Help-- somebody smarter than me

[Bill1565]

I put in 4 new T-105's wired up into two pair. Read in the Ample Power primer that you need to run new batteries down 3 times before actually using them. Never read that anytime anywhere else, but I gave it a try. I get 200ish amp hours and 11.8 volts after 24+ hours at 5-10 amp draw. All cabin lights on, plus refer cycling 5 amps and off.

Total capacity S/B 450 AH. Do T-105's have a lower fully discharged voltage????

 

[Don S/V ILLusion]

The way you describe the voltage, it sounds like you are not measuring a resting voltage. It could be that the draw is actively showing an artificially low voltage. If you are reading 11.8 with some draw on the bank, that sounds pretty close to what in theory corresponds to a 50% reduction in capacity.

 

[Stu Jackson]

Um, do the math --- 24 hours for a fridge is 60 ah (50% duty cycle), 10 amps lights times 24 hours = 240 ah, total 300 ah maybe less with only 5 amps lights would be 180 ah, less than half the capacity of your 450 ah house bank. Ample says to draw them down to 10.5 with a low 5-10 amp load. Turn the fridge off and wait longer.

 

[timvg]

We have 4 T-105's. We just put them in and use them. They work great.

 

[Bill1565]

Thanks Stu. I missed the 10.5 volt low.

I'm good then with 200 AH at 11.8 v, didn't run stuff long enuff. BTW all my cabin lights is about 5 amps, ref on is 6 so I am drawing average 8 to get to 200AH in 24 hours.