Batteries dead while connected to shore power

[Thom&Teresa]

our 2018 Thor Windsport is connected to shore power and something is draining my batteries dead, (both, vehicle battery and house batteries). The TV and refrigerator didn't work, of course. I charged up the battery bank for 24 hours and all was well.

Until 3 days later, the batteries died again, while on shore power. I checked fuses and circuit breakers, converter. Inverter wall panel shows over 13 volts.


Any ideas appreciated....

[javelin]

Whenever you are on shore or gen always make sure your use/store switch is in the use (on) position. Thi ensures (assuming all systems are working correctly) that the coach converter (battery charger) is connected to the batteries. Of course there could be other reasons for this charging to not work as well.


The best thing for all RVers is to purchase a digital mulitmeter and learn how to use it. Then use the voltmeter portion to actually measure your battery voltage and see if the charging system(s) is working to charge batteries or not. Typical wet cell full charge is 12.6vdc (when not charging; light or not loaded). When charging you should see 13vdc or higher approximately. If not then something is wrong; time to investigate.

[Oneilkeys]

Check the voltage at the batteries with a volt meter and see if you are getting power from the converter charge4 to the batteries. If not, the use/store is the first place to look and the 50 amp breaker to the house batteries (in my Axis it is on the left rear side of the battery box) is the second.

[Trkyte@msn.com]

My guess is that your use,store switch is in store position. The invertor is wired directly to the coach batteries. Which would draw down the batteries.
If you are sure you are in use position, then the latching relay might be bad.

Charge the coach batteries again, disconnect the shore power, put the switch in use and verify that the coach has power. (This proves that the latching relay is working) Then reconnect the shore power.

If the batteries still discharge you’ll have to get a knowledgeable troubleshooter involved.

[SANDDOG]

Originally Posted by javelin

Whenever you are on shore or gen always make sure your use/store switch is in the use (on) position. Thi ensures (assuming all systems are working correctly) that the coach converter (battery charger) is connected to the batteries. Of course there could be other reasons for this charging to not work as well.


The best thing for all RVers is to purchase a digital mulitmeter and learn how to use it. Then use the voltmeter portion to actually measure your battery voltage and see if the charging system(s) is working to charge batteries or not. Typical wet cell full charge is 12.6vdc (when not charging; light or not loaded). When charging you should see 13vdc or higher approximately. If not then something is wrong; time to investigate.

100% correct the multimeter has been a lifesaver for me, I can double check when the shore power is on and the battery show a charge.

[cavie]

Inline fuse near the battery.
two reverse polarity 30/40 amp fuses on the converter.
120 volt 15 amp breaker in the main breaker box.

120 volts to the converter? DC volts out of the converter?

[Brett]

Question. My store use switch is either on or off its actually kind of strange the way it works to me. As an electrician. I do not have any indication of on or off other than the light. Maybe its just too simple ....Can you educate me please.

Thank you

Brett

[Yaktop]

Victron BMV-712 Battery Monitor https://www.amazon.com/dp/B075RTSTKS..._pRL9Db2KTK62A

[Trkyte@msn.com]

to Brett:
Some rvs have a light on the use/store switch. The way thor wired these is confusing at best.

I don't have the light, so my procedure is to leave a light on in the coach. operate the store switch and the light goes out. (of course rv is not on shore power.)

Before! going to shore power, operate use switch and the coach light comes on.

[petefoss]

I do have a light so when plugged in, I can't use the light to know if the converter is on or off. Since I do have a inverter, I pop it on to check the battery voltage. Below 13 the converter is off. I tend to leave the inverter off when plugged in because if I lose power the inverter will deplete the batteries quite quickly.

[16ACE27]

Originally Posted by Brett

Question. My store use switch is either on or off its actually kind of strange the way it works to me. As an electrician. I do not have any indication of on or off other than the light. Maybe its just too simple ....Can you educate me please.

Thank you

Brett

The light is not an indication of the position of the USE/STORE switch/relay or battery connect/disconnect. It is simply an indication of power on the DC buss. That power may be coming from the converter (if on SP or generator running) or it may be coming from the house batteries if the switch/relay has the house batteries connected to the DC buss; but you can't use it to tell the position of the USE/STORE switch/relay unless there is no 120 VAC coming into the converter.

