Battery charger

[Robmac]

I have recently purchased a Paco 7 stage battery charger (12V,20A).

I now wish to permanently connect this to my battery bank which consists of 2xTrojan T125's (6V) connected in series.

Is it just a matter of connecting the positive to the + to the + on battery 1 and the _ to the _ on battery 2 to treat them as a single 12V battery?

Thanks in advance.

 

[pappajohn]

Connect the same as the existing outgoing hab feed wires.

 

[TheBig1]

yes, but the charger should be a minimum of 10% or higher than the bank capacity
corrected typo

 

[pappajohn]

I assume you are removing the existing charger?
If so simply connect to the existing charger wires.
If no, the old charger may interfere with the various functions of the new charger.

 

[Robmac]

I assume you are removing the existing charger?
If so simply connect to the existing charger wires.
If no, the old charger may interfere with the various functions of the new charger.

There is no charger fitted at present.

It is a self build and so far the electrics have all been helped by my son. Unfortunately he is abroad at the moment and I cannot contact him so I thought I'd better ask to be sure.

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[pappajohn]

Don't forget to put a 25a fuse near the batteries.

Normally the charger wires would go to the control panel but not knowing how it's all been wired its probably safer to feed direct to the batteries.

 

[Robmac]

yes, but the charger should be a minimum of 20% or higher than the bank capacity

Excuse my ignorance, but 20% in terms of? I did read of a chap who used this charger with 2xT125's on a boat so I hope it's suitable.

My knowledge of electronics is limited as you can tell!

 

[TheBig1]

Excuse my ignorance, but 20% in terms of? I did read of a chap who used this charger with 2xT125's on a boat so I hope it's suitable.

My knowledge of electronics is limited as you can tell!

the combined AH of the attached batteries, so 2xT125 is 240AH. You need a 25A charger ideally. just noticed my fat fingers hit 2 instead of 1, should be 10%

 

[pappajohn]

But your 20a charger will take a little longer to charge to full.
It will still get there eventually.

 

[two]

Bigger tends to be better but there's no need for overkill. Hopefully, you'll be topping-up when charging and not recovering from rock-bottom, so 20A will suffice.

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[Robmac]

Many thanks all.

 

[bigtwin]

the combined AH of the attached batteries, so 2xT125 is 240AH. You need a 25A charger ideally. just noticed my fat fingers hit 2 instead of 1, should be 10%

If they were in parallel the capacity would be 240Ah but they are in series so the capacity remains 125Ah (at 12V).

On that basis, the charger is adequate.

Ian

 

[autorouter]

If they were in parallel the capacity would be 240Ah but they are in series so the capacity remains 125Ah (at 12V).

The data sheet says a single T125 6V battery has a capacity of 240Ah. A pair in series would have the same capacity, 240Ah, but the voltage would obviously be 12V.

 

[bigtwin]

The data sheet says a single T125 6V battery has a capacity of 240Ah. A pair in series would have the same capacity, 240Ah, but the voltage would obviously be 12V.

I made the assumption, as I think other posters have, that a T125 had a 120/125Ah capacity. Based on the information you’ve presented, that was clearly an erroneous assumption.
However, my main point, on which we agree, was that series connection doesn’t result in an additive summation of the two batteries capacities.

Ian

 

[autorouter]

I made the assumption, as I think other posters have, that a T125 had a 120/125Ah capacity.

I did the same a few weeks ago, that's how I know.

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