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Victron BMV-712 Smart - Lead Acid Battery Capacity??

HelotesAg

Active member
Has anyone gotten one of these? I got one this weekend and in the setup it wants to know what the capacity of my (stock) lead acid battery is. I have no idea how to figure out what the Amp Hours rating for the battery that came with the trailer is. It's a regular 12V lead acid battery and the only thing I can tell from reading the label is that it's a Contenental Battery, it's a model TM-24, it has 525 CCA, and RC (reserve capacity?) of 120. I've looked on the web for how to determine this battery's capacity but all I can find is formulas for how to figure out how many Amp Hours I need for the items that I want to power from my battery. Does anyone know how to figure out what the aH capacity for my battery is so that I put the correct setting in the Victron app?
 

Jim Beletti

Owner Experience Liaison
Staff member
Has anyone gotten one of these? I got one this weekend and in the setup it wants to know what the capacity of my (stock) lead acid battery is. I have no idea how to figure out what the Amp Hours rating for the battery that came with the trailer is. It's a regular 12V lead acid battery and the only thing I can tell from reading the label is that it's a Contenental Battery, it's a model TM-24, it has 525 CCA, and RC (reserve capacity?) of 120. I've looked on the web for how to determine this battery's capacity but all I can find is formulas for how to figure out how many Amp Hours I need for the items that I want to power from my battery. Does anyone know how to figure out what the aH capacity for my battery is so that I put the correct setting in the Victron app?
See if this is helpful in determining your settings: https://community.victronenergy.com/questions/9039/bmv-712-settings.html
 

HelotesAg

Active member
OK, thanks - I found those specs on the continental site as well, but I didn't know what "CAH 20HR" meant. Had no clue!

I found this where someone asked "What does 105ah@20hr mean for a battery?"

Amp hour capacities for lead-acid batteries are quoted at the 20 hour rate, or 1/20th of the capacity of the battery.
If you divide the Ah rating by 20hours then that is the constant draw at which you will achieve 105Ah of capacity.
So, if you had a steady load of 5.25A for 20 hours, your battery will provide all of the available 105Ah stated.
However, if you doubled the draw, to 10.5A, you would not get 105Ah out of the battery. If you halved the draw, you would get a few more Ah.

I guess I'll update the settings on the Victron from 200 to 88!

Thanks again!
 
OK, thanks - I found those specs on the continental site as well, but I didn't know what "CAH 20HR" meant. Had no clue!

I found this where someone asked "What does 105ah@20hr mean for a battery?"



I guess I'll update the settings on the Victron from 200 to 88!

Thanks again!
Glad to help.
I dont have the 712 but several other victron items. So i dont knw the terminology of your settings.
But you should also set the discharge floor to 50% (or 44 usable amps).
 
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