2,200w, toaster 800w as opposed to 1800w etc etc.
If not plugged into shore power we use a 10,000w inverter which runs everything when cruising, the Adverc keeps the 900 amp battery banks charged.
We use gas for cooking and have a 12v Vitrifrigo fridge and separate deep freeze
I have no connection with Adverc other than as a very satisfied customer.
When

ranger58sb · Aug 12, 2018

mahal said:
Is this with load, no load, or both?

My voltage drops to 12.1V with load and goes back up to around 12.5v or better, depending on the bank's charge level, when load is removed. Is this acceptable? What should the lowest voltage be under load? Thanks.

No load. And measured after resting from charging.

I said 12.2 but FWIW, in the doc I linked (p32), Lifeline says 12.18V is 50% DoD OCV at 77F/25C.. That voltage likely varies by manufacturer/product.

-Chris

Seevee · Aug 12, 2018

Just to be clear:

When charging, both the alternator and the generator charge the batteries with a smart charger, programmed for the AGMs, and will put out ~14.6v charging. This was set up with an ABCY electrician, and I went over it with him.

I do not normally run the genny at night unless it's hot and then none of the about is a issue

At night, after eng or gen running, I shut down any non essential stuff. I leave the two fridges going, pumps, and 12v outlet for Ipad/phone charging, and anchor light. After the battery settles down, I'm seeing at most 12.5v, usually 12.3 or 4, with the above running. (I'll check it next time with everything off).

In the morning, I'll make coffee. After brewed, with the coffee maker and the above still on, I've seen as low as 10.3v. If it hits 10v the inverter shuts everything down. My goal is to charge the batteries when it goes below 12v, unloaded, or reduce the load to keep it at 12v +.

As for the original alternator, unregulated..... they don't recommend them for the AGMs because there is no control over the voltage, it's either all or none, and floating the AGMs with high voltage kills them, according to the mfg.

Westiculo · Aug 12, 2018

Thanks for the clarification.
It's unlikely your batteries were damaged from the internal regulator with only 3-4 years of use unless the boat was used every day.
Your problem is probably not that your batteries are bad, but that you simply don't have enough.
I have a total 650Ah of new AGM batteries and my 1500 watt coffee maker will drop the voltage down to 11.3 volts by the end of the pot. You'd need a crapload of capacity to keep it above 12V for the full coffee cycle.

Maerin · Aug 12, 2018

I'm in the "Lifelines are expensive" column. I had a bank of (6)-GPL-16-2V, about 1200 AH. Mine failed prematurely. If you read the Lifeline manual, you'll see that they measure service life in cycles vs. state of charge/depth of discharge. Chronological age is meaningless.

My bank did not survive due to inadequate charging. If you have no accurate means of measuring accumulated amp hours, e.g. a battery monitor of the coloumb counting technology, then investing in a Lifeline bank is a huge waste of money and effort, since you have no way of assessing the state of charge of the bank. Chronic undercharging is death for a battery bank.

I'll strongly 2nd David's assessment, all sound advice.

Your use of the bank and how you cruise must be what establishes the design of the system, of which the battery bank is a part. So, rather than tunnel focus on the batteries, expand the view to the whole system. Set it up to do what's required for the intended use of the boat. If you spend considerable time at anchor, solar is a great option, since it will complete the float portion of the charge cycle, critical to the life of the bank. Fully charging by genset can take MANY hours of running under minimal load. Wasteful, and not good for the generator, but critical for the bank. If you're underway a lot of the time, assess your alternator capacity, invest in a smart regulator and abandon the internal regulator that is inadequate for charging a large bank. At that juncture, you need to determine if your alternator will survive heavy loading that accompanies charging a large bank. Most OEM will not. Again, without a battery monitor, you're just guessing. Battery state simply cannot be determined by glancing at a voltmeter.

If you decide to change batteries, consider Full River AGM's. Less initial cost than Lifelines, available in similar configurations, good quality. It bears repeating that no bank, regardless of manufacturer, will endure the abuse of chronic undercharging.

Westiculo · Aug 12, 2018

Ultimately I switched to pourover coffee when I'm on anchor, water heated with the propane stove. I don't have a problem running the microwave or toaster oven, somehow the coffee maker just cranks.

dhays · Aug 12, 2018

SeaVee, being a former sailor, I am cheap. As such, I don’t like to spend money on expensive batteries and really don’t like to see my batteries fail due to poor charging.

