How often to you swap the batteries

[RonR]

How often do you guys change out house/main batteries? Or is there a way to load test them? Our boat sat at a dock plugged in for the last 4 years. The batteries are 5 years old. The boat has a built in charger for when its plugged in. They show 13.6 while on the charger, we have never ran a set down yet to see how long they will last. They are hard to get to and I know they cost a bunch! Just seeing how others go about it.

 

[Comodave]

Depending on type and how they have been used and maintained probably around 6 to 8 years. But if they are LA batteries and run dry then all bets are off.

 

[High Wire]

Do they have removable caps? If so is there any electrolytes left?

 

[Larry M]

Our house bank is 10-6 volt golf carts. I change them out every 5-7 years. I can tell when they’re due by our SOC meter and the voltage when we get up in the morning. I changed them last month after six years. I was on the hard for bottom paint and the yard plugged me into a dead outlet and never checked. When I came back the battery bank read 0.200 volts.

The boat stays in Florida or south so the high temperatures shorten their live spans. The amount of cruising which means duty cycles also shortens the time between replacement.

 

[Nomad Willy]

I swap (replace) Batteries when they no longer perform.

Actually I disconnect my start batt after anchoring and use 100% house batts through the night running lights and Wabasto heater. Then in the am I start the engine w the house batts and if it's weak (iffy) I'll replace.

 

[gsholz]

One data point. I have 6 high-quality Lifeline 4DL AGM batteries in our coach. Pretty easy duty cycle, mostly on the charger or alternator, a few times/year we dry camp for a few days running the generator in the mornings and evenings. Usually they show 25V in the mornings before starting the generator. They lasted 7.5 years until this trip when they crashed below 23V overnight on the third night dry camping.

On the boat our house bank consists of 5 group 921 FLAs that I "inherited" from the previous owner. Don't know how old they are. I'll have to do a load test this spring before we anchor out.

 

[jungpeter]

Hi RonR,

I do not believe there is an easy, accurate method of measuring battery State of Health (SOH) while your batteries are installed and cabled in your boat. There is some hope that the Balmar SG200 battery monitor can "learn" your boat's SOH, with (in my opinion, not yet definitively proven) accuracy. There are various "battery meters" on the market, ranging from a few dollars to a few hundred dollars. In my opinion, they're worthless. Short of rousting out your batteries and either performing a lab-quality 20-hour discharge test at home, or maybe testing them with a variable-resistance load tester at a shoreside battery retailer, I'm at a loss for help.

Rod Collins at Marine How To (https://marinehowto.com/) has about the most comprehensive set of discussions of this topic I'm aware of, so for more detailed information, I strongly suggest you visit his web site. And contribute $$ if you can-he's a valuable asset to the boating community. And while I'm not a Nigel Calder fan, he has much to contribute as well.

Personally, I monitor both my start and house batteries' State of Charge (SOC) and voltage via a Victron battery monitor, and try and develop a sense of how much my SOC has degraded, and what my battery voltage should be, after staying overnight off of shore power. If I feel my SOC is low for my usage overnight, I start to get goosey regarding my SOH. And as I've never had a battery fail gracefully (in my experience, they're here today, gone tomorrow), I probably buy more batteries than I should.

But I've never had to paddle home, either.

Regards,

Pete

ps-sorry there's no definitive qualitative answer to your question. An honest answer is "it depends".

 

[grahamdouglass]

Don't forget the start battery

When you change out the house batteries don't forget the start bank. Even if yiou don't need a new one. Changing out all batteries at the same time ensures you don't forget.

 

[Ken E.]

Like Larry said above, watch your house bank voltage in the morning after being on anchor and having all your 'hotel' loads running all night with no charging. If you see degraded voltage, get a load test. I have 8 LA golf carts in my house bank and I get 6 - 8 years of life out of them.

 

[O C Diver]

Our house bank is 10-6 volt golf carts. I change them out every 5-7 years. I can tell when they’re due by our SOC meter and the voltage when we get up in the morning.

