something drains car battery while on shore power

[Ronnyrenner]

Hello Again,

I use a '95 Roadtrek 190 Popular on a Dodge B3500 Chassis to travel around Southamerica. The first couple of months I never used shore power since they have 220V everywhere. In Peru I got an Inverter from 220 -> 110V and now I'm using shore power whenever possible. Here in Ecuador they have 110V so I can connect directly.
Now I noticed that when I'm parked for 4-5 days something completely drains the Car Battery. I noticed it because the remote control for the door locks wasn't working anymore. It already happened once and I bypassed the isolator with a jump-start cable to re-charge the main battery for a while until there was enough energy to start the engine and recharge the car battery. I guess this is not really recommended but unless I disconnect the car battery when I'm on shore power I have no other solution.
Since they always work a bit dodgy here in southamerica, they often don't have the ground connection on their sockets. Could this be the problem?

I'm not a 100% sure if this would not happen while not on shore power, since I usually drive every couple of days or run the generator when being remote somewhere. But the 2 times it happened so far, it was on shore power.

Any Idea how this could be solved? Or should I just disconnect the car battery while on shore power?

Thanks in advance
Ronny

[obiewan kanobe]

most inverters use your batteries, whichever one you wired the inverter to, to make ac. they make 60 cycle square waves and filter it. some inverters will make 120 volt or 220 volt ac output. you need to know how this inverter is connected. how is shore power connected to the power converter panel that charges your batteries.......it's possible, judging from the symptoms, that you are just using an inverter connected to your batteries and are draining them of charge.

[Mike]

The engine battery should be protected from drain down, by the isolator, when the engine
isn't running, and the house batteries are in use. It is standalone, in that respect.
So, either there is a light on, or some other draw on the engine battery, while you're camped,
which must be found and stopped/disconnected, like a courtesy light somewhere in the van
or the radio clock, or something like that,
or, your battery isolator isn't working, possibly a bad diode. I had that problem over a year ago.
I picked up a replacement isolator in Texas in October 2009 and finally had it installed last March,
and my car battery has been fine ever since. I often leave my coach/house batteries enabled
(just forget sometimes) and I haven't drained the engine battery yet, even after days of inactivity.
Unless the inverter has somehow been tied into the engine battery and electrical system, I doubt
it's the problem.

Just my opinion.
Good luck.
btw, I was able to verify that my old isolator was bad, by using a multimeter with a diode checker
setting on it. I had to contact the isolator manufacturer (Hehr Power Systems) and get instructions
on how to do it first. I have the Chev van, so I think yours is probably different (Dodge).
However, if your isolator is a Hehr isolator, you can google HDPSI.com and send them an email and
ask for instructions on how you can test your isolator.

[Ronnyrenner]

The Inverter is externally. Its a box which you plug in to 220V and on the other side you plug in the cars power chord for the 110V 60Hz. I don't think its using battery power to run.

I guess the only thing that is using power from the starter battery is the clock of the radio and the small lightbulb light above the light knob. I now turned it completely clockwise so this is not lit anymore. I'll try to find out if I can check the isolator but like I said in the first post It's only happening when connected to shore power, when I'm "offline" everything seems fine.

[Mike]

It doesn't happen when you're not static, because you're probably recharging the engine
battery by driving more often. My experience was similar. If I drove the van every few
days, and didn't use the house batteries, I was fine. If I didn't drive it, and used the house
batteries, or just forgot and left them enabled, the engine battery would go dead after 3 or 4
days of just sitting in the driveway.
Is there any way you can stop and camp for a few days, without using the inverter, to take it
out of the equation, and see if your engine battery still drains?
The little light bulb may have been enough to draw down your engine battery over a day
or two, particularly if your engine battery has been "deaded" more than a few times and is now
weakened. Turning it off when you're camped, may solve your problem of dead engine battery.
If it still goes dead while you are camped, and not driving the vehicle for a few days, and there
aren't any draws on the engine battery at all, I'd still suspect the isolator, or that the house electrical
system has somehow been connected to the engine electrical system, possibly through mis-wiring of
your inverter system.
If you can't figure it out, you could prevent the engine battery from being drained by putting in a
disconnect switch of some sort to keep it isolated while you're camped and using the inverter.
You said you got an inverter to allow you to use 220V in the 110V system? Could it be miswired into
the engine battery? Could you do without it next time you camp, and just use your generator or
house battery to run things and see if the problem happens again?
I'm grasping at straws, 5500 kms away.