Forum Discussion
ktmrfs
Jul 13, 2014Explorer III
I have the 45a unit in two trailers. One has about 15ft of #4 wire to the battery on the positive side and about 2ft on the ground side to the frame. Charging 4 Trojan T-125's.
The other has about 4ft of #4 to the positive side and 2ft on the ground side. Charging two Trojan T-125's.
The first will give me a max of about 40A, the second will give me 45A. If the first was a pair of GC I suspect max current would be slightly lower.
Why the difference?? Cable resistance. PD doesn't have a voltage sense at the battery and in bulk mode charger output is 14.6V that could turn ito 14.4, 14.2 or lower at the battery terminals depending on cable resistance. And battery acceptance current is highly dependent on the voltage at the battery terminals. I get 60A for a long time with this combo, but it pretty much eats up all the output of a honda 2000.
So to answer your question. It depends.
a) cable voltage drop
b) what type and how many batteries your charging
c) how discharged the batteries are.
The other has about 4ft of #4 to the positive side and 2ft on the ground side. Charging two Trojan T-125's.
The first will give me a max of about 40A, the second will give me 45A. If the first was a pair of GC I suspect max current would be slightly lower.
Why the difference?? Cable resistance. PD doesn't have a voltage sense at the battery and in bulk mode charger output is 14.6V that could turn ito 14.4, 14.2 or lower at the battery terminals depending on cable resistance. And battery acceptance current is highly dependent on the voltage at the battery terminals. I get 60A for a long time with this combo, but it pretty much eats up all the output of a honda 2000.
So to answer your question. It depends.
a) cable voltage drop
b) what type and how many batteries your charging
c) how discharged the batteries are.
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