Moby Dick

mobydick

I have just installed 4 solar panels that check out as 17.78 volts and 6.68 amps of output. Everything seems to work right except my sunforce 12v 10amp charger/controller. As the batteries (2-12volt deep cycle) get low the sunforce says it is charging. The digital readout says it goes up to about 12.5 volts and then the readout slowly leaks down to where my inverter alarm says low battery. The charger controller never charges back up. Can anyone tell me what may be wrong?
Moby Dick

RCinFLA

Re: Moby Dick

Sounds like bad batteries. How much was the inverter drawing?

Batteries should charge up to 14.3 vdc for a period of time. What do the batteries read after fully charged and let set disconnected for a few hours? Should be 12.7 vdc.

Put a known load on inverter and watch battery voltage to see how fast it drops.

Cariboocoot

Re: Moby Dick

I'm a little unclear on the details: Is the current from the panels 6 Amps each, or for all four?
The next question is the battery capacity. If this is two 100 Amp hour batteries being charged with 6 Amps of current you're not going to get very far.

There's definitely an imbalance here, because like RC says the charging Voltage should be over 14.

mobydick

Re: Moby Dick

Both of the 12v Batteries are brand new, just for this project. The 6.68 amps is for all four panels combined. How do I tell how much how much voltage the inverter is drawing. As you can see, I am really new at this. Would I be better off having my solar panels in parallel and drawing 1.6 amps and 19 volts than where I am now. Moby Dick

mobydick

Re: Moby Dick

P.S. I forgot to say that I have not completely charged the batteries as the charger/comverter starts leaking back when they get about 12.7 according to my charger. Should I try charging with a regular battery charger and letting them set? This would tell me what the full charge would be after setting..

Cariboocoot

Re: Moby Dick

Definitely give those batteries a good recharge from another source or they will be toast, if they aren't already.

I think you're a bit confused about panel wiring: putting them in parallel ups the Amperage (current). Putting them in series will increase the Voltage. I don't know what you're using for a charge controller, but if it isn't an MPPT type you can only connect your panels in parallel to charge a "12 Volt" system. 6-7 Amps isn't much; at best it could charge 120 Amp hours of battery.

I also don't understand what you mean by "the charger/converter starts leaking back". I think we need a few more details here to figure out what's going on. A basic system design goes like this:

Panels -> Charge Controller -> Batteries -> Inverter

The inverter will draw current (Amps) from the batteries as needed. The panels recharge the batteries via the controller as best they can. Getting the numbers for all the components to equate is the tricky part. You have to have enough inverter to supply your power requirements, enough battery to run the inverter under those load conditions, and enough panel/controller capacity to recharge the batteries in a reasonable amount of time.

mobydick

Re: Moby Dick

Thank you so much for the input. I need to digest what you have said and maybe redo all of my wiring. In the meantime I will charge both batteries and let them set as you suggested. I have a 12 amp charger that I charge my trolling motor with so I will use that. As soon as I do that I will come back to you and try to let you know just what is going on.
Thanks again.

mobydick

Re: Moby Dick

Alright, Cariboocoot, here goes. I charged one of the batteries overnight, let it stand for a while and it checks out at 13.10 amps. I left the other one hooked up to the system overnite and it did not leak down enough for the alarm to go off. I check the voltage on it and it was still 11.72. Evidently the system does not like to have the two batteries. I am going to try just one battery for a while and see if it works O.K. Just to let you know what I am using, here is a list of how I have my system arranged.
I have four panels, each with 36 cells at .5 volts and 1.7 amps each.
This checks out at 18.4 volts and 1.7 amps as I have them in series.
I have 2 of the panels hooked in parralel as a set and the other 2 I also have hooked in parralel. Then I hooked these two sets together in series so that I get the 17.7 volts and 6.7 amps down at a 20 amp circuit breaker. This goes to my Sunforce 12 volt - 10 amp Charger/Controller. From here I go to my battery bank of 2 (now just one) 12v deep cell marine battery. From the battery bank I go to my Bravo 200/400 watt inverter. From the inverter I go to a single recepticle that I have installed to run a couple of 13 watt lights, my computer moniter, my printer and my internet modem. So far I have only hooked up the two lights and my printer. They do not seem to drain my 2 battery bank if the 2 batteries are fully charged. I am only using about 70 watts of power so far.
Well that is it. Tell me if you think it will work or any suggestions as to how I can improve it. As I told you earlier, I am very new to this and open to any suggestions I can get. Thanks for being patient with me and asking questions. This makes me think and I learn so much more than just reading out of a book.
Moby Dick

