| Onan battery charger [message #283109] |
Sat, 25 July 2015 12:06  |
Luvn737s
Messages: 1106
Registered: June 2007
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Does the Emerald II have a dedicated battery re-charger capability for the starting battery or does it rely on the battery being part of a circuit getting DC power through the PD unit to recharge itself? I may have had a bad battery but as the Onan ran, the battery discharged to the point that it couldn't maintain ignition and quit.
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
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| Re: Onan battery charger [message #283112 is a reply to message #283109] |
Sat, 25 July 2015 12:24  |
Bullitthead
Messages: 1411
Registered: November 2013
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ANY generator with an electric starter should have a battery recharging function built in. Wouldn't make sense to have it without that because the battery would eventually run down. They won't charge 30 amps or more like a vehicle alternator is capable of, but it needs to make up for the ignition and/or fuel pump and a little extra to replace what was used in starting. All three of the Onans I have are supposed to recharge the starting battery, including an Emerald and a stand-alone unit. Unfortunately, the one in our GMC has a faulty charging circuit that I have not delved into yet, so I am in a similar situation to yours. My temporary solution is to use a separate battery charger and a really big battery. I have wired an alternator-energized relay that connects it to the 455 charging system whenever that alternator is charging the engine battery.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: [GMCnet] Onan battery charger [message #283113 is a reply to message #283109] |
Sat, 25 July 2015 12:38 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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On Jul 25, 2015, at 1:06 PM, Randy wrote:
>
> Does the Emerald II have a dedicated battery re-charger capability for the starting battery or does it rely on the battery being part of a circuit
> getting DC power through the PD unit to recharge itself? I may have had a bad battery but as the Onan ran, the battery discharged to the point that it
> couldn't maintain ignition and quit.
The Emerald II was not the OEM generator for the GMC so whoever put it in might have used the charger capability or they might have disconnected it.
In the GMC the Onan power drawer had two configurations - some of them had a dedicated starting battery and in that case the alternator/voltage-regulator circuit was connected.
In later configurations the starting battery - and its charging circuitry - was eliminated and those units depend on the house battery for starting. These units may still have the voltage regulator mounted on the forward side near the fuel pump but the regulator was disconnected and its wires taped up.
--Jim "saving the lives of Onans...one unit at a time" Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: [GMCnet] Onan battery charger [message #283119 is a reply to message #283114] |
Sat, 25 July 2015 13:35 |
Jim Miller
Messages: 501
Registered: March 2008
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> On Jul 25, 2015, at 1:52 PM, Terry wrote:
>
> Jim, my GMC onan has the regulator on it and 2 of the 3 terminals are connected. 1 terminal is not connected to anything. I have looked for pics on
> the photo site and IIRC, what I saw was the same as mine, with the same terminal unconnected. Is a wire missing or does it not need that terminal to
> charge? I thought I looked at the schematic and determined that it was not necessary, but that was months ago and many other things have clouded my
> brain since then and now I can't recall what I had for breakfast... :lol:
Hi Terry, I have never seen a coach that had the separate starting battery in place so I cannot authoritatively say - however from looking at the schematic and just having examined five Onans here at the Miller compound it appears that only two terminals were used on the regulator.
I did notice that one of the terminals has two wires running to it via a “spade doubler”.
Personally I like the idea of having a separate starting battery for the Onan - it would provide the ability to “bootstrap” yourself back into action if you happened to run down the house battery with the fridge and lighting while dry camping and the kids playing the dash stereo ran down the engine battery. Don’t ask me how I know this. :(
--Jim "saving the lives of Onans...one unit at a time" Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: [GMCnet] Onan battery charger [message #283121 is a reply to message #283119] |
Sat, 25 July 2015 14:26 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Jim
Sounds like it time to move a wire from the dash radio from the engine battery to the house battery. I did this many years back and it would prevent your radio from running down the engine battery.
That would be a lot cheaper and a lot less maintenance than having a third battery.
Emery Stora
77 Kingsley
Frederick, CO
> On Jul 25, 2015, at 12:35 PM, Jim Miller wrote:
>
>
>> On Jul 25, 2015, at 1:52 PM, Terry wrote:
>>
>> Jim, my GMC onan has the regulator on it and 2 of the 3 terminals are connected. 1 terminal is not connected to anything. I have looked for pics on
>> the photo site and IIRC, what I saw was the same as mine, with the same terminal unconnected. Is a wire missing or does it not need that terminal to
>> charge? I thought I looked at the schematic and determined that it was not necessary, but that was months ago and many other things have clouded my
>> brain since then and now I can't recall what I had for breakfast... :lol:
>
> Hi Terry, I have never seen a coach that had the separate starting battery in place so I cannot authoritatively say - however from looking at the schematic and just having examined five Onans here at the Miller compound it appears that only two terminals were used on the regulator.
>
> I did notice that one of the terminals has two wires running to it via a “spade doubler”.
>
> Personally I like the idea of having a separate starting battery for the Onan - it would provide the ability to “bootstrap” yourself back into action if you happened to run down the house battery with the fridge and lighting while dry camping and the kids playing the dash stereo ran down the engine battery. Don’t ask me how I know this. :(
>
> --Jim "saving the lives of Onans...one unit at a time" Miller
> 1977 Eleganza II
> 1977 Royale
> Hamilton, OH
>
>
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| Re: Onan battery charger [message #283130 is a reply to message #283109] |
Sat, 25 July 2015 17:22 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
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IIRC Duane said to leave the 2 wires on the doubler as such but removed from the regulator and taped up. The single wire gets removed and taped over as well. I think this is on his video.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Onan battery charger [message #283131 is a reply to message #283109] |
Sat, 25 July 2015 17:29 |
Luvn737s
Messages: 1106
Registered: June 2007
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Thanks. I'll look for the voltage regulator output. My old Kohler had no battery charger on it either but my combiner seemed to keep everything charged. It may have charged off the alternator when the engine was running though, now that I think about it.
I am trying to say cool with the roof AC while working on a tranny drip at 107F outside, which precludes running the engine for recharging.
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
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| Re: Onan battery charger [message #283141 is a reply to message #283131] |
Sat, 25 July 2015 19:15 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Randy,
In the 73 & 4 versions, the coaches had a dedicated APU start battery.
The early Emeralds did have (iirc)a WAFWOT battery recharge circuit.
I no longer have any Emerald documentation.
Good Luck
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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What Emery said makes perfect sense regarding the dual charging scenario, as any charge going to the battery is going to put a higher voltage on the system and another charger will see that bias and so less current will flow from it, or none at all if the voltage set point is lower than the battery voltage with the Onan (or any other current source) charging it.