I made the switch to L16 AGMs myself after the original sealed LA batteries had started to perform poorly. I found a great buy on US Batteries L16s. 4 of them give me 780Ah. David is right that a load test will determine the current capacity of your batteries and would be a great idea. I’m way too lazy to do it so it isn’t something I’ve ever done.

Often, the control for a three stage charger/inverter will show what charging state it is in, bulk/absorb/float. When you are plugged into shore power, the charger should get you to float. When running the genset, an hour of charging may not get you past even the bulk stage if the batteries are particularly low. You won’t want to run the genset to get your batteries to 100%, but it would be good to at least hit and hold the absorb voltage for a couple hours twice a day. This won’t fully charge your batteries and if this is all you ever do, the capacity of your bank will be decreased over time. However, it will get you buy for a couple days away from the dock. If you are going to make a longer run that day, running the genset for 2-3 hours in the morning before you leave will give the engine alternator a good opportunity to get the batteries to full charge after cruising for a day.

It is all guesswork without a good battery monitor. An AH counter would work great if you do a load test and figure out what your current capacity is. A Balmar SmartGauge would be able to tell you state of charge without knowing what your capacity is.

If you are decide to go with new batteries, consider wet cell golf cart batteries if you have easy enough access to the batteries to keep them watered. I had great success with Costco GC2. Costco or Sam’s club are two options where you could get 6 x GC2s for well under $600 and get about 600 AH.

janice142 · Aug 12, 2018

dhays said:
If you are decide to go with new batteries, consider wet cell golf cart batteries if you have easy enough access to the batteries to keep them watered. I had great success with Costco GC2. Costco or Sam’s club are two options where you could get 6 x GC2s for well under $600 and get about 600 AH.

If I may be so bold? Locally try Electro Batteries. It's inland some place (I was a passenger) however the prices were great for the 8-volt batts a friend's Hatt required. I rewired them, fixing issues as I found them.

Article here: Diagnosing a Bad Battery article on janice142

The article about Electro (and more) is here:
St. Pete's Electro Battery article on janice142

Now on to test the batteries...
This will just let you know of potential problems and batts that are on their way to the graveyard.

First make sure all the batteries are full. Use distilled water or from your watermaker only. City or tap water is bad for batts.
Of course you knew that...

Next get out your infrared temperature gun. Shoot the tops of the batteries. Specifically shoot the cap for each cell. It should read ambient.

Now, at your dock plug in to power. Turn on the electric battery charger.
If you have a CO alarm it will blast you if you're off-gassing/over-charging incidentally.

About an hour later shoot the batts again. If you find a "hot spot" that is a battery that is going bad. It is overheating. That is never a good thing. All the temps should be within a degree or two of each other EXCEPT for the one where the power feeds into the bank. That one can be a bit higher.

Touch your cables. Are they hot? That's bad.

And, after you've done all that, buy more batteries. Separate the new ones into Bank Two. (Age counts but if you've got any that are still good, I would keep them.

In my opinion you do not have nearly the capacity required for a boat your size. Buy more batteries. You don't want to have to worry about power, especially before caffeine.

And the idea to switch from your brewer to another coffee method is a good one. Some items simply take too much power. Perhaps a unit that is more efficient would be better. The example to switch from an 1800 watt toaster to an 800 watt one is something to keep in mind.

Good luck. Hope to see you one of these days over at the Legion...

Seevee · Aug 12, 2018

dhays said:
SeaVee, being a former sailor, I am cheap. As such, I don’t like to spend money on expensive batteries and really don’t like to see my batteries fail due to poor charging.

I made the switch to L16 AGMs myself after the original sealed LA batteries had started to perform poorly. I found a great buy on US Batteries L16s. 4 of them give me 780Ah. David is right that a load test will determine the current capacity of your batteries and would be a great idea. I’m way too lazy to do it so it isn’t something I’ve ever done.

Often, the control for a three stage charger/inverter will show what charging state it is in, bulk/absorb/float. When you are plugged into shore power, the charger should get you to float. When running the genset, an hour of charging may not get you past even the bulk stage if the batteries are particularly low. You won’t want to run the genset to get your batteries to 100%, but it would be good to at least hit and hold the absorb voltage for a couple hours twice a day. This won’t fully charge your batteries and if this is all you ever do, the capacity of your bank will be decreased over time. However, it will get you buy for a couple days away from the dock. If you are going to make a longer run that day, running the genset for 2-3 hours in the morning before you leave will give the engine alternator a good opportunity to get the batteries to full charge after cruising for a day.

