Two Problems

asteroids

(1) I have two 110AH AGM batteries in parallel. During late November the batteries dropped down to 10.3V for a few cycles. They don't seem to go into float mode anymore. Are these batteries pooched?

(2) I purchased two panels to add to my system. They appear to have run well when installed. About 5 days ago the panels produce voltage but very little current. What could be wrong?

My system is at a remote location so it might be a month before I can actually get to the site to inspect and test. Thanks for the help.

BB.

Re: Two Problems

The older the batteries are, the less likely they will bounce back from a 10.3 volt state of charge (basically zero state of charge). I would not trust them any more.

But, before you replace them, need to understand what is happening now.

Do you have a hydrometer and a DC Current Clamp Meter (something like this is only $60 from Sears)?

Basically, the system looks like this:

Solar array => Charge Controller => Battery bank

I could be a bad panel (not often, but does happen), bad wire connections, failed charge controller, or other issues (Battery bank is charged or nearly no capacity and appears to charge to 100% SOC in a few minutes or so--And the charge controller "thinks" the battery bank is full).

So, you need to look at voltage at various points in the system. What is the voltage at the battery terminals, at the output of the charge controller, at the solar panel input of the charge controller, etc...

You can also test for short circuit current of the panels (near noon, clear day, you should see >> Isc short circuit current), etc.

With a DC current clamp meter, you can measure the current from each panel (or string of panels) in the array. In general, the current in each string should be pretty close to its mate--If not, then look for bad connections, failed panel, etc.

You can also disconnect the panels and short circuit their output with a DMM (typically 10 amps maximum, double check meter against Isc from the panels so you don't damage meter). Voc (voltage open circuit should be pretty close to Voc spec'ed for the panels)...

It is possible, if the batteries are truly "dead" (less than ~10 volts), some charge controllers will not even "turn on".

Will you be able to post on the forum when you are there?

-Bill

westbranch

Re: Two Problems

Is your data in the OP from 24 Hr. telemetry or on site collection?

asteroids

Re: Two Problems

I have a Morningstar CC. The site is connected to the internet. I connect to the web interface on the Morningstar and look at live values and daily logs.

asteroids

Re: Two Problems

These are sealed AGM batteries, no way to check with hydrometer. They were purchased in last July. Some useful suggestions, I'll check the wiring and post back. Thanks.

westbranch

Re: Two Problems

Where is the system located? Do you get snow? have you cleaned the panels lately? Debris on them can cut output.

Sounds like there is a constant load on to have telemetry. What inverter are you using?

asteroids

Re: Two Problems

Bright and sunny Willcox AZ. No snow. The Inverter claims to be 1000W pure sine wave. I have my doubts.
http://reviews.canadiantire.ca/9045/0111892P/motomaster-motomaster-1000w-pure-sine-wave-inverter-w-remote-control-reviews/reviews.htm

westbranch

Re: Two Problems

What is the time line of this issue? Like how long did you run the inverter before connecting the solar to the batteries?
What was charging the batteries before solar? What are the panels specs?