Did I just kill my FLA battery bank? 10V!

socalrider · Jul 6, 2020

Some things you learn the easy way...

Today I learned that my new-to-me CHB 41 is wired such that the AC breaker labeled "LPG Range" switches off my battery charger. On my way out one day I flipped it off, even though the tanks were manually shut off, just 'cause. Ugh.

I am not 100% sure how long ago this was, at most 10 days. Anyway, I got the the boat today and my bank (4x 6v US Battery 2200's, 3yrs old) was sitting at 10VDC. I'm a little bewildered as to how this could have been drawn down so far but it's possible the charger was off while I had the family on board for a night about a week ago. Still, only lights, almost all of which are LED.

Anyway, I'll figure out if I've got some weird vampire loads - I'm finding lots of questionable wiring decisions. Bigger question is: did I kill the bank? Charger's on now, so I guess we'll see. I'll disconnect and check the float voltages tomorrow, and I have a hydrometer coming in a couple days.

High Wire · Jul 6, 2020

No refrigerator? That’s my biggest DC amp-hour drain.
Does your charger have an equalize mode. If so read your manual and perform an equalize charge after you get back to full charge.

twistedtree · Jul 6, 2020

You probably took a bit off their overall life, but I expect they will come back OK. Check water levels and specific gravity (good you are getting a hydrometer), and equalize as needed. The trick to preventing permanent sulfation will be to ensure you get all the cells back to their rated specific gravity. That's the only reliable indication that you have fully reversed the chemical process. Check the US battery specs, but full charge is probably 1.260 to 1.270

bayview · Jul 6, 2020

twistedtree said:
You probably took a bit off their overall life, but I expect they will come back OK. Check water levels and specific gravity (good you are getting a hydrometer), and equalize as needed. The trick to preventing permanent sulfation will be to ensure you get all the cells back to their rated specific gravity. That's the only reliable indication that you have fully reversed the chemical process. Check the US battery specs, but full charge is probably 1.260 to 1.270

+1

caltexflanc · Jul 6, 2020

+2

When you are done doing that, get a mulitmeter with amp clamp. Turn all the DC loads off, then on/off one at a time and see what draws you have to help you find the culprits.

The LPG range runs off AC? That seems a little off but others here would know that better than I. Regardless the battery charger should have its own breaker.

socalrider · Jul 6, 2020

Thanks guys - encouraging. The fridge can run off ac or dc - I have it running off shore power. I’ll let you know what I find.

sbman · Jul 6, 2020

I would seriously consider adding a battery monitor so that you can see the current in/out of your battery whenever you want to, you'll always know if you have extra loads you don't expect.

rsn48 · Jul 6, 2020

I frequently post links to Jeff Cote's electrical and electronic talks, usually delivered at the Seattle or Vancouver Boat shows. One of his favourite lines is: "Flooded lead acid batteries don't die, they are murdered." His pitch for Firefly batteries is they aren't subject to sulfation problems so even though they are more expensive, when you factor in all the sets of FLA's that are murdered, they come out cheaper.

And I am especially proud of myself, I successfully killed 4 FLA's before they even made it onto my old sailboat (don't ask how, it will only re-open the wound). This is why I had four FLA's on my old (new to me) power boat removed even though they were perfectly fine, and added 6 new Fireflies. I didn't want to be responsible for yet another death.

If you are feeling bad because you done your batteries wrong and want to take the road to redemption, you'll need to take a number as the line up is long for those living with regret when it comes to FLA's.

I decided I'd add a Jeff Cote link to his Seattle Boat Show presentation on boat batteries. As you will hear, if you aren't an OCD type individual, FLA's aren't the best choice, he will explain why. Jump to the 3 minute 40 second part of the video to miss the intro.

Moonfish · Jul 6, 2020

rsn48 said:
I frequently post links to Jeff Cote's electrical and electronic talks, usually delivered at the Seattle or Vancouver Boat shows. One of his favourite lines is: "Flooded lead acid batteries don't die, they are murdered." His pitch for Firefly batteries is they aren't subject to sulfation problems so even though they are more expensive, when you factor in all the sets of FLA's that are murdered, they come out cheaper.

