Solar and batteries

[grizzlygiant]

Chris,
If you are really interested in knowing what is drawing down your battery you could pull each 12 v fuse and place your test meter across the empty fuse socket. With the meter on the amp scale you could read the current draw, if any, on each circuit. Of course a properly installed battery disconnect would disconnect all possible draws EXCEPT a bad cell(s) in your battery bank.

One possible draw that has not so-far been mentioned is a bad or missing diode in the solar system. The diode stops the battery from reversing current flow when the panel is dark.

 

[wyleyrabbit]

Gary,

So, all I need to do is pull the fuse, set my meter to "Amps", then (carefully) connect the meter probes to each side of where the fuse would plug in? That is incredible information! I will do this today.

I hadn't considered the possibility of a bad diode. So if this was the case, at night the panel array would suck power out of the batteries? Interesting. No idea how I'd test this.

Chris

 

[ibrick]

Found it, the one with the red key.

http://www.jcwhitney.com/COLE-HERSE...ES/GP_2006124_N_111+10207+600010098_10107.jcw

Even when standing outside by the basement I can hear its operation, when power is turned on I get a beep from the O2? sensor and a long drawn out dying beep when I shut the power down.

Hope it helps.

 

[grizzlygiant]

Gary,

So, all I need to do is pull the fuse, set my meter to "Amps", then (carefully) connect the meter probes to each side of where the fuse would plug in? That is incredible information! I will do this today.

I hadn't considered the possibility of a bad diode. So if this was the case, at night the panel array would suck power out of the batteries? Interesting. No idea how I'd test this.

Chris

Correct, re meter. you have to observe polarity; the + would go on the "hot" side if the fuse socket.

You can test for a bad diode using the same meter set on AMPS. Place the leads between the battery (+) and the positive end of the solar panel (which you have first disconnected from the battery). With sunlight on the panel you should see a charge +1 or 2 amps. Then blackout the panel and you should see zero. If the meter goes negative the diode is bad and the panel is sucking watts out of your battery.

 

[SmokeyBare]

Here are a couple types of good battery switches.

Perko is one brand... I'm sure there are others as well.

 

[boatto5er]

You can find those Perko switches at almost any Marine store (e.g. West Marine, Boater's World) or online in their catalogs. I used one of the dual battery models in my boat for years. Never had a problem with them.

 

[wyleyrabbit]

Hi everyone,

So, for amusement, today my son and I went to the farm where our trailer is stored armed with my trusty very cool digital volt meter. Following GrizzlyGiant's advice, I started pulling fuses. At first, I wasn't getting anywhere, and then I figured out that for amp measurements, I had to plug one of my leads into a different hole in the meter. Oops.

So, after putting the lead in the proper hole, I re-pulled the same fuses as before and actually started getting measurements from them. I forgot to write down what each of these fuse banks is for (and will post that info after our next visit to the trailer).

Here we go:

Bank 1: 0 draw, or 57 mA if antenna booster is on. (wow, very efficient!)
Bank 2: 0
Bank 3: 1.07 mA (This is labeled as "off-door side", but no idea what's using the power)
Bank 4: 0
Bank 5: 0
Bank 6: 18 mA
Bank 7: 0
Bank 8: 75 mA (this is the circuit that the propane detector feeds off of)
Bank 9: 0
Bank 10: 0
Bank 11: 0
Bank 12: 0
Bank 13: 0

So in all, our trailer was using 151.07 mA with the antenna booster on, or 94.07 mA with it off. Pretty minor, I think.

I pulled the trailer's positive wire off the battery, but left the solar regulator's wire on.

Batteries were at 12.4 volts today, and the graph on the regulator indicates we're at 60% charge.

I phoned the dealership today, and the first guy I talked with told me that 12.0 volts was a full charge, but I immediately said "No! Everything I've read indicates that a full charge is much higher than that" so he put me on to a more senior employee who promosed to do some tests on the batteries when I next bring it in for some warranty deficiencies.

Aside from a possible defective battery (or two) or perhaps a bad diode, is there anything else that might be contributing to my woes?

Chris

 

[jmgratz]

Generally speaking a 12 volt battery will read 12 volts or maybe slightly over when the battery is fully charged. That is if the battery has been disconnected from everything. When you have a charger connected to the battery you might get a reading of 13.4 or even 14.5 volts as the charger is putting more than 12 volts into the battery to charge it. It is my understanding a deep cycle battery (that is probably what you have in your RV) should only be charged to about 80-85 percent to keep it from becoming sufinated. That is when then plates become messed up. (not sure of the technical term) So your reading of 12.4 volts with the battery disconnected would indicate to me your battery is fully charged. Now how long it holds that charge is the big question. If you have a bad cell, it is possible to fully charge the battery but the battery will not keep the charge. So if you measure it right after disconnecting it you would read 12 volts and 5 minutes later (or less) it might read 8 volts without it being connected. Wal-Mart sells a cell checker for less that $5.00 that works pretty good. (I think I got that all correct...my head is swimming now from all that information LOL

 

[wyleyrabbit]

Jim,

Just had a peek on Walmart.com, but wasn't able to find anything that looks promising. Any idea what the brand might be for the battery checker?

