Chinook RV

I am similarly inclined to remove our noisy, smelly Onan 4KY generator that has become 150 lbs of unwelcome ballast jouncing the rear axle more. Our need for 110V AC became negligible after we ditched the rooftop A/C and microwave. Now it’s absurd I only run it once a month for exercise so it starts reliably next month for more exercise!

Soooo… my basic question - does the Onan slide out horizontally through the access hatch or drop down vertically for removal underneath? Either way, my preliminary inspection was daunting with limited clearance for necessary disconnects. My search turned up few specifics so I appeal here to those who have already performed the surgery.

Hi Ted,

Yours may be different but this is what I did...
Remove the exhaust, remove the door and frame, remove the four bolts from underneath, slide to the right as far as possible to remove the electrical connections and the fuel connection, then get a friend to help you lift it out through the access hole. Mine was about 170 pounds.

Thanks Scott. I shall proceed accordingly after enlisting a burly assistant. A tip I saw on YouTube was to have a spare tire laying flat to dump the generator on outside the door. This was for a Class A that had a lot more room to slide it out.

Lots of great input...learning as I go....

How about one of theses options;
1. Just get 2 group 31 flooded batteries to replace the 27s and call it a day.
2. Get 2 group 31 AGMs but in tray where the 27s are, install a PD4645v smarter charger for the AGMs, leave wiring as stock
3. Do 2. and run larger wire from charger directly to batteries and eliminate the LVD and install a manual or remote disconnect. With this I'd need some sort of monitor to "watch" what going on with the batteries.

With any of these I'll remove the genset and use a Honda 2000 when needed.
Next spring upgrade the Solar.

The beast hath begone! Suitably emboldened by Scott’s tips I removed the Onan 4KY this morning.

First, I attempted to remove the hatch trim and door for more wiggle room. No such luck; it was still held firmly in place by some mysterious force even after all perimeter screws were extracted. Prying didn’t budge the trim and only threatened damage.

It was easy to remove the exhaust pipe and five bolts underneath that held the unit to the plywood floor. Now for the harder part - those pesky 4 electrical connections plus fuel hose that were wedged against the left wall. The generator had to be leveraged sideways to the right, just as Scott advised, to gain more working space. Then everything came off with a liberal dose of patience but I finally resorted to wire cutters on the red/green/white wires disappearing under the control board.

Extracting the untethered generator then proved the hardest part. It needed to come out square to the opening otherwise the case hung up on the door flange. It certainly would be better with this piece off. Damage to the flange became inevitable after I found no way to finesse the situation.

The pictures tell the tale. I wisely placed a hand cart to catch the generator and remove it from the scene for later disposal. Now I’m pleased with all that extra storage space but need to seal the bottom with a nice floor. The original plywood is rather distressed and full of gaping holes that naturally let in dust. Finally, I remembered to plug the fuel line in such a hazardous location under the gas fridge!

autox: Just thinking out loud here. (And of course the usual caveats of don't try things you don't feel comfortable with, double check info, etc.).

If you want to keep it a bit more simple for now, you could stick with the stock charger* (which is pretty tough on batteries), and the stock lossy wiring to the batteries (also hard on them), and just get a couple of relatively cheap flooded cell batteries. Just plan on them as consumables (all batteries are consumables, but I mean a year or two vs. five+ years). Then in a year re-evaluate.

For me, if I'm going to upgrade one major link in the chain (say you are going to get a pair of Lifeline Group 31+ batteries -- 125 ah each, same case size as a 31), then I'm going to upgrade other links too, so I don't kill them. For me doing just part of it is like buying a big heavy anchor but keeping the "string like" original anchor rode. Unbalanced. Here would be my minimum for the upgrade scenario (and considering your often-plugged-in use case).

1) Promariner ProCharge Ultra 40 amp charger (if you decide to do this we can talk more about what's involved in installing it).

https://www.amazon.com/ProMariner-63140 ... B004NPOT4G

(This is also produced as the Sterling ProCharge Ultra, if I have the name right. Both made by Sterling.)

2) Heavier cable run along couch wall to batteries/matching heavier cable to frame for chassis ground.

3) Blue Sea MRBF on house bank (overcurrent protection).

4) Two Lifeline GPL31XT batteries (you could consider moving battery bank to under couch, but these would also fit in battery compartment and give you 250 total amp hours).

5) Balmar Smart Gauge and/or Victron BMV 702 battery monitor(s). Like having a gas gauge for the batteries. The LVD that is in many Chinooks is, to my mind, not that useful as a battery saving device. By the time that thing crows, your batteries are gasping for life. It's like having a light on the dash that shows you when you have a tenth of an ounce of gas left in the tank instead of a gauge. Hey thanks.

The latter is more work, and obviously quite a bit more money. You may prefer to just grab a couple of new "disposable" flooded cell batteries and go camping, then re-evaluate in a year. That's what I might do if I wasn't sure which direction my usage would be taking and/or I wasn't up for a project.