mike95490

Re: Moby Dick

I'm suspicious of the Sunforce . While sun is out, try connecting the PV directly to the battery, and monitor with a volt meter , stop at 14.5V, and then install the sunforce, and see what it does.

mobydick

Re: Moby Dick

Thanks for the suggestion. I had the same suspicion so I ordered a Morningstar 15 amp Charger/Controller. When it gets here I will install it and let you know what the results are. Thanks again for all you have suggested. It has helped me a lot.
Moby Dick

Cariboocoot

Re: Moby Dick

Okay I'm just going to do a little editing here and see if we can get all the data right. I'll use Niel's famous "my comments in bold" to highlight changes

mobydick wrote: »

Alright, Cariboocoot, here goes. I charged one of the batteries overnight, let it stand for a while and it checks out at 13.10 amps. I think you mean 13.1 Volts I left the other one hooked up to the system overnite and it did not leak down enough for the alarm to go off. I check the voltage on it and it was still 11.72. Evidently the system does not like to have the two batteries. I am going to try just one battery for a while and see if it works O.K. Just to let you know what I am using, here is a list of how I have my system arranged.
I have four panels, each with 36 cells at .5 volts and 1.7 amps each.
This checks out at 18.4 volts and 1.7 amps as I have them in series. Homemade panels?
I have 2 of the panels hooked in parralel as a set and the other 2 I also have hooked in parralel. Then I hooked these two sets together in series so that I get the 17.7 volts and 6.7 amps down at a 20 amp circuit breaker. This goes to my Sunforce 12 volt - 10 amp Charger/Controller.

Is this your charge controller?: http://www.leegraphics.com/~sunforce/product_details.php?PRODUCT_ID=152 If so, it is not MPPT and can not take two 18 Volt panels connected in series, which would be 36 Volts. It may now be damaged.

From here I go to my battery bank of 2 (now just one) 12v deep cell marine battery.

Usually these batteries are 100 Amp hours each, and 6 Amps won't do much towards charging two in parallel. There could also be trouble with the way you wire the batteries together. You may not be getting good current flow through both batteries, but that's probably not the chief problem.

From the battery bank I go to my Bravo 200/400 watt inverter. From the inverter I go to a single recepticle that I have installed to run a couple of 13 watt lights, my computer moniter, my printer and my internet modem. So far I have only hooked up the two lights and my printer. They do not seem to drain my 2 battery bank if the 2 batteries are fully charged. I am only using about 70 watts of power so far.
Well that is it. Tell me if you think it will work or any suggestions as to how I can improve it. As I told you earlier, I am very new to this and open to any suggestions I can get. Thanks for being patient with me and asking questions. This makes me think and I learn so much more than just reading out of a book.
Moby Dick

mobydick

Re: Moby Dick

Yes, I did mean Volts. Yes they are home made panels. Yes that is the charger/controller that I have. This is the exact charger/controller that the instructions from "Power 4 Home" gave me to get. It is also on the u-tube instructional video for "Power 4 Home" . Why in the world would they give me wrong information? Boy are you good ! !
Moby Dick

mikeo

Re: Moby Dick

Yes they are home made panels. Yes that is the charger/controller that I have

You will need to wire the 4 panels in parallel for 17 volts at 6.8 amps. Your VOC on these panels are the 18.4 volts, your Vmp will more then likely be around 17 volts or so for 115 watts worth of solar. This will maintain about 60 to 100 amp hours of battery, any more and you will be deficit charging and will ruin them quickly.

