Hello all,
I would like to add peak WBJR + amps to monitored data for any given 24hr period - so that I can confirm that my batteries are never charged to quickly.
Is this possible? Or does it already exist somewhere?
In the same vane but should likely be in a different post:
Is it possible to limit the max current output on the classics based not on total output but instead based on WBJR + input (while still leaving an overall max in place) - again, to protect the batteries while accounting for inverter loads? This is likely complicated by the fact that I have 2 classics.
Thanks,
Travis
Second question is yes - that feature was recently added to the Classic in a recent firmware. I will have to look and see where the instructions are for how to set that up.
Larry
Attached is setup for limiting charging amps for batteries while still having all available power for loads.
Larry
Why do you think your batteries might be getting charged too fast ?
Larry
Thanks Larry,
That will solve the problem. I have a max charging capacity from my arrays/classics of about 170 amps. I have oversized arrays to account for daytime power tool use for my home business. I don't expect to ever see 170 amps since the arrays are at different angles but it still concerns me that when I have perfect solar days and I am not otherwise using tools/loads it will be possible for the batteries to be charged at just about a 20% rate (856 Ah bank). I know that a 20% rate is within the safe range for my batteries - but just barely and I like margins of safety. - Same reason I have my inverters setup to shutdown when my batteries reach 50%. So, I will use the current limit document you provided to reduce my max charge rate to 130A and not worry about charging the batteries to quickly. I am running rev. 296, so I am going change the settings now:)
It is probably overkill but it will give me some peace of mind that my batteries will have a long life.
Thanks for your help Larry, I appreciate it,
Travis
That was a good new feature that was added after people on the forum asked for it .
Larry
With a normal sunrise and gradual ramp up of PV output, by 10:30am when the panels are really starting to crank, the battery voltage is often high enough that they won't accept the full 170A. Like when you hook a 40A car charger to a half charged battery and it only takes 30A.
What can cook the cells, is low battery, cloudy all morning, and then clearing right at solar noon. +150Amps baby!
Quote from: Mainewoods on February 06, 2017, 09:34:40 AM
...
(856 Ah bank). I know that a 20% rate is within the safe range for my batteries - but just barely and I like margins of safety. - Same reason I have my inverters setup to shutdown when my batteries reach 50%.
It is probably overkill but it will give me some peace of mind that my batteries will have a long life
50% discharged batteries before you shutdown inverters?
If you do that DOD too often then that long life may be elusive. Have you looked at the battery manufacturer's info and see what they say the life cycle count at various DODs is?
Shallower DOD usually means longer life 😀
Dgd
Larry, I got it setup the other day - no problems. Thank you again.
DGD, Correct, 50% discharge before the inverters shutdown - if I set it higher I am afraid that a heavy load will draw the battery voltage below the threshold and falsely trigger a shutdown. I am not too worried about it because I think this will be extremely infrequent. Its is a new system so I don't have alot of history but the lowest we have seen in the last two weeks was 22% discharged - this was with snow sitting on one of the arrays and while it was snowing for two days. Even on cloudy days I am up to 100 SOC by 10:30 or 11am unless I have heavy loads on the inverters. Rolls claims the batteries will go 1400 cycles at 50% DOD (see attachment), which based on the current limited data I don't think we will see in a 10 year period that I am hoping to get out of the batteries. What do you think?
Mike, I have been observing that too. It is amazing that the bank comes up so quickly in the morning - even without direct sunlight. It is easy to picture your scenario after watching the charge characteristics. - So, I am glad I got it setup to max at 130 amps.