It is all guesswork without a good battery monitor. An AH counter would work great if you do a load test and figure out what your current capacity is. A Balmar SmartGauge would be able to tell you state of charge without knowing what your capacity is.

If you are decide to go with new batteries, consider wet cell golf cart batteries if you have easy enough access to the batteries to keep them watered. I had great success with Costco GC2. Costco or Sam’s club are two options where you could get 6 x GC2s for well under $600 and get about 600 AH.

Dhays,

Thx for the info... did a search on L16s and come up with a number of different manufacturers, but all in the ~$400 range, so the same price as the Lifelines. What batteries did you get that gave you 780ah? That would be great and double my current capacity (no pun intended).

I've got three stage regulator (Balmar on the alternator, and the Magnum inverter/charger with the rest of the stuff, gen or shore. I've also got a battery monitor and can monitor the amps hours.

I'm not going back to wet cell... WAY too much hassle and worried about the quality. Seems like no reputable battery mfg is doing wet cell anymore and Im not buying Chinese junk. I'm cheap, too, but a hundred or more per battery is not an issue if it's quality and the Lifelines CLEARLY are a step above the rest. I've use Concord (Lifeline manufacturers) in my plane for many years and I'm convinced of their quality, getting over 6 years and when changing them the capacitance check is still good. And their tech support is second to none.

Right now, running the loop, I'll get hooked to shore power perhaps once a week or less. Occasionally make a 6 to 10 hour run so that helps charge the batteries.

Have a new 80a alternator with the Balmar regulator, so 8 hours should come close to charging them with the gen running first in the morning for the second coffee brew.

However, I'm all ears with other suggestions.

O C Diver · Aug 12, 2018

To repeat what others have said:
You need more battery capacity
You really need a SOC (state of charge) gauge
You really really need to know what your alternator and shore power are actually doing.

An external 3 stage regulator for your alternator will allow you to charge most all battery types. Imo, I really don't think you have an accurate idea of your overnight battery loads. A SOC gauge will show you current loads (including the inverter), how many amps you consumed overnight, and what percentage of the battery bank is left. Without this information, you're just guessing.

Imo, you've trashed your current batteries. You under charged them; you've over discharged them; you've probably exceeded the drawdown rate. Deep cycle batteries aren't designed for extensive draws (coffeemaker or microwave through inverter) at high amperage. Simply, with the 2 refrigerators and the microwave going for some number of minutes, the amp draw is well over 100 amps. Not familiar with the current batteries you have, bur there is a specifications sheet that will give you draw rates with corresponding time limits. My guess would be that you're exceeding that amp / time parameter. Please understand that doubling the number of batteries in the bank would half the amp draw rate and likely keep the voltage higher in your system.

If it were me installing a SOC meter would be my first step. Once you have determined both your peak consumption rate and your overnight amp hour needs, you can then figure out how big a bank you really need.

Ted

Seevee · Aug 12, 2018

djmarchand said:
Well, I see several problems with your current set up and operation:

You say the engine alternator was over charging the batteries in the past? With an internally regulated alternator that is unlikely.

You now recharge the batteries at anchor by starting your genset at less than 11 volts on the batteries. I suspect that voltage is measured with significant load on it which really makes it worthless for diagnosis. But that is too low in any case and you are slowly killing them by doing that. BTW all of the voltages I talk about here and below are measured after killing ALL loads for at least an hour, except for the voltage measured while charging.

How does your genset recharge the batteries? I assume with a shore powered three step charger. You say you shut it off whn it reaches about 12.5 volts. That is way, way too low. A genset powering a large (50+A) charger should go to 14+ volts to get even close to fully charged. I suspect that your current batteries have gone bad and that is what is limiting charging voltage. When it gets up to 12.5 it expends all of its current on heating the batteries- feel them next time. But you may just be operating them badly- too much current draw and not enough genset running time, or not a big enough charger.

So what to do about it?

First do a load test on your current batteries. You need to put a constant load of 1/20 * 380 for ten hours, then let the batteries sit for a couple of hours and measure the voltage. Anything below 12.0 volts indicates you don't have the original capacity. Or if you are ready to scrap them and try something else, skip this step and do the following:

We don't really know what the cumulative load is between the time you shut off the genset in the morning and when you turn it on in the morning. If it is more than 190 AHs (or your current batteries have much less than 390 AHs of capacity) then you need to reduce load, improve your recharging capability or add more battery capacity.