I'm on year 5, so far so good.

Replaced the start and generator batteries in February. The start battery was a red topped Optima given to me by my mechanic from a totaled car. It lasted 6.5 years. The generator had a West Marine AGM that was probably 7 or 8 years old. Both were replaced with red topped Optima batteries. Have had great luck with them in start and bow thruster applications.

Ted

 

[koliver]

I am in a temperate climate, so my batteries last a lot longer than those in hot climates. My last change was after 10 yrs on the house set and 12 yrs on the start.

 

[slowgoesit]

Batteries need to be changed based on condition, not just age. If you are in doubt as to the health of your batteries, I recommend that you:

• Ensure that your charger is working properly, then
• Charge them for 24 hours with no load, then
• disconnect cables from each battery, and
• test with a battery load tester.

There are many out there, just google "Battery load tester".

If they test good, keep doing what you are doing, if they test marginal, replace, and go over how you maintain/care for them.


Some basic items that are often overlooked:

• Use appropriately sized wiring, and of the right type.
• Inspect terminal ends on a regular basis.
• If wet cells, regularly inspect for electrolyte level, add distilled water as needed, never battery acid, or tap water.
• Do not draw them down excessively. What is excessive? Lots of opinions out there, mine is do not draw down below 50% SOC.

As a rule of thumb, properly maintained, quality batteries should have a useful life of from 6 to 8 years.
The ones in my RV are 8 years old and will probably be replaced this year . . . if we are able to use it again with everything that is going on that is. . . .

 

[FF]

Next time you will be onboard for a weekend , simply turn off the shore power. .

The voltage will drop to 12.8V or so if the batts are OK,watch the voltage as you live on the boat as you would anchored out. 12.0V with no house loads is the lowest you should allow the test to go.

This is a sort of a load test that will give you an idea of the batt condition as well as the size of the house bank.

Usually the reefer is the biggest load on the house bank .

Most boats not setup to anchor out will only get 12 hours , the better will get 20-24 before good batts are almost dead.

If you wish to anchor out much any brand of SOC , state of charge , meter will be a big help in keeping the house batts healthy. There is no need for lab grade info, just a good shot at weather you are nearing the 50% discharge point , where you need to recharge. $150 to $200, or so.

 

[Larry M]

:... The start battery was a red topped Optima given to me by my mechanic from a totaled car. It lasted 6.5 years. The generator .....Both were replaced with red topped Optima batteries. Have had great luck with them in start.... Ted

We’ve been using Optima’s for 22 years on our generators and start banks exclusively. I’ve never had a battery failure, slowly age yes but I get more life than from an equivalent wet cells with no watering required. The only chargers on both are the alternators from the generator and engine. I let them sit all summer and in the fall they start with out additional charging. The Opitma’s have a very low discharge rate.

 

[MYTraveler]

Our house bank is 10-6 volt golf carts. I change them out every 5-7 years. I can tell when they’re due by our SOC meter and the voltage when we get up in the morning. I changed them last month after six years. I was on the hard for bottom paint and the yard plugged me into a dead outlet and never checked. When I came back the battery bank read 0.200 volts.

You should try equalizing your "dead" batteries. Those 6-volt golf cart batteries seem to have 9 lives.

 

[Larry M]

You should try equalizing your "dead" batteries. Those 6-volt golf cart batteries seem to have 9 lives.

I though about it but at the time we were getting ready to for a 2-4 month cruise and felt it wasn’t worth the risk.

 

[Wayfarer]

My house bank of 6v golf cart FLAs was apparently ten years old when I exchanged them. They probably needed to be replaced at nine.

 

[Brooksie]

My batteries seem to last 5 years. I use Walmart deep cycles as I have found that premium batteries are not worth the extra money. In the case of my lobster boat, both banks are the same and have an ACR. I alternate which bank I start on and can hear a failing bank by the starters sound. (or at least I think I can hear it) Next time I start, I have someone watch the digital volt meter and if it falls below 10.5v I know I am ready for a new battery or batteries. Like a built in load tester. That's just for my engine, starter, cable, battery combination.

