6v or 12v?
All else being equal, which is preferable and why? 2 220 AH 6v batteries or 2 110 AH 12v batteries
Forum Discussion
Hi,
Batteries are designed around a 25 amp per cell discharge rate. When that is exceeded there may be excessive voltage drop. If the voltage falls enough, then the inverter may cut out, even though there is still lots of power to be had.
Example:
If you have a 220 amp-hour six volt jar in series with another, then you have a 220 amp-hour twelve volt battery with six cells. If a load of 50 amps is placed on it, then each cell must provide 50 amps. There may be lots of voltage drop.
If you have two 110 amp-hour twelve volt batteries wired in a balanced manner, then you have a 220 amp-hour capacity but with 12 cells. If a load of 50 amps is placed on it, then each cell only needs to provide 25 amps. There will be less voltage drop than in the six volt twins.
I often do 70 amps loads, so having 4 12 volt jars means the load per cell is 70/4 =17.5 amps per cell.
My microwave draws 156 amps. With 4 six volt jars each cell must do 78 amps, but with 4 twelve volt batteries it is 39 amps.
I hope this helps.
Batteries are designed around a 25 amp per cell discharge rate. When that is exceeded there may be excessive voltage drop. If the voltage falls enough, then the inverter may cut out, even though there is still lots of power to be had.
Example:
If you have a 220 amp-hour six volt jar in series with another, then you have a 220 amp-hour twelve volt battery with six cells. If a load of 50 amps is placed on it, then each cell must provide 50 amps. There may be lots of voltage drop.
If you have two 110 amp-hour twelve volt batteries wired in a balanced manner, then you have a 220 amp-hour capacity but with 12 cells. If a load of 50 amps is placed on it, then each cell only needs to provide 25 amps. There will be less voltage drop than in the six volt twins.
I often do 70 amps loads, so having 4 12 volt jars means the load per cell is 70/4 =17.5 amps per cell.
My microwave draws 156 amps. With 4 six volt jars each cell must do 78 amps, but with 4 twelve volt batteries it is 39 amps.
I hope this helps.
Freep wrote:pianotuna wrote:
It depends.
My own preference is 12 volt. I do that because I run a medium size 3000 watt inverter.
This is interesting. How does the inverter figure into this? At some point I'd like to add an inverter too. The hope is to one day be able to run the MW for a few minutes without running the gen.
