Best batteries for houseboat bank

[Cajun Bill]

Haven't posted anything in awhile, but here goes. I am building a houseboat and will transfer my small two panel system to run some items on the houseboat. Looking for recommendations as to what batteries to buy for a 24V system. I know the first question will be what do I intend to use it for so I foresee using it for lights, TV, demand water pumps, etc. when the genny is not running. Don't want to break the bank by using lithium-ion and I really don't know if it would work with my controller anyway. I'm thinking small, like two 12V batts in series either flooded or agm, probably group 31's. Looking for advice on brands, businesses, amp hours, etc.

[SunEagle]

For a wet area I would go with AGM type but remember they may not last as long as an Li chemistry type battery but will be cheaper.

As for the size. It depends on what your panels can generate in amps. A Lead battery requires about 1/10 the amount of Ah the batteries are rated.

As for brand, my guess would be ones that are not expensive to ship to you.

[Cajun Bill]

Thanks SunEagle. Not sure about the calculation, but according to my meter, the panels are producing 4 amps. So what would be the recommended Ah be for the batts. 10 x 4= 40 Ah? That doesn't seem right.

[SunEagle]

40Ah is correct for the 4 amps the panels generate. If you want a bigger battery then you will have to get more amps which means more panels

[Cajun Bill]

I get that, but if my draw on the batt(s) during the night when there is no sun to recharge is less that what the panels can provide during the day, does it matter how large the batts are? Just asking.

[SunEagle]

If the batteries are too big (Ah rating) then you run the risk of sulfating the plates due to not having enough amps to keep them clean. That is why going with Lead acid type batteries can be cheaper in the short run but expensive to keep replacing them. Li chemistry do not necessarily require high amp input to charge and have more cycles but are more expensive in the beginning

[littleharbor2]

If the batteries are too big (Ah rating) then you run the risk of sulfating the plates due to not having enough amps to keep them clean. That is why going with Lead acid type batteries can be cheaper in the short run but expensive to keep replacing them. Li chemistry do not necessarily require high amp input to charge and have more cycles but are more expensive in the beginning

I'm finding that building your own LFP batteries from scratch is cheaper than lead acid these days.

[Cajun Bill]

SE, does that tendency to sulfate lessen or stay the same if AGM batts are used?

[SunEagle]

SE, does that tendency to sulfate lessen or stay the same if AGM batts are used?

Just about any type of Lead Acid batteries can sulfate if not charge correctly. So IMO even AGM type may not work after a while of low charge rates

[SunEagle]

I'm finding that building your own LFP batteries from scratch is cheaper than lead acid these days.

I agree that doing that can work if you have the knowledge and workshop to build that type of battery

[Cajun Bill]

I think I might resolve the sulfation issue by periodically charging the batts with the Simplex 24V charger I already have. I can do this when the genny is running. What say you Sun Eagle?

[SunEagle]

I think I might resolve the sulfation issue by periodically charging the batts with the Simplex 24V charger I already have. I can do this when the genny is running. What say you Sun Eagle?

That may work but you should always have a generator to charge a battery set in case you do not have enough sunlight.

[Cajun Bill]

The genny will probably always be there because I need it to run the small AC and MW (when needed) that I plan to have onboard the houseboat. (I'm in South La.)

[Cajun Bill]

Last question for SE, if the charger works to desulpucate (sic?), how often would think I have to use to charge as opposed to the ever present low power charging of the panels?

[SunEagle]

Last question for SE, if the charger works to desulpucate (sic?), how often would think I have to use to charge as opposed to the ever present low power charging of the panels?

It really depends on both the use of the battery and manufacturers recommendations on what state of charge (SOC) it should be at.

I would charge the battery bank at least once a week or sooner.