House battery draining when disconnect switch is off

[DRich]

What could cause house battery to drain when the disconnect switch is off?

The battery is only 2 years old. It started last fall. I would charge to full and in a couple of days the battery is dead. The battery disconnect switch is off. The chassis battery is not draining.

It fully charges when plugged in and when driving. I have a RT 170. The only changes I made in the last 2 years was upgraded to a Novakool and a Truma Aquago.

I've had it in to a shop but they can't seem to find anything wrong.

Any insights would be appreciated.

[mkguitar]

load test the battery to ensure it has capacity


autozone can do this, they load the battery and see how many amps current the battery can supply



it is possible that what you think is "charged" is the battery no longer to accept a charge at rated capacity


if a known good battery:



could be a bad/failed diode in battery separator allowing battery to discharge
this is checked with a meter easily




what does the disconnect switch control ? on some it disconnects the battery negative and nothing works- on other models it may control the + power to the DC fuse box leaving the ac/dc converter connected


this is a question for roadtrek owners


Mike

[DRich]

Originally Posted by mkguitar

load test the battery to ensure it has capacity


autozone can do this, they load the battery and see how many amps current the battery can supply



it is possible that what you think is "charged" is the battery no longer to accept a charge at rated capacity


if a known good battery:



could be a bad/failed diode in battery separator allowing battery to discharge
this is checked with a meter easily




what does the disconnect switch control ? on some it disconnects the battery negative and nothing works- on other models it may control the + power to the DC fuse box leaving the ac/dc converter connected


this is a question for roadtrek owners


Mike

The repair shop says the battery holds a charge for 2-3 days before it completely discharges. That is what I was seeing too. They say they are "checking everything" although I don't have info on exactly what they are checking.

Nothing works when the disconnect switch is off.

[mkguitar]

ask them if they have done a "load test"


if not, go get it & throw it in your trunk and get tested


electrical system diagnosis cannot be done with a bad battery






a bad battery may cause other systems to "act" as if they have failed, when in truth they are good.


this results in "parts replacement" which is very very expensive


---------------------------------------


does the battery switch remove the battery from ALL connections ?


if it is only to the DC circuit breakers


"Nothing works when the disconnect switch is off."


possible the battery still "live" to the battery separator or to ac/dc converter ?
if so a bad diode could allow battery to drain


all these are easy checks



mike

[DRich]

Originally Posted by mkguitar

ask them if they have done a "load test"

if not, go get it & throw it in your trunk and get tested

electrical system diagnosis cannot be done with a bad battery

a bad battery may cause other systems to "act" as if they have failed, when in truth they are good.

this results in "parts replacement" which is very very expensive

---------------------------------------

does the battery switch remove the battery from ALL connections ?

if it is only to the DC circuit breakers

"Nothing works when the disconnect switch is off."

possible the battery still "live" to the battery separator or to ac/dc converter ?
if so a bad diode could allow battery to drain

all these are easy checks

mike

I will get in touch with them about the load test and the diode.

I just remembered something else. I had them install a battery monitor. It's a pretty simple thing with a % of battery readout. I didn't have a problem with battery drain before it was installed. Could they have installed that improperly somehow? I'll mention that to them too.

Thanks.

[mkguitar]

if the battery monitor works when your disconnect switch is to the off position


this would indicate that the battery is not fully disconnected from the van

the monitor or a wiring fault could be draining the battery

a meter placed in line would show the current draw

could be you also have a generator which retains connection to the battery with switch to "off"


the "deep cycle" batteries we use are pretty good at recovering from a full discharge, but possible multiple full discharges have affected the battery's capacity



I've never drained mine all the way dead



mike

[Rlum]

Originally Posted by DRich

What could cause house battery to drain when the disconnect switch is off?

The battery is only 2 years old. It started last fall. I would charge to full and in a couple of days the battery is dead. The battery disconnect switch is off. The chassis battery is not draining.

It fully charges when plugged in and when driving. I have a RT 170. The only changes I made in the last 2 years was upgraded to a Novakool and a Truma Aquago.

I've had it in to a shop but they can't seem to find anything wrong.

Any insights would be appreciated.

A couple of years back, I had same problem. It was the battery separator. Stayed closed so chassis battery and house battery stayed connected. Was draining several amps/hour from house bank. Resulted in run down house bank. Interesting, my Victron 712 BMS shows a 0.87 amp draw after everything is turned off? It runs like this for about 3-5 minutes? Finally goes to zero? I think it is the Victron charger/inverter. It seems to take several minutes after being turned off to not draw any power? The Victron multiplus is being controlled by a remote switch and not the switch on the unit.

