House battery connect 'cycling' on and off...

[smithbill]

'Tis the season for electrical problems it seems - based on recent posts.

Went out to the coach yesterday to run the genny and take the rig for a short (20 mile) run. The coach is stored under cover, on a sand/gravel pad. I have 2 small solar panels 20/25W with separate controllers to just 'float' both the house and the chassis battery while in storage.

I always use the internal panel to check the voltage on the house and chassis batteries before I even sit down in the pilot seat - they were fine... 13.5 house and 12.9 chassis.

Coach started up and moved no issue. Went to start the generator and it wouldn't start. Ultimately - I noticed that when I went to start the generator or drop the levelers, the light indicating the house battery connected (red light on = house batteries connected) was cycling on and off and from somewhere I could hear a mechanical whining sound. When it was doing this 'cycling' I went back to the panel and checked the house battery - it was also cycling between 0V and 13.5V. I checked the house batteries with a meter - they were solid 13.6.

I'm THINKING I have a bad connection (ground or power - probably ground) from the house batteries to either the ground - or first point of connection for the power. I am not afraid of electricity (trained as an electrical engineer so many years ago) but I like to work with drawings and diagrams which are probably nowhere to be found.

Any suggestions from the combined experience of the ages here? The coach is a 2003 Dolphin 6342 LX.

Arden

[Scooter]

Drawings and diagrams could be here...I have some for our '03, 6355LX. Alas, I am too inept to bring them up. Someone else will be able to do so. And...they might be helpful. Do a search.

[twinboat]

When I used to run into things like your experiencing, I would make it happen a few times and then start feeling the connections for heat.

That energy is going somewhere and it will be lost thru heat.

[smithbill]

Originally Posted by twinboat

When I used to run into things like your experiencing, I would make it happen a few times and then start feeling the connections for heat.

That energy is going somewhere and it will be lost thru heat.

Hmmm... that's not a bad approach. And with our cooler temps here in TX right now - that heat may be quicker found than on a hot summer day.

Thanks twinboat

[Injuneer]

One of the best accessories I have purchased for the motorhome is one of the less expensive FLIR cameras.
One can find them under $400, or even less if one uses the kind which docks to a smartphone.
By the way, I would wager the mechanical whirring you hear is the fantastic fan - if you have one, of course. They power up attempting to close the already-closed vent cover, so the motor runs for a bit until it sees the current draw increase from turning against an already closed vent cover.

[Home Builder]

Originally Posted by smithbill

'Tis the season for electrical problems it seems - based on recent posts.

Went out to the coach yesterday to run the genny and take the rig for a short (20 mile) run. The coach is stored under cover, on a sand/gravel pad. I have 2 small solar panels 20/25W with separate controllers to just 'float' both the house and the chassis battery while in storage.

I always use the internal panel to check the voltage on the house and chassis batteries before I even sit down in the pilot seat - they were fine... 13.5 house and 12.9 chassis.

Coach started up and moved no issue. Went to start the generator and it wouldn't start. Ultimately - I noticed that when I went to start the generator or drop the levelers, the light indicating the house battery connected (red light on = house batteries connected) was cycling on and off and from somewhere I could hear a mechanical whining sound. When it was doing this 'cycling' I went back to the panel and checked the house battery - it was also cycling between 0V and 13.5V. I checked the house batteries with a meter - they were solid 13.6.

I'm THINKING I have a bad connection (ground or power - probably ground) from the house batteries to either the ground - or first point of connection for the power. I am not afraid of electricity (trained as an electrical engineer so many years ago) but I like to work with drawings and diagrams which are probably nowhere to be found.

Any suggestions from the combined experience of the ages here? The coach is a 2003 Dolphin 6342 LX.

Arden

Check the ground wires to the chassis, and batteries, and the red wire that attaches to the starter. 2002 National #6355 towing 99 saturn sl2

[smithbill]

Thank you everyone for all for your suggestions and input. I also checked with my brother (automotive mechanic) who said it could well just be connection corrosion from lack of use.

I spent Monday and removed all the batteries from the tray and recognized corrosion build up on connections - but no significant material as I have seen on connections in the past. I scraped and wire-brushed the bay and tray and then repainted the whole thing since I was in there.

Putting it all back together - I sanded and wire-brushed all the connections, connectors and battery posts. Once back together... it all worked as expected.

I guess I just have to find a way to use that thing more than I do... sigh/

[Cpl Ed]

This may help: https://www.nrvclub.com/dolphin

[Julia2005]

The generator starts off the house batteries. Try connecting a volt meter to the house batteries and try and start the gen. see what voltage the batteries read when trying to start. If the voltage drops below 10 volts your batteries are bad.

[AnotherMike]

Originally Posted by Julia2005

The generator starts off the house batteries. Try connecting a volt meter to the house batteries and try and start the gen. see what voltage the batteries read when trying to start. If the voltage drops below 10 volts your batteries are bad.

I disagree. It's probably a bad / corroded connection between the genny starter and the battery. Might just be a battery ground cable.

A volt meter takes zero current to operate. You could have a corroded / bad connection between the battery and the genny control box or even to the genny starter that passes no current but passes full voltage but has a total loss of voltage when any real current flows.

So start with your volt meter from the battery to the chassis and see full voltage. Punch the genny starter and see full voltage at the battery.

Then move the voltmeter and measure from the genny control box to chassis and then have someone punch the start button. The from the genny starter to chassis and punch the button. When you find point where the voltage drops when your partner hits the genny start button then you've found the problem... Somewhere between the location that had full voltage and the location that had a serious voltage drop is the bad connection. Fix that bad connection so it has full voltage under load and it will work fine. I spent most of a day trying to find the issue on my friends genny and found a corroded ground strap from the genny frame to the RV frame.

It's when you have the voltmeter on the actual battery posts and then hit the starter and the voltage drops to 10 or lower that the battery is bad.

10 volts is a significant number for a 12 volt battery as it is made up of 6 cells of 2 volts per cell. A battery showing 10 volts with nothing connected to it has a cell that is shorted internally.

Mike

[Julia2005]

Originally Posted by AnotherMike

I disagree. It's probably a bad / corroded connection between the genny starter and the battery. Might just be a battery ground cable.

A volt meter takes zero current to operate. You could have a corroded / bad connection between the battery and the genny control box or even to the genny starter that passes no current but passes full voltage but has a total loss of voltage when any real current flows.

So start with your volt meter from the battery to the chassis and see full voltage. Punch the genny starter and see full voltage at the battery.

Then move the voltmeter and measure from the genny control box to chassis and then have someone punch the start button. The from the genny starter to chassis and punch the button. When you find point where the voltage drops when your partner hits the genny start button then you've found the problem... Somewhere between the location that had full voltage and the location that had a serious voltage drop is the bad connection. Fix that bad connection so it has full voltage under load and it will work fine. I spent most of a day trying to find the issue on my friends genny and found a corroded ground strap from the genny frame to the RV frame.

It's when you have the voltmeter on the actual battery posts and then hit the starter and the voltage drops to 10 or lower that the battery is bad.

10 volts is a significant number for a 12 volt battery as it is made up of 6 cells of 2 volts per cell. A battery showing 10 volts with nothing connected to it has a cell that is shorted internally.

Mike

Mike, thanks for making my point. What I was trying to say was to check the batteries for their condition. You said the same thing just with more words.