And I am especially proud of myself, I successfully killed 4 FLA's before they even made it onto my old sailboat (don't ask how, it will only re-open the wound). This is why I had four FLA's on my old (new to me) power boat removed even though they were perfectly fine, and added 6 new Fireflies. I didn't want to be responsible for yet another death.

If you are feeling bad because you done your batteries wrong and want to take the road to redemption, you'll need to take a number as the line up is long for those living with regret when it comes to FLA's.

I decided I'd add a Jeff Cote link to his Seattle Boat Show presentation on boat batteries. As you will hear, if you aren't an OCD type individual, FLA's aren't the best choice, he will explain why. Jump to the 3 minute 40 second part of the video to miss the intro.

I am SO glad we have the Firefly batts. I have unintentionally tried to "murder" them a few times over the last 5 years (down to low 11s), but they keep forgiving me. They probably like me a little less, though...

rsn48 · Jul 6, 2020

Well Jeff talks about 20 % discharge but I have seen several references to 10 % discharge for Fireflies with no effect.

Beaverlake · Jul 6, 2020

Just be prepared to dig deep. Firefly purchases are not for the faint of heart. In other posts recommendations were also added to consider how long you will keep your boat, how often it’s used, how often you run your generator, total loads, etc - in fact IIRC Cotes covers many cost of ownership factors. FF’s are appealing but in our case I couldn’t justify the cost. If you have a good smart charger, set the profiles correctly, invest a relatively small amount in a battery watering system and hygrometer and simply do a quick check every once in a while FLAs can live a long and healthy life.

socalrider · Jul 7, 2020

Broke out the hydrometer today. I have 6 6v US2200’s.

Fwd bank is fine.

The middle bank of two each has a single dead cell (no reading at all). The other two cells are reading fine.

The aft bank is mixed from poor to ok.

I suspect that the dead cells in the middle bank are causing the bank to self-discharge. Will keep digging to see if I can find a root cause.

I know FLAs like to be replaced together. I might have to pull the whole pack. Fireflies looking good right now - prob only need 3-4 for the same useable capacity, and I can always add more later.

sbman · Jul 7, 2020

socalrider said:
Broke out the hydrometer today. I have 6 6v US2200’s.

Fwd bank is fine.

The middle bank of two each has a single dead cell (no reading at all). The other two cells are reading fine.

The aft bank is mixed from poor to ok.

I suspect that the dead cells in the middle bank are causing the bank to self-discharge. Will keep digging to see if I can find a root cause.

I know FLAs like to be replaced together. I might have to pull the whole pack. Fireflies looking good right now - prob only need 3-4 for the same useable capacity, and I can always add more later.

It's doubtful that a single discharge event was the cause of multiple dead cells, sounds like an issue that has been brewing for a while.

socalrider · Jul 7, 2020

sbman said:
It's doubtful that a single discharge event was the cause of multiple dead cells, sounds like an issue that has been brewing for a while.

I think that’s right. I disconnected the middle bank and am charging the other banks again to see if the aft bank comes back. Middle port batt reads 4.4V so it’s definitely toast.

I am considering pleading “not guilty” to murder and accusing the PO but not quite sure how the crime was committed.

sbman · Jul 7, 2020

socalrider said:
I think that’s right. I disconnected the middle bank and am charging the other banks again to see if the aft bank comes back. Middle port batt reads 4.4V so it’s definitely toast.

I am considering pleading “not guilty” to murder and accusing the PO but not quite sure how the crime was committed.

One advantage the FLAs have is the ability to diagnose the issue pretty easily with a Hygrometer. Pretty easily being a relative term depending on where your batteries are located of course!

Probably time to visit the charging system and battery wiring if you decide to put new batteries no matter what you purchase. You might also have to get new charging equipment if the stuff in place doesn't support the profiles you'll need for a different battery type.

socalrider · Jul 7, 2020

The charger is a Xantrex Truecharge 40+. Looking at Amazon there' a guy complaining that it cooked his #2 battery bank repeatedly!

Current working hypothesis is that the middle bank was pretty much dead when I bought the boat, but it wasn't noticed because the PO's lived on the boat with it plugged in almost all the time. Leaving it off the charger for a couple of days very quickly brought pack voltage down to 10V even with no load due to the dead cells.

