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Topic: Keeping chassis battery charged for trip home (Read 587 times) previous topic - next topic - Topic derived from WANTED: Foretravel wi...

Keeping chassis battery charged for trip home

Quote from: Tim –
Bought the aforementioned 1997 U270 for $28,000. Here is my analysis:

N E E D S
- Charging voltage at coach battery, which runs the engine, reads low.
  I will buy a digital voltmeter today and investigate whether it has a bad alternator.



Has anyone ever ran a jumper from the house batteries to the chassis battery? Would it do any harm? I did this in my Fleetwood Southwind and worked fine.



[split this out from the original topic - Michelle]
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Keeping chassis battery charged for trip home (split from Re: WANTED: Foretravel...)

Reply #1 –
Won't boost switch give you the umph?
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: Keeping chassis battery charged for trip home (split from Re: WANTED: Foretravel...)

Reply #2 –
That is exactly what the boost rocker switch does.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Keeping chassis battery charged for trip home (split from Re: WANTED: Foretravel...)

Reply #3 –
Boost switch consumes 3amp.  magnetic switch zero.

But to get it home the boost switch is safer
"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: Keeping chassis battery charged for trip home (split from Re: WANTED: Foretravel...)

Reply #4 –
Tim,

Congratulations.

If the coach has been sitting, and did not have an owner-added charging system (several different kinds) for the chassis batteries, they could have just run down and just need a charge.

Yes, to check the alternator is pretty easy with a digital voltmeter (even a cheap $10 one):

Engine running at high idle-- around 1000 RPM (use cruise control to bump up idle speed if no helper along).

Check voltage at both chassis and house battery banks.  Should be 13.5- 14.2.

If not, locate the battery isolator (about 4X10 inch finned box with battery cable size wires to it).  Check voltage at the center lug which comes from the alternator B+ terminal.  Should be 14.0- 14.7 VDC.

Let us know what you find.
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: Keeping chassis battery charged for trip home (split from Re: WANTED: Foretravel...)

Reply #5 –
Quote from: Tim –
Has anyone ever ran a jumper from the house batteries to the chassis battery? Would it do any harm? I did this in my Fleetwood Southwind and worked fine.

I removed the combiner and installed this. It works both ways (chargers house batteries from alternator OR charges engine batteries from battery charger)
1998 U270 34'
 

Re: Keeping chassis battery charged for trip home (split from Re: WANTED: Foretravel...)

Reply #6 –
Tim,

No problem using a jumper, assuming you do it properly.  Do NOT use alligator clips or battery cables that could jump off a lug and have a very high amp dead short to ground were either end to touch any coach metal.

And, as you are aware, this would allow all batteries to discharge together as well as charge. Could leave you with no batteries to start the coach or generator.
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