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brandss · 08-02-2021, 03:50 PM

Don't know where to begin other than the fact that I went to move the coach after being parked for a week and no power, nothing. Had to use the auxiliary start, got it running, ran it for about an hour on the road, and now a few days later the same thing.

The first time the batteries were dead they read 6.7 volts. Once I got it started could tell the alternator was working because the voltmeter read over 14 volts. I think I have something draining the batteries but have no idea where to start looking. Any thoughts, suggestions appreciated.

MrMark52 · 08-02-2021, 04:21 PM

Assuming you mean the chassis battery? We’re you on shore power?

If chassis battery - do you have a dash radio and is it tied into the ignition (ignition off, radio off)?
Headlight or parking light alarm - sounds when ignition is turned off and eithe of the lights are on?

RightUR · 08-02-2021, 04:27 PM

I hope you have a switch (you should, it's an Allegro Bus) where you can disconnect the chassis Battery/engine Battery. Unless you're in shore power, cut it off. But I'm sure you know that.
Obviously you have a parasitic drain somewhere, do a Walkthrough of your coach look for "drains:" convection oven. Microwave, dishwasher, Radio unit in the bedroom. make sure all TVs are off. ck the Radio up front. Some times when you Retract your slides, they cover certain Recessed lights and you don't notice; make sure they're off before you retract (it used to happen to me. 2x). Also, what's in your basement? A dometic electric cooler/freezer? Do you have the Red Devil vacuum unit near the floor?
Once you do that, if the problem persists, check the battery for a bad cell or if it's sulfated (if that's what you have).
good luck.

Skip426 · 08-02-2021, 05:01 PM

How old are the chassis batteries?

Parked without shore power chassis batteries in good condition, will only last three weeks, if not disconnected, older batteries, even less.
Chassis batteries, will not tolerate being drawn dead , and if one of the two has a bad cell, it will draw both down, quickly.
Remove the batteries for charging and load testing, as a first step.

A few hours of running the engine , did NOT fully charge the batteries, so they would go dead very quickly.

amosnandy · 08-02-2021, 05:31 PM

Quote:

Originally Posted by brandss

Don't know where to begin other than the fact that I went to move the coach after being parked for a week and no power, nothing. Had to use the auxiliary start, got it running, ran it for about an hour on the road, and now a few days later the same thing.

The first time the batteries were dead they read 6.7 volts. Once I got it started could tell the alternator was working because the voltmeter read over 14 volts. I think I have something draining the batteries but have no idea where to start looking. Any thoughts, suggestions appreciated.

I would start by disconecting the batteries, physically remove the cables. Put a separate charger on each. Make sure they are fully charged, disconnect the chargers, check the voltage, then let them set for 2 hours to stabilize, check them again. They should only drop .1 volt. Now test them with a good digital battery tester. A good one will load test, test for shorts, and test capacity. You can take them to an auto parts store and have them done for free, but my experience is when they test, they are always bad. Don't know if the kid behind the counter doesn't know how to run one, if they do and want to sell batteries, but as far as I'm concerned a $79 digital battery tester is as important as a VOM.

Lets say they test good. You can test parasitic draw 2 way. Most VOMs have an amp connection. Just need to connect the leads from positive cable to positive battery terminal. Just keep in mind. Most are limited to 10 amps.

I prefer a clamp type ammeter. I have a VOM that is also a clamp type load tester. Connect the battery cable. See if you get a little spark when you put it on. I'm assuming you have everything turned off and the chassis battery disconnect off. Put your ammeter on it and see how much it is drawing.

If it is much, say even a couple amps there is your problem. Now start pulling fuses and see if you can find it go away. If it does circuit is your problem. You either need to move it to something you can switch off, or put a switch in the line.

If you can't find it, it is something that is not supposed to turn off and you need to find a way to keep a trickle charge to your unit. Or remove the batteries.

mlpeloquin · 08-02-2021, 06:14 PM

At 6.7V I would change the battery. I would install a cut off switch as well. I did in my class C when we had it. You can also purchase a DC clamp on current meter and see just how much power it is drawing. They don't cost much. You might be able to chase down the current draw.
If you want to keep the battery, it will have reduced life. Purchase a battery load tester. They do not cost much.

https://www.amazon.com/Battery-Tende...NsaWNrPXRydWU=

https://www.amazon.com/KAIWEETS-Mult...dDbGljaz10cnVl

MrMark52 · 08-02-2021, 06:17 PM

Uhmmmm - I’m not totally up to snuff on the fancy, smancy, new electronics - but last I knew, you can’t measure DC amps with a clamp on ammeter. AC, yes, but not DC.

