Reply
 
Thread Tools Display Modes
 
Old 08-19-2018, 10:20 PM   #1
Mini-Skoolie
 
Join Date: Jul 2018
Location: Central Arkansas
Posts: 14
Year: 1999
Coachwork: Aerotech
Chassis: E-450
Lift battery charge wiring??

I took a wheelchair lift off of my Ford E450 shuttle. I canít figure out the wiring on it and maybe you guys can help. Thereís a positive 2awg that runs from the start battery to a charge battery, then on back to where the lift was. The negative wire that was on the charge battery is connected to a lug on the starter. I canít find a relay of any sort. Any ideas why not? No need as the bus is usually running when the lift would be used?? Iíd like to use the existing positive wiring and splice an isolator/relay into it to charge my battery bank, but I canít figure that negative wire to the starter out- any help? Thanks!
Foxpen is offline   Reply With Quote
Old 08-20-2018, 12:32 AM   #2
Bus Crazy
 
roach711's Avatar
 
Join Date: May 2010
Location: Farmington Hills, Mi (Detroit area)
Posts: 1,733
Year: 2000
Coachwork: Eldorado Aerotech 24'
Chassis: Ford E-450 Cutaway Bus
Engine: 7.3L Powerstroke
Rated Cap: 19
Mine has that same negative cable attached to one of the starter hold down bolts. I assume it's there to provide a good ground for the starter.
__________________
The Roach Motel
roach711 is offline   Reply With Quote
Old 08-20-2018, 10:52 AM   #3
Bus Crazy
 
Join Date: Jun 2013
Location: Picton,Ont, Can.
Posts: 1,160
Year: 1997
Coachwork: Bluebird
Chassis: GMC
Engine: Cat 3116
Rated Cap: 72
Sounds like both batteries are getting charged by the alternator now.

grounding to the starter was probably one of the easier options but works ok.

To reuse the lift cable for charging the battery you may want to shorten it up if it goes front to back, can't really say without pics.
Isolator is an easy addition and can be used to boost the staring battery if needed.



John
__________________
Question everything!
BlackJohn is offline   Reply With Quote
Old 08-20-2018, 11:18 AM   #4
Mini-Skoolie
 
Join Date: Jul 2018
Location: Central Arkansas
Posts: 14
Year: 1999
Coachwork: Aerotech
Chassis: E-450
Can you explain why the negative grounds from the starter? My battery bank is in the very back of the bus- which the positive and neg already run to. Do you think it needs to be shortened due to drop in voltage?
Foxpen is offline   Reply With Quote
Old 08-21-2018, 09:56 PM   #5
Bus Crazy
 
roach711's Avatar
 
Join Date: May 2010
Location: Farmington Hills, Mi (Detroit area)
Posts: 1,733
Year: 2000
Coachwork: Eldorado Aerotech 24'
Chassis: Ford E-450 Cutaway Bus
Engine: 7.3L Powerstroke
Rated Cap: 19
There are two ways to complete a DC circuit, run dedicated positive and negative cables from the battery to the device or run only a positive cable to the device and ground the device to the steel body or frame.



Most grounds in a vehicle are attached to the body/frame. The problem with this setup is that there can be bad connections between the battery and the device which can limit the current available to the device. The dedicated ground from your starter to the battery just gives a direct and high current ground connection for the starter. You'll find several of these ground straps connected between the engine and frame and the frame to the body (well, not your fiberglass body).



Your starter has that large negative ground attached to the starter frame, a large positive cable attached to the top of the starter and a small wire attached to the starter solenoid which is what makes the connection when you turn the key.



As connected, both of your batteries cabled together become one large starting battery so you don't want to connect your house bank to them without some way to prevent the house bank from drawing down the starting batteries while camping. You can use a simple relay or an electronic isolater to do this.
__________________
The Roach Motel
roach711 is offline   Reply With Quote
Old 08-21-2018, 10:34 PM   #6
Bus Crazy
 
Join Date: Jun 2013
Location: Picton,Ont, Can.
Posts: 1,160
Year: 1997
Coachwork: Bluebird
Chassis: GMC
Engine: Cat 3116
Rated Cap: 72
Quote:
Originally Posted by Foxpen View Post
Can you explain why the negative grounds from the starter? My battery bank is in the very back of the bus- which the positive and neg already run to. Do you think it needs to be shortened due to drop in voltage?

Starting and lift batteries both in the back? How far from the alternator?
I don't know the physical layout of your start battery and lift battery and alternator. Your info doesn't mention this and didn't you say that you want to keep and use the lift power for something else? What and where is this going?
Short cables will allow better charging and save your alternator from a lot of hard hot work trying to charge at long length from it.


Grounding of the starter is most important for it to function properly with enough cranking power to do the job. Everything grounds through the main block then for continuity to ground on the frame.


John
__________________
Question everything!
BlackJohn is offline   Reply With Quote
Old 08-21-2018, 11:00 PM   #7
Mini-Skoolie
 
Join Date: Jul 2018
Location: Central Arkansas
Posts: 14
Year: 1999
Coachwork: Aerotech
Chassis: E-450
Thanks to you gentleman for getting back to me. Should have been clearer BlackJohn- my starter battery is under the hood as normal, 18-24 inches from the alternator. The lift battery was approximately halfway down bus length on the chassis, with 2awg running on back to the rear where the lift was. My intention is to move my two battery bank to the very back where the lift was. Unfortunately, this is pretty far (14 feet) from the alternator. Do you guys know how critical it is to keep a VSR/isolator close to the start battery? Can I splice it in 4-6' away from the start battery with 2awg and be alright?
Foxpen is offline   Reply With Quote
Old 08-21-2018, 11:15 PM   #8
Bus Crazy
 
Join Date: Jun 2013
Location: Picton,Ont, Can.
Posts: 1,160
Year: 1997
Coachwork: Bluebird
Chassis: GMC
Engine: Cat 3116
Rated Cap: 72
If you have a certain isolator in mind, then check its specific limitations with the manufacturer. Electrical characteristics will vary from brand to brand.
What kind is your alternator and what output is it rated for?



John
__________________
Question everything!
BlackJohn is offline   Reply With Quote
Old 08-21-2018, 11:20 PM   #9
Mini-Skoolie
 
Join Date: Jul 2018
Location: Central Arkansas
Posts: 14
Year: 1999
Coachwork: Aerotech
Chassis: E-450
Hmm, I don't know that John- I'll check it out and get back
Foxpen is offline   Reply With Quote
Old 08-22-2018, 02:59 AM   #10
Bus Crazy
 
roach711's Avatar
 
Join Date: May 2010
Location: Farmington Hills, Mi (Detroit area)
Posts: 1,733
Year: 2000
Coachwork: Eldorado Aerotech 24'
Chassis: Ford E-450 Cutaway Bus
Engine: 7.3L Powerstroke
Rated Cap: 19
I'm assuming you're putting your house bank in the back, not the starting batteries.



In that case you should size the cable from the isolater to the house bank to handle charging current (not starting current) unless you want the option to connect the house bank and the starting bank for emergency starting.



When it comes to electrical cables bigger is better. I'd be tempted to change out that #2 cable and put in some 2/0 cable to give some future flexibility.
__________________
The Roach Motel
roach711 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 08:13 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2018, vBulletin Solutions, Inc.