Engine battery dies.

[Virago-Rider]

. Trying to resolve a problem of the engine start battery going dead when everything is off. I am following the trouble shooting guide in my battery control center manual. On page 7 part B the book says to test for voltage at J1-5 with the engine off to test the battery isolator.

I have zero volts initially. However, if I press the Aux Start Button, I hear a solenoid click, and there is battery voltage present at J1-5. This would make me think the isolator is working.

I am hoping for some advice, ideas, suggestions of where to look next.

Thank you.




🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum

[Skip426]

First two questions.
How long does it take for the battery to go dead?
Have you had the battery load tested?

[FIRE UP]

Originally Posted by Skip426

First two questions.
How long does it take for the battery to go dead?
Have you had the battery load tested?

Yep, that was going to be my questions too. Before I'd get too involved with that BCC, I'd make sure that
1. Your alternator is working correctly to charge you chassis battery adequately in the first place.
2. If that is working fine, then I'd do what Skip has suggested and, get that chassis battery tested for load capability.
3. How old IS the chassis battery?
4. There are some facets of a coach that operate from the chassis battery and not the coach battery. Things like memories on radios, auto-extend and retract front steps, and a few other things. Make sure there's no possible draw on the chassis battery when the coach is off.
5. A simple test can reveal if you have a draw or not. Remove the negative cable from the battery. Place a test light, in between the cable end and the negative battery post. If it lights up, you've got a short, or a light is on in a cabinet/compartment, or other source is trying to drain down the chassis battery.

6. If the test light does light up, a possible second test may reveal the culprit. While that test light is lit up, go into the coach and, start removing the fuses of the 12V circuits, one at a time. If the test light goes out when you pull one, that circuit is the issue. Then, all you have to do is, find out the problem with that particular circuit.

Now, if the test light does not light up during the test, that does not mean you still don't have a draw. It just means it can less of a draw than what it takes to light up the test light. In that case, a volt ohm meter can be used in place of the test light. Set the meter to 12VDC and see what it says.

Hopefully some of this info helps you to find your problem. And, like Skip asks, just how long does it take for your chassis battery to go dead or, start to die?
Scott

[Virago-Rider]

All 3 batteries are less than 6 months old.. All were load tested and checked good. Alternator is putting out 13.6. I will try the light bulb test.


🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum

[Skip426]

How soon after engine start up did you get your alternator voltage reading?

If the batteries have been drawn down by cranking the engine the alternator should be putting out 14.2 volts and not settle down to 13.6 for some time 20 mins half an hour.

[Virago-Rider]

Perhaps 15 minutes or so. The problem occurs when stored.... And not always. The batteries are all good... Go out to start it the next time... House batteries are good. But, starting battery is down to 5 volts or so. I am always sure to hit the disconnect switch to the store position.... I usually double check just to make sure I did it.


🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum

[Skip426]

Do you have two disconnect switches ?
One for coach and one for chassis ?
If only one then you're only disconnecting the coach batteries.
You could try disconnecting the main feed from the alternator, with the low-ish out put there could be an internal problem causing this erratic drain.

[Virago-Rider]

I have two switches.


🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum

[Skip426]

Originally Posted by Virago-Rider

I have two switches.

Then testing of the chassis battery disconnect relay is in order, too.

When the chassis battery is down to 5 volts ; how long has the coach been sitting ? Hours ? days? weeks?

[beenthere]

when I had this problem it was bad diode in alternator..found out when I had engine door open and touched the alternator...it was warm as battery was back flowing thru alternator...and starting varied as to how good battery was charged since last time...jeff

[DDDonkey]

Originally Posted by Virago-Rider

All 3 batteries are less than 6 months old.. All were load tested and checked good. Alternator is putting out 13.6. I will try the light bulb test.

Voltage is good but how many amps is it putting out? I just replace my alternator and it was also putting out 13.6 volts but just 20 amps at 1500 rpm, it was an 130 amp unit. Just thinking out loud here.

[Virago-Rider]

How do you test the amps?


🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum

[Virago-Rider]

Originally Posted by beenthere

when I had this problem it was bad diode in alternator..found out when I had engine door open and touched the alternator...it was warm as battery was back flowing thru alternator...and starting varied as to how good battery was charged since last time...jeff

When the disconnect switches are in the "store" position, is the alternator still connected?


🚌🚍🚌
1998 Thor Windsport 33SL on 1997 F53 chassis.
2007 Chevy Uplander TOAD.
1985 Yamaha Virago XV700

Sent from my iPad2 using iRV2 - RV Forum

[Skip426]

Originally Posted by Virago-Rider

How do you test the amps?

Clamp on amp-meter , check around for pricing , mine was less than $30 Canadian.

Depending on the way; and where; your chassis battery disconnect wiring is hooked up , the main lead to the alternator may still be hot. Easy enough to check out, with the disconnect activated, check the wire at the alternator with a test light or volt meter.