Kirkland battery question (amp hours)

[Canuck_in_NJ]

Hey everyone!

Will be picking up my battery monitor next week and I will have to enter how many amp hours my battery bank holds.

I have 2 Kirkland (Costco 6volts ) 2-GCS

The only real info on the battery states reserve capacity @ 75amps is 107. ( I assume the 107 is 107 minutes)

Is there a calculation I can do to find my actual amp hours?

Thanks

[Lwiddis]

“Can you teach a man to fish?”

I can’t but you all already assisted the OP who, IMO, needs to do some reading, internet searching etc. before asking questions.

[BFL13]

naturist wrote:

Canuck_in_NJ wrote:

Can you teach a man to fish?

Is there a calc to get it from the 75 amps? Is it usually listed with a 25/amp draw?

Love to, but the problem is that there is no calculation to get there from either of those datapoints.

Both the 75 and 25 figures are a function of "wire size" or rather terminal and buss-bar size while amp-hour capacity is a function of plate surface area, thus they are completely independent and unrelated variables.

RC is at 25 amps. EG, a battery with RC of 160 minutes has 66.6AH. (at the 25 amp rate--NOT the 20 hr rate)
(25 x 160 = 4000 amp- min or 66.6 AH)

Golf car batts use 75 amps as their rate, not 25. RC 107 is 133AH at the 75 amp rate. (not the 20 hr rate for AH)

The 75 and 25 are just the "rates" in amps like the 20 hr rate is in amps. Peukert calculation will get the AH to compare the 75 and 25 with the 20 hr rate.

The 20 hr rate for 208AH is 208/20 = 10.4 amps. Naturally the battery will go flat sooner with a 25 amp draw and much sooner with a 75 amp draw.

A 100AH battery has 5 amps as the 20 hr rate. But at 25 amps it will only do 2.7 hours

Going from either RC rate in minutes to AH at the 20 hr rate can be different with different battery brands and types because of different Peukert Factors among batteries.

It is all in this bible:
http://www.bestconverter.com/Books_c_67.html

[3_tons]

time2roll wrote:
I agree 208 is the realistic number.

X2, 208a/hr per 6volt battery, with a 208a/hr combined total when two are wired in series to arrive at 12v.

[naturist]

Canuck_in_NJ wrote:

Can you teach a man to fish?

Is there a calc to get it from the 75 amps? Is it usually listed with a 25/amp draw?

Love to, but the problem is that there is no calculation to get there from either of those datapoints.

Both the 75 and 25 figures are a function of "wire size" or rather terminal and buss-bar size while amp-hour capacity is a function of plate surface area, thus they are completely independent and unrelated variables.

[wa8yxm]

GC-2's are from about 210 to 230 but I agree 208 is a good answer. oVer time and with the use of a hydrometer you may "Fine tune" that but 208 is a good starting point.

[Canuck_in_NJ]

Thanks everyone

[BFL13]

https://www.usbattery.com/products/6-volt-batteries/us-1800-xc2/

[time2roll]

I agree 208 is the realistic number.

[Canuck_in_NJ]

grizzzman wrote:
208 AH is the easy answer.

Can you teach a man to fish?

Is there a calc to get it from the 75 amps? Is it usually listed with a 25/amp draw?

[grizzzman]

208 AH is the easy answer.