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I have a pair of golf cart deep cycle batteries rated 6v @220ah. Connected in series for 12v 220ah.
I understand according to the rating they should carry a 11ah load for 20 hours from 12.8v full charge to about 10.5v stone cold dead.
I would never run my batteries to flat dead 10.5 volts but I might to 11.5 if really needed and I've been doing some testing the past few evenings regarding capacity and load.
This is my experience:
I can begin with a full battery reading 12.8v and connect these devices:
a. A 1100w modified SW PowerBright converter @ ~90% efficiency
b. A desktop computer drawing 0.84ah
c. A monitor drawing 0.89ah
Total 1.73ah not including the inverter.
These run for about 3hrs until I shut them off when the battery reads 11.5v. I mean to say that I shut it off while loaded (Items running) @ 11.5v. After the load is removed the voltage bounces back into the low 12's.
The load of the devices was determined using a new Kill-A-Watt meter. I just need to know if that 3 hrs is normal (or not) given the load.
My system will power a few CFL yard lights at night when put to its intended use so the load will be less. Right now I am trying to get a bearing or feel to how much power 220ah actually is in practical use.
Also, I was wondering what kind of hydrometer people here use.
I've tried two automotive style battery hydrometers. The first one was this model:
It read both my known good fully charged vehicle batteries and both solar batteries as flat dead. I returned it and got an eyedropper type with the floating balls.
The floating ball eyedropper shows every cell fully charged when the voltage is only 11.8 volts. The balls are colored but neither the printing on the eyedropper nor the packaging indicate how to determine the actual electrolyte weight and the temperature compensation simply say "All temperature readings".
But it does say in big letters "MADE IN CHINA"
So what do you use? Do you bother even testing the electrolyte weight or just keep a proper physical water level?
I understand according to the rating they should carry a 11ah load for 20 hours from 12.8v full charge to about 10.5v stone cold dead.
I would never run my batteries to flat dead 10.5 volts but I might to 11.5 if really needed and I've been doing some testing the past few evenings regarding capacity and load.
This is my experience:
I can begin with a full battery reading 12.8v and connect these devices:
a. A 1100w modified SW PowerBright converter @ ~90% efficiency
b. A desktop computer drawing 0.84ah
c. A monitor drawing 0.89ah
Total 1.73ah not including the inverter.
These run for about 3hrs until I shut them off when the battery reads 11.5v. I mean to say that I shut it off while loaded (Items running) @ 11.5v. After the load is removed the voltage bounces back into the low 12's.
The load of the devices was determined using a new Kill-A-Watt meter. I just need to know if that 3 hrs is normal (or not) given the load.
My system will power a few CFL yard lights at night when put to its intended use so the load will be less. Right now I am trying to get a bearing or feel to how much power 220ah actually is in practical use.
Also, I was wondering what kind of hydrometer people here use.
I've tried two automotive style battery hydrometers. The first one was this model:
It read both my known good fully charged vehicle batteries and both solar batteries as flat dead. I returned it and got an eyedropper type with the floating balls.
The floating ball eyedropper shows every cell fully charged when the voltage is only 11.8 volts. The balls are colored but neither the printing on the eyedropper nor the packaging indicate how to determine the actual electrolyte weight and the temperature compensation simply say "All temperature readings".
But it does say in big letters "MADE IN CHINA"
So what do you use? Do you bother even testing the electrolyte weight or just keep a proper physical water level?
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