Troubleshooting

[Sunking]

One more thing to keep in mind. Batteries are limited in duration both by cycles and by years.

That will be the warranty period.

[PNjunction]

Hi Midrover - a few things which might save some gray hairs..

Those UPG UB8D's are general purpose agms, and as such I'd recommend lowering the CV absorb voltage to 28.8v minimum. You may also try just a tad lower than what you are running now, to no more than 29v. I'm assuming that temperature compensation, and slight variations in voltage sensing are just pushing your inverter over the edge.

You'll note that their cycling chart at the bottom shows that 28.8v CV would be an acceptable value. And, while we know that ocv is not the best indicator of health and life, for now we'll assume they are ok. If you are not pulling more than C/10, drop your LVD to 24.8v. We'll concentrate on your overall dod later..

Simple stuff to check - are you switching on the inverter FIRST, and then switching on the lighting? If you still have issues after turning on the inverter FIRST, have you tried bringing the lights up one at a time?

Which brings us to the battery bank itself ....

How much power are you running and for how long each day?

This will help determine if your bank is over-sized, and you end up "shallow cycling" the bank daily. While days of autonomy are a good thing, if your normal operations are shallow cycling (less than 10% of the total overall capacity), then a reduction in your bank size would be in order.

Normally an over-sized bank is a rare problem, but it does happen if the loads are relatively puny and the array is large.

Note too that you are into the big leagues now with those bad boys. Normally an agm needs a "commissioning charge", or extended CV before being placed into service. This would consist of about a 2-stage CC/CV charge of about 0.1C, to 28.8v and held there in CV for 12-24 hours, *especially* if you are running strings. Either that, or a WEEK or so on 27.6v float before placing into service. Keep an eye on it.

This is actually what should be done to smaller agm's, but most consumers and consumer chargers murder them prematurely, but I digress....

For more in depth info on what the more commercial side does, you may want to see the EXCELLENT docs from C&D Technologies in regards to agm charging.

[Midrover170]

Hi PNjunction -

That's the process I've been using for the inverter/lights. Inverter goes on first. The over-voltage light normally starts flashing when there's little, if any, load in the cabin. Midday stuff during the PWM cycle. On the batteries, the system and my use of it is still in its infancy. I've spent two days running power after the install. The max power being used at any time during that period was about 12 4w LED bulbs. We did fire up a vacuum just to see, and it worked fine. Soon I'll have a modem and router running continuously, but again, small stuff - probably about 12-15w. Eventually, more load will be added in the way of some small appliances and television.

The batteries did receive an AC charge, followed by a long float charge by the system before being put into service. So hopefully that was adequate. As you mentioned, I will probably throttle things back this weekend, having it top out at 29.0v during absorption instead of 29.2.

I'll take a look at the docs from C&D. Thanks for the recommendation.

[Midrover170]

Thanks, everyone. I am grateful for the help.