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Topic: Start Battery Wiring Modification (Read 1361 times) previous topic - next topic

Start Battery Wiring Modification

Start Battery Wiring Modification

My 2001 ISM11 starter always seemed to turn slower than I though it should, about 50% of the time I would use the boost switch.  I replaced the OEM starter with a gear reduction starter and that made starting easier but it still didn't turn over very fast. It was always much faster with the Boost Switch.  The start batteries were replace about 3 years ago.

I check battery post torque and clean the battery terminals regularly.  I rotate the start batteries once a year. None of that seemed to make any difference.  The start batteries were wired to two posts on the side of the battery carrier frame, one plus, one minus along with many other connections to each including cables to the starter motor.  I could neither tighten or loosen the nuts on either post.

So I made a new panel with a pair of plus and minus battery side three post bus bars, a negative battery side switch, a shunt to my second Victron BMV 712, and a new pair of three post plus and minus bus bars for the output cable connections.  I made three sets of equal length (within a quarter inch) 3/0 plus and minus cables, one for each battery that go to the battery side bus bars. 

When working on batteries, I wear safety glasses and gloves.  I clean every connection and put a light coat of electrically conductive grease (not dielectric grease) on the lugs, post threads and inside threads of the nuts. For this job I had the fire extinguisher out and handy as well.

With all power sources disconnected and the start batteries out, I tried once more to remove the cables from the OEM posts.  A thin tappet wrench will hold the bottom nut.  Both posts sheared off at the nut. I removed what was left of the posts and connected the remaining cables to the new output bus bars.  I was going to make new 4/0 cables to the starter but modified the original 3/0 cables and used them.  There is an awful lot of wiring along the side of the engine that needs to be freed up from wire ties to get to the start cables. I elected to leave it alone for now.

I finished hooking everything back up, put the start batteries back in the rack and connected the plus side cables to the plus bus bar and then the negative side cables to the negative bus bar.  I double checked torque on all of the connections and turned the switch on the negative side.  Nothing unexpected happened, no smoke, no sparks. I turned the switches for the solar charger and the LiFePO4 house batteries back on.  It looked like all was back in business.

When I started the ISM11 with no boost, it turned over as fast as it ever had before even with the boost switch on, maybe even faster. It started in just a second or two.  I am very pleased with the improved start performance. It has to be easier on the starter and the engine.  The 3/0 cables to the starter seem adequate. The Victron shunt seems to carry the short high amp start loads with no problem. I made a short 4/0 jumper cable as a work around, just in case.

My conclusion is that the OEM post connections we not very good.  There were certainly more wires connected to each post than is commonly suggested today. (Three connections per post, maximum). And while the parallel wiring scheme used originally is OK, connecting each battery individually to a pair of bus bars adds a lot more current carrying capacity to the set of three batteries.

I had all of the parts for this project for a couple years, I was just waiting for a convenient time.  I should have done it sooner. The starting improvement is very significant.  A project worth consideration is your engine start performance is sluggish.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Start Battery Wiring Modification

Reply #1 –
Roger,

Yet another great project writeup from you!  I keep bookmarking your work.....now I just have to find the time to implement some of them!
Tom and Lisa

2003 U320 38' PBBS
Build No. 6217

Re: Start Battery Wiring Modification

Reply #2 –
Brilliant!!!  Thanks, Roger.  Added to my list.
2001 4010 U320 build #5865 "Bluto-d-Bus" since 09/18
2006 Honda Element ESP Toad
Full timing since 2016 in Western MT
Copilot: Sitka
1975 GMC 260 Avion: sold

Re: Start Battery Wiring Modification

Reply #3 –
Wish you could of measured the loss across posts to isolate resistance before removed. I still have reserves about the shut off switch in the start circuit. Even though its rated for the loads it always gets reduced during its life. I'm sure it works fine this week but would be susceptible to failure down the road IMO. Nevertheless thanks for the great information and I will review my own cables and connections this weekend. Having a bypass cable is a home run IMO
Scott

Re: Start Battery Wiring Modification

Reply #4 –
I like Roger's switch and will remove our boost switch when I get that far on the to do list as it's only for emergencies. Each one of our fire trucks had a switch like Roger installed. They were turned to the off position when the truck was parked and switched to the on position when we got into the cab (mid-engine with batteries and engine right behind cab). The largest was a 930 CI Hall Scott with all the diesels starting 8V-71 Detroits with 19/1 compression ratio, two points higher than our 6V-92TAs in the Foretravels. The Detroit 71 series with higher CR, didn't like just one 8D battery so used the BOTH position on them. Detroit 92s will start fine on one 8D.

Bottom line is that none of the switches ever failed or even got warm. All trucks were started at least once a day with multiple starts on the first line apparatus.

This is a way to install a mechanical "boost" switch without any wiring to the front and eliminates the possibility of failure.

While many switches will look the same, the specs must be read so they will support the amp requirement of the engine, especially in sub-freezing weather.

The switch's electrical position cannot be moved with the engine running without the risk of a voltage spike and component damage.

