Batteries

ON EDIT: Thanks to all who posted below who corrected my "BAD MATH". Concept correct, math not so much. Rather than leave questions, I will edit to supply, as others have done the correct answer: 430 AH @ 12 VDC.



The 20 hour rate is the most common rating.

So, each of your batteries is 215 AH @ 6 VDC. So each pair wired in SERIES is 215 AH @ 12 VDC.

Both pairs together (your battery bank) is 430 AH @ 12 VDC.

The most commonly used rating is the 20 amp hour rating

"The amount of amp-hours (AH) a battery can deliver when discharged at a constant rate at 80°F (27°C) and maintain a voltage above 1.75 V/cell."

1.75 V/cell is past the typical amount you would discharge a battery to and, if done repeatedly, will shorten the life of the battery. For maximum life, do not discharge past 80% "state of charge" (SOC) which is 2.08V/cell. (12.48V for a 12V battery bank.)

Minutes at 25 amps (also referred to as Reserve Capacity) is another good reference, but not all manufactures publish this.

Yours are 215 amp-hours, typical for most 6V golf cart batteries. If they are wired 2 in series and then 2 in parallel, you have 430 amp hour @ 12V.

Duracell 225?

Try 208

Trojan T-105 are 220

wolfe10 wrote:
Both pairs together (your battery bank) is 550 AH @ 12 VDC.

-100

2oldman wrote:

wolfe10 wrote:
Both pairs together (your battery bank) is 550 AH @ 12 VDC.

-100

Some incorrect math in this thread.
-120
For a total of 430 AH @ 12VDC :B

"20 amp hour rate 215
5 amp hour rate 157
6 amp hour rate 156"

It's the 20 Hour rating is 215 amp hrs
Means it can supply 10 amps for 20hrs 45 mins
To reach 10.5v

The 5 hrs rate is 157 amp hrs
That is discharging at a rate roughly 30 amps load
3x the load for 1/4 the time period and less total capacity

mclainfarm wrote:
I have 4 6 volt Duracell batteries and trying to figure out the amp hour rating. The specs are
20 amp hour rate 215

That is the figure we use (more on that later)
you ahve 430 amp hours at 20 hour rate and 215 usable amp hours.
(That was easy)

Now if you draw at what is that. 10 amps it will last a bit over 21 hours but if you draw 20 amps. no they won't make it to 10.

IF you want to learn why I will provide a link or two

The first link

The Second link

wa8yxm wrote:
10 amps it will last a bit over 21 hours but if you draw 20 amps. no they won't make it to 10.

And we all know those rating are figuring a draw down to what.. something unusable that nobody should ever do?

450ah is essentially 225, in the real world.

mclainfarm wrote:
I have 4 6 volt Duracell batteries and trying to figure out the amp hour rating. The specs are
20 amp hour rate 215
5 amp hour rate 157
6 amp hour rate 156
Minutes at 25 amps 395
Minutes at 75 amps 105
Most batteries I read about state they are 100 amp hour batteries. What are mine? I’m trying to put together a solar system and need to know the size of my battery bank. Thanks for any help

If we put all the confusion aside you have a 430 AH battery bank with your four 6V batteries.

wolfe10 wrote:
The 20 hour rate is the most common rating.

So, each of your batteries is 225 AH @ 6 VDC. So each pair wired in SERIES is 225 AH @ 12 VDC.

Both pairs together (your battery bank) is 550 AH @ 12 VDC.

Yes, sorry for the bad math-- know RV's, math-- not so much.

CORRECTED:

So, each of your batteries is 215 AH @ 6 VDC. So each pair wired in SERIES is 215 AH @ 12 VDC.

Both pairs together (your battery bank) is 430 AH @ 12 VDC.