Engine Battery

Everything to do with engines, options, upgrades.
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dsh
Posts: 16
Joined: March 9th, 2016, 9:49 am

Engine Battery

Post by dsh »

While out boondocking recently our engine battery got pretty low. Strange, because at home the MH can be sitting for a month and starts right up the minute we start the engine.
So my question is.....what could be draining the engine battery? We are always mindful of being sure everything is turned off right down to the cup holders that cool and heat.
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caconcourse
Posts: 489
Joined: October 31st, 2014, 10:25 pm

Re: Engine Battery

Post by caconcourse »

dsh wrote:While out boondocking recently our engine battery got pretty low. Strange, because at home the MH can be sitting for a month and starts right up the minute we start the engine.
So my question is.....what could be draining the engine battery? We are always mindful of being sure everything is turned off right down to the cup holders that cool and heat.
One item that many don't know runs off the engine battery is the rear compartment stereo. On many units the generator starter runs off the engine battery. Leaving a front door open for extended periods can leave the map lights on draining the battery some as well.

Clay
Clay
2001 Concourse
Santa Barbara, CA
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Blue~Go
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Posts: 3716
Joined: July 31st, 2014, 1:01 am
Location: 1999 Concourse

Re: Engine Battery

Post by Blue~Go »

Those would be the three things that would come to my mind too, with a fourth being some sort of malfunction of the Sure Power separator (that isolates start and house batteries when not charging).

You mention that this doesn't happen at home, but do you leave the coach plugged in at home? Because if you do, the Sure Power separator/combiner could mask the issue. Presuming you have something like the 1315 (mine had that one), it is bi-directional. That means that if there is charging present in either of the battery banks it will "share" with the other one. So any shore power charging would also go to the start battery and could mask an issue.

It's even possible that your coach solar is sharing in this way and that it's enough to keep your start battery topped off when not camping, but when you are camping you are just "overwhelming" the very small amount of power coming from the solar panel (and making its way to the start battery via the combiner), so that it no longer does that.

This is all presuming certain things that may or may not be the same on your particular Chinook of course.

Couple of notes:

1) Following the example of Chinook owner Bob Will, I re-wired my coach stereo to not use any start battery power. This was not too difficult. The potential downside is that when your coach batteries are in "store" position, you'll lose any station presets on the coach radio (the wire that goes to the start battery and always has power is what holds these). Since I travel and therefore the presets are fairly meaningless on the coach radio, this was of no concern to me.

2) My Ford cab had a couple of dome light "things." One was their "illuminated entry" feature. This was so that as soon as someone touched an exterior door handle, the cab lights would come on. But boy was it sensitive. Just breath on the exterior door handle and they'd come on.

But the thing that really annoyed me was that there was no way to shut off the darned dome (and mirror) lights. Sometimes I have my front doors open for longer periods, plus often I don't want to ruin "dark sky" moments or my night vision. I wanted to be able to not have the dome lights on (like in most cars, ahem Ford). I ended up re-wiring the overhead dome light so that I can switch it off when desired (and it will stay off unless I switch it to door operation - just like most vehicles).

3) Prior to 2000, the generator used the Ford start battery to start. This is not actually Onan's recommended configuration, and Chinook used a much too long/too thin wire. One relatively easy way to mostly fix this is to move the start lead to the house bank. The wire is still a bit under spec, but much less as it is about HALF as long then. (If one is wanting to start the generator consistently in cold climates, then upping the wire size wouldn't hurt). I did this and cut out around 20' of wire. The wire runs pretty close to the house batteries along its path to the start batteries.

4) Some of the Sure Power 1315 separators have been recalled (mine was), so that is something to check on. It wasn't for not separating, but I think it was because they could burst into flames (minor inconvenience :roll: ). They are somewhat of an older design, and not mounted in a very good location, so if yours is either recalled or malfunctioning, you might consider replacing it. But if your house bank wasn't drawn down, this is probably not the culprit (because if the two banks were sharing power due to a separator malfunction, but the house batteries were not run down, then it wouldn't really matter in that case).

5) A friend had a continual mystery parasitic load in his E-450 other brand RV. Turned out it was an OBD gauge he had installed (an Ultra Gauge).
1999 Concourse
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