Community Forums

Troglegs · 02-22-2019, 02:51 AM

My son has a 2019 Forest River Sierra 357RE fifth wheel and today he had issues with his power converter not seeming to work when he pulled into a campsite tonight. We have 120vac on the power pedestal (so it seems). The battery seems as if it’s low. The 1000watt Inverter kept clicking on and off every few seconds (like it obviously had not enough battery to power the Inverter). I measured 119-121vac at the 120v outlets inside the trailer - but it also seems the power converter won’t stay running either (as I can hear the fan cycling on and off too). Since this fifth wheel has an all electric control panel (my son can control stuff from his phone app) I was wondering if the 12vdc batteries were run down - will nothing work? (Inverter and Power Converter both?). Just looking for advice on how to shoot this bug. Thanks

Tom (for Matt)

2019 Forest River Sierra 357RE
2017 Chevy 1 Ton Duramax Diesel Truck

twinboat · 02-22-2019, 03:22 AM

First, turn off the inverter or things running from it. It will draw more battery power then the converter/charger can provide.

Then with it plugged in, it should charge the battery back up.

A 5 amp 120 volt item running on an inverter will draw 50 amps at 12 volts. Your converter may only be able to supply 50 amps at 12 volts.

While driving, the battery would have been drawn way down and now needs time to charge back up.

Troglegs · 02-22-2019, 03:35 AM

Thanks Twinboat...

I’ll help him diagnose it in the morning...

Only one clarifying point: it was plugged into the power pedestal with a SurgeGuard protector which shows digital readout of the AC voltage. (50 amp trailer plug however at this particular park only on 30 amp pedestal with a 50 to 30 dogbone adapter). While inside the coach - all 12vdc circuits dead. Even while plugged in — which seems to tell me something’s screwed up with the 120ac to 12vdc Charger / Converter. I kept hearing the fan cycle every few seconds on the Converter unit. If I shut off the AC breaker (15amp) which supplies power to the Converter then the cycling of the fan on the device stops). I will try to somehow charge up the coach batteries tomorrow and see if anything changes. My son did say he got stuck in bad weather on the highway and was idling for three hrs while the snowplows opened the road but I’d expect his 1 Ton Diesel Truck’s alternator should have been still charging the batteries? Maybe not? And of course the 1000 watt inverter was indeed ON powering the residential fridge while he was driving... a lot to digest I know.

Thanks

Tom

twinboat · 02-22-2019, 04:11 AM

3 hours ideling in traffic wouldn't do much charging back there. The charging system needed to keep up with the truck loads, heater, wipers, lights,...., and at idle, that may all it could do.

Alternators don't do well at idle, A high idle would have helped.

bigchick · 02-22-2019, 07:39 AM

can you clarify the statement 'all 12vdc circuits dead'? is this when you are plugged into the pedestal? does this include 12 vdc lights and fans?

you seem to be getting 120vac power in. you even say the converter fan runs so it is getting 120vac. if the converter were working i would expect the 12vdc lights and fans to work when plugged into shore power regardless of the charge in the batteries.

if you have a multimeter it would be nice to the the 12 volt reading at the batteries terminals when you are disconnected for shore power and again when you are. this will tell if the batteries are receiving a recharge from the converter.

cavie · 02-22-2019, 08:02 AM

Quote:

Originally Posted by Troglegs

Thanks Twinboat...

I’ll help him diagnose it in the morning...

Only one clarifying point: it was plugged into the power pedestal with a SurgeGuard protector which shows digital readout of the AC voltage. (50 amp trailer plug however at this particular park only on 30 amp pedestal with a 50 to 30 dogbone adapter). While inside the coach - all 12vdc circuits dead. Even while plugged in — which seems to tell me something’s screwed up with the 120ac to 12vdc Charger / Converter. I kept hearing the fan cycle every few seconds on the Converter unit. If I shut off the AC breaker (15amp) which supplies power to the Converter then the cycling of the fan on the device stops). I will try to somehow charge up the coach batteries tomorrow and see if anything changes. My son did say he got stuck in bad weather on the highway and was idling for three hrs while the snowplows opened the road but I’d expect his 1 Ton Diesel Truck’s alternator should have been still charging the batteries? Maybe not? And of course the 1000 watt inverter was indeed ON powering the residential fridge while he was driving... a lot to digest I know.

Thanks

Tom

Check the two 30/40 amp reverse polarity fuses on the converter. Be sure the battery disconnect switch in ON.

Persistent · 02-22-2019, 08:04 AM

The periodic starting and stopping of the converter/charger fan indicates 12 volt overload or 12 volt under voltage.

There are lots of different TT power systems. In some of them, the converter/charger will not charge the batteries when the battery voltage is extremely low. The periodic running of the fan may indicate the charger is periodically testing the batteries.

