Skip to main content ↑ ↓
Topic: Battery tutorial (Read 645 times) previous topic - next topic

Battery tutorial

Excellent write up on the basics of automotive/RV batteries:
 The 12volt Side of Life (Part 1)
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Battery tutorial

Reply #1 –
That is one of the sites I found that listed 40% charge as being acceptable. Others list 50% as minimum. Looks like this is a Ford vs. Chevy opinion type issue.
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: Battery tutorial

Reply #2 –
OK Sven, you opened the door for me--I just have to ask.
Can I have a 12V engine start battery and two 6V golf cart batteries and still use the same charging system?
What problems might I have?
Kind of been thinking about this for a couple years but not sure.
Currently have an 8D wet cell and a 12V--1000CCA truck battery.
New 125A Leece-Neville alternator.
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD

Re: Battery tutorial

Reply #3 –
Two 6V golf cart batteries are wired in series. If you have more than one 12v battery, they are wired in parallel. Using the isolator, you should have no troubles.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Battery tutorial

Reply #4 –
I used four 6 volt golf cart batteries for the coach and two Costco 12 volt batteries for the start system on the Monaco I had and had no issues, Monaco uses an isolator system also.
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: Battery tutorial

Reply #5 –
Thank you, good article, once I aquire a coach I will probably swap the 8ds for the golf cart batteries out of my boat. Also have access to scissor lift batteries at work, since they change the entire set if they have any issues. Bought one of the schuamaker smart chargers a few years back that has the desulfication mode, and have been able to successfully revive about 2/3 of "dead" batteries. Until a inexpensive lithium set appears on the horizon. Next step is building/modifying the roof A/C to inverter drive compressors, with ECM fan motors that use only 900 watts per 12,000 btuh, with so little inrush current that you could start a pair with a 2 kW generator or alternater.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Battery tutorial

Reply #6 –
Quote from: nitehawk –
OK Sven, you opened the door for me--I just have to ask.
Can I have a 12V engine start battery and two 6V golf cart batteries and still use the same charging system?
What problems might I have?
Kind of been thinking about this for a couple years but not sure.
Currently have an 8D wet cell and a 12V--1000CCA truck battery.
New 125A Leece-Neville alternator.
Sure, charging system won't know if all the cell's are wired in series inside one case(12v) or inside two cases (6v)
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Battery tutorial

Reply #7 –
Pierce, Craneman and Phred answered the question.  The charging system will read the 6volts in series as 12v.  Same thing with two sets of 6v (in series), wired in parallel with two more 6v batteries.  Same pressure (voltage) with more storage capacity.
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: Battery tutorial

Reply #8 –
Thanks, Pierce. Now, next question: Does our 1989 have an isolator and where might it be?
Also, will batteries charge equally?
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD

Re: Battery tutorial

Reply #9 –
Our isolator shares an under the coach electrical panel with the boost solenoid, etc. On the driver's side not far from the house batteries. It isolates the two battery systems so the coach battery can't drain the engine battery when the inverter is on, etc. The engine alternator charges both when running.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Battery tutorial

Reply #10 –
Quote from: nitehawk –
Thanks, Pierce. Now, next question: Does our 1989 have an isolator and where might it be?
Also, will batteries charge equally?

Easy to trace.  Raise the bed and follow the large gauge red wire from the alternator B+ terminal.  Should lead you right to the battery isolator.  It will be between the alternator and batteries.
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: Battery tutorial

Reply #11 –
On the 89 the isolator should be mounted on the left frame rail behind the left rear wheel
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Battery tutorial

Reply #12 –
Quote from: red tractor –
On the 89 the isolator should be mounted on the left frame rail behind the left rear wheel

Yes, a common (and IMO not very good) location on many Foretravels. Electrical components outside and right behind the two rear tires???

Many of us have moved it "indoors".
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: Battery tutorial

Reply #13 –
Hey!! I think I remember where it is!! And what it looks like!!
A red "thing" with fins and cables. When I opened the engine access door on the driver's side I could see it--almost straight down from the inside wall at the foot of the bed. (this is using memory recall, seeing as how the coach is 18 miles away)
Often wondered what its function was.
Now I have got another thing to worry about--vulnerable position behind the wheels!! Thanks a lot, Brett!!!!  :))  :))  :))
I guess I will have to add moving the isolator to my spring list.
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD

Re: Battery tutorial

Reply #14 –
Norm,

If on an inside wall in the engine compartment, you should be OK.  Many were mounted on a separate metal piece right behind the driver's side rear wheel (not on engine room wall).
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: Battery tutorial

Reply #15 –
Thanks, Brett. Forgot to mention that our isolator is mounted (if it is the one I saw) on the outside of the frame and kind of behind the inside dual. Vulnerable position if an inside dual tire blows up.
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD