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We're not dead yet - here's a question !! [message #371209]

Thu, 09 March 2023 12:05

SteveW

Messages: 538
Registered: June 2005
Location: Southern California - Ora...

Karma: 1

Senior Member

Greetings from Southern California !!

I'm about to install some LiPo batteries for my house electrical supply...

And I'm exploring the feasibility of using this same battery bank to crank the Onan to life.

Might any of you know the amperage draw of the starter for the 4K Onan ??

Thanks in advance.
Steve W

Steve W 1973 : 23' Southern California

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Re: We're not dead yet - here's a question !! [message #371210 is a reply to message #371209]

Thu, 09 March 2023 12:23

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

Steve,
You happen to be lucky here. I actually measure the cranking current for my BF Onan.
With the system dead cold, it was 80~85 amps. It cranked and fired so fast that I did have any way to average this, but the meter I was using will record the peak and that was 85.
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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Re: We're not dead yet - here's a question !! [message #371211 is a reply to message #371209]

Thu, 09 March 2023 13:13

SteveW

Messages: 538
Registered: June 2005
Location: Southern California - Ora...

Karma: 1

Senior Member

Thank you Matt !!

I was expecting 80ish. Perfect.

SW

Steve W 1973 : 23' Southern California

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Re: We're not dead yet - here's a question !! [message #371212 is a reply to message #371211]

Thu, 09 March 2023 16:42

Carl S.

Messages: 4186
Registered: January 2009
Location: Tucson, AZ.

Karma: 13

Senior Member

Steve, I don't know how many amps a 4KW starter draws, we'll have to trust Matt on that. I CAN tell you that I have two Battle Born (BBGC2) LiFePo4 batteries (100 amp each) and they crank my 6KW without issue.

My starting battery went bad last Summer and I used the battery boost switch to crank the 455, and it cranked over just fine. The BIM DID shut down the batteries after cranking for a while, but re-set almost immediately and started the engine on the second attempt.

Carl Stouffer '75 ex Palm Beach Tucson, AZ. Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member

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Re: We're not dead yet - here's a question !! [message #371213 is a reply to message #371209]

Sat, 11 March 2023 09:01

JohnL455

Messages: 4447
Registered: October 2006
Location: Woodstock, IL

Karma: 12

Senior Member

Well the early coaches used a small garden tractor battery and those range from about 150-350 CCA depending on price. So that is plenty to do the job. In fact the Onan engine IS a garden tractor engine repurposed as generator duty and running at 1/2 rated speed and 1/2 rated HP. Roughly 9HP @ 1800 vs 18HP @ 3600RPM.

John Lebetski
Woodstock, IL
77 Eleganza II

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