Parasitic draw spec on E450 Coach(cab) Battery

[don_kleinschnitz]

I did some searching here on this subject and although there is lots of good information I couldn't find a clear answer.

Seems that house battery parasitics is pretty common but this is the coach battery that is making me uneasy.

I have been checking my coach & house batteries regularly during the winter. My house battery gets charged about 1x a month when I run the generator and the cab. My house is connected to ac so my house batteries stay charged.

Last month I found the coach battery totally dead and used the house batteries to start the vehicle. Now it seems the battery is draining at a much higher rate than I remember last year. I installed a remote battery monitor to watch it and get better info.

My question is what is the normal parasitic draw when in the off state on an E450 electrical system. I read that it should be in the range of 50ma. I think I measured about 500ma on mine?

What is your experience with how long your coach can sit before the coach battery cannot start the vehicle?

I plan to install a trickle charger and/or battery switch but I want to make sure that something else is not wrong and I am just masking it with these devices.

[Stavman]

Only truck battery I don't really see any drains...that said I left my OBD ugges in and two cigarette lighter USB chargers, one is a volt checker, and killed my battery.
The house does get sucked dry so I'll disconnect the Neg on it, but never an issue with the Coach battery

I'd say u have something on or sucking on it that shouldn't be

[pconroy]

My 200 watt solar panels keep the house battery topped off and a 20 watt solar panel now keeps the chassis battery topped. But before those, I don't recall having a dead Ford. And it would easily be two months before I'd make it out to the storage lot to fire things up.

[dxrobertson]

I oftentimes go 1 month or more on my 2021 E450 battery without starting/charging. Battery strong, no hesitation in starting. Seems to be no worse parasitic drain than a normal car.

[JFlightRisk]

snip...

Originally Posted by don_kleinschnitz

Last month I found the coach battery totally dead and used the house batteries to start the vehicle. Now it seems the battery is draining at a much higher rate than I remember last year. I installed a remote battery monitor to watch it and get better info.

My question is what is the normal parasitic draw when in the off state on an E450 electrical system. I read that it should be in the range of 50ma. I think I measured about 500ma on mine?


I plan to install a trickle charger and/or battery switch but I want to make sure that something else is not wrong and I am just masking it with these devices.

The coach battery has been compromised by going completely dead, and I would say it won't come back to 100% now. Newer vehicles with all the electronics and computers will have a bigger parasitic draw. The hose battery will have some draw from it too. Our '16 F150 will drop to 12.2 volts after a few days being idle. I put a battery maintainer on it if I know I'm not going to drive it for a while. I haven't put a meter on it yet to see exactly what the milliamp draw is. i just know it's happening. Just the nature of the systems.


Our TT stays plugged in at home when we're between trips, and the original battery has lasted up until this spring. It drops to 10.2 volts after resting for a few hours off the maintainer., so it gets a new one this year.

[GABob]

My battery died and could not figure out what was drawing current until I opened the hood and saw the light on for the TPMS booster. I now use a small solar panel to keep it charged and that seems to work well. By the way, the low power caused my leveling system to go funky, so I had to reset and all was fine.

[JudyB]

The excessive heat in the southwest will also kill a battery. On cars, its about a 2 year limit on a chassis battery.

[bucko]

A rep from Interstate batteries once told me to never buy a battery that has over a 3 year warrantee, no matter what they advertise. He said to stick with a 3 year battery, as they are at their peak up to 3 years. Some will get lucky and get over 4 years on one, but that's usually if they keep a battery tender on it when not in use. The average vehicle owner rarely does this however.

[anf76]

i had the same trouble this winter. 2021 jayco greyhawk. i had a battery minder on it and it still was losing a charge. had to start it with house battery. don't know this happen.

[J05H]

My 2020 Redhawk 31F does the same thing. Actually, this is the first season it has done it and I’ve had to use the house battery switch on the dash to start it. I’ve been looking into the Trik-L-Start. Anybody have any experience with this or something like it?

