Achieving full charge with solar system
Here is a question for the learned solar system folks.. I have a Tracer 40 am MPPT charge controller and a Xantrex 20a smart charger. Currently, the Xantrex is across the batteries. I do have maste...
Forum Discussion
What are you considering 100% full?
Do you think that charging to the point that not one amp will go into the battery means that it is full? It will never really do that.
With 4 golf cart batteries, you could be charging at 14.4 volts at 10 amps, and just boiling away water from batteries that are completely full.
I never really liked charging by golf cart batteries to more than 13.8 volts. After reaching that voltage and amperage below 15 amps, the battery is very close to full, and just boiling a lot of water. When my 70 amp charger is charging at 45 + amps, the battery gets warm. I know that is not 'good' for them. Usually I would restrict amperage to less than 50% of my 70 amp capacity, both to keep the cooling fan off, and keep the battery cooler.
I have a E-Meter, and it carefully measures the amperage going out of the battery, and gives a reading like -120 AH when I have been running the TV a lot at night. Then I would run the generator for about 1/2 hour at breakfast, and shut it off. My 400 watt solar system could finish the charge by 5 pm.
Normally my e-meter reads about -10 amps say at 3 pm, and might read +10 to +15 amps when it is finished charging. This means that more than 15 amps went back into the battery bank, more than came out. This makes up for the in-efficiencies of the battery chemicals.
This place had some 140 watt panels for $229 each a few weeks ago. SunElec.com
Have fun camping!
Fred.
Do you think that charging to the point that not one amp will go into the battery means that it is full? It will never really do that.
With 4 golf cart batteries, you could be charging at 14.4 volts at 10 amps, and just boiling away water from batteries that are completely full.
I never really liked charging by golf cart batteries to more than 13.8 volts. After reaching that voltage and amperage below 15 amps, the battery is very close to full, and just boiling a lot of water. When my 70 amp charger is charging at 45 + amps, the battery gets warm. I know that is not 'good' for them. Usually I would restrict amperage to less than 50% of my 70 amp capacity, both to keep the cooling fan off, and keep the battery cooler.
I have a E-Meter, and it carefully measures the amperage going out of the battery, and gives a reading like -120 AH when I have been running the TV a lot at night. Then I would run the generator for about 1/2 hour at breakfast, and shut it off. My 400 watt solar system could finish the charge by 5 pm.
Normally my e-meter reads about -10 amps say at 3 pm, and might read +10 to +15 amps when it is finished charging. This means that more than 15 amps went back into the battery bank, more than came out. This makes up for the in-efficiencies of the battery chemicals.
This place had some 140 watt panels for $229 each a few weeks ago. SunElec.com
Have fun camping!
Fred.