Open question is what caused the dead cells in the first place. Crappy charger? FLA watering neglect? I don't see any obvious wiring issues, though it's a bit of a dog's breakfast down there as you can see.

If the other two banks are ok I might just leave it for the time being so I can replace it (along with a solar install) more thoughtfully. Should be fine for a week or two on Catalina with the fam. I'm letting them sit on the charger again to see if the aft bank recovers. If not, I'm going shopping.

sbman · Jul 8, 2020

If you don't already have one, you'll want to add a battery monitor. With the cabling there, it doesn't look like you do, there are too many connections to the negatives to have it centralized like you need for a battery monitor's shunt. Without one you are really just kind of blind to the state of your batteries, performance of your charging equipment, and usage.

The Balmar SG-200 and the Victron BMV-712 are both very popular.

rsn48 · Jul 8, 2020

FLA watering neglect?

If as you said, the guy lived on the boat and it was always plugged in, why would he do any maintenance on the batteries, obviously he was not dependent on them at all.

For problem solving, start out with the obvious, bad batteries and replace them, then see if the charger is working properly. One way to kill batteries slowly is to have an undersized charger. So your charger must be 10 % of total amp battery hours or larger, if it is lower than this figure, your batteries will slowly deteriorate.

socalrider · Jul 8, 2020

rsn48 said:
FLA watering neglect?

If as you said, the guy lived on the boat and it was always plugged in, why would he do any maintenance on the batteries, obviously he was not dependent on them at all.

For problem solving, start out with the obvious, bad batteries and replace them, then see if the charger is working properly. One way to kill batteries slowly is to have an undersized charger. So your charger must be 10 % of total amp battery hours or larger, if it is lower than this figure, your batteries will slowly deteriorate.

Yeah that's what I'm thinking. I suspect they weren't on the watering, or missed a month and that started the spiral.

I watched the video posted earlier where Jeff explains the charger size - it's a 40A charger, and a 700Ah bank, so definitely undersized by the 10% metric.

There's an almost brand new 5.5kW generator on board, and almost nothing for it to do other than heat water via the 1.5kW 120V heater. Aside from that I only have maybe 800W of load max (LPG stove). Weird they didn't spring for at least a 100A charger to take advantage of all that power.

Any recommendations on pulling out the whole bank versus replacing only the bad batteries?

WayneDana2 · Jul 8, 2020

There is all kinds of hard science out there about why you should always replace the whole bank. Not the whole boat if you only run one bank at a time, but never mix old batteries with new ones in one bank.

I replaced both my banks at the same time. I coulda gotten another year or two maybe out of the bank that was still fair, but it wasn't worth the misery. 8 golf cart batteries were `$1100, but much greater amp range now and better peace of mind.

Bonus was I only had to pay the strapping 20 something lad one time to do the replacement!

socalrider · Jul 8, 2020

Re-tested this morning and I’m giving up on the bank. Fresh set of US2200’s will be delivered to my slip tomorrow for $780. I just don’t have the time to figure out an alternative system, and I think these batteries should do fine for a few years at least while I figure things out so long as I keep on top of the watering.

Gonna keep the existing 40A charger for now but will seriously consider a bigger one after the summer. Thanks for all the help guys, particularly @sbman!

twistedtree · Jul 9, 2020

socalrider said:
Re-tested this morning and I’m giving up on the bank. Fresh set of US2200’s will be delivered to my slip tomorrow for $780. I just don’t have the time to figure out an alternative system, and I think these batteries should do fine for a few years at least while I figure things out so long as I keep on top of the watering.

Gonna keep the existing 40A charger for now but will seriously consider a bigger one after the summer. Thanks for all the help guys, particularly @sbman!

It's nice that the batteries answered the question for you about whole-bank vs partial-bank replacement

BTW, I would get rid of that Xantrex charger ASAP. I had problem with one of those too on an older boat. It went bonkers and massively over charged my bank, setting off the CO alarm because of the off-gassing. Replace with a MasterVolt or Victron, set the voltages correctly, and you should be good to go.

socalrider · Jul 9, 2020

twistedtree said:
It's nice that the batteries answered the question for you about whole-bank vs partial-bank replacement

BTW, I would get rid of that Xantrex charger ASAP. I had problem with one of those too on an older boat. It went bonkers and massively over charged my bank, setting off the CO alarm because of the off-gassing. Replace with a MasterVolt or Victron, set the voltages correctly, and you should be good to go.