I’ve also wondered if I could replace the momentary push button switch with a toggle and if I switched it to on while the RV was plugged into shore power if it would trickle charge my engine battery too. Any thoughts on that?

[bucko]

What about the cab dash radio? It's powered by the cab and coach battery on most models.

[Scoutmaster253]

When my 31FS is in storage (more than a week) I disconnect the negative from the chassis battery. Never had a problem with it going on 5 years now.

[201822j]

I lost my first battery on it's 2nd year. I wasn't able to use the RV that year, didn't have a tender on it and killed it. Now I have a tender plugged into the RV so when I plug the RV in, the Cab battery tender comes on. I am getting an indicator light on my tender when it goes into Float. Instructions say that can be because of a draw larger then a certain amperage. So I'm suspecting it's a parasitic draw.
While I do plug my RV in during winter and non-use, I will unplug for a couple days once in awhile so as not to possible over charge.
I need to disconnect the batteries so as a kind of re-boot on every thing

[don_kleinschnitz]

After more investigation, measurements, and a round of questions with Jayco here is what I found out.

According to Jayco your coach battery (the truck battery) is always under load (approx .5amps) from:

1. The aux start solonoid
2. The CO2 detector
3. The leveling controller.

Aux Start Relay:
Part #Rogers 120-105751-6
Clearly, this is the bulk of the draw as the coil on that relay is spec'd at .75 amps continuous and I measured .5 amp constant drain on the battery. I also can hear that relay drop when I disconnect the battery.

I have not yet rationalized why that relay is always on. Does it use normally closed contacts that have to be held open unless the aux switch is pushed?? I need to better understand how the aux function works. I have not yet found a part # and spec for the Aux switch. If anyone knows where to find the specs that would help.

Choices to stop the chassis battery from going dead:

1. Start the RV and top off the battery at regular intervals
2. Add a manual battery disconnect switch
3. Add a trickle charger

#1 works for me during the summer but not during winter storage

#2 I tried to add a manual battery disconnect switch and the only one I found that would fit on the short cable also interferes with the hood. Note these are designed to go on the negative terminal only. If anyone has found one that fits please let me know.

#3 This is my current solution. I got a trickle charger that I have some confidence properly trickle charges the battery. I connected it to the chassis battery through the cigarette lighter. I keep my RV connected when parked and this way I run it from the AC inside the camper avoiding any extra AC cords to the camper.
I added a small voltmeter at the intersection of the charger and the lighter plug so I can monitor the charging voltage. See pictures.

I previously installed switched house & chassis battery voltmeters in the dash This lets me monitor both battery groups. I can compare what those meters say vs the trickle charger. Redundant yes, but this way I am measuring both ends of the trickle charge circuit.

Parts:
Trickle charger: https://amzn.to/3kPzYiH
Aux Solenoid: https://amzn.to/395j79e
Small Voltmeter: https://amzn.to/3MU05B8

[dxrobertson]

Originally Posted by don_kleinschnitz

After more investigation, measurements, and a round of questions with Jayco here is what I found out.

According to Jayco your coach battery (the truck battery) is always under load (approx .5amps) from:

1. The aux start solonoid
2. The CO2 detector
3. The leveling controller.

Aux Start Relay:
Part #Rogers 120-105751-6
Clearly, this is the bulk of the draw as the coil on that relay is spec'd at .75 amps continuous and I measured .5 amp constant drain on the battery. I also can hear that relay drop when I disconnect the battery.

I have not yet rationalized why that relay is always on. Does it use normally closed contacts that have to be held open unless the aux switch is pushed?? I need to better understand how the aux function works. I have not yet found a part # and spec for the Aux switch. If anyone knows where to find the specs that would help.

Choices to stop the chassis battery from going dead:

1. Start the RV and top off the battery at regular intervals
2. Add a manual battery disconnect switch
3. Add a trickle charger

#1 works for me during the summer but not during winter storage

#2 I tried to add a manual battery disconnect switch and the only one I found that would fit on the short cable also interferes with the hood. Note these are designed to go on the negative terminal only. If anyone has found one that fits please let me know.

