Engine Batteries run down boondocking

Topic: Engine Batteries run down boondocking (Read 943 times) previous topic - next topic

Engine Batteries run down boondocking

July 01, 2018, 02:53:38 pm

Our 1999 U270 has all new batteries summer 2016, coach and motor. We were boondocking at FMCA rally last weekend and after 3 days the batteries wouldnt turn over the engine. had to run the generator for 5 min to get engine started. had the batteries tested and they are perfect. is there a switch or incorrect connection that pulls power off the engine batteries instead of the coach batteries?
Dale Bernice and Gracie
1999 U270 36ft

Re: Engine Batteries run down boondocking

Reply #1 – July 01, 2018, 02:56:59 pm

Three days to discharge does indicate more than a normal parasitic draw.

Could someone in the last 19 years have wired something to the chassis battery-- sure.

Could the points in the battery combine/boost solenoid be stuck-- less likely but easy to check.

Re: Engine Batteries run down boondocking

Reply #2 – July 01, 2018, 03:11:42 pm

the solenoid sounds logical. where would I find it on my coach and what do I look for?

Re: Engine Batteries run down boondocking

Reply #3 – July 01, 2018, 03:29:06 pm

Re check battery connections. Sometimes when batteries get replaced they don't clean and tighten connections like they should.

Re: Engine Batteries run down boondocking

Reply #4 – July 01, 2018, 03:32:45 pm

Stuck boost solenoid would drain all of the batteries and the gen set would not start . IMHO

Re: Engine Batteries run down boondocking

Reply #5 – July 01, 2018, 03:39:30 pm

Quote from: Protech Racing – July 01, 2018, 03:32:45 pm

Stuck boost solenoid would drain all of the batteries and the gen set would not start . IMHO

Yes, would drain all of them. BUT, takes a lot less amps to start the generator than the 8.3 liter Cummins.

Open the bed and look at the forward wall of the engine compartment. You can pull out your wiring schematic to identify the wire numbers. What you would look for is that even with the boost switch off, voltage is exactly the same on both large lugs (each representing a different battery bank).

If the same, check for voltage from the small signal terminal to ground- should be 0 with boost switch off. If voltage present, disconnect the small positive wire and trace why it has power with switch off.

Re: Engine Batteries run down boondocking

Reply #6 – July 01, 2018, 04:01:56 pm

ok that makes sense. will have some time this week to work on it. Thanks

Re: Engine Batteries run down boondocking

Reply #7 – July 01, 2018, 06:38:05 pm

Do you have a:

Ultra TRIK-L-START Starting Battery Charger/Maintainer ?

Re: Engine Batteries run down boondocking

Reply #8 – July 01, 2018, 06:48:33 pm

Looks OK but would rather have one specifically designed for AGM batteries,if you have the Optima red tops they are AGM.

Re: Engine Batteries run down boondocking

Reply #9 – July 01, 2018, 09:28:57 pm

Quote from: Carol & Scott – July 01, 2018, 06:38:05 pm

Do you have a:

Ultra TRIK-L-START Starting Battery Charger/Maintainer ?

x2 but dead batteries in 3 days means there is a pretty serious problem.

Re: Engine Batteries run down boondocking

Reply #10 – July 01, 2018, 09:50:00 pm

Maybe it seems fast but what we're you running that is actually wired to the start batteries. On my u300 there is stuff like the front radio for instance that is wired to the start batteries

Re: Engine Batteries run down boondocking

Reply #11 – July 01, 2018, 10:29:50 pm

Dead batteries times two in my experience need replacing. Each time damaged them.

Re: Engine Batteries run down boondocking

Reply #12 – July 01, 2018, 10:48:34 pm

Trik-L-Start is a very handy device - we have one on our coach. Keep in mind, however, that in a true boondocking situation (no shore power hookups) it will only be "active" when your house batteries are being charged (by generator or solar panels). If you have a large parasitic draw on your start batteries, and you don't have a "automatic" charging source (like solar or auto-start generator) connected to your house batteries, then even with a Trik-L-Start installed you could still end up with dead start batteries after a few days.

Re: Engine Batteries run down boondocking

Reply #13 – July 01, 2018, 11:08:58 pm

Could the Trik-L-Start be misbehaving?

Re: Engine Batteries run down boondocking

Reply #14 – July 02, 2018, 04:56:50 am

Original poster does'nt have a trik-l-start.

Re: Engine Batteries run down boondocking

Reply #15 – July 02, 2018, 08:33:36 am

Engine alternator bad diodes or bad diodes in the isolator?

Re: Engine Batteries run down boondocking

Reply #16 – July 02, 2018, 08:35:22 am

Could have bad cell in one battery taking both down

Re: Engine Batteries run down boondocking

Reply #17 – July 02, 2018, 09:15:57 am

Quote from: turbojack – July 02, 2018, 08:33:36 am

Engine alternator bad diodes or bad diodes in the isolator?

Really easy to check:

Voltmeter in dash is chassis battery
Monitor voltage is house battery

Start engine, rev to around 1,100 RPM and see what they read!

Re: Engine Batteries run down boondocking

Reply #18 – July 02, 2018, 10:02:52 pm

My U270 has a switch to disconnect the engine battery when not in use.

Re: Engine Batteries run down boondocking

Reply #19 – July 04, 2018, 12:17:51 am

Thanks everyone for the great suggestions. Finding out I cant chase it this week and next week is out as well Will try to isolate the possibilities in a couple of weeks. I will update as I make discovery.
Thanks again everyone.

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