My battery set-up

My current battery system set up by the previous owner consists of 2 - 4d starting batteries and 2 4d batteries for the house 12v system. One of my starting 4d batteries is bad and will need to be replaced. I was thinking of taking one of the 4d house batteries switching it with the bad battery and getting deep cycle batteries for the house system. What do you think?

If I had the opportunity to get rid of the 4D batteries (and I will on my boat shortly), I'd do it. They are not space efficient and too heavy to deal with. 4C (golf cart) 6V are worth consideration. Available also as 6C (150% capacity and 13" tall) and L16 (200% capacity and 18" tall). L16 are getting heavy again. I've got two 4D house batteries and one 4D start, I'm planning on replacing the house batteries with four 6C batteries which will take far less space and add 50% capacity, and replacing the 4D start battery with two G24, more CCA and smaller footprint.

L16s are heavy, but IMO, their shape and handle placement makes them not quite as bad to lift as a 4D, even though the L16 is only a few pounds lighter.

How much money are wanting to spend? How much room do you have? 1 or 2 engines? Generator?

I completely rebuilt my battery system about 5 years ago.

You can go with 6Vdc golf cart batteries for the house and Group 31 batteries for start batteries, all connected with ACRs.

https://www.bluesea.com/systems

Good plan to replace the 4D house batteries. Here is an article I uploaded to the TF Library on this subject: https://www.trawlerforum.com/forums/downloads.php?do=file&id=113

While you are at it, consider the following:

How are the start and house banks isolated.

How is each bank charged: from shorepower charger and from the propulsion alternator.

A bit of rewiring and a battery combiner or ACR will resolve those issues and won't require relying on switches.

David

Not sure if the golf batteries are worth the investment. How often do you use your 12v system? I have a generator with seperate battery and twin cummins diesels with their own starting battery.

larman said:

Not sure if the golf batteries are worth the investment. How often do you use your 12v system? I have a generator with seperate battery and twin cummins diesels with their own starting battery.

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A lot of us try to run our generators as little as necessary, so having a solid battery setup is important. Personally, I've got a house bank and 2 start batteries (generator shares with one of the engines). When away from shore power, assuming I'm not sitting in the same place for days, the generator usually runs for an hour in the morning and an hour in the evening. That's enough for coffee, cooking and to re-heat the hot water tank for showers and such. If I'm traveling and have at least some engine runtime in a day, I don't usually need any extra generator runtime for battery charging and I tend not to run the thing overnight for A/C or anything (although I'll sometimes run the A/C in the evening to cool the boat down on a hot day).

Yes I am you on running the generator as little as possible. I essentially want to do the same thing as you do. Could you recommend a brand and model of 6v batteries and quantity.

rslifkin said:

A lot of us try to run our generators as little as necessary, so having a solid battery setup is important. Personally, I've got a house bank and 2 start batteries (generator shares with one of the engines). When away from shore power, assuming I'm not sitting in the same place for days, the generator usually runs for an hour in the morning and an hour in the evening. That's enough for coffee, cooking and to re-heat the hot water tank for showers and such. If I'm traveling and have at least some engine runtime in a day, I don't usually need any extra generator runtime for battery charging and I tend not to run the thing overnight for A/C or anything (although I'll sometimes run the A/C in the evening to cool the boat down on a hot day).

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Thanks David was able to download article.

DavidM said:

Good plan to replace the 4D house batteries. Here is an article I uploaded to the TF Library on this subject: https://www.trawlerforum.com/forums/downloads.php?do=file&id=113

While you are at it, consider the following:

How are the start and house banks isolated.

How is each bank charged: from shorepower charger and from the propulsion alternator.

A bit of rewiring and a battery combiner or ACR will resolve those issues and won't require relying on switches.

David

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Personally, my house bank is a pair of L16 Mastervolt 6V AGMs in series for 400 amp-hours at 12V. There are other good battery choices in that size, both flooded and AGM.

