We have 2020 Montana 3121RL which we purchased new in December of 2020 and have put a lot of miles on since we purchased. Just recently replaced both batteries with the same type that came with the unit. Prior to replacing we could park the camper for months with the power turned off and when we would pick it up we would turn the power back on and the slides plus some lights would work, however since the installation of the new batteries this is NOT the case. Batteries drain down to nothing in a week and nothing will work until plugged in the truck. Any ideas???
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Larry & Marilyn Gubbels
2019 F-350 Diesel 4X4, Short Bed, BW 18K slider,
closely followed by a 2020 Montana 3121RL
We have 2020 Montana 3121RL which we purchased new in December of 2020 and have put a lot of miles on since we purchased. Just recently replaced both batteries with the same type that came with the unit. Prior to replacing we could park the camper for months with the power turned off and when we would pick it up we would turn the power back on and the slides plus some lights would work, however since the installation of the new batteries this is NOT the case. Batteries drain down to nothing in a week and nothing will work until plugged in the truck. Any ideas???
Is your inverter shut off?
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Tony & Donna
2022 Montana HC, 295RL, Solar Flex 400, Onan 3600 LPG, 2K inverter, 200AH Lithium. 2020 GMC Denali 2500 6.6 Duramax, Demco 21K Auto Slide
You are seeing parasitic drain on your batteries due to things connected directly to the batteries that are not disconnected with the installed battery disconnect switch. Install one of these on the negative side and use it when you are away from the rig and you will have full power when you return. https://www.amazon.com/battery-disco...connect+switch
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Bob & Becky
2012 3402RL
2012 Chevy 2500HD D/A CC 4WD
The OP stated that he used to be able to leave with the battery disconnect off and return to charged batteries. Since he replaced with new batteries this is no longer the case. So something has changed.
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Tony & Donna
2022 Montana HC, 295RL, Solar Flex 400, Onan 3600 LPG, 2K inverter, 200AH Lithium. 2020 GMC Denali 2500 6.6 Duramax, Demco 21K Auto Slide
Couple thoughts on the battery: If you found the problem like parasitic drain, the inverter left on, or disconnects left on but the batteries don’t hold a charge anymore, you might need new ones if they are FLAs and were discharged too many times if you trying to use them as-is or troubleshoot with repeated recharges. They’re usually warrantied for 12 months so you could take them back.
If you found the problem, you still might want to check the charge more frequently at first to see if they are holding.
It’s also possible that the batteries are defective but best to rule out potential causes for drain first.
Couple thoughts on the battery: If you found the problem like parasitic drain, the inverter left on, or disconnects left on but the batteries don’t hold a charge anymore, you might need new ones if they are FLAs and were discharged too many times if you trying to use them as-is or troubleshoot with repeated recharges. They’re usually warrantied for 12 months so you could take them back.
If you found the problem, you still might want to check the charge more frequently at first to see if they are holding.
It’s also possible that the batteries are defective but best to rule out potential causes for drain first.
The OP said they were new....He replaced them.
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Tony & Donna
2022 Montana HC, 295RL, Solar Flex 400, Onan 3600 LPG, 2K inverter, 200AH Lithium. 2020 GMC Denali 2500 6.6 Duramax, Demco 21K Auto Slide
If the inverter and the battery switch is off, you have a drain of some kind. Or the batteries that you bought are bad. It does happen. I'd start by charging them to full capacity and doing a load test. If they pass then I'd start checking for a current draw. You can get on amazon cheap.
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Tony & Donna
2022 Montana HC, 295RL, Solar Flex 400, Onan 3600 LPG, 2K inverter, 200AH Lithium. 2020 GMC Denali 2500 6.6 Duramax, Demco 21K Auto Slide
So I don’t see where you say what type of batteries they are. If they are lithium then do they have built in battery heaters that could be draining them, kind of like an upgrade to the old style you had in there. If lead acid then after the first time they went dead there will be damage to the battery and from my experience you will have to keep a trickle charger on them to keep them charged or maybe the water level is low or was low below the top of the plates and damage was caused when that happened. The only other possibility might be that a wire was nicked during new installation of the batteries.
I don’t know how your previous batteries lasted months without being plugged in. My CO detector will drain the battery within two weeks. If you don’t disconnect the negative battery cable, it will kill the batteries. Your CO detector is probably your parasitic drain.
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Don and Kathleen
2019 Montana 3791RD 20th anniversary.
2014 Ram 3500 Dually CC, CTD, Aisin “Kasper”
typical drain items
clocks (microwave)
TV/Stereo
Internet/router/switch/etc
phone chargers left in outlets
any sort of transformers - some cords can have transformers built in
refrigerator left on?
Thermostat set
Dehumidifer
maybe non-typcial but could have been added underneath like light for freezing pipes