URGENT! Who is right on battery re-charge question?

CBear42

Re: URGENT! Who is right on battery re-charge question?

Actually, the system is about six weeks old now... :-(

There IS a remote heat sensor attached to one battery. The jerk left the battery sensor for the charge controller sitting in the bag on the shelf under it. The jerk told me it "wasn't necessary".

So - I have a question.

Should I be running the generator for two hours each day until I get the voltage drop resolved? To try and keep the batteries charged closer to 95%-100%? (Since running smalll runs isn't helping and could be hurting the set?

CBear

CBear42

Re: URGENT! Who is right on battery re-charge question?

I received this from Morningstar Corp this morning after they reviewed the log file I sent them:

"There are several possibilities regarding the panels. They could just be bad panels. Partial shading and improper angling of the array. Loose or poorly terminated wiring. Bad diodes in the panels. Unfortunately, I am not able to say which those possibilities is indeed the issue, but I would start with the easiest fix first; the wiring. Then have someone check blocking diodes. If neither of those two issues are the cause, move on to the array positioning. I would also look into making use of the older panels you have. Any additional charge current to the batteries would be beneficial.

25.3 V really isn't all that low for a 24V battery. The average resting voltage for a fully charged 12V battery is 12.7V. Double that for a 24V system and you end up with 25.4V. The issue is seeing the immediately drop to that voltage after your charger is shut off. It normally would be a gradual decline in voltage over the course of a few minutes, but keep in mind that all batteries are different.

Your biggest concern at this point should be the fact that even after a few hours on the charger, the MPPT is not able to bring the batteries up to FLOAT(at minimum). And again, this is due to extremely low solar input."

He, of course, is seeing this from the "charge controller" perspective...

I am going to re-ask this again (it was sort of buried in an earlier response).

Given that I don't know what is causing this drop - and we know that batteries MUST be kept as close to charge as possible - should I run my generator for two hours a day as a precautionary measure to prevent deep discharge? After my two hour run yesterday - this morning it is sitting at: 24.9...since the light is coming up it has moved from 24.4 to 24.9 in the space of an hour...

Thanks SO much everyone! You're are an awesome resource!

CBear

Cariboocoot

Re: URGENT! Who is right on battery re-charge question?

CBear;

Run the generator. Charge the batteries. They're being brought up to the right Voltage, but not being held there long enough to get a full Absorb cycle. If you can use the gen to do the Bulk charging the panels should take them to Float. This is the big advantage in being able to measure specific gravity; you can really tell the state of charge. Voltage alone is not the whole story.

CBear42

Re: URGENT! Who is right on battery re-charge question?

Thanks for your reply. I will do this...

I also spoke to NABCEP again this morning. The installer called me last night and proclaimed everyone else "wrong" and that he was NABCEP-certified. I called them again this morning - just to be sure that they hadn't "found" him in their records in the interval. According to NABCEP - he is NOT certified. So - another question is --- I have been calling him "the installer". Are we allowed to name names in this forum? I don't want to malign any innocent parties - but I really want to make sure that no one else in this region goes through this experience...

Thanks,

CBear

Cariboocoot

Re: URGENT! Who is right on battery re-charge question?

Probably best not to name him. There have been a few incidents in the past here that got rather heated with public exposé of bad companies. It's probably not relevant to most as it would be a local issue. If you have any recourse there you should pursue it; bad installers like that hurt the reputation of good ones. There are several on the forum and not one of them would think of walking away from a system without it working as it should.

However if anyone in your area wants to know who it is there's no rule against disclosing that information.

kellylipp

Re: URGENT! Who is right on battery re-charge question?

Perhaps a complete diagram of your system would help all of us. Manufacturer and part number of the panels you have. If you are not getting enough voltage/current from the panels to the charge controller it's either the panels don't have a large enough voltage rating (unlikely) or the wiring between them and the CC is inadequate (likely). How many panels and how are they wired? Series, parallel and wire sizes to the junction box and on to the charge controller. You will be up there wiggling wires you might as well diagram this too.

I don't know official policy but letting the world know about the shysters can't hurt, can it?

Kelly

westbranch

Re: URGENT! Who is right on battery re-charge question?

the panels maybe.... but not as likely as the wiring, particularly the connections, if there are any crimps recrimp them, retorque ALL bolts etc.

hth

BB.

Re: URGENT! Who is right on battery re-charge question?

Start with the solar array... How is it wired (series/parallel, any fuses/breakers/extra hardware)?

If you have paralleled panels, get a DC Current Clamp type DMM (here is one that is "good enough" for ~$60 from Sears).

Play with the DC current clamp a bit first on your car battery (head lights on/off, car running/not, etc.). The "Zero" button is a bit of confusion. With no current flowing (or clamp removed from wires), push the Zero Button and you should see a ZERO displayed on the LCD and read close to 0.0 Amps. Now connect the meter to the wiring (note +/- sign--With DC, the meter will show the direction of current flow).

After a few minutes, the zero will "drift" and you may need to disconnect the current clamp, push the zero button twice to get 0.0 amps again, then continue your measurements.

You can go through each section of your off grid power system and verify connections are good/etc... (best to do they current measurements under heavy charging and/or heavy loads).

If, for example, you have 2 panels in series, then those two strings in parallel--You can clip the DC current meter on each string and see if both are sharing current or if one is supplying current and the other is not. Also, at this time, check the voltage at the charge controller solar input (and/or combiner box, if there is one). The current/voltage readings on the array (vs how it is wired) is the first place to look. Also, if you can, estimate the length of wire run and wire awg (should be marked on the wire insulation--if you can see it).

-Bill

Photowhit

Re: URGENT! Who is right on battery re-charge question?

search, Rec 215pe, add pdf for information sheets. Lots of info from competing sites.