L16s are tall though, so they may not fit in your existing space. It would be good to know what space you have before suggesting alternatives to your 4Ds.

larman said:

Yes I am you on running the generator as little as possible. I essentially want to do the same thing as you do. Could you recommend a brand and model of 6v batteries and quantity.

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The Deka GC2 batteries from Batteries Plus or Sams Club or Costco is a good solid choice. Should be about $100 each with one 4D as a core return for two GC2s. Trojans are the top of the line for GC batteries but are about $50 more.

David

With a proper DC system, running the genset can be a rare event. In fact you don't need it at all. The exception being living aboard on a mooring (so not going anywhere) or living in the SE where AC is necessary to support life.

DDW said:

With a proper DC system, running the genset can be a rare event. In fact you don't need it at all. The exception being living aboard on a mooring (so not going anywhere) or living in the SE where AC is necessary to support life.

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Last year we moored for the season so we relied on the genset. This year we have a slip so I will have shore power.

DavidM said:

The Deka GC2 batteries from Batteries Plus or Sams Club or Costco is a good solid choice. Should be about $100 each with one 4D as a core return for two GC2s. Trojans are the top of the line for GC batteries but are about $50 more.

David

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Are these the batteries you are referring to?

https://www.samsclub.com/p/duracell-golf-car-battery-group-size-gc2/prod3590228?xid=plp_product_1_1

DDW said:

With a proper DC system, running the genset can be a rare event. In fact you don't need it at all. The exception being living aboard on a mooring (so not going anywhere) or living in the SE where AC is necessary to support life.

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It depends somewhat on your systems layout. For me, to be totally genset independent outside of A/C, I'd need a much bigger battery bank and a very big inverter. My galley is all electric and I haven't plumbed a coolant loop to the water heater from either engine (not a big deal to heat it electrically and it's less plumbing in the way and that can potentially fail). So for my boat, for example, it just doesn't make sense to try to eliminate the generator. Especially considering that if I don't physically remove it, I'm adding a lot of weight with extra batteries.

Costco lead acid golf cart batteries are the only way to go. I bought 6 in June 2019 to replace the 6 I bought from Costco in 2012.

After cruising the summer of 2019, anchoring 75% of the time, I noticed on my battery monitor that the battery efficiency was not where it should be for new batteries. I suspected that one of the 6 batteries was defective and not holding a full charge or some other issue that I did not want to troubleshoot or deal with. I talked to Costco Auto Center about the issue and they advised me to bring them in and get 6 new ones.

Took the 6 batteries in and they exchanged them for 6 new ones without any fuss nor cost to me. I expected to pay some sort of prorate. I don't think any other battery store would offer a liberal return policy as Costco.

Costco batteries are currently manufactured by Interstate Battery.

Plus I get money back at the end of the year from Costco and Costco Visa for purchases. I'm getting $980 back this month from Costco Visa

larman said:

Are these the batteries you are referring to?

https://www.samsclub.com/p/duracell-golf-car-battery-group-size-gc2/prod3590228?xid=plp_product_1_1

Click to expand...

Yes, I think Deka and Duracell are made by the same folks.


David

Thanks one and all for the replies. I now have some direction as to where to go. I think 6 - 6v batteries will fit for my house bank going to take some measurements.

If one battery is dead or dying the others are not far behind. If all your batteries are not the same age you will never get on top of the issue of one always dying. Not a good idea to add one new battery to a bank comprised of older batteries, they all become the same age, old.

Now would be a good time to get an entire new battery group. House and Starting. if you have one or two batteries which you know are fairly young and good use them as stand alone batteries either for your windless, generator or to have as a spare.

pete

The one bad battery was due to a faulty alternator which I have since replaced. It gave me issues all of last season.

Sam's Club golf cart batteries are $10 less.

I'd get those if there was one near me.

I bought Sam's Club golf car batteries in 2000 and 2006 when there were SC in my area. They were good batteries.

To compare batteries, weigh them. More weight, more lead.