BG

*Speaking of chargers, the reason I don't really like the "drop in" replacement chargers that fit into the brown box is that they are not adjustable for various battery parameters, and they don't have temperature compensation. Temp comp is a big one for any lead acid batteries (this includes flooded cells and AGMs). The batteries want specific charging voltages, to within a tenth of a volt. But the specified voltage is only good at 77ºF. At any temperature that is warmer, that number goes down. At colder temps it goes up. So let's say you get the Lifelines, and they want to absorb at 14.4 volts (at 77ºF). Now let's say they are in the outside battery compartment and it gets down to 40ºF overnight. By morning the mass of the batteries is down to 40º, and it likely won't be too much warmer for much of the day (I can see the temp of my batteries via a meter and let's say I'm solar charging at 11 a.m. the charger (under my couch) may be at 75º but the batteries (which are also under the couch so never get as cold as if they were outside) could easily be at 50ºF.

If the charger is not temperature compensated, then it will be pumping the same 14.4 volts in that the batteries want to see at 77ºF. BUT, at 50ºF, they want to see 14.72 volts. That may not sound like much difference, but in the world of charging lead acid batteries, that's a large gap.

The temperature compensation itself is nothing hard to install; it's typically just a ring terminal you put on a battery lug and then click the other end into a socket on the charger. But the charger has to be equipped for it. As far as I know the "brown box" drop in units aren't adjustable and don't have temperature compensation (last time I checked).

This is essentially the reason the stock "lossy" wiring to the batteries is bad. It's so long and thin that there is a lot of voltage drop. So you (if you have a capable charger) set things up "just so" and the precisely right voltage heads out to the batteries, but then by the time it gets there, it's a completely different voltage (due to voltage drop/loss).

Rokrover: Whoa, score!! I've been wanting to take out my generator for ages, but just haven't gotten around to it. Now I'm inspired! (And you have the same door/gen setup as me, so the photos are great.)

Just look at ALL THAT storage space!! (Especially if you don't plan to carry a portable generator.)

BG

PS: Ironic on that hatch surround. All of the other ones that I've removed/replaced have basically fallen off by just looking at them (which is why I removed/improved/replaced them). The main culprit in most of mine was the little plywood strips that were essentially bondoed in place on the backside. Polyester has a pretty weak secondary bond. Figures that the one you want to remove is on there "permanently."

Oh, although looking at your photo, I think you might have the newer style, wherein instead of having exterior screws (with a vinyl cover to hide them) you have the smooth ones that are clamped from the inside instead?

After some trial and error, I found a place where you can order custom-sized exterior hatch doors like the stock ones (so you could get a new frame, plus a door without expanded metal sections). I can't find the info on my computer, but have the box in storage (I ordered one to replace the water heater door). My guess is you'll come up with a fix though

Rokrover wrote:The original plywood is rather distressed and full of gaping holes that naturally let in dust. Finally, I remembered to plug the fuel line in such a hazardous location under the gas fridge!

Great job, Ted! Thanks for posting the pics and text.

The generator enclosure in my Chinook is all fiberglass, so again we're different, but I wanted to show how I handled the holes in the floor. 1/4 inch plywood, a couple coats of oil based primer, fixed to the fiberglass with acrylic caulk. Underneath I sprayed black undercoating. For the fuel line, the hose is fixed to the bottom of the rig and plugged with a steel dowel pin and hose clamp; it's just as safe as the Onan connection IMO. The three holes to the left are covered by the batteries (not pictured). My door has only one screen section (at the rear); very little dust gets into the compartment. I considered covering it from the inside but it provides ventilation for the batteries.

Blue, I think that's good advice, I'll wait for a couple trips to see how the batteries hold up. I'm saving your recommended new set up and if I go sooner than later the new 31 flooded batteries I can use on the ranch with the diesel pumps.
In the meantime I think I'd like to get a monitor to see my usage and available hours on the batteries, all I have now is the stock solar controller showing voltage.I'll look at getting either the Balmar or Victron.
Just finished putting in some LED lights in the center fixtures (Cabin Brights) from Amazon, $31 expensive. I have the LED tape and pig tails coming next week as I saw on this forum allot cheaper if they work as good.

Blue, I think that's good advice, I'll wait for a couple trips to see how the batteries hold up. I'm saving your recommended new set up and if I go sooner than later the new 31 flooded batteries I can use on the ranch with the diesel pumps.
In the meantime I think I'd like to get a monitor to see my usage and available hours on the batteries, all I have now is the stock solar controller showing voltage.I'll look at getting either the Balmar or Victron.
Just finished putting in some LED lights in the center fixtures (Cabin Brights) from Amazon, $31 expensive. I have the LED tape and pig tails coming next week as I saw on this forum allot cheaper if they work as good.