The problem seems to be that the batteries charge up fairly quickly, but die equally fast. I'm beginning to think I might have a bad battery but I don't think I have the equipment to figure that out. If a battery has a problem, will it charge up quick but die equally fast?

Chris
"I'm learning more and more about stuff I had no idea about yesterday"

 

[Bob&Patty]

Chris, so far I agree with everyone that has posted. I just want you understand that all thing's that run by electricity uses amperage to work ( horse power) if you will. Yes voltage is part of it (OHM'S law). You have done all the right things to find the problem. One thing I might add to this. If the weather where you are is cold or very cold, that will effect charging rate and how long it will hold that charge. Sulfation was mentioned. When battery plates get old or the battery was charged low on water. The plates get flakey and fall apart. When the plates start to flake they fall against each other and cause that cell to short out. Thus you have a shorted or bad cell. A fully charged 12V battery should show about 12.8 to 13.2 volts. All batteries have amp hour ratings. The math is easy, 1 amp draw on a 600 amp battery will take 600 hours to drain the battery. BTW, an open cell (broken wire inside the battery case) can cause a generator on a car to run wild, no resistance. my2cts Bob

 

[wyleyrabbit]

Bob,

Great info...thanks.

I keep reading different things about battery voltages when fully charged, and have seen everything from 13.2 up to 14.3. I suppose the good thing is that it's not up to me at all and these systems are all pretty intelligent and automatic.

I also read that it's possible that while my truck did come factory wired for towing, it might not have the fuse installed that would enable the trailer batteries to charge. I'd be surprised, but I suppose I better check to be sure.

What an adventure.

Chris

 

[sailorand]

Wylie
Go out to Princess Auto and get a what you need. A Hydrometer will check each cell by specific gravity of the water. This is one of the best ways of checking a battery.
Even a cheap one will do the job

 

[jmgratz]

Jim
Just had a peek on Walmart.com, but wasn't able to find anything that looks promising. Any idea what the brand might be for the battery checker?

The problem seems to be that the batteries charge up fairly quickly, but die equally fast. I'm beginning to think I might have a bad battery but I don't think I have the equipment to figure that out. If a battery has a problem, will it charge up quick but die equally fast?

Chris
"I'm learning more and more about stuff I had no idea about yesterday"

The brand that I found at Wal-Mart was Haslyn brand battery tester. It is displayed in the same area where the battery chargers are. I don't know if you can find it online.

 

[jmgratz]

And again if your battery read 12.4 volts to 13.5 volts when disconnected it is probably fully charged but if the reading drops within a short period of time (5 minutes or less) you more than likely have a bad battery. This usually indicates a bad cell. Also you can take you battery out and take it to any reputable auto parts store, Western Auto, Sears Auto Center, or any other place that sells batteries and they can check the battery for you and tell you if the battery is defective.

 

[Bob&Patty]

Jim has a good idea. Take the battery and have it checked. They will put a load test on it and then you will now whats up. Just because a battery shows 12V's doesn't mean it will stand a load being put on it. If a battery falls below 9V's, its junk. Make sure you are there and watch them do the test. You should have a warrenty on the battery since your coach is new. You may have to take it back to the dealer, dont know for sure what brand it is. Remember the dealer installed the battery not Heartland. The battery could have been setting for a year before you got it. New doesn't always mean its good. Good luck. Bob

 

[jmgratz]

Yes, and I got two brand new batteries in a row from the Interstate distributor in Conroe Texas and one of them had one dead cell and the next one had 2 shorted cells. Just goes to show you ..

 

[Bob&Patty]

Jim, I really think that Chris has a bad battery. Hope he lets us know what happens. Bob

 

[Bob&Patty]

OOOPS, well I guess I should have read this all again. He has 2 6V battery's. I guess Chris is taking a reading across both battery's? If so, maybe just one is bad and is causing the excessive drain or lack of getting fully charged. He needs to take both battery to have them checked. He mentioned about the fuse not being installed to charge the batterys from the TV. Its my understanding, in the last few years they come installed from the factory, but maybe his is not or the fuse was blown by something. Chris you need to check this with a test light or volt meter at your trailer plug with the truck running. Bob

 

[jmgratz]

Another thing that could be happening is if you are using 2 or more batteries they need to be all the same age. If one is a new battery and one old the new battery will drain to fill up the old one.

 

[Terry H]

On the new Chevy/GMC the charge line to the trailer plug is in the loom that goes to the trailer plug. But, it is not connected to the under hood fuse block. Under the fuse block back towards the firewall you will find the lead with a round lug. Untape it and attach it to Lug #1 on the front of the fuse block.