[Yaktop]

Happened to me. Converter was bad, boiled the batteries.

[seaspys02]

The emergency start switch could be stuck in the open position, this will drain both house and vehicle battery. I also had to replace inverter. I have had many problems with electrical systems on a 2019 Thor Hurricane, it’s been in the shop more then it’s been on the road.

[16ACE27]

Originally Posted by seaspys02

The emergency start switch could be stuck in the open position, this will drain both house and vehicle battery. I also had to replace inverter. I have had many problems with electrical systems on a 2019 Thor Hurricane, it’s been in the shop more then it’s been on the road.

The emergency start switch is a Normally Open (NO) switch; it would have to stick in the closed position. Closed switches allow current flow; open switches interrupt current flow.

[Chief]

Originally Posted by 16ACE27

The light is not an indication of the position of the USE/STORE switch/relay or battery connect/disconnect. It is simply an indication of power on the DC buss. That power may be coming from the converter (if on SP or generator running) or it may be coming from the house batteries if the switch/relay has the house batteries connected to the DC buss; but you can't use it to tell the position of the USE/STORE switch/relay unless there is no 120 VAC coming into the converter.

The store use switch (master switch) must be in use position for the batteries to stay charged. There is also a fuse/breaker on the coach battery box if is hanging down it is open Also if you call Thor they can help you and send you a wiring diagram

[16ACE27]

Originally Posted by chief

the store use switch (master switch) must be in use position for the batteries to stay charged when plugged into sp or running the generator. It must be open if storing the coach without sp and you don't want the batteries to drain quickly. There is also a fuse/breaker on the coach battery box if is hanging down it is open also if you call thor they can help you and send you a wiring diagram

ftfy

[dokrob]

Originally Posted by Thom&Teresa

our 2018 Thor Windsport is connected to shore power and something is draining my batteries dead, (both, vehicle battery and house batteries). The TV and refrigerator didn't work, of course. I charged up the battery bank for 24 hours and all was well.

Until 3 days later, the batteries died again, while on shore power. I checked fuses and circuit breakers, converter. Inverter wall panel shows over 13 volts.


Any ideas appreciated....

Had the same issue, the batteries were totally dead. The dealer told me that the batteries from the factory are typically 18 month batteries, and they were surprised mine had lasted 2 years. (2018 Thor Chateau). Ended up buying two new batteries at CostCo. Just my two cents.

[Jacktextor]

All excellent suggestions! I purchased an inexpensive digital volt meter that plugs in the dash lighter outlet. This way I know the condition of my coach/start batteries all the time.

[Brad2018]

I just learned all of these lessons about the house battery and the use/store switch after having the RV for over a year. Found the house battery was dead after doing some work on the RV. It stays on shore power all the time but the switch wasn't in the "use" position. I assumed that I could use the battery level indicator to monitor the batteries in every scenario. It showed 100% on the indicator but the battery was dead. I'm guessing that I was seeing the chassis battery?

Apparently, it's best to turn the use switch on before connecting to shore power to ensure that it's in the correct position.

I added this small panel to monitor the house batteries. It's connected right to the house wire at the relay. It also gives us a USB charging port at the table.

[16ACE27]

Originally Posted by Brad2018

I just learned all of these lessons about the house battery and the use/store switch after having the RV for over a year. Found the house battery was dead after doing some work on the RV. It stays on shore power all the time but the switch wasn't in the "use" position. I assumed that I could use the battery level indicator to monitor the batteries in every scenario. It showed 100% on the indicator but the battery was dead. I'm guessing that I was seeing the chassis battery?

Apparently, it's best to turn the use switch on before connecting to shore power to ensure that it's in the correct position.

I added this small panel to monitor the house batteries. It's connected right to the house wire at the relay. It also gives us a USB charging port at the table.

The battery level indicator indicates the voltage on the DC buss, not the battery itself. So if the converter is supplying power to the DC buss it will always indicate 100%.