Onan QD Question

[jmblake]

I bought a used Onan 7500 QD with 260 hours on it, My question is after it got delivered and I got it unpacked I noticed this sticker on the bottom of the control panel

Does this mean it wont charge the start battery?
And if that's what it means can it be hooked back up?
Thanks Jason

[buswarrior]

Do you know what its original install was?

My guess is that there was a 120 powered battery charging/tending method used.

You can choose to do the same.

Does it have an alternator on it?

Happy coaching!
Buswarrior

[Utahclaimjumper]

You need the Onan schematic to wire it for your application,,The QD series Onan's have an internal "inverter" and uses the 12V."inverted" power to operate and control the engine RPM and output.>>>Dan  ( MY 7500QD has b2650 hours on it )>>>Dan

[richard5933]

A lot of generators had a built-in charger to keep their start battery charged if they were equipped with a separate start battery. From what I've read they were not the best chargers and could boil a battery, at least the older ones.

I agree that it sounds like you system was set up to power a 120v system only so its internal battery charger was disconnected. Most likely the original install had a 120v to 12v charger which kept the start batteries charged.

I'd suggest setting it up in the same fashion, especially since you can get a pretty decent 3-stage or 4-stage charger for not too much money which could just be plugged into a 120v outlet and set up to run whenever the generator is operating.

[gumpy]

These were set up to be connected to the RV engine starting batteries, and relied on the engine alternator to recharge said batteries. Mine is that way. No charge circuit. I use a separate start battery for the generator. I used to have a wire from the house 12v converter hooked which kept the gen start battery charged. Now I just have a small 12v charger connected to the gen battery which I periodically plug in and let recharge. I don't use the generator much, so this works fine. When I use it more often, I charge the battery more often... manually.

[luvrbus]

Just install a small one wire alternator and be done with I have one I will send you if you have room to install it

[Geoff]

I've seen a lot of generators without a gen-start charging system.  A small group 24 battery with a 2amp battery charger running off the generator will keep the generator starting system away from the main engine start batteries. 

[jmblake]

Okay, Thanks for the replies, It was out of a RV, I took the one side panel off but couldn't see much, so I don't know how much room is in there, I thought it might be something simple that just needed hooked up. I plan on a separate start battery for the generator but I would like it to just automatically charge the battery when the genny is running.
Thanks Jason

[richard5933]

On our previous bus I needed to have a set of squirrel fans turn on without fail every time the generator was used. They provided the ventilation and cooling to the bay  housing the generator.

I installed a single 120v outlet with built-in circuit protection (fuse). It was wired directly to the generator control box and mounted on the back of the generator control box. The squirrel fans were plugged into this outlet. It was set to run whenever the generator ran.

You could easily set up something like this and use it to power a small 12v charger. Generator starts - so would the charger.

[TomC]

My generator is wired to the 2-31 starting batteries. I disconnected the belt driven alternator on the generator since it would goof with the big Delco DN50 alternator. Hence, now the generator alternator only is used as belt tension tightener. I also have a jumper relay that connects the house and starting batteries. The generator takes very little juice to run. I have sat for as long as a week running the generator everyday with no problems. On the last day, I just kick the jumper relay on to charge back up the starting batteries. Good Luck, TomC

[luvrbus]

My generator is wired to the 2-31 starting batteries. I disconnected the belt driven alternator on the generator since it would goof with the big Delco DN50 alternator. Hence, now the generator alternator only is used as belt tension tightener. I also have a jumper relay that connects the house and starting batteries. The generator takes very little juice to run. I have sat for as long as a week running the generator everyday with no problems. On the last day, I just kick the jumper relay on to charge back up the starting batteries. Good Luck, TomC

That is the easiest way for Jason just use a continuous duty solenoid with a switch on the dash     

[jmblake]

Thanks for the reply's, I will probably just go with a  battery tender charger for now and hook up a outlet that is powered when the generator is running. I did get to look in there tonight and there is no alternator on the engine, I couldn't see if there was enough room to install one or not.
Jason

[luvrbus]

The little alternators are only 4 inches around and 4-1/2 inches long,practice on changing the belt those are a real pain to change

[jmblake]

Yah, there's not much room in there, I would have to remove the rest of the enclosure to even see if one would fit. That maybe something I look into later once I get my rust issues fixed lol.
Jason

[Fredward]

I wouldn't even mess with trying to fit an alternator inside a QD genset. The belt only drives the water pump and there is no tightener for it. On my MC5 I connected one output from the battery charger to the genset battery. On our current Country Coach, the genset starts from the house batteries. If they become too depleted, I use the "boost" switch that connects chassis batteries to house batteries and start it that way. No genset battery at all.

By the way, it takes a good strong battery with good connections to start that little diesel. 
Fred