YMMV

mlpeloquin · 08-02-2021, 06:25 PM

Quote:

Originally Posted by MrMark52

Uhmmmm - I’m not totally up to snuff on the fancy, smancy, new electronics - but last I knew, you can’t measure DC amps with a clamp on ammeter. AC, yes, but not DC.

YMMV

You are correct on the point that "you are not totally up to snuff on the up to date electronic meters". If you fallowed the URL to amazon, you wold have seen such a DC current clamp on meter. I own one. I have used them even thirty years ago. Though back then they were an option with an oscilloscope.

MrMark52 · 08-02-2021, 06:38 PM

Quote:

Originally Posted by mlpeloquin

You are correct on the point that "you are not totally up to snuff on the up to date electronic meters". If you fallowed the URL to amazon, you wold have seen such a DC current clamp on meter. I own one. I have used them even thirty years ago. Though back then they were an option with an oscilloscope.

Interesting - and I did read up on how it works - makes sense.

My days of using Amprobe will tell my age.

And FWIW - I did go to that page, but the description didn’t quantify that it could measure DC amps in clamp on mode.

Thank you for the lesson! 😀

brandss · 08-02-2021, 07:33 PM

Wow all, thanks so much for all of the information.

I did mean chassis batteries and I am hooked up to 50amps. What I don't get is what could possibly be draining the batteries. Hooked up to electric I didn't think there was much other than the radio that would run off the chassis batteries. I'm often wrong though.

I think I will invest in a good battery charger and charge each independently and see what I get. I too agree that if I have them tested at a auto store, new batteries will be in my future whether it's the issue or not.

I kind of hope the batteries are bad as opposed to chasing a hidden drain somewhere.

Jim_HiTek · 08-02-2021, 08:43 PM

All modern RVs have several parasitic battery draws and they may or may not be disconnected when you operate the Main and Aux battery switches.

And example of this is the engine ECM and the transmission TCM. Both of those devices have memories just like your dash radio. If your batteries die or are disconnected it takes 100 miles for them to *relearn* your style of driving. Then there are the CO and propane detectors. Since those are safety devices, they are often wired to bypass the Main and Aux relays. Then there are the steps. Those are often powered all the time.

Then there are the mystery wires that go who knows where, that the manufacture connected directly to the battery buss because it was cheaper to do it that way. And then there are the millions and millions of RVs that were and still are built without an auxiliary charging circuit for the chassis batteries. Why? Because they can save a few cents that way, and it's tradition.

What I do when I'm going to store my RV is just let the refer empty out naturally, park it and then just disconnect the chassis batteries grounds and disconnect the jumpers between the 6 volt house batteries. Last time I did that I was gone two months. Reconnected when I got back and it started right up, no worry about losing power or something bursting into flame while gone. If you're going to leave your RV sitting without shore power, with new batts, usually you can get 5-7 days without needing a charge, with old batts, 3-5 days. Large solar panels on the roof help add days.

That battery that reads 6.7 volts is toast. A 12 volt battery is dead at 10.5 volts, any lower and it's been damaged. Once you've replaced those, then hook up to shore power, wait an hour for the batts to stabilize with the converter charging them, and read the voltage across the chassis batts. It should be in the 13.xx range if your RV has an auxiliary charging system for chassis batts. If you only read 12.xx or less (you should read within ~0.4 volts of what the house batts read as provided by the converter/charger), than you probably need a Trik-L-Start battery maintainer. It draws current from the house charger and sends it to the chassis batts.

MrMark52 · 08-03-2021, 07:35 AM

Just for grins - do you know what kind of charger is on your coach? Is it a linear charger like MagnaTek (and others) used manufacture or is it a multistage, microprocessor controlled charger?

Those old linear chargers will definitely cook your batteries, and that’s what it sounds like might have happened to you - assuming your coach has something similar to the IntelliTec BIRD control that flip-flops the Emergency start solenoid based on coach and chassis battery charge state.
OTOH - how old are your batteries? For a 2014 coach, I’m thinking you might be at your EOL of the 2nd set of batteries.

I would also agree that an hour or two of charging with the chassis alternator (or anything for that matter) isn’t sufficient to get the battery(s) fully charged.