Deep cycle or dual purpose battery?

[jnr4817]

An item to consider is how often you intend those batteries to drop below 50%. Lead acid batteries if they drop below 50% will lose charge to 50% or below on first dip below 50%.

AGM batteries won’t suffer as much loss when falling below 50%, but at best will recover only 65% of original state.

The problem lies in that Lithium batteries usually don’t have cranking amps that LA or AGM batteries have, but have more Amp hours as a result of being able to be dissipated to 5% without charge loss.

LiFePo batteries are more stable across temp extremes than LA or AGM batts.

Problem is that automotive ( thus boat) regulators are not adjusted to charge LiFePo batts, and don’t appropriately adjust float or bulk charge.

So, to answer the question we must know what you have on the good bank (LA or AGM, deep cycle or cranking batt) and what you intend is use it for (starting or radio play). Neither will last beyond 50% dissipation, but the likelihood of a cranking Batt going below 50% is infrequent, but possible. I would consider putting the good bank on the starting leg, and get a deep cycle AGM battery for the “Party” leg. Both will start the boat, the cranking Batt has shorter use, but faster dissipation.

A deep cycle “Party” battery will last longer, and typically offer enough reserve for starting and retain charging cycles for longer.


Sent from my iPhone using Tapatalk

If I go this route will my Pro Sport 12 battery charger be able to maintain both batteries even though they are different?

I am currently running deka marine batteries that came with the boat but one is getting weak because we use it as party/chill battery. The cranking battery is still
Going strong

[2in2out]

LiFePo batteries use different charge cycles and rates than LA or AGM batteries.
That charger should cycle fine, but I would verify with the battery vender what they recommend.


Sent from my iPhone using Tapatalk

[MLA]

I would not suggest recharging a LiFePo with anything other then its manufactures suggested charger. Further, then Pro Sport does not allow for charging 2 different types of batteries at once, one on each bank. Even further, IIRC, the pro sport 12 does not have the selectable charge profiles like the larger pro sports, so I would not suggest charging large AGMs with it.

[jnr4817]

I’m only going to change the batteries then. What should I get?