mobydick

Re: Moby Dick

Well I have problems. It rained last night and some how I got moisture inside my panels. I had to take them apart dry them out and when I put them together this time I did not hold back on the sealant. I guess I was being to frugal and in a hurry when I put them together the first time. They are now sealed right.
Now I have a couple of questions. In an earlier response you mentioned VOC and VMP. Being a beginner I have no idea what these are. I get the drift of what you are saying but not the exact meaning. Would you be so kind and explain what those two things are.
By the way, I did get one of the panels hooked back up and it is drawing
17.79 volts and 1.5 amps by itself. I would have hooked the other 3 up but being a 78 year old man, I WORE OUT. I will finish up tomorrow and let you know the results.
I have been using just one of the batteries and it has supplied about 65 watts off and on for about 12 hours and is still not below the 12 volt level. Both batteries charged up and held their charge real well so both of my batteries seem to be good.
Thanks again for all of your help.
Moby Dick

mikeo

Re: Moby Dick

In an earlier response you mentioned VOC and VMP. Being a beginner I have no idea what these are. I get the drift of what you are saying but not the exact meaning. Would you be so kind and explain what those two things are.

Hi Voc is the open circuit voltage from your panels with no load. If you hook a voltmeter across the panel leads in strong sunlight, what you are reading is the panels Voc. The Vmp is the loaded voltage where voltage and amps are both at their max. Since photovoltaic panels are current sources, the current dosen't vary much in good light, while the voltage varies more with intensity. Isc is the short circuit amperage that your panels can put out if you put an ampmeter across the panel terminals. Your Imp (current at max power will be somewhat but not much less the the Isc. IHTH

Cariboocoot

Re: Moby Dick

mobydick wrote: »

Well I have problems. It rained last night and some how I got moisture inside my panels. I had to take them apart dry them out and when I put them together this time I did not hold back on the sealant. I guess I was being to frugal and in a hurry when I put them together the first time. They are now sealed right.
Now I have a couple of questions. In an earlier response you mentioned VOC and VMP. Being a beginner I have no idea what these are. I get the drift of what you are saying but not the exact meaning. Would you be so kind and explain what those two things are.

Let's see ... we have a glossary of terms around here somewhere ... Oh yes! http://forum.solar-electric.com/showthread.php?t=6136
Gosh, that's clever! (Inside joke)

By the way, I did get one of the panels hooked back up and it is drawing
17.79 volts and 1.5 amps by itself.

Actually you mean "putting out" not "drawing". It's amazing how easy it is to get terms reversed!

I would have hooked the other 3 up but being a 78 year old man, I WORE OUT. I will finish up tomorrow and let you know the results.

Oh yeah, I know what you mean! I can get worn out doing up my laces, which is why I wear slip-ons!

I have been using just one of the batteries and it has supplied about 65 watts off and on for about 12 hours and is still not below the 12 volt level. Both batteries charged up and held their charge real well so both of my batteries seem to be good.
Thanks again for all of your help.
Moby Dick

It's important to keep both batteries charged. Even one not in use will slowly discharge over time, so keep an eye on it. In the meantime you can evaluate whether or not you really need both, and probably see first hand why more panel capacity is always good.

mobydick

Re: Moby Dick

Boy are you good. I understood everything you said, although I will probably forget it by morning and have to look it up again. As for the batteries, I will probably check all three and rotate the charging from one to the next unless the solar panels keep the one that they are hooked to up to the correct level.
You notice I said three batteries. I have a deep cycle marine battery that I use on a trolling motor of a small fishing boat. I figured that if I kept this charged, I could use it in a pinch. This way I will have one connected to the solar panels, one in reserve and my trolling motor battery as a back up.
Thanks again for answering to where even I can understand. Not every one can do that.

Moby Dick