Onan 4.0 cck resistor

[len k]

If you can, when you do test things, what would help me is to disconnect the wires from the resistor and measure resistances between EACH terminal. Also with the hot supply lead to resistor disconnected measure it's no-load voltage when running. And ideally it's voltage when supplying several amps (like if you have a couple of headlights in series for a load). That should give me enough info to calculate needed resistances.

Overcharging..... I've posted here in several threads.... Onan was not too fuzzy about protecting the battery from overcharging . You can't prevent this with just a resistor, you need something else to shut off the charging. Their older 2 stage relay regulators did this. (voltage sensitive relay). I'm a bit surprised there is not an aftermarket selling this stuff.

With just a resistor you are forced to:
1) design resistor so it's too little charging amps and people will complain bat is dies.
2) or you design it with too much amps and people are happy and when bat dies they assume they bought a cheap battery.

---------- Post added at 12:19 AM ---------- Previous post was at 12:14 AM ----------

Guess which option onan picked.

The original transistor control board did have a 2 stage regulator. I know some people here do repair them, they look pretty basic to repair (if you can read the #'s off the transistors). If they read this they might post something here.

---------- Post added at 12:24 AM ---------- Previous post was at 12:19 AM ----------

Coldshot....If you still have the control board, I think I know someone else here who would like it, working or not.

---------- Post added at 12:38 AM ---------- Previous post was at 12:24 AM ----------

MBB ...... I can calculate a 1 resistor design but it would be a compromise, enough amps to supply loads (spark coil, and fuel pump) plus some more to charge bat. (I'm faced with the same issue onan engineers were faced with.)
But it would have to be a GUESS that also involves bat age, how long you are going to run it between starts. (a run of 30 min would need more amps, then a run of 20hours to reload the bat. A better design to save battery $$$ would be a 110volt automatic charger.

[PnishrPW]

OK, hint taken...

Mike, looking at the same charging issue on my 6.5 NH, Len and I have been bouncing a few ideas around on my 6.5 NH thread. Len`s had some very good input there. I`m looking into several options:

1). Repair/modifying the 859: Since it`s already there... I don`t believe it`s as bad as it`s rep, a couple of minor mods and tweeks and I believe it`s entirely workable. Would be my first choice, as I believe it could be completely rebuilt/modified at least twice for the cost of a Dino or FS board, provided the board itself is re-useable. A1Q1 is the prime offender, I believe. No special/expensive components on it - save for maybe the switches, (if you don`t mind toggles, real cheap...). I figure maybe an hourish of my time to R/R every comonent on that board, less if I just pull 1 leg of the resistors, test and re-install. Still seeking some donor 859`s, to go all Frankenstein on. Some to take up to the lab, and put onto the slab... My 859 is currently (pun intended) doing fine, and is set up presently to test some charging mods I`m considering. I have a CHEAP cure/deletion for the A3/1227 board already.

2). If you dump the 859, you still have a charging issue to contend w/. I`m looking into this now. I`m trying to find something reasonable and off the shelf. Leading contenders at this point are (drum roll please...): Solar charge controller and motorcycle/atv/snowmobile voltage regulators. If pricing and configuration are right, either could be an option. Barring those options, I`m considering designing/building what I need myself. I`ll try to incorperate G1R1, for a variety of reasons.

Not real keen on the 110v charger idea, strictly fron an aesthetic/efficiency point of view, but it`s definately a valid, workable solution - if a tad bit inelegant.

Stay tuned, I`ll be posting more updates on my NH thread as time and progress permits.

Quick, cheap, easy, sleazy, scaleable 12v load bank: 1156 bulbs, pull right on 1 amp/ea. Brass base units are easier to solder wires onto...

---------- Post added at 10:58 PM ---------- Previous post was at 10:47 PM ----------

#94 glass wedge base bulbs are good for ~.25 Amp, for fine tuning...

[MBB]

Len K, Pnishpw
I bought my cck with the modefied wiring already. I took quite a bit of it apart. Installed onan type electronic ignition, cleaned, painted, converted to n/g propane. Replaced what parts were needed. I never even botherd to check charging. I was using an old car battery. I let it run for a couple of hours and shut it down. Since the battery was old I would always charge it before use. Im not sure how much time it would take to run down the battery. I will run it for ahwile and see what its drawing. I will also check the resistor and voltage as described. I too had always figured I would use a battery charger wired into the ac and place a switch in line. For as often as it would be used that would be fine. I could do that also with the resistor just have a switch in line or even a timer and just let it turn on and off at 15 minute intervals. Intermatic makes one thats programable not sure how long battery would last being there is no ac all the time. But even the cheap ones that turn the lights on and off would work.

Thanks again Mike

[len k]

MBB .... Forgot to mension. If you do measure charger output voltage (at brush lead with light bulb loads on it) please also measure current bulbs draw. That way I can calculate the gen's source resistance.

I have a NHM, it draws more 12V amps than yours. Coil, pump, electronic governer. Has two 5 amps fuses. Ran it for a while jumpered to a car (with old bat). After hour or so of testing. Bat wouldn't start it. My gen has the windings for bat charging, but nothing else factory installed. No 12VDC regulator. Got to design my own.

[MBB]

Len K
Just did a few checks of the voltage. First Voltage fromthe output to the resistor is about 26.5 v It fluctuates .5 v Then checked at the other side of the resistor going feeding the control box and I guess the charging circuit and I get 11.25 v I cant disconnect it because it feeds the control box and will kill it. The voltage to the control box through the resistor appears low. I would guess it to be about 12.5 to 14. v I will disconnect the resistor and measure resistance between the taps.

1 to 2 = 50.8 1 to 3 = 60.5 1 to 4 = 64.3

1 to 2 = 50.8 2 to 3 = 9.7 3 to 4 = 3.8

It appears the resistor is good.

Battery voltage at battery not running 12.5v
Battery voltage at battery running 12.5v