#3 This is my current solution. I got a trickle charger that I have some confidence properly trickle charges the battery. I connected it to the chassis battery through the cigarette lighter. I keep my RV connected when parked and this way I run it from the AC inside the camper avoiding any extra AC cords to the camper.
I added a small voltmeter at the intersection of the charger and the lighter plug so I can monitor the charging voltage. See pictures.

I previously installed switched house & chassis battery voltmeters in the dash This lets me monitor both battery groups. I can compare what those meters say vs the trickle charger. Redundant yes, but this way I am measuring both ends of the trickle charge circuit.

Parts:
Trickle charger: https://amzn.to/3kPzYiH
Aux Solenoid: https://amzn.to/395j79e
Small Voltmeter: https://amzn.to/3MU05B8

Here are my tests/observations on my 2021 Ford E450 Entegra. These are with the Ford ignition off (key not even in) and the camper battery disconnected via the disconnect switch.

I believe the loads you are reporting while Ford is off, only occur on my Ford when the ignition SW is on.

My CO2 detector is not on (green light) when Ford is off. I turn Ford SW to on, and the CO2 powers, green light on. This makes sense as its the needed circuitry when driving down the road with the camper battery off- CO2, ice box, slideout and awning lockouts...

I did a quick volt test on the aux start solenoid control wire (mine is orange). No voltage when Ford is off. Obviously this makes sense as this should only be powered when either the dash button is pressed or Ford SW is on. Of course there is 12V at both sides of the solenoid battery connections. I dont see how the solenoid itself could consume power just sitting idle without power to the control wire?

From examining my particular system, the aux start solenoid is powered via the orange wire which is connected to the aux start switch at the dash. This SW is powered from either pressing it (from camper battery), or by a feed directly from Ford (whether the dash sw is pressed or not). And my "feed from Ford" appears to only be when Ford ignition SW is on.

2 things to note. I do not have auto levelers (I would check that potential drain). I also ripped out the irritating kwikee step controller and replaced with a simple toggle sw. Only reason I mention this is that the electric step is also tied into Ford.

My particular unit does not drain the Ford battery in short time. Good Luck with this.

[Suprnova74]

It may be time-consuming, but one way to track it down would be to use an amp-meter of some kind to measure the draw that's happening on the battery and then pull one fuse at a time to narrow down the circuit that's draining it. Once you know the circuit you can track down the device(s) in question and address them accordingly.

[don_kleinschnitz]

Thanks for the info all.

I previously found the parasitic circuit and it's the aux switch solenoid.
This is also what Jayco told me was the main draw.
When I disconnect the battery I can hear and feel it drop out.

I am not yet sure why this solenoid needs to be on all the time. In mine, it is on with no key in the ignition.

Yes, the auto steps are wired through an auto-reset fuse to the chassis battery. I found that out when the steps jammed and killed that battery. You have no way to know that the step is jammed with power still applied other than a dead battery.

As an aside, I am pretty sure I found out why the steps fail. You have to wait a bit when the step is on the out stroke before you put weight on it. It's tempting to step on it before it's fully out and that jams and over time damages the gear set.

[Stavman]

Picking mine up in 3hrs, now I'm wondering about what powers the c02 sensore

I'll update later

2018 Entegra 25r

[pconroy]

Those are great investigative findings don. I too wonder why the leveling controller is always on? I think you said Solar is not an option, but I'll mention to others that my $50 20 watt solar trickle charger from Amazon has done a good job of keeping the chassis battery topped off. For those that can park/store their rig in sunshine, I recommend one.

[J05H]

Does anybody have experience with Trik-L-Start or Amp-L-Start? They are made for resolving this problem a lot of us are facing with or motorhomes. I’m tempted to try one but I’d like to know from someone that is running one, and if there negatives using the produc