 

[Greggnvt]

I look at doing a load test on my 8-D’s but couldn’t find a tester that could handle the AMP’s. Any suggestions on a load test for 8-D’s?

 

[RickyD]

You should try equalizing your "dead" batteries. Those 6-volt golf cart batteries seem to have 9 lives.

I don't have a proper house bank from the PO. Basically I have 4 8D start batteries with three used has the house. I equalized a couple weeks ago for the first time. (finally read the charger/inverter manual). Took the boat to Catalina for a 3 day weekend. The performance was much improved. I did not wake up in the morning in the red zone. Still planning to change two 8Ds for 6 Trojan L16s. Need to add a couple inches to the battery box first though.

 

[RonR]

Do they have removable caps? If so is there any electrolytes left?

Yes, and yes

 

[Brooksie]

I look at doing a load test on my 8-D’s but couldn’t find a tester that could handle the AMP’s. Any suggestions on a load test for 8-D’s?

I have a 200A load tester I got years ago on ebay. But my $13. digital voltmeter does the same job on the boat and I can look at it when I start as many times as I want w/o hookup.

 

[sledge]

Another data point: A load test finally indicated it was time, but we got about 10 years out of the four large 8D AGM (maint. free) batteries in our boat. 3 were house and one was start.
They might have run even longer (engine was starting and everything was running fine) but we were planning some extensive cruising and didn't want to press our luck and have one or more of them fail possibly in a remote area.

 

[NCheaven]

At 8 years one of four house batteries started leaking between cells, detected by noticing slightly lower # on voltmeter, replaced all four and the starter battery. Peace of mind. Prior owner had installed LEDs, so draw is light. Dock power, running, and solar panel keep the batteries up well. Batteries spent 6 years in RI, 2 in NC, moderate temps. 15 year old Volvo TAMD41-PA cranks in 1 second every time off one battery. Thankful for great diesel and electronics guys.

 

[catalinajack]

Your batteries last only five years but premium batteries are not worth it??? You get what you pay for.

My batteries seem to last 5 years. I use Walmart deep cycles as I have found that premium batteries are not worth the extra money. In the case of my lobster boat, both banks are the same and have an ACR. I alternate which bank I start on and can hear a failing bank by the starters sound. (or at least I think I can hear it) Next time I start, I have someone watch the digital volt meter and if it falls below 10.5v I know I am ready for a new battery or batteries. Like a built in load tester. That's just for my engine, starter, cable, battery combination.

 

[garychurch]

Depends on their performance. If you have 5 200 amp-hr rated 12v batteries they provide 1,000 amp-hrs at 12v or 500 amp-hrs at 24v. Assuming or measuring your average current draw is say 20 amps per hour with the batteries drawn down to 50% capacity you should be able to be on batteries for 25 hours at 12v and 12.5 hours at 24v with a minimum battery voltage for AGM batteries of 12.23v for a 12v system and 24.46 for a 24v system.

If you cannot manage these numbers you should think about battery replacement as the voltage numbers deteriorate with time. At some point you will decide that you just cannot leave your batteries on long enough to support your needs (8, 6, 4? hours) and then replacement is in your future. Generally performance will deteriorate faster as you near end of useful life.

 

[Bigsfish]

I use to swap out batteries every five years but with these new electronic charges I think I may get an extra year or two. Having dead batteries in the Bahamas out islands won’t be fun.

 

[castellah22]

How often do you guys change out house/main batteries? Or is there a way to load test them? Our boat sat at a dock plugged in for the last 4 years. The batteries are 5 years old. The boat has a built in charger for when its plugged in. They show 13.6 while on the charger, we have never ran a set down yet to see how long they will last. They are hard to get to and I know they cost a bunch! Just seeing how others go about it.

if you push the start button and goes grunt, then replace them.

 

[Bigsfish]

Cast22

That’s what we are trying to avoid. If that happens in a remote place you are SOL.