Onan generator issues?

topwop · 02-17-2021, 03:27 PM

I have a 2006 Roadtrek 210 Popular with an Onan generator that just started to give me a little problem. I have it plugged in for winter storage and go out and crank up the genny every 3-4 weeks and let it run for about an hour but yesterday something different happened. I have power to the batteries and when I try to turn it over it cranks for like 2 seconds then nothing and my interior lights go dim for about a minute. After that the lights brighten back up and I try again I go through the same thing. Any ideas? It has been below freezing here for about a week or two so I wasn't sure if that would have anything to do with it or not? By the way it only has about 120 hours on it. All help or ideas will be greatly appreciated!
Has anyone every replaced the old Onan with something different (other than solar because that's not happening

) like a Honda or whatever?

booster · 02-17-2021, 03:47 PM

Quote:

Originally Posted by topwop

I have a 2006 Roadtrek 210 Popular with an Onan generator that just started to give me a little problem. I have it plugged in for winter storage and go out and crank up the genny every 3-4 weeks and let it run for about an hour but yesterday something different happened. I have power to the batteries and when I try to turn it over it cranks for like 2 seconds then nothing and my interior lights go dim for about a minute. After that the lights brighten back up and I try again I go through the same thing. Any ideas? It has been below freezing here for about a week or two so I wasn't sure if that would have anything to do with it or not? By the way it only has about 120 hours on it. All help or ideas will be greatly appreciated!
Has anyone every replaced the old Onan with something different (other than solar because that's not happening

) like a Honda or whatever?

That sounds like classic low battery symptoms. Could be a combination of weak batteries, poor charging, on top of the cold weather. If the van is runnable, you may want to start the van for a bit and then leave it running and try the generator.

IMO, solar is great, but can't replace a generator for all it can do.

topwop · 02-17-2021, 04:04 PM

New batteries last fall, started and ran the RV for about 15 minutes before trying the genny, and tried again after about an hour still nothing.

booster · 02-17-2021, 04:46 PM

Quote:

Originally Posted by topwop

New batteries last fall, started and ran the RV for about 15 minutes before trying the genny, and tried again after about an hour still nothing.

Did you try leaving the engine running, that is important. 15 minutes run time in cold weather will not give you much charge at all and could actually reduce usable charge.

New batteries last fall might indicate a loose connection someplace also as that is a recent change.

I assume it is not on a trickle or shore charger? If not, especially wet cells could be pretty low when combined with the weather. AGM not as much, but the generator may have thick oil in which would make it much tougher, although if it is very cold it will be tough anyway to get it to turn fast enough to start.

topwop · 02-17-2021, 06:42 PM

Doesn't leaving hooked to shore power charge the battery through the inverter?

booster · 02-17-2021, 06:51 PM

Quote:

Originally Posted by topwop

Doesn't leaving hooked to shore power charge the battery through the inverter?

Yes, if you have shore power to the van, that was one of the questions, but it also could be that you are not charging because of a bad connection with new batteries. What voltage are you seeing on the system with shore power on and and shore power off?

topwop · 02-18-2021, 01:24 AM

I went out and checked the voltage and the batteries were down to almost nothing. Set up the charger and will check it out tomorrow. Thanks for getting back with me.

JohnnyFry · 02-19-2021, 06:50 PM

If you are in below freezing temperatures you should be aware that a fully discharged FLA (flooded lead acid) battery can freeze, which, of course, will ruin the battery.

topwop · 02-20-2021, 12:11 AM

I was aware of the freezing issues as I have worked on cars as a hobby for the last 50+ years but what I don't understand is when the RV is plugged in to shore power the battery should be fully charged and mine were not. Not that it should make any difference but I do run 2-6V golf cart batteries and both were down to 1v. Does anybody know how to check to see if I'm getting shore power to them while plugged in?

JohnnyFry · 02-20-2021, 02:24 AM

I agree that the coach batteries should be charging. Something is amiss: possibly a fuse in the battery circuit, a circuit breaker on the AC side, a faulty converter or inverter/charger.. clearly some trouble shooting with a multimeter is in order.

Twinbridges · 02-20-2021, 05:30 PM

Just had installed the new model D2-L Espar heater. It is quiet and very efficient. Fuel source is the diesel van tank and fuel use is very miserly. This is a serious heater with great engineering.

joeski · 02-21-2021, 08:28 PM

I rigged up a voltmeter with a cigarette lighter plug and check the coach batteries in my TV outlet socket.. I had problems in my inverter the leads were arcing, after tightening and cleaning, the batteries are charging.also as it was said, check the battery terminals clean and tighten. And remember before you shut the generator down let it idle with no load for a few minutes, I didn't and ruined the wires in the armature. I also put a shut off valve in the fuel supply line and run the generator dry so the carb doesn't have any standing fuel in it. Also you can put a 100 watt bulb under the generator to warm the oil up. I hope this helps good luck!

Hatteras Jim · 02-21-2021, 10:50 PM

Looks like you are on your way to correcting your problem. For future reference, Flight Systems publishes a free Onan Genny Troubleshooting guide. https://www.flightsystems.com/troubleshooting/

190Roadtrek190 · 02-21-2021, 10:53 PM

Start the vehicle and the motors alternator will supply power to the rv battery and then start the onan and if that doesn’t work the starter may be bad. I’ve taken mine out twice to work on the unit which has been working fine other then a starter issue.

rowiebowie · 02-22-2021, 03:51 AM

Quote:

Originally Posted by 190Roadtrek190

Start the vehicle and the motors alternator will supply power to the rv battery and then start the onan and if that doesn’t work the starter may be bad. I’ve taken mine out twice to work on the unit which has been working fine other then a starter issue.

Welcome to the forum!

Bertiboo · 02-23-2021, 02:20 AM

Note also that older converters can overcharge batteries and “boil off” the fluid in lead acid batteries, even if newer deep cycle batteries. In my case I upgraded my 2008 RV to a 3 stage smart (digital) converter due to several instances of winter destruction of my coach batteries. Also invested in Trojan system to more easily top up my Trojan batteries with water using a pump with interconnected tubes and valves... this keeps them topped up so they don’t run dry. But in the case of the generator not starting that might also be due to the chassis battery being low. A cigarette lighter battery tender plugged into an outlet (while your RV is on shore power) will do the same thing as the aforementioned smart converter does for the coach batteries. As said by others, a poor connection may also be at fault if you’re running the van, and the genny still doesn’t start.

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