Interstate does not manufacture batteries. They market batteries made by other companies. Johnson Controls is one.

syjos said:

Costco lead acid golf cart batteries are the only way to go. I bought 6 in June 2019 to replace the 6 I bought from Costco in 2012.

After cruising the summer of 2019, anchoring 75% of the time, I noticed on my battery monitor that the battery efficiency was not where it should be for new batteries. I suspected that one of the 6 batteries was defective and not holding a full charge or some other issue that I did not want to troubleshoot or deal with. I talked to Costco Auto Center about the issue and they advised me to bring them in and get 6 new ones.

Took the 6 batteries in and they exchanged them for 6 new ones without any fuss nor cost to me. I expected to pay some sort of prorate. I don't think any other battery store would offer a liberal return policy as Costco.

Costco batteries are currently manufactured by Interstate Battery.

Plus I get money back at the end of the year from Costco and Costco Visa for purchases. I'm getting $980 back this month from Costco Visa

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Well I am an electric boat with 2 five cf freezers on board. Run my genny for about 2 hours in the morning and 3 hours in the evening. I have 2 house banks. Each bank has 4 six vdc gulf cart batteries. One bank is only for the inverter (remember 2 freezers) the other is for boat 12v stuff. I do have my alternator tied into the system (100amps total). So I tend to run my genny a little longer. No apologies here for running my genny.

“The Deka GC2 batteries from Batteries Plus or Sams Club or Costco is a good solid choice. Should be about $100 each with one 4D as a core return for two GC2s. Trojans are the top of the line for GC batteries but are about $50 more.”
If you happen to live near golf-centric communities, consider calling the local golf cart dealers. They usually sell high quality GC2 batteries for less since they literally buy them by the truckload. I bought a Trojans for $108 last time.

Larman
I'm catching up and just noticed your post re MS Battys.
I had some issues after purchasing our MS34HT used.
Here is a link re: what I found and installed as an improvement. My biggest finding & concern was the diode isolators MS installed. Eliminating them was a primary objective.
https://www.trawlerforum.com/forums/s11/ms-34ht-charging-system-mods-24228.html
I agree (as always) with DavidM. I went a slightly different path than he outlines, however, and I am currently contemplating what to replace my current AGM 8Ds with when the expire. I lean towards 6V GC AGMs instead of FLAs as I store the boat on the hard for 7 months +/- and have no charging capability during storage. The factory 8Ds were next to impossible to remove / replace each season so I decided the premium $ of AGMs was necessary. My unanswered question is whether it is worth the trouble and expense of separating house from start as MS has them tied together. I'm also undecided at this point whether to go with deep cycle or start battys for the thruster bank, but that's a different discussion and don't mean to confuse your topic. I have monitored battys each spring after unwrapping and track V. The objective seems to have been satisfied as my AGMs are always at around 12.6V after the 7 mos of storage. I would not expect the same with FLAs
I moved my CO detectors from always on (bypassing the batty SW) to powered via the atty SW to avoid that drain. My feeling is that battys will only be shut down when I'm not aboard and I don't need CO protection in that case.

Personally, I keep engine start power separate from house, as I consider that safety critical. I also don't bypass the battery switches for anything, not even charging. I don't ever turn the switches off in normal use, so I'd rather have them be a 100% "this bank is isolated from everything".

If you're adding a thruster bank, I wouldn't be too afraid of sharing that with engine start, as a thruster wouldn't be used without an engine running.

I also went an extra step with my setup and have the 2 ACRs that tie the engine banks to the house banks interlocked to the engine ignitions. That way the engines charge the house bank while running, but when on shore power or generator, the 3 bank charger feeds them independently and the ACRs stay disconnected.

