Parasitic draws on coach batteries?

[Sandy Swede]

I have been operating under the assumption that parasitic draws only effect the house batteries, not the coach (starting) batteries. True or false? Not sure if parasitic draw was the culprit, but after three weeks at a campground connected to shore power, my coach batteries were deader than doornails. Also, wouldn't being connected to shore power have kept these charged? I have had no problems in the previous several weeks, but max stay at a campground was 5 days. Also was plugged into shore power during last winter with no issues. Even with the boost switch depressed for approx one minute prior, the engine barely turned over. It started right up jumping from the toad. The batteries were three years old Interstate sealed lead acid.

[jacwjames]

Yes the chassis does have it's own parasitic draw but it is probably substantially less then the house side.

Does your chassis battery charge when plugged into shore power?? Do you have a solar charger??

You may be seeing the symptoms of a failing battery. Check each cell with a hydrometer to see what the SG is, this will tell you the condition of each cell.

I had 1 bad cell on my chassis battery and it would not even start to turn over, I could hold the boost down to start. The coach was always plugged in and chassis battery charges on shore power or solar. New battery and problem solved.

[Lt Dan]

Also, if you have anything turned on that might be drawing from the chassis battery like the radio, map light, etc, that can cause a drain. I learned that lesson when I use the map light on in our Itasca when we were parked for a week and it drained the chassis battery. After that, I installed a Trik-L-Start between the two battery banks to keep the chassis battery charged when parked.

[Sandy Swede]

Originally Posted by jacwjames

Yes the chassis does have it's own parasitic draw but it is probably substantially less then the house side.

Does your chassis battery charge when plugged into shore power?? Do you have a solar charger?? Yes, chassis battery is supposed to charge when plugged in to shore power. There is also a solar charger.

You may be seeing the symptoms of a failing battery. Check each cell with a hydrometer to see what the SG is, this will tell you the condition of each cell. They are sealed batteries, so that is not an option. What I failed to do was get out my load tester after I jumped from the toad battery and ran the coach to the next campground. All a moot point now (hopefully) as I have replaced the batteries. I will be monitoring these closely.

I had 1 bad cell on my chassis battery and it would not even start to turn over, I could hold the boost down to start. The coach was always plugged in and chassis battery charges on shore power or solar. New battery and problem solved.

Thanks much for your reply.

[Sandy Swede]

Originally Posted by Lt Dan

Also, if you have anything turned on that might be drawing from the chassis battery like the radio, map light, etc, that can cause a drain. I learned that lesson when I use the map light on in our Itasca when we were parked for a week and it drained the chassis battery. After that, I installed a Trik-L-Start between the two battery banks to keep the chassis battery charged when parked.

We don't run the radio, but your suggestion about the map light could be spot on. Occasionally, I have left the porch light on during the day and my wife charges her cell phone from the cig lighter port virtually every day. I also wonder about the four status lights, small as they are, from the leveling system always being on.

What perplexed me is why the shore power and/or the solar panel connections do not keep the chassis batteries charged.

Thanks for your reply.

[l1v3fr33ord1]

SandySwede-

Any individual coach can be different, and certainly yours is old enough to where this may not be the case, but all that said you may have a house-to-chassis charging system that is installed but not working correctly. With some investigation and repair, you may be back in business. If you find your coach does not have a house-to-chassis charging system, then you can purchase a device such as a Trik-L-Start or Amp-L-Start to perform that function.

[twinboat]

If using the boost switch wasn't effective, there is a strong possibility that the boost solenoid if failing.

Find it, engage it and check for even voltage on both sides.

With that failing, it will also affect your house charging system maintaining your chassis battey.

The isolation relay serves double duty as the boost relay on most MHs.

[Sandy Swede]

Thanks Mark and twinboat. Good points. Getting out the voltmeter this pm. Just have to locate the solenoid.

[gatorb8]

get a good multi meter with "clamp on DC current (amps)" capability.

clamp it on either of the wires connected to your chassis battery
then go test all your ideas about what could cause the parasitic draw or if it's charging while plugged into camp power. Those meters are worth their weight in gold when chasing gremlins like you are!

[Smitty77]

Originally Posted by gatorb8

get a good multi meter with "clamp on DC current (amps)" capability.

clamp it on either of the wires connected to your chassis battery
then go test all your ideas about what could cause the parasitic draw or if it's charging while plugged into camp power. Those meters are worth their weight in gold when chasing gremlins like you are!

Use that same meter to validate that once your house batteries are up to snuff, your BIRD system is properly 'sending a charge' to your chassis battery.

We had the Echo charge in our coach before changing every thing over to Magnum. The Charger/Echo had to be 'reset' by pushing a few buttons on the unit. Then everything worked well after that until replaced.

Finally, how old is he chassis battery? Are you sure it is not possibly 'Maintenance Free'? If so, then they do have the ability to pop off covers to access the water level. (MF - is not really MF!).

Best of luck to you,
Smitty

[dennis45]

Your Newmar coach has a BIRD system that directs charging current to both the chassis and house batteries when plugged into shore power, on generator or off the engine alternator when driving.
You have a problem with the BIRD that you need to deal with. Attached is a manual for the BIRD and the Battery Disconnect.

The BIRD and disconnect solenoid are located in the shore power cord bay behind a black panel that is held in place with velcro strips. Pull the panel back to reveal the solenoids.

[dennis45]

This is what you are looking for.

[dennis45]

Sorry, meant to include this one also. A slip of the thumb,,,,