Some 12 volt systems would require you to use an external battery charger to bring the batteries up to a minimum starting voltage before the built in converter/charger will take over.

Another scenario is a shorted battery. Again, the charger may periodically test the battery and shut down.

In my rig, I have a simple power system. I would disconnect the negative battery bank terminal. My converter charger would provide 12 volt power without batteries connected.

Definitely shut off the inverter. It can be a huge 12 volt power drain. Shut off any other 12 volt power hungry appliances. Only turn them on one at a time after you restore proper 12 volt system operation.

At this point the battery voltage may rise enough to start the charger/converter again.

Measure the battery voltage. If it is flat out dead, disconnecting the battery may get you started on shore power.

Troglegs · 02-22-2019, 12:46 PM

Thanks all... I checked the batteries and found the cells low on water - but much worse, I found that the parallel connection cables to the two 12v batteries were “finger tight” which would cause higher resistance. Also found the main lugs in the power distribution center coming from the batteries to be loose as well. Also bad. Tightened them up, topped up batteries and finally got the 12vdc systems to power up and the Inverter stays on when powered up now (turned it off as he’s on shore power now. Hopefully the Converter/Charger module will top up his batteries now. Does anyone know if that 1000watt pure sine wave inverter is only used for the refrigerator? Or do the household AC plugs also run through it. If it’s the latter - then that may have contributed to his dead batteries too since he found his 55” TV in the “on” position when he pulled in last night and the batteries were not properly working.

Thanks again for all your help.

Tom

bigchick · 02-23-2019, 05:05 AM

i am glad that you resolved the problem. most likely a 1000 watt inverter will only power a residential refrigerator, but of course i cannot be absolutely certain of that without seeing it. our residential refrigerator says it uses 8.5 amps which it nearly the total capacity of a 1000 watt inverter.

sounds like your son needs to pay a bit more attention to the batteries.

finally there are different opinions on whether to turn the inverter off when connected to shore power. there will be a small transfer switch either in the inverter itself or a small external one that will transfer the refrigerator to shore power when it is present. when it does this the inverter is simply in standby mode and is not consuming any battery power (other than the amount to keep it in standby mode). should you lose shore power the inverter will then kick in and supply power to the refrigerator. many people say leave the inverter on. others say turn it off when on shore power as even if you lose shore power the refrigerator will stay cold for many hours.

cavie · 02-23-2019, 05:10 AM

Quote:

Originally Posted by Troglegs

Thanks all... I checked the batteries and found the cells low on water - but much worse, I found that the parallel connection cables to the two 12v batteries were “finger tight” which would cause higher resistance. Also found the main lugs in the power distribution center coming from the batteries to be loose as well. Also bad. Tightened them up, topped up batteries and finally got the 12vdc systems to power up and the Inverter stays on when powered up now (turned it off as he’s on shore power now. Hopefully the Converter/Charger module will top up his batteries now. Does anyone know if that 1000watt pure sine wave inverter is only used for the refrigerator? Or do the household AC plugs also run through it. If it’s the latter - then that may have contributed to his dead batteries too since he found his 55” TV in the “on” position when he pulled in last night and the batteries were not properly working.

Thanks again for all your help.

Tom

Troglegs · 02-23-2019, 08:32 AM

Thanks for the info. I passed it on. I also noted that his battery voltage on his systems monitor panel showed 12.38v - even after it was plugged in overnight. It almost seems as if the charger converter put in by FR is not very good. So we drove to WalMart and picked up a “battery tender” and after a few hours it was up to 13.24v. Hmmm.

Another factory “cheap crap” replacement: they had very thin gauge wires connecting the two Interstate 12vdc batteries together in parallel... so we swapped them out for 4 gauge heavy battery cables... so hopefully the two batteries will operate more like a true battery bank should now. And I did find out that with the Inverter off the fridge still has power so there must be an internal transfer switch inside it or connected with it.

Thanks for your help!

Tom

Persistent · 02-23-2019, 09:03 AM

Quote:

Originally Posted by Troglegs

Thanks for the info. I passed it on. I also noted that his battery voltage on his systems monitor panel showed 12.38v - even after it was plugged in overnight. It almost seems as if the charger converter put in by FR is not very good. So we drove to WalMart and picked up a “battery tender” and after a few hours it was up to 13.24v. Hmmm.
...

Great that you found the problem. Been there done that. Road vibration does strange things threaded joints. Connections loosen. Tow vehicle is no longer helping out. Refrig kills batteries.

That voltage profile does seem to be charging slow. Were the batteries actually dead? Dead to 12 volts can take a while with some chargers. It may charge slowly at very low battery voltages and then pick up again as the voltage rises.

What is the converter charger maximum current output? A 40 amp charger should bring the voltage up substantially on a 200 amp hour battery bank in 5 hours.