Bacchus said:

Larman
I'm catching up and just noticed your post re MS Battys.
I had some issues after purchasing our MS34HT used.
Here is a link re: what I found and installed as an improvement. My biggest finding & concern was the diode isolators MS installed. Eliminating them was a primary objective.
https://www.trawlerforum.com/forums/s11/ms-34ht-charging-system-mods-24228.html
I agree (as always) with DavidM. I went a slightly different path than he outlines, however, and I am currently contemplating what to replace my current AGM 8Ds with when the expire. I lean towards 6V GC AGMs instead of FLAs as I store the boat on the hard for 7 months +/- and have no charging capability during storage. The factory 8Ds were next to impossible to remove / replace each season so I decided the premium $ of AGMs was necessary. My unanswered question is whether it is worth the trouble and expense of separating house from start as MS has them tied together. I'm also undecided at this point whether to go with deep cycle or start battys for the thruster bank, but that's a different discussion and don't mean to confuse your topic. I have monitored battys each spring after unwrapping and track V. The objective seems to have been satisfied as my AGMs are always at around 12.6V after the 7 mos of storage. I would not expect the same with FLAs
I moved my CO detectors from always on (bypassing the batty SW) to powered via the atty SW to avoid that drain. My feeling is that battys will only be shut down when I'm not aboard and I don't need CO protection in that case.

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How many AGM's do you have in your housebank? I was thinking about going with 400Ah housebank.

Here's a different opinion. I do not see keeping the banks separate as safety critical. My boat has eight golf batteries used as a combined start/house bank. I also have separate start batteries for my generators. If, in the highly unlikely - the aforementioned safety issue - I can either use the generator to recharge the batteries or use jumper cables to start the engines. I once dumbly discharged the house bank down to 20%. The engines started with no hint of struggle. The fact is, it is not right or wrong setting it up either way. Don't be frightened into going to great expense to reconfigure to a set-up that gains you, in my opinion, nothing. Others will disagree with me strongly while many others with a setup such as mine won't. All this, however, presupposes having a generator with its own starting battery.

rslifkin said:

Personally, I keep engine start power separate from house, as I consider that safety critical. I also don't bypass the battery switches for anything, not even charging. I don't ever turn the switches off in normal use, so I'd rather have them be a 100% "this bank is isolated from everything".

If you're adding a thruster bank, I wouldn't be too afraid of sharing that with engine start, as a thruster wouldn't be used without an engine running.

I also went an extra step with my setup and have the 2 ACRs that tie the engine banks to the house banks interlocked to the engine ignitions. That way the engines charge the house bank while running, but when on shore power or generator, the 3 bank charger feeds them independently and the ACRs stay disconnected.

Click to expand...

Given a big enough house bank, yes, you're in better shape using it for engine starting (compared to smaller house banks), as the required charge level before it can't start an engine is much lower.

When I say safety critical, I'm thinking of a situation like shutting down engines in a lock or something where I'd want to minimize the risk that either me doing something dumb or a system failure would prevent me from being able to start them "right now" when I need them. Having to wait for the generator to charge a battery up wouldn't be great in that kind of situation. And there's no concern for any electronics power-cycling due to a voltage dip during engine start (especially with low house batteries) as they never see that dip. I've seen plenty of electronics that will cycle if you get under 10.5 volts, which with a lot of engines and assuming the batteries are only at 50%, you'd need a very big house bank to avoid.

On the safety critical logic, I also go with every engine should have 2 sources of starting power readily available. I've got my 2 start banks, which we'll call S1 and S2. Either engine or the generator can be started from either one with the flip of a switch. Normal switch positions are port engine starting from S1, stbd engine and generator starting from S2. Starting anything from the house bank requires jumper cables in my setup. If I've reached the point where I need to do that, something has gone very wrong, killing both independent start banks.

I prefer separate house and start battery systems.

There are two G31 batteries for starting the single engine. They also start the generator and power the windlass and bow thruster. There is no 110 VAC charger on the start batteries.

For house, I have 6 golf cart batteries and a 120 amp, 3000 watt inverter/charger.

There is an 100 amp alternator for the start and an 150 amp alternator for the house batteries.

The generator has a 65 amp alternator.

The house and start circuits are totally isolated from each other. A crossover switch allows cross connection in case of problems.

This system has been in place for 19 years without issue.