Interstate M-27HDC ah capacity

[GD-340RDS]

Can anyone shed some light on what the ah capacity for this interstate battery is? Ive seen some say you can device the CCA by 7.25 but that only gives you a general number (675/7.25=93.1). Its baffling that modern batteries are being sold without this information readily available, especially since this battery is advertised to boat and RV owners.


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-Bryan
2021 Grand Design Reflection 340RDS
2015 GMC Denali HD DWR
2004 Jayco Eagle 283RKS

[twinboat]

There is formula you can search for that Will calculate the RC minutes to AHs.

It works out to be about 1/2 the RC.

Close guess is 80 AH.

https://sciencing.com/how-8681870-co...amp-hours.html

[Mark_K5LXP]

Interesting, they show Ah for other models of marine batteries but not this one.

https://www.interstatebatteries.com/...ies/deep-cycle

The direct calculation is

RC=160, 25A for 2.667hrs. 66.675Ah at 25A rate.

Batteries deliver less Ah at rates greater than the 20 hour rate, so the actual Ah rating for this battery would be higher than 66.675. My guess would be closer to 75Ah. One way to get a closer guess would be to find specs on another group 27 marine battery with the same weight, since Ah and lbs of lead are closely tied.

Mark B.
Albuquerque, NM

[GD-340RDS]

thanks for the help, ill keep digging but for now ill go with 80ah