House battery not charging. Please help

[diver94]

Hi,
I need your help!
I am new to RVing. I recently bought a 1997 Gulf Stream Conquest. The house battery will not charge with the alternator or when plugged to 110v. However, my engine battery will charge Ok with the alternator.
I checked the power going into the battery isolator (and the terminal in the middle)and they both read 13 v (with the engine running). However, the cable that goes from the isolator to the house battery reads 11v (with the engine running).
It might be a bad isolator, but maybe there's a switch that I need to turn. Please let me have your thoughts.
Thanks!
Lui

[Murf2u]

No switch required, the relay is probably old and burnt a little causing resistance.

They're not expensive, any decent auto parts place will have them, it's just a 100 amp constant duty solenoid.


Edit: I just noticed (not enough coffee yet) that you said the house battery won't charge off shore power either. Are you sure the house battery isn't toast?

[diver94]

The battery is new.

So, the converter inside the house...When plugged to 110v, does it charge both batteries (engine and house) or just the house battery?

Maybe the power converter is bad too. I do hear the humming noise when I hook up to 110v and it gets a bit warm around that area.
Thanks for the assistance!

[diver94]

Im charging the house battery with a trickle charger. The battery is charging Ok, but there's no power going into the house. Im starting to think that it might also be a faulty connection (bad cable)....or a fuse!

[tompen]

OK, start with the first question. If you have a diode isolator and the engine is running you should have charging voltage from the alternator and to both batteries. If you are showing 11 volts to the coach batteries and the batteries are charged, something is goofy. The diodes are just one way valves. Power can go to the batteries from the alternator but power is prevented from going from battery to battery. Carefully disconnect the wire that is showing 11 volts , start the engine and see if the voltage is on the diode terminal or the wire to the convertor. If you have no voltage or 11 volts on the terminal with the engine running, and charging voltage (13.5-14.5) on the other terminals, you have a bad isolator. You should have coach battery voltage on the wire going to the convertor. If that is 11 volts and the battery is charged, there is high resistance somewhere. You may not have the ability to charge the chassis battery from the convertor. I would start with the other problem first and see where you are after that.
Tom

[diver94]

The solenoid is bad...I removed the cable and run the engine...0 volts coming out of the terminal that goes to the house battery (ill buy a new one).
Now, my other problem or concern is that the house battery (even thou is charging Ok when I use the battery charger or when I bypass the solenoid) its not powering the house at all (no light bulbs working).
So, im guessing that I have another problem (remember that the house battery will not charge when connected to 110v).
do you think it might be a blown fuse.
thanks again for your help!

[diver94]

I found the cable that comes from the power inverter to the house battery (it had a bad connection...a back plate was broken on the connector,,,See "before" picture).
I just bypassed the connector. Please let e know if that "bridge" was important
. The battery now charges when connected to 110v and powers the house when not.
thanks!

[tompen]

They don't usually put on unimportant things. I can't tell from the picture if that is a fuse, circuit breaker, or part of a relay. How was it mounted and can you show us the bottom. Good job on figuring things out.

[Murf2u]

That's a fuse to protect you from an electrical fire. It's VERY important.

You need to do a little investigating to see why it blew in the first place. If the condition still exists you need to correct it, FAST!

[diver94]

I don't think the fuse was blown It seems like the whole piece broke (when I put the new super-heavy marine grade battery, it seems like I clipped the fuse and the plastic cover) It was attached to a plastic piece on the frame of the chassis/next to the battery.

I will buy a replacement fuse (im not sure how to order it..or the name of that type of fuse).
I appreciate your help!

[diver94]

I am having a hard time finding that type of fuse.

Somebody, please let me know what type of fuse and the recommended amps.
The inverter/charger in my RV is rated at 5 amps. So, Im assuming that a 5 amp fuse might do it. But I don't think I can put ANY fuse there (a small wire might drop the current coming from the charger to the battery).
Thanks,

[tompen]

Look closely. They are usually marked. Your convertor/charger probably is capable of a minimum of 45 amps. Some are higher.

[diver94]

Tompen,
I think its called a straight mount circuit breaker. I will go back to the RV tomorrow to see if I can check the required amps.
Again, the 110v/12 v charger/inverter is a 5 amps charger. But you might be right, it might need a 50amp circuit breaker.
Thanks again!
Lui

[camaraderie]

I believe you could use something like this in safety once you've determined the amps you need in an ANL fuse. ANL Fuses & Kits - DonRowe.com