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Genset start

My genset starter is wired to the house batteries. This seems backwards to me. What's your opinion?
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Genset start

Reply #1 –
Pretty standard across the industry.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Genset start

Reply #2 –
Quote from: Old phart phred –
My genset starter is wired to the house batteries. This seems backwards to me. What's your opinion?
Designed like that. If you shut down engine and maybe leave the driving lights on and your start battery goes dead, you can start generator and close boost switch to recharge start batteries. It works the other way automatically from your alternator and isolator.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Genset start

Reply #3 –
Thanks Jim I was thinking that I was more likely to run the house battery down while boondocking. New smart isolator will keep both charged while plugged or running genset. I now have a 80 amp 4 stage charger for only $30.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Genset start

Reply #4 –
If you run the house battery down to where the genny doesn't start you are ruining the batteries.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Genset start

Reply #5 –
Quote from: craneman –
If you run the house battery down to where the genny doesn't start you are ruining the batteries.
What house voltage is too low for lead acid combo deep cycle/start? My genset isn't currently autostart. Years ago when I had sailboat I seen a cycle chart that compared life span to discharge %, maybe west marine
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Genset start

Reply #6 –
About 12.2 is 50% discharge. Wet cell life below that voltage is short.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Genset start

Reply #7 –
Quote from: Old phart phred –
What house voltage is too low for lead acid combo deep cycle/start? My genset isn't currently autostart. Years ago when I had sailboat I seen a cycle chart that compared life span to discharge %, maybe west marine
General rule is 12.2 volts is 50% discharged, and many gen autostarts are set at this, or lower. Personally I think that is too low for lead acid batteries and will shorten your number of charging cycles. I start mine at 12.3 or 12.4. Investing in a trimetric or other battery monitor is a good idea.
You will then know your real battery capacity and lite off gen. accordingly.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Genset start

Reply #8 –
Ours will start off of either bank.  Isuzu requires 3-400.  Ran cable to chassis battery's and installed a marine dual bank switch.  Ends limit on boost switch. Both have independent solar.  No issues so far.  Can't bring myself to have genset auto start.  Try to manage so it isn't necessary.  Just a personal preference.
George and Steph
1997 U270 36 Build 5081 "Honu"
1180w Solar 400A lithium all Victron house system
Motorcade 17670, SKP 128300, FMCA F459019
73 VW Camper, 79 VW Camper, 2363 Sunline, and an Arctic Fox 25P

Re: Genset start

Reply #9 –
Chart (approximate, no/little  load, no surface charge):
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Genset start

Reply #10 –
Chassis batteries start coach engine, house batteries start generator. Two chances to start a engine to begin charging.  (not to mention boost switch on many Foretravels).
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Genset start

Reply #11 –
Some fancier coaches sometimes had a separate gen start battery
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Genset start

Reply #12 –
Quote from: Caflashbob –
Some fancier coaches sometimes had a separate gen start battery
As does my old '81 FTX
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Genset start

Reply #13 –
If all else fails. I always carry this one with  40 amp 12 volt charger. Had a buddy that got stuck in a field and ran both battery banks down, [left boost switch on], carried it out to him and he charged start batteries for 30 min. and started coach. It is as quiet as a Honda 2000 and runs about 12 hours on less than a gallon of gas. Great for boondocking if you don't want to run your big gen. https://www.youtube.com/watch?v=FEHVQd9WG6Y
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.