|12-31-10, 04:16 PM||#1|
Join Date: Feb 2009
Location: Woburn, MA
Thanked 245 Times in 225 Posts
Solar Back-Up power project
I tested the new inverter yesterday, after checking out the guts..
Hooked it up to the 48V bank and ran it while charger was running. It came with some short cables.
In the evening, when there was no more solar, I decided to run the bank down a little bit,
and test the inverter at the same time.
I ran the inverter for about 6 hours, using incandescent bulbs as loads.
Using 200 to 300 watts, while watching the bank voltage closely.
Under load, (at 14:30) the bank started at off at 50.7 volts. (12.675 per battery).
My target voltage was 49.5v, (12.375v per) which we hit at 20:30.
I think that 12.375 is about 70 to 80% of a full charge. (See chart below).
This morning started off real hazy and got better around 10AM.
A little after lunch, the TS-45 charger & 500w of tracker PV
had re-charged the bank to the tune of about 21.6 amp hours.
This afternoon, I tested the inverter with a computer and CRT and they worked fine.
At the end of the day, I checked the battery under load and it was
52.0v (13v per).
I think this higher voltage is due to the temperature compensation function.
Which increases the voltage slightly during the different charge modes.
It's under 55 deg F in my basement..
I never saw the charge state go into 'Float' mode, but the charge current
dropped from 7A (Bulk mode) in the morning, down to 2A at 13:00 (Absorption mode).
But, So far, I'm pleased with performance of the charger and PV.
I might have to adjust the temperature compensation off-set,
after I take some more under-load voltage readings tonight.
This chart shows how different loads affect the voltage during discharge. I was using around 4 amps.