I can't really comment on the first two without more information, but there might be an easy, if not cheap way to add capacity. First of all Lifeline batteries while good are terribly expensive. I believe that plain old FLA batteries, either golf carts or the higher capacity L16s (used in floor polishers) give more bang for the buck.

L16s will almost double your capacity. They have more or less the same footprint as your current batteries but are much taller. But you say you have space. So replace all of your current 6V AGMs with L16s. You might not even need to do any rewiring.

Then make sure you recharge to above 14V on the genset powered shorepower charger and don't draw them down below 12.0 volts (measured after you turn off the load and let them sit for an hour).

I presume you are not a full time anchored out boater. If so then you need to consider a way to fully and I mean fully at 14.5 volts or greater, recharge the batteries at least once or twice a week. Otherwise the new ones won't last long either.

David

David,

Good info and thx......

Re overcharging the AGM with an unregulated alternator (internal)..... I've been told by too many electricians that this will kill AGMs. It's either on or off, 100% charge at ~14.6 or nothing, so no float mode.

Both the alternator (with a Balmar regulator) and the genset or shore power (with the Magnum regulator) will charge up to ~14.6v but will regulate for float charge when necessary. I never turn of the charger is on shore or genset.... it's regulated to do the right job for the AGMs.

Agreed, on the "reduce load" or "add capacity" and that's the gest of this thread. Looking for a better battery capacity to fit where the West Marines will come out, but also looking for other options if they are there.

Solar is out....no space, period.

Reducing power is an option. Can turn off the portable freezer and it will stay frozen for at least 12 hours if not opened. Can put all chargers on 12v instead of the inverter, except my computer which I really don't need charged overnight. But coffee maker is a must in the morning and the 950 watt unit should not be an issue..... I think....

I'm not a full time anchor out, but doing the loop, so out perhaps 5 to 7 days at times.

Still looking for the L16s, a search shows many but at the same price as the Lifelines....

Seevee · Aug 12, 2018

janice142 said:
If I may be so bold? Locally try Electro Batteries. It's inland some place (I was a passenger) however the prices were great for the 8-volt batts a friend's Hatt required. I rewired them, fixing issues as I found them.

Article here: Diagnosing a Bad Battery article on janice142

The article about Electro (and more) is here:
St. Pete's Electro Battery article on janice142

Now on to test the batteries...
This will just let you know of potential problems and batts that are on their way to the graveyard.

First make sure all the batteries are full. Use distilled water or from your watermaker only. City or tap water is bad for batts.
Of course you knew that...

Next get out your infrared temperature gun. Shoot the tops of the batteries. Specifically shoot the cap for each cell. It should read ambient.

Now, at your dock plug in to power. Turn on the electric battery charger.
If you have a CO alarm it will blast you if you're off-gassing/over-charging incidentally.

About an hour later shoot the batts again. If you find a "hot spot" that is a battery that is going bad. It is overheating. That is never a good thing. All the temps should be within a degree or two of each other EXCEPT for the one where the power feeds into the bank. That one can be a bit higher.

Touch your cables. Are they hot? That's bad.

And, after you've done all that, buy more batteries. Separate the new ones into Bank Two. (Age counts but if you've got any that are still good, I would keep them.

In my opinion you do not have nearly the capacity required for a boat your size. Buy more batteries. You don't want to have to worry about power, especially before caffeine.

And the idea to switch from your brewer to another coffee method is a good one. Some items simply take too much power. Perhaps a unit that is more efficient would be better. The example to switch from an 1800 watt toaster to an 800 watt one is something to keep in mind.

Good luck. Hope to see you one of these days over at the Legion...

Seaweed,

Great to hear from you!

Nothing is not, not cables or battery. Have a monitor. Use only the sealed AGMs so no gassing or alarms.

A second bank "could" be a solution, but will it work with the first bank as all house batteries? But would be a really tight fix.

I don't have a solution for a low powered coffee maker and not going to put propane on board, or get a lower watt coffee maker. Mine is only 950 watts and that's pretty low to start with. And that's the only major thing needed before starting the engines running off the inverter unless we hand around long enough to charge computers or make a second pot.

As for the Legion, would love to see you there again. Was a hoot when we met over Christmas and you were so well decorated. I'll get home just before Christmas this year so look me up.... I'm buying!

O C Diver · Aug 12, 2018

Seevee said:
Have a new 80a alternator with the Balmar regulator, so 8 hours should come close to charging them with the gen running first in the morning for the second coffee brew.

