Solar not charging starting batteries.

saline · 10-31-2012, 11:25 AM

On a recent trip I went to start my SMB in the morning and it hesitated. During cranking the voltage on the ScanGauge read as low as 8.8volts. It was only reading 12 volts before startup. The thing is, my house battery was reading 13.2v. I had thought that my starting and house batteries were always around the same level with the solar and battery separator. Has my separator gone tits up? Also, any of you with a Scangauge notice a fluctuation of your voltage while driving. Any help is appreciated.

**daveb** · 10-31-2012, 12:28 PM

If your starting battery side is lower than 12.8 (or around that) the seperator will not close and charge via solar. If (on the surepower) you pull the ground wire on the separator it will keep it from operating and you can test the starting batteries by cranking over the engine and testing voltage at a power port on the dash (or scangauge). With the engine running you should be able to tap the separator's ground and hear it open and close if the alternator is putting out. Sometimes the separators stick open or closed. You can also jumper the separator with a fairly heavy wire to see if the house battery voltage brings up the voltage at the dash. The surepower does have a delay to keep from chattering but you should here it work if a charge of 13.2V or higher is being applied to either side of it. SMB once had them rigged to always assist start, then hooked up the assist function to a push button switch.

A bad cell is enough to pull the starting system down enough to keep the separator open. With my van I noticed the inverter was pumping unusually high amps into the starting system but the separator was working correctly.

saline · 10-31-2012, 01:01 PM

Thanks for the info. I'm good with mechanical, not so much with electrical.

Here is what I have found out with mine just now:

Not running: House 13.4v Starting 12.0v
Pulled the ground on the Surepower heard the "click" House battery begins to go up to 14.5v then reaches "charge" on the solar controller. (It does this cycle over and over) Starting battery has no change on voltage.

Running: House: 14.2v Starting 13v after dropping to 8.8v on startup.

Plugged in to 110v House 14.4v Starting 14.2v

So if plugged in to 110v the starting batteries are being charged but when not plugged in the solar is not charging the starting batteries. Any more input??

Thanks,
Josh

saline · 10-31-2012, 01:07 PM

Edit to add: The inverter is cranking out pretty good right now. I assume it's charging the starting batteries. I pull the ground wire from the Surepower and the inverter stops cranking so hard and the Scangauge drops back to 12v.

Bad starting batteries?

But still doesn't explain why the starting batteries aren't being charged by the solar...

Ford_6L_E350 · 10-31-2012, 02:05 PM

I once had a problem with my Surepower separator. Everything looked good, all connections tight, but it would not charge across the thing. I could hear it 'click' when the house side was charging, but it would not charge the starting batteries.

When I pulled the connections off I found a little bit of corrosion was stopping the electrical connection. I carefully wire brushed the contacts, coated them with a liberal coat of grease and put it back together. Then everything worked as intended.

The grease (almost any grease will do, I use a synthetic grease) stops the air from getting to the metals and thus it stops corrosion from starting. I use it on battery terminals and any electrical connection that is exposed to moisture.

Mike

Scalf77 · 10-31-2012, 02:20 PM

Josh,
if your starting battery is bad, all the current that the solar can supply would be going to the bad battery. This would not keep the house battery above 12.8 volts and thus the surepower would disconnect. There is about a 5 sec connect debounce circuit. This means the separator will remain connected a minimal of 5 seconds once connected. There is also a 7 sec disconnect debounce circuit, this means once it disconnects it will stay off for at least 7 seconds. This could explain part of your cycling. When the surepower disconnects the solar brings the voltage up. upon connecting again the bad battery brings the voltage down and disconnects the Surepower. A lot would depend on how much charge you are getting out of your solar controller. It takes about 1.5 amps to keep the Surepower closed, so just low solar output could give you the same cycling issue.

I expect the charger is pumping out a lot more current then your solar can, and thus it keeps the voltage high enough to keep the surepower connected. I would get your starter(s) checked, also I expect the starter or one of them was probabbly getting warm when you had the charger going. I hope this helps. Feel free to PM if you have any other questions.

-greg

**daveb** · 10-31-2012, 03:45 PM

What you did seems to point to a bad battery. I agree with Greg...sounds like one battery has a shorted cell. Find someone with a load tester and test each battery on its own. Make sure they test the battery completely disconnected. It don't hurt to check the connections but my bet is on the starting battery(s)
Solar just can't put out what a shorted battery pulls. It's like trying to fill a tank with a garden hose when the tank has a 1-1/2" hole it it. The inverter is more like a pump that can supply a good steady flow out of a 3" line. The result is a lot of current flow which shows as heat in the bad battery. Soon the battery will boil.
If I see a higher than normal amp flow during a charging session and it doesn't taper off, I start looking for trouble.

If you find one battery bad replace them both. If you don't, the now good older ones life might run out before the new one and ruin them both down the road.

Good luck Josh
[edit] I was loosing a starting battery about every 2 years. I finally switch over to AGM starting batteries and have had good luck since 09. I just think an AGM can handle a continous charge better than flooded sealed batteries. My inverter and solar controller are both set to charge AGM batteries not flooded batteries and it seemed to make sense to install AGM's because of that alone.

saline · 10-31-2012, 04:36 PM

Thanks a bunch fellas!! I appreciate you taking the time to help me out. I left the van plugged into 110 just to see what the batteries would read after a while. I went out about an hour later and smelled a sulphur smell and one battery was hotter than the other (sound familiar). I dropped both batteries and took them into Batteries Plus. They are going to charge them overnight (that one won't last long) and load test them both in the morning.

Now to figure out why the solar won't keep my AGM house battery up to 14.4v (the charge set point on the controller) and keep it there or why the voltage drops off so quickly after the sun goes down. It's a newer AGM 4d.

Baby steps...

Thanks again!

**daveb** · 10-31-2012, 05:46 PM

Well 12.8 is considered a full state of charge. Above that is only a float level. But yeah, if the solar is putting out and nothings on in the van, by mid day you should be seeing about 14.2 when the batteries are in a float state. At night the battery can slowly return to it full saturation point of around 13V. If it's dropping below 12.8 by morning either something is on in the van or the battery's full state of charge has been reduced (damaged).

After you take care of the bad starting battery I wouldn't be surprised if things return to normal.

saline · 10-31-2012, 06:56 PM

It sounds like i've had a bad starting battery for a while now and not getting a full charge on the house battery as a result. I just checked the house battery since it's dark out right now and it's 12.8, with no starting batteries in the van at all. That's higher voltage than I have had in a while.

You guys rock!