[mkguitar]

Originally Posted by Rlum

Interesting, my Victron 712 BMS shows a 0.87 amp draw after everything is turned off?

good chance that is a cooling fan running on a charge convertor or similar device


what we are seeing is a perception "everything is off" when everything is not disconnected


if storing pull the negative cable(s) off the battery that will truly be "off"



mike

[Rlum]

Originally Posted by mkguitar

good chance that is a cooling fan running on a charge convertor or similar device


what we are seeing is a perception "everything is off" when everything is not disconnected


if storing pull the negative cable(s) off the battery that will truly be "off"



mike

This makes sense about the cooling fan. Inverter/charger is turned on to run 110 outlet. I use a charger to charge the chassis battery when it has been sitting. Run the power from generator. This way, I exercise the genny and use the power to charge chassis battery. Batteries are left connected during winter months since I am in Southern California. I get some solar for the house battery. It has been cold this winter. Some nights get down to 36. Mostly above 40. For you guys this is nothing but for me, it is cold. Coldest/dry winter in awhile. Not much rain. During the day, it gets above 70 and sometimes 80s.

[booster]

It is actually pretty common, at least on the older than the OP's, Chevy Roadtreks to accidentally have the inverter on. I am not certain that it would happen with the 12v switch turned off though so it would pay to look at the wiring diagram or simulator to confirm that.


The reason that the inverters get turned on by mistake is that the switch for it and the porch light may be unmarked and look the same. We had that setup in our 07 190P.


On edit: The simulator doesn't go that new and doesn't show the inverter switch anyway.


The 2012 Roadtrek manual doesn't show the inverter switch wiring either, unfortunately.


The manual did show the inverter and porch light switches and they are in the same place ours were on the short area above the third seat wall by the control panel area. They still would be easy to confuse or bump, but the inverter one is marked.


Checking that switch would be a place to start.


The Tripplites do take a bit of power when just sitting that won't go away, but it is quite small a and would take a long time to kill a battery. Always is best to disconnect the batteries physically if possible when in storage for a while.

[DRich]

Originally Posted by mkguitar

ask them if they have done a "load test"

mike

I heard back and he said the load test showed the battery tested in fair condition.

The battery monitor does not work when the disconnect switch is off.

I don't have a generator. I've never used the inverter but I'll ask whether he tested it.

[avanti]

Disconnect the battery terminals, get a multimeter and measure the ohms across the disconnected terminals. Then start pulling fuses and breakers until you read zero ohms. If you pull them all and it still isn't zero, you have a deeper wiring problem.

When measuring ohms, connect the meter both ways just in case the offending item is acting like a diode.

[rtbill]

Originally Posted by DRich

The battery monitor does not work when the disconnect switch is off.

That does not necessarily mean the monitor is not connected to the battery. The Link monitor I installed in our RT 200 is powered by a direct connection to the battery's positive terminal. I suppose this makes the monitor as accurate as possible. The monitor draws 200 mA, which will run down the house battery in a few days, resulting in a dead battery if you have to leave the van for service, for example. Once I realized this I moved the monitor's power connection to the DC panel.

Look at your battery. It should only have one big heavy cable connected to each terminal. (And perhaps a temperature sensor if your charger has a temperature input.) Any other wires are red flags for connections that do not go through the battery switch.

[mkguitar]

Originally Posted by avanti

When measuring ohms, connect the meter both ways just in case the offending item is acting like a diode.

good tip


I'd probably try this with 2 meters, with polarity reversed


mike

[Diver007]

Originally Posted by DRich

What could cause house battery to drain when the disconnect switch is off?

The battery is only 2 years old. It started last fall. I would charge to full and in a couple of days the battery is dead. The battery disconnect switch is off. The chassis battery is not draining.

It fully charges when plugged in and when driving. I have a RT 170. The only changes I made in the last 2 years was upgraded to a Novakool and a Truma Aquago.

I've had it in to a shop but they can't seem to find anything wrong.

Any insights would be appreciated.

You might want to check and see if the inverter is on, it will drain a battery.

[JML]

Agreed - check the isolator. (Also, I have heard a bad ground can cause a discharge and it is hard to find/trace.) My issue was an isolator not set up for a lithium house battery, especially when the engine battery was connected to a battery tender. It would not isolate the battery - it appeared it was overwhelmed by the charge voltage difference. When I took off the tender, the isolator allowed the house battery to charge the engine battery. This happened a few times - unless I started the engine the isolator appeared to be 'stuck' open. I just replaced my 100Amp LiPo with a 270Amp and installed a DC to DC charger. Wiring is done but I have yet to energize the system to test it out- The weather turned nasty so I need to wait for a better day. Hopefully the Dc to DC charger corrects this issue. Good luck - electrical issue are a challenge - almost as bad as dealing with a Dometic 3-way fridge! (Which I replaced with an IsoTherm 115 Compressor fridge.) 2013 Pleasure Way Excel TS.

[RossWilliams]

Our webasto furnace is wired directly and is not disconnected by the battery disconnect. This is specifically required by webasto. Perhaps one of your new additions requires something similar.