However, I'm all ears with other suggestions.

80 amps? You're not doing much in the way of charging your battery bank. Between refrigerators, electronics and other loads while underway, your charge rate is probably only half of the alternator's output.

For my 900 AH battery bank, I have a 220 amp alternator with a 3 stage regulator. I see you needing to at least double your battery bank, multiply that by at least 20% and add 40 amps for underway loads. I would be thinking about a 150 to 200 amp heavy duty alternator.

Ted

Seevee · Aug 12, 2018

O C Diver said:
80 amps? You're not doing much in the way of charging your battery bank. Between refrigerators, electronics and other loads while underway, your charge rate is probably only half of the alternator's output.

For my 900 AH battery bank, I have a 220 amp alternator with a 3 stage regulator. I see you needing to at least double your battery bank, multiply that by at least 20% and add 40 amps for underway loads. I would be thinking about a 150 to 200 amp heavy duty alternator.

Ted

Ted,

Good point, but there's a HUGE price increase for that. Need a new alternator, plus new pulleys and belts and realignment, etc. Underway, unless we're using the inverter for the crock pot, power is minimal. Just the radios and Ipad/phone charger, and the fridges, not much more than overnight with only the batteries.

But will look into that again, just to see if it's an option that's close to affordable....

janice142 · Aug 12, 2018

You have a better set-up than I realized at first... the boat is beautiful of course. The plan is to be south by Christmas.

I replaced the lights with some newer ($$$) low-draw LED Christmas twinklers... there were only two strings left and I bought them both. The power draw was significant (135 watts, whereas the two new strands were 5.8 watts)

I didn't get the article written last year so will hopefully get it done for this year. Always behind...!

Space is a consideration regarding batts.

Those spiffy lithium batteries have caught my attention. The problem (besides cost) is that the charging system from my understanding is Very precise. And the cost at this point is too high. But by the time my batteries are on their last legs I'm hopeful the smart folks like Calder will have it all mapped out for me.

Your boat is beautiful. I'd love to meet your bride too.
And thanks. I could probably be talked into a sangria at the American Legion.

Good luck. I'm sure the big boys know loads more than I do about the technology. It is fascinating.

BruceK · Aug 12, 2018

The "undercharged and overdrawn" diagnosis sounds right. 10V is rock bottom. I suspect testing will show the batts are bad,new ones needed, but do test them. Fridges are no minimal demand, they are likely the hungriest item on the boat.
You need to get more amps in, and be kinder to them. An obvious part solution, along with other steps, is adding some solar,it will nag away at the batts to get them full,and once installed it`s "free",no demands on alternator or charger.

dhays · Aug 12, 2018

Seevee said:
Thx for the info... did a search on L16s and come up with a number of different manufacturers, but all in the ~$400 range, so the same price as the Lifelines. What batteries did you get that gave you 780ah? That would be great and double my current capacity (no pun intended).

I got a very good deal on the batteries. The US AGML16 have a 20 hr AH rating of 390AH. Four of them then give 780AH. Given how the prices went up, I should have bought two more!

I understand not wanting to water wet cells, but if the batteries are easily accessible, I think they are the best AH for the buck and the cheap wet cells perform really well. However, if they aren’t readily accessible, then outside of using a watering system, it can be a pain. Having said that, when my lifeline AGM batteries that power my thrusters and windlass die, I may just replace them with wet cell GC2s and using a watering system.

It sounds like your charging system is setup well, you just need to be sure that you charge the batteries enough to avoid long term loss of capacity.

C lectric · Aug 13, 2018

Do not write the solar off yet, not entirely.

A couple panels could be installed atop your Bimini, especially the flexible ones.
200W total or so would make a big difference to your batteries.

Anytime there is sun there will be output. It may not be enough to run the boat on but it can help seriously.

An MPPT controller is worth about 20% extra power from the panels vs a PWM controller.

I agree that a higher output alternator is needed. We all forget that that alternators only produce maximum amps when the alt. is run near its maximum rpm which for many engines means at least 1800 revs. At idle or just above there is very little. Your standing loads, VHF, GPS, Radar, fridge, and so on can all add up as OC Diver mentioned to use 1/2 the capacity of a small alternator and 80A is small meaning the batteries get very little recharge.

FF · Aug 13, 2018

Before buying batteries a SOC meter would be the best investment.

The state of charge meter works as a gas gauge , the only way you can keep batts is to not abuse them , without a SOC there us no way to asses the state of charge.

