onboard battery charger question

[BrendanC]

hello, i have a promariner pro sport 6 charger mounted in my amp rack (6amp max). it has the flooded/agm pin installed and maintains 2 diehard platinum group 34 AGM batteries with an XSPower XP750. all batteries are wired in parallel. i’m wondering if the little charger is enough to keep the batteries in good health/charged. attached is a photo of how the rack is laid out.

 

[Kira]

So your little charger is charging 2 G34 AGM batteries and a small 12v. accessory battery....all in parallel?
With this setup together and powered up, can you measure what each battery is getting?

With internal resistance a major factor in battery charging, I'd bet the calculation would be complex.

I assume the chargers "flooded/agm pin" keeps it from overcharging the AGM batteries.
Off the top of my head, you may be frying the 12v. battery.

 

[BrendanC]

So your little charger is charging 2 G34 AGM batteries and a small 12v. accessory battery....all in parallel?
With this setup together and powered up, can you measure what each battery is getting?

With internal resistance a major factor in battery charging, I'd bet the calculation would be complex.

I assume the chargers "flooded/agm pin" keeps it from overcharging the AGM batteries.
Off the top of my head, you may be frying the 12v. battery.

the XSpower battery is a supplemental audio system battery. it is rated to be run in parallel with car electrical systems. doesn’t matter where i take readings with my meter it’s all the same. everything is interconnected with 2/0 welding lead.

 

[Kira]

I remember such layout exercises from class...years ago.
Now that I'm thinking (while watching a football game where the right team is winning at the mo) I'd guess your XSpower battery is warm.

Did you measure the batteries before you started this? I'm guessing they're all getting a trickle.

 

[fsdork]

The answer to your question depends on (at least in part) the net draw from the batteries. If you generally arrive at home with your batteries at/near 100% charge and there isn't anywhere near 6 amps of parasitic/standby draw when parked, your charger should be fine.

 

[BrendanC]

The answer to your question depends on (at least in part) the net draw from the batteries. If you generally arrive at home with your batteries at/near 100% charge and there isn't anywhere near 6 amps of parasitic/standby draw when parked, your charger should be fine.

i will plug it in overnight and take a reading in the morning. then drive it normally and take a reading again and report back. thank you!

 

[eljefino]

I'd be more concerned with the mismatched battery types, even though your XSPower one "says" it can coexist. Whether the power comes from your alternator or this charger is immaterial.

The charger is more than fine. Some trickle chargers for full sized batteries are under an amp and they work well.

 

[BrendanC]

I'd be more concerned with the mismatched battery types, even though your XSPower one "says" it can coexist. Whether the power comes from your alternator or this charger is immaterial.

The charger is more than fine. Some trickle chargers for full sized batteries are under an amp and they work well.

all three batteries are AGM

 

[Rand]

all three batteries are AGM

but not matched.

 

[meep]

With your use case it’s basically a robust trickle charger, and 6 amps is plenty. I assume it cuts out around 14v or so. It may not bring the agms to a full 100%, which could require 14.5-14.8v max before pulling back. Realistically, it’s a nice size for too-offs and general care.

As Rand mentioned, matching chemistries is important … the naturally higher volt’ed batteries will always be ever so slightly depleting their charge into the lower volt’ed chemistry, hence shortening their life. the extent of this could be non-existent, minor, or more if it’s a nasty mismatch. But if this is a DD and they are all in reasonable health, it’s probably close. the starter batteries are AGM and imma assume the aux battery is a gel cel - and these are pretty similar. Nice hobby.

 

[BrendanC]

With your use case it’s basically a robust trickle charger, and 6 amps is plenty. I assume it cuts out around 14v or so. It may not bring the agms to a full 100%, which could require 14.5-14.8v max before pulling back. Realistically, it’s a nice size for too-offs and general care.

As Rand mentioned, matching chemistries is important … the naturally higher volt’ed batteries will always be ever so slightly depleting their charge into the lower volt’ed chemistry, hence shortening their life. the extent of this could be non-existent, minor, or more if it’s a nasty mismatch. But if this is a DD and they are all in reasonable health, it’s probably close. the starter batteries are AGM and imma assume the aux battery is a gel cel - and these are pretty similar. Nice hobby.

they are all AGM batteries.

 

[eljefino]

So what's the point of the third battery, does it discharge super quickly so you can hit those bass notes? The point we're all trying to make is if you have three donkeys pulling your ox-cart, and one of them works harder than the rest, he's gonna need a longer nap.