Community Forums

Aircraftace2 · 10-01-2018, 03:20 PM

Greetings. We need battery help.

We replaced our chassis battery last year after it wouldn't hold a charge above 12v. We are experiencing the same problem again -- the chassis battery drops below 10v, and sometimes well below 9v, within an hour of stopping. The engine still turns over, but our generator won't start until we get the chassis battery voltage back up.

We use the battery disconnect switch for the house batteries, and we manually disconnect the chassis battery even if we store the coach for a day. When it's stored for any length of time, we turn over the engine and exercise the generator at least monthly. We store the coach under cover at an outdoor facility, but we do not have the ability to add an electrically-powered trickle charger.

The battery needs to be replaced, correct?

What else can we do to maintain our chassis battery?

We have a 2014 Canyon Star 3911.

Buly · 10-01-2018, 04:08 PM

You should never let battery go down to 10V. At 10V and below, the battery is getting damaged. If you can, have the batteries load tested and see if they need replacement.

twinboat · 10-01-2018, 04:53 PM

If your battery is reading 9 to 10 volts AND still starts the engine, I would be suspecting an inaccurate volt meter.

Aircraftace2 · 10-01-2018, 07:02 PM

Quote:

Originally Posted by twinboat

If your battery is reading 9 to 10 volts AND still starts the engine, I would be suspecting an inaccurate volt meter.

That is the reading from the coach's power panel, not a volt meter.

DoghouseII · 10-01-2018, 10:09 PM

It sounds like something is draining the battery once the engine is shut down. I would try and figure that out before changing batteries. I do not understand the part about the engine turning over, but the genny not starting. Also, once you figure out the issue, maybe an Automatic Gen Start might be the answer.

dons2346 · 10-01-2018, 10:28 PM

Take a volt meter and measure at the battery. If the reading is above the voltage you stated, you have a problem elsewhere and not the battery

Aircraftace2 · 10-01-2018, 10:30 PM

Here’s a typical scenario from a recent trip:

We are boondocking. We manually disconnect the chassis battery to prevent it from draining due to ghost draws. Battery was above 12v when we arrived. After we get set up, we leave on a three-hour hike. Upon returning, we reconnect the chassis battery, which now reads below 9v. Generator will not turn over. We start the engine with no problem and idle for 10 to 15 minutes. Chassis battery voltage jumps above 12v. Generator now starts.

twinboat · 10-01-2018, 11:55 PM

The house battery starts generator.

The chassis battery starts engine.

Take some pictures of which batteries you are disconnecting.

Seems to me that your house batteries are discharging.

When you start the engine, with the chassis battery, the engine alternator charges the house battery enough to get the generator to start.

You shouldn't have to disconnect any battery connections. I think you need a service person to explain the workings of your RV electrical system and do a through battery and charging system evaluation.

Arch Hoagland · 10-02-2018, 12:02 AM

Did you buy this coach new?

Has anybody done any rewiring?

Have you ever checked the water level in any of the batteries?

You need to use a voltmeter to start doing some actual voltage level checking at the batteries themselves.

I'd be astounded if a battery at 9 volts would start your engine.

Aircraftace2 · 10-02-2018, 12:21 PM

Quote:

Originally Posted by twinboat

The house battery starts generator.

The chassis battery starts engine.

Take some pictures of which batteries you are disconnecting.

Seems to me that your house batteries are discharging.

When you start the engine, with the chassis battery, the engine alternator charges the house battery enough to get the generator to start.

You shouldn't have to disconnect any battery connections. I think you need a service person to explain the workings of your RV electrical system and do a through battery and charging system evaluation.

Thank you for your reply.

The house batteries have a battery disconnect on the power panel. We only use the disconnect for the house batteries when storing the RV. The chassis battery must be disconnected manually with the lever in the engine compartment. I know the difference between the house batteries and the chassis battery. We were advised to manually disconnect the chassis battery by our service tech at our dealer. The house batteries never drop below 12v and are newish.

Aircraftace2 · 10-02-2018, 12:24 PM

Quote:

Originally Posted by Arch Hoagland

Did you buy this coach new?

Has anybody done any rewiring?

Have you ever checked the water level in any of the batteries?

You need to use a voltmeter to start doing some actual voltage level checking at the batteries themselves.

I'd be astounded if a battery at 9 volts would start your engine.

Purchased used from a dealer. Coach was less than two years old with 6,500 miles on it. No rewiring has occurred, as far as I know. Water levels on house batteries are fine - we check monthly and top off as needed. The chassis battery is a maintenance-free, sealed battery. We will check with a volt meter this weekend. Thank you.

Aircraftace2 · 10-02-2018, 12:47 PM

Quote:

Originally Posted by twinboat

The house battery starts generator.

This is incorrect. I called Newmar to verify. On my coach, the chassis battery starts the generator.

96 Wideglide · 10-02-2018, 01:23 PM

Quote:

Originally Posted by twinboat

If your battery is reading 9 to 10 volts AND still starts the engine, I would be suspecting an inaccurate volt meter.

+1..

varkwso · 10-02-2018, 10:36 PM

I have a 99 MADP have similar issue with chassis batteries. On my coach Genny definitely starts from chassis batteries, if I turn off chassis batteries manual disconnect in the bay with the inverter just forward of rear wheels the Genny gets no start power. If I leave the cut off switch on chassis batteries will drain in less than two days even when plugged in to shore power. Have changed both solenoids in left electric bay but no improvement. Haven't been able to isolate leak but there is definitely a parasitic drain on chassis batteries at least in my coach.