AGM and Led acid mix

[zacblotter]

I am a rookie liveaboard (at anchor) and am figuring things out as I go.
I have two AGM batteries maintained by 200 watts of solar and was just gifted two flooded lead acid batteries.
The agm's run the house and also serve as starter batteries.
My question is how to best integrate the new lead acid batteries into the system?


The system only pulls 6 amps with everything .
I could use one of the led acid as a starter batterie abut that still leaves one more that ii'm not too sure what to do with.
would i need a second charge controller to run it on the solar would it be ok to run in parallel with the tw agm's?

Thank you in advance for the advice.
ZB

[Pete7]

So how old do you think these free lead acid batteries are and what are they, make and model would be useful. How old are your AGMs whilst your at it.

There are a variety of options here btw but we would need to know the battery detail first.

Pete

[GordMay]

Greetings and welcome aboard the CF, Zac.

It's not generally recommended, to mix battery chemistries, in a bank.

[tkeithlu]

The central reason for Gord's advice is that the two types of batteries have different ideal charging schedules. You might see that in a sophisticated charger that has different setting for the two. However, you do not appear to be demanding very much of your batteries, and may be able to live with a single charging routine that does not get the most out of one or the other type. Battery purests/experts will bristle at that suggestion.

[MartinR]

You can use a DC/DC charger if you split the batteries into two different banks. One for normal use, one as spare. You could get away with a small charger in this case, they are fairly cheap.

[zacblotter]

Originally Posted by Pete7

So how old do you think these free lead acid batteries are and what are they, make and model would be useful. How old are your AGMs whilst your at it.

There are a variety of options here btw but we would need to know the battery detail first.

Pete

The batteries are four years old. And they are Duracell ultra sli24mdp. Both are still testing at 100%. They came off a boat that just upgraded to AGM batteries

[zacblotter]

Thank you that is a great suggestion

[Tomodore]

Consider putting energy into a separate starting battery since at some point you will probably run down the batteries or have a failure that will leave you unable to start your engine. Perhaps you have a generator if so that would give you some backup for the batteries.