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

Re: Start Battery Wiring Modification

Reply #5 –
Good writeup. My engine turns over good even in cold weather. This is the first
electronic engine engine I have had to start and I'm still not used to that it takes
a couple of revolutions to start. On my last coach the mechanical 8.3 engine fired
as soon as the first piston on compression stroke hit the top of its stroke.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Start Battery Wiring Modification

Reply #6 –
The BEP Marinco switches are rated for 600 amps for 5 min, 1500 amps for short cranking time.  BlueSea makes similar HD switches with a bit higher ratings.  The Marinco bus bars are rated for 650 amps continuous, more for short durations. I like the Marinco products because they have a variety of high amp solid copper link bars that let you nest components close together.  The shunt was higher then the the bus bar so I made a solid copper bar, 1/4x3/4" for that link.  Makes for a tidy and compact installation.

The start wiring switch is on the negative side of the start batteries.  I have one on both the negative and plus side of the house batteries. And the switch on my solar is in the plus side between the combining fuse block and the solar charge controller.

I am not sure but it seems like the ISM11 needs to make a couple revolutions as well and then it starts.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Start Battery Wiring Modification

Reply #7 –
Quote from: Roger & Susan in Home2 –

I am not sure but it seems like the ISM11 needs to make a couple revolutions as well and then it starts.

I think electronic engines require a couple of revolutions to determine when the number 1 cyl. is on the compression stroke.
Tim Dianics
Pam Sapienza
Vader PupZilla Labrador Canine Beast (AKA Pup)
Columbia, MO
1996 U320 4000
2021 Jeep Gladiator, Diesel

Re: Start Battery Wiring Modification

Reply #8 –
Quote from: TGordon –
I think electronic engines require a couple of revolutions to determine when the number 1 cyl. is on the compression stroke.
Not our Detroit. Fires instantly. Naturally, when #1 comes up, it's always on a compression stroke.

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

Re: Start Battery Wiring Modification

Reply #9 –
Quote from: Pierce & Gaylie Stewart –
Naturally, when #1 comes up, it's always on a compression stroke.

Pierce

Now, THAT'S FUNNY!!!!

A real two stroke joke.
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: Start Battery Wiring Modification

Reply #10 –
Quote from: wolfe10 –
Now, THAT'S FUNNY!!!!
A real two stroke joke.
:)  You spoiled it Brett. I just put on my flack jacket waiting for the letter bombs.  :)  :)

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

Re: Start Battery Wiring Modification

Reply #11 –
Quote from: Pierce & Gaylie Stewart –
:)  You spoiled it Brett. I just put on my flack jacket waiting for the letter bombs.  :)  :)

Pierce
I think you were stroking us Pierce..:O)
Hans & Marjet
1995 U300 "Ben" (#4719)
3176B Cat,4060HD,Jake
SKP#139131
Motorcade#17579
2006 Honda Element (towed)

Re: Start Battery Wiring Modification

Reply #12 –
Sorry Roger...didn't mean to hijack the thread
Hans & Marjet
1995 U300 "Ben" (#4719)
3176B Cat,4060HD,Jake
SKP#139131
Motorcade#17579
2006 Honda Element (towed)

Re: Start Battery Wiring Modification

Reply #13 –
Its OK Hans, it was already hijacked into irrelevancy at #8.

And it continues on after this.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Start Battery Wiring Modification

Reply #14 –
I just took a close look at Rogers and see that it's an on/off type. The one I referred to in my post is a 4 position, off, A, B, both A&B (off, 1, 2, both 1&2). An excellent site for the 9001e is found here with wiring diagrams plus warnings about changing positions while the engine is running. It's also 600 amps with a 10 second rating for higher draw.

This is a manual type of "boost" switch without the electrical connections required to actuate.

1/2/BOTH Battery Switch Considerations - Marine How To

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

Re: Start Battery Wiring Modification

Reply #15 –
Start Battery Wiring Modifications. Parts List, Sources, Tools, and Schematic

I suggested sources, not hard to find elsewhere. Other components will work too.

BEP Marinco Pro Installer 770-EZ Switch
  BEP Marinco Pro Installer 770-EZ

BEP Marinco Pro Installer 650 Amp, 3-Stud Heavy Duty Bus Bar
  BEP Marinco Pro Installer 650 Amp, 3-Stud Heavy Duty Bus Bar

BEP Marinco Pro Installer Link Bars, LB-1, LB-2, LBJ-2
  BEP Marinco Pro Installer 650 Amp, 8-Stud Heavy Duty Bus Bar

1/4 x 3/4 x 12" copper bar (used about 3.5"
  Amazon.com: 110 Copper Rectangular Bar, Unpolished (Mill) Finish, H04...

Victron Energy BMV-702 Battery Monitor
  Victron Energy BMV-702 Battery Monitor

Battery Cable Terminal - Tin Plated FTZ Power Lug
  https://baymarinesupply.com/ftz-tinned-power-lug-battery-terminal.html

FTZ Correct Crimp Heavy Duty Lug Crimp Tool
  https://baymarinesupply.com/ftz-correct-crimp-heavy-duty-lug-crimp-tool.html
    I have a hydraulic crimper too that sits in its box. The FTZ crimper is much faster and makes consistently good crimps.

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN
 

Re: Start Battery Wiring Modification

Reply #16 –
Roger, I hadn't seen this until someone else referred to it.  This is really nice work.  I'd like to see this sort of set up in my rig one day.
Rick and Donna
1997 U320 4000 WTBI Build 5152 "Molesley"