House battery charging?

TraceyAZ · 05-08-2012, 11:40 AM

I did go through ALL the other threads in the sticky, but did not seem to find what Im looking for.
It seems my house battery is not charging via the isolator from the alt. I have good power coming to it 14 plus volts. But it is not coming out the other side. Over there I have 10. 18 volts.
How do I test the isolator itself?
For what its worth I might actually have two problems. My house battery is very old. It is the original put in it from SMB in 2005. I can get it to charge from shore power but as soon as I unhook from there the battery will quickly drop back down to about 10.08 volts.
Even with a dead house battery It (isolator) should still show as charging while the van is running?
Connections all look real good. Where do I go from here?
Thank you.
TraceyAZ

Forgot to add that while on shore power charging, the isolator does have power coming in and going out.

Do I simply have a bad house battery causing this?

Further testing I have done is now is telling me it is charging as it should??? Both during running the engine and on shore power. What is going on? I sure wish I understood this stuff a bit better.
There is suppossed to be a 50 amp circut breaker acording to my smb info. Ive found the one that is under the rear bench seat, the 40 amp one. (50 floor plan) but I can't seem to locate the other 50 amp one. Could this be a possible faulty piece? The one under the rear bench does not seem to be getting tripped, and the 50 amp one is an auto reset one.

Viejo · 05-08-2012, 02:16 PM

You defiantly have a dead house battery.
Is that the only problem? - I can't say, but I'd give even money that it is.
Replace it and go from there.

TraceyAZ · 05-08-2012, 02:32 PM

Quote:

Originally Posted by Viejo

You defiantly have a dead house battery.
Is that the only problem? - I can't say, but I'd give even money that it is.
Replace it and go from there.

Considering the house battery is 7 years old I think that is the root of the issues. I seem to recall that systems like these will throw fits if you can't get the house battery to take a charge and keep it. It had to do with the house battery being so dead that it would interfer with the electronic workings of the isolators?

Thank you Viejo.

**daveb** · 05-08-2012, 04:06 PM

That's a pretty old battery. I'm assuming you have a 210A AGM battery and a surepower separator. If the house battery drags the charge voltage down below 12.8, the separator will open up. But that would mean the battery in almost in a shorted out mode and it might not be wise to try to charge it in the van. On the other hand if the battery just needs a good solid charge but the separator won't close keeping the battery from receiving a charge, you should single out the battery and put a good charge to it by itself. Then see if it will hold the charge. If the battery off gasses or gets hot, stop the charge right away.

I agree that you probably just have a bad battery but the surepower separator have been known to stick open. With the engine running and charging, the separator should close and you should see the voltage rise above 10.8 volts to around 13-14vDC. If you pull the black ground wire from the separator when the engine is running, you should be able to hear the separator click open and close when tapping the black wire back to the ground block where it was connected. If the contacts in the separator are corroded, you might have to replace it. I prefer the blue sea 7622 but it’s your choice. If the separator is failing, you’ll know when you install a new battery…it will also go dead.
Do some testing first.

TraceyAZ · 05-08-2012, 04:32 PM

daveb,
It is a surepower 1315 when I start the engine, it is now clicking on and the volts jump up to that of charging. Before when the battery was very very low (10 volts) it seemed like it would not let the surepower open up and start charging.
It has been charging on shore power for about 5 hours today and when I unplug that the voltage starts to drop off very fast. Down to around 10.18 volts again.
Im still under the idea that the house battery has done gave up long ago.

Another question, how is it that some of the house lights stop working (the two pod lights and the outside porch light) when this voltage drops, but the floresent lights work along with the fridge? The van battery switch is on the aux. side.
Thanks
TraceyAZ

**daveb** · 05-08-2012, 04:43 PM

It sounds like the battery is shot.

Are you saying some stuff works when the shore power is off, the engine is not running, and the house battery is at 10v?

TraceyAZ · 05-08-2012, 05:49 PM

Quote:

Originally Posted by daveb

It sounds like the battery is shot.

Are you saying some stuff works when the shore power is off, the engine is not running, and the house battery is at 10v?

Yep.
I can understand the old style bulbs used in the lights that don't work, but why would the fridge work? Im not sure how much voltage the flouresent bulbs need.
Maybe the fridge is only cycling the fan and not the pump?

I did just double check charging via the alt. and it indeed is kicking on now and charging the house battery, but the house battey just won't come above 10.18 volts. Im going to guess that there is a bad cell or two on that old battery and because of that it will never come up and stay at a healthy voltage.
TraceyAZ

**daveb** · 05-08-2012, 07:05 PM

Are you sure that all the 12v stuff runs off the house battery. Maybe the PO had some items wired up to the starting system. A volt meter would tell you. Also you posted about a battery switch. What is that for? It doesn't switch some things to the starting batteries does it?

TraceyAZ · 05-08-2012, 07:25 PM

Quote:

Originally Posted by daveb

Are you sure that all the 12v stuff runs off the house battery. Maybe the PO had some items wired up to the starting system. A volt meter would tell you. Also you posted about a battery switch. What is that for? It doesn't switch some things to the starting batteries does it?

The switch I was talking about is the standard "extra battery radio" switch smb installs, so when you are parked camping you are not using your main starting batteries. There would be no way that the fridge would be able to run off the main start batteries for long and still be able to fire up my engine. I will double check using my multimeter tool but I suspect that there has been nothing changed from what smb installed.
My starting batteries have been holding very strong with 12.87 volts or better, engine off. Those have been very consistant.
Thanks daveb

**daveb** · 05-08-2012, 08:27 PM

I would avoid using the refrigerator with extremely low voltage. Even if it turns on more than likely it will not cool much. They run off AC and have inverters in to covert DC to AC I've been told. I don't know what voltage that low will do to the inverter inside the refrigerator. Mine runs fine around 11.5v but I notice mine ran on 9.5 volts when the shop let my batteries go too low once.

Dave