rsworden59@gmail.com
Member
Bought a lightly-used 2019 Thor Hurricane 29M from a dealer. Took one long-drive overnight trip, camped with no shore power and all 12V systems worked fine. Parked at home, connected to shore power briefly, and it was then unplugged for the last month. I went in and out a few times; step extended and lights worked, but didn’t go in during the last 2 weeks or so. Yesterday I went to give the generator its recommended monthly run, and *everything* was dead: both house batteries (new) and the chassis battery (2 years old). All reading about 5.9 volts. Plugged into shore power, microwave worked, 12V lights worked. Power at all batteries was still 5.9V. My smart charger tried to charge them but shut off and they drained back to a few volts in a few seconds; a shop’s charger indicated the chassis battery won’t hold a charge. I know that if batteries are left uncharged for a long time they can be ruined. I’ve bought all new batteries and I am topping off their charges but have not installed them yet.
1. I assume some appliance drained the house batteries by 2-3 weeks after parking. I’ll troubleshoot that after I install new batteries. I suspect the fridge or water heater is trying to light, because I heard a spark clicking while I was checking other things. The fridge was coming on after I turned it off, so maybe the Firefly central control was left in a state telling it to run. Any other common culprits you know of?
2. Draining the house batteries should not drain the chassis battery, so I suspect the isolator relay or the dashboard Emergency Start switch has failed. All 3 batteries read ~5.9 volts. After I removed the chassis battery, the house batteries read 4.x volts, which tells me they had been receiving power from the chassis battery, which *should not happen*. Does it sound like I’m on the right track? Is it common for the isolator to fail? I see a few notes about it on various forums. Now that I have the house batteries out of the way, I can reach it to remove it, but haven’t yet. There are a *lot* of wires going into (what I think is) the isolator, so I want to document them all before pulling it. Once I know the model, I can look for troubleshooting instructions. If the isolator failed some time ago, the batteries could have been not charging for a long time without me knowing.
3. I assume if I pull the isolator, I should still be able to use the house systems and the chassis systems independently while I look for what drained the bats from my batteries. Correct?
4. Thor manual says “Battery charging is accomplished by: Automatic charging through the converter or inverter (shore power or generator)"… (and other means). But looking at the converter, the only wires out I can see go to the 12V fuse block and to the Firefly unit. No fuse is labeled as going to the batteries. So I don’t see a route for the converter to charge the house batteries. The Thor schematics are not all accurate, but the one for the battery compartment seems to pretty well match reality. There is one small orange wire going to a house battery positive terminal that is not on the schematic, and I don’t know where it goes, but I would expect a charging wire to be much bigger. When I plugged into shore power, the house batteries read 5.9V, not the 13+ I would expect to see if it was being charged. Maybe there is a route from converter to batteries that goes through the isolator (as the manual states), and the isolator failed in a way that also cut off the ability to charge - has anyone seen this?
5. Thor manual also says “When connected to a 120VAC power source, the converter (or the inverter) will trickle charge the house, and in some installations, the chassis battery.” In the battery compartment I saw the big wire that goes to the inverter, but assumed it was for power *from* the battery *to* the inverter for appliance use… but since I don’t see a diode, maybe the inverter also charges through that same wire? If so it must be able to do that in the “off” state. That wire does *not* go through the isolator. When I was troubleshooting the inverter looked idle, no LEDs lit or fan running, so I assumed it was not involved in charging. When plugged into shore power, the Firefly showed the house batteries at 13.x volts (as if they were being charged), and showed the chassis battery at 5.x volts.
6. With all batteries removed, plugging into shore power has no effect, I imagine because all circuits are open, i.e. no negative battery connection completes the circuit. Do people who stay in one place for a long time ever run strictly on shore power (with no batteries), and if so is it necessary to connect the battery wires in some way to allow the converter to function?
Thanks in advance!
1. I assume some appliance drained the house batteries by 2-3 weeks after parking. I’ll troubleshoot that after I install new batteries. I suspect the fridge or water heater is trying to light, because I heard a spark clicking while I was checking other things. The fridge was coming on after I turned it off, so maybe the Firefly central control was left in a state telling it to run. Any other common culprits you know of?
2. Draining the house batteries should not drain the chassis battery, so I suspect the isolator relay or the dashboard Emergency Start switch has failed. All 3 batteries read ~5.9 volts. After I removed the chassis battery, the house batteries read 4.x volts, which tells me they had been receiving power from the chassis battery, which *should not happen*. Does it sound like I’m on the right track? Is it common for the isolator to fail? I see a few notes about it on various forums. Now that I have the house batteries out of the way, I can reach it to remove it, but haven’t yet. There are a *lot* of wires going into (what I think is) the isolator, so I want to document them all before pulling it. Once I know the model, I can look for troubleshooting instructions. If the isolator failed some time ago, the batteries could have been not charging for a long time without me knowing.
3. I assume if I pull the isolator, I should still be able to use the house systems and the chassis systems independently while I look for what drained the bats from my batteries. Correct?
4. Thor manual says “Battery charging is accomplished by: Automatic charging through the converter or inverter (shore power or generator)"… (and other means). But looking at the converter, the only wires out I can see go to the 12V fuse block and to the Firefly unit. No fuse is labeled as going to the batteries. So I don’t see a route for the converter to charge the house batteries. The Thor schematics are not all accurate, but the one for the battery compartment seems to pretty well match reality. There is one small orange wire going to a house battery positive terminal that is not on the schematic, and I don’t know where it goes, but I would expect a charging wire to be much bigger. When I plugged into shore power, the house batteries read 5.9V, not the 13+ I would expect to see if it was being charged. Maybe there is a route from converter to batteries that goes through the isolator (as the manual states), and the isolator failed in a way that also cut off the ability to charge - has anyone seen this?
5. Thor manual also says “When connected to a 120VAC power source, the converter (or the inverter) will trickle charge the house, and in some installations, the chassis battery.” In the battery compartment I saw the big wire that goes to the inverter, but assumed it was for power *from* the battery *to* the inverter for appliance use… but since I don’t see a diode, maybe the inverter also charges through that same wire? If so it must be able to do that in the “off” state. That wire does *not* go through the isolator. When I was troubleshooting the inverter looked idle, no LEDs lit or fan running, so I assumed it was not involved in charging. When plugged into shore power, the Firefly showed the house batteries at 13.x volts (as if they were being charged), and showed the chassis battery at 5.x volts.
6. With all batteries removed, plugging into shore power has no effect, I imagine because all circuits are open, i.e. no negative battery connection completes the circuit. Do people who stay in one place for a long time ever run strictly on shore power (with no batteries), and if so is it necessary to connect the battery wires in some way to allow the converter to function?
Thanks in advance!