Thanks. Did you follow the 10% rule? For me that would mean a 70a charger, which seem hard to find and very expensive ($1200 - more than the batteries!)

dhays · Jul 9, 2020

Can someone explain the "10% rule" to me? Amperage should be 10% of the total Ah capacity? Seems more than a bit arbitrary....

A lower charging rate would mean that it would take longer in Bulk to get to Absorb charging, it could also be slow in the early absorb phase as well. Beyond simply shortening the Bulk and absorb phases, what is wrong with a lower amperage charger?

rsn48 · Jul 9, 2020

BTW, I would get rid of that Xantrex charger ASAP. I had problem with one of those too on an older boat. It went bonkers and massively over charged my bank, setting off the CO alarm because of the off-gassing. Replace with a MasterVolt or Victron, set the voltages correctly, and you should be good to go.

My refit guy and owner of a marine supplies sales stopped carrying Xantrex after having customers having problems with them and his own coming to an early demise.

Can someone explain the "10% rule" to me? Amperage should be 10% of the total Ah capacity? Seems more than a bit arbitrary....

Below is the link I supplied earlier, its long but you will be well versed on batteries and the 10 % rule. I tried to be a good boy scout and find at what minute he begins the conversation about the 10 % rule but didn't find it. You can try starting at about the half way mark, its an hour and a half video, Jeff Cotes presentation at the Seattle Boat Show:

Ventana · Jul 9, 2020

If you decide to replace the charger, let me know. No offense to anyone elses opinion, but those were some of the best chargers made. It isn’t a Xantrex charger, it was made by Statpower before they were bought out by Xantrex. When I was involved in battery testing, we used one of those as a standard because it was the most reliable with the tightest tolorences.
Also, the blanket statement about sizing a battery charger depends on so many other factor that it is pretty much worthless.

socalrider · Jul 10, 2020

Ventana said:
If you decide to replace the charger, let me know. No offense to anyone elses opinion, but those were some of the best chargers made. It isn’t a Xantrex charger, it was made by Statpower before they were bought out by Xantrex. When I was involved in battery testing, we used one of those as a standard because it was the most reliable with the tightest tolorences.
Also, the blanket statement about sizing a battery charger depends on so many other factor that it is pretty much worthless.

That's encouraging, thanks. I have now heard that from a few different sources - apparently the newer Xantrax "Truecharge 2" units have been less reliable, but the 40+ that I have might be worth hanging on to. Last thing I want to do is create more problems changing something that's working fine.

Got the new bank in this afternoon. Between that and getting the new RIB unboxed, moved to the water & engine installed, no need to work out today!

I found another electrical oddity: the Norcold fridge (relatively new retrofit) doesn't go through the electrical panel, and runs even if the main battery switch is "off". If AC is present, it runs on the AC, but only if DC is present as well. Too tired to figure that one out today.

Darlin · Jul 13, 2020

I had terrible problems with 6v golf cart batteries. I suspect it was caused by low water. I replaced all my batteries with Optima 12 volt. They are truly maintenance free and much easier to lift. No problems now.

sdowney717 · Jul 13, 2020

I have 2 Duracell 12vdc lead acid marine batteries from Sam's club for one house bank. They are about 2 years old. Left on a 12vdc cabin light, we had a storm that disconnected the shore cable from the boat, so no power to the AC charger, about 10 days later, (admit may have been a month, it was wintertime) was back at boat, and those Duracells read 10 volts or less, got the power connected, in an hour were reading in the 12's. So left boat, and a few days later checked them and they were ok. I had been thinking they were ruined.

Here they are, never seen them gas or smell or anything bad.
https://www.samsclub.com/p/duracell-marine-battery-group-size-27dc/prod3590231?xid=plp_product_1_9

AMG · Jul 14, 2020

My boat is called Serenity so I really wanted those firefly batteries, but then I saw the cost.;-) Very interesting read and great video.

Did I just kill my FLA battery bank? 10V!

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