O C Diver · Aug 13, 2018

This is a 2 step process. You really need to figure out your consumption and have a corresponding battery bank size that comfortably takes care of those needs without going below 75%.

O C Diver said:
To repeat what others have said:
You need more battery capacity
You really need a SOC (state of charge) gauge
You really really need to know what your alternator and shore power are actually doing.

An external 3 stage regulator for your alternator will allow you to charge most all battery types. Imo, I really don't think you have an accurate idea of your overnight battery loads. A SOC gauge will show you current loads (including the inverter), how many amps you consumed overnight, and what percentage of the battery bank is left. Without this information, you're just guessing.

Imo, you've trashed your current batteries. You under charged them; you've over discharged them; you've probably exceeded the drawdown rate. Deep cycle batteries aren't designed for extensive draws (coffeemaker or microwave through inverter) at high amperage. Simply, with the 2 refrigerators and the microwave going for some number of minutes, the amp draw is well over 100 amps. Not familiar with the current batteries you have, bur there is a specifications sheet that will give you draw rates with corresponding time limits. My guess would be that you're exceeding that amp / time parameter. Please understand that doubling the number of batteries in the bank would half the amp draw rate and likely keep the voltage higher in your system.

If it were me installing a SOC meter would be my first step. Once you have determined both your peak consumption rate and your overnight amp hour needs, you can then figure out how big a bank you really need.

Ted

Seevee said:
Ted,

Good point, but there's a HUGE price increase for that. Need a new alternator, plus new pulleys and belts and realignment, etc. Underway, unless we're using the inverter for the crock pot, power is minimal. Just the radios and Ipad/phone charger, and the fridges, not much more than overnight with only the batteries.

But will look into that again, just to see if it's an option that's close to affordable....

Step 2 is recharging the battery bank. With an 80 amp alternator, you're clearly not getting the bank full. Solar can be a good option, but you still need an alternative plan when you get a couple of cloudy days. The part that is so important to understand is that if you're not getting the batteries recharged completely on the days you motor, you dramatically shorten their life. You have to put back what you take out!!!

Imo, you have 3 choices going forward. You can get a bigger battery bank to handle your needs, a larger alternator to completely recharge the batteries when you cruise, and a SOC meter to know the battery status. You can switch to using the generator for all your galley loads when not underway (this will also give you battery charger time). You can keep doing what you're doing and plan on regular battery bank replacements.

Ted

DavidM · Aug 13, 2018

I have kind of lost track of the facts behind this thread. This is what I think I know:

1. 390 AH house bank of AGMs
2. Charged with a genset driving a ???? amp Magnum? inverter/charger
3. Daily AH demand is ???? Must be large with two 120V?? fridge and freezer, coffemaker, other appliances run off inverter
4. At end of day/overnight no genset running period, voltage (resting?) is 11.0.
5. Morning genset running charges house bank to 14.5+V.
6. OP spends as much as 6 days at a time at anchor

Next steps- Install a battery monitor ($250 or so) and determine 24hr DC load. Or spend a thousand $ or two and double battery capacity. Or maybe try running genset morning and night to keep from discharging existing batteries too low- try it.

David

mahal · Aug 13, 2018

Does a boat with a genset and a good AC battery charger like the OP really need a large alternator? If Seevee arrives at his achorage with fully charged batteries (I'm assuming), doesn't that mean that his alternator is sufficient?

BTW, I understand the benefit for those without generators as an alternator might be their only charging source. Is there something I'm missing? If my alternator is able to keep up with my DC needs while underway without taking anything away from my batteries, isn't my alternator good enough?

O C Diver · Aug 13, 2018

mahal said:
Does a boat with a genset and a good AC battery charger like the OP really need a large alternator? If Seevee arrives at his achorage with fully charged batteries (I'm assuming), doesn't that mean that his alternator is sufficient?

BTW, I understand the benefit for those without generators as an alternator might be their only charging source. Is there something I'm missing? If my alternator is able to keep up with my DC needs while underway without taking anything away from my batteries, isn't my alternator good enough?

Good question!

The answer is based on how you plan to replace the power consumed by the batteries overnight. If you plan to run your generator all night, then the alternator and inverter need only handle the underway consumption. If you plan to use your batteries overnight for all electrical needs, then the alternator needs to be able to charge the batteries and handle the underway consumption. The devil in the details is that you likely need to get through the Bulk and Absorption stages in 3 or 4 hours so that there is adequate time in the Float stage to completely recharge the bank.

Ted

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