Wiring under front seat of Leader E350 Ambulance. *Not for the weak of heart!*

[Ambolorian]

The following post may cause heart palpitations and/or nightmares. Read on at your own risk.



Here is my 2002 E350 Super Duty with Leader Ambulance package.
This rig comes with 2 starter batteries and 2 "spare" batteries that I will be replacing with a 300ah bank of Renogy AGMs.
My current project is to create two separate battery banks that are independently charged by the dual alternators up front.
I was able to get a bunch of schematics from Leader (no easy feat!) and some pics from another user on the forum that unfortunately is no longer active.

Here is what I have under the driver's side seat:





Here is breakdown of what each component does:
A: This solenoid is controlled by the Module On/Off switch above the driver.
B: This is the Manual ON/OFF switch mounted on the side of the front seat
C: This is a timer that shuts off rear power 5 minutes after the ignition key is removed.
D: This is a Battery Isolator that takes power from the positive post (which is connected to the alternators and starter batteries) and sends it to the "spare" bank.
E. This solenoid is for Emergency Start and combines all batteries to start the diesel in very cold weather.


Here is the power schematic that Leader sent me:


A closer look at D (Battery Isolator)


A closer look at the TImer:




Wiring at this level is a little daunting to me.. I'm hoping someone gifted with an electrical engineering background can chime in and answer some of my questions.
Here is my plan:

1. I'd like to remove C (Timer) and D (Isolator) and effectively have an independent "house" bank of batteries that runs the camper conversion led lights and sockets in the back.
2. I want to replace the current isolator with a Blue Seas ACR 7620 but I'm not clear on how to wire it into the system.
3. How can I bypass the timer?

Has anyone else worked on a rig like this before or have some suggestions for me?

Thanks!

 

[Bikersmurf]

When I ditched my isolator for a Blue Sea's ARC, I connected the alternator output lead to the starting battery lead, and house battery lead to the other pin on the ARC.

I originally wanted to charge the house batteries directly and then connect the starting, but the Alternator's regulator wasn't wired to work that way. I'd get a voltage spike until they connected, and then the regulator would correctly read the charging voltage. Rather than rewire how the alternator worked, I hooked it up as Ford designed it and now it works as it should.

It now looks like your isolator is connected as a diode to protect one set of batteries from draining the others (to take a stab at it. If I had more time I could study the wiring diagram, but I don't at the moment.

 

[Ambolorian]

Thanks for the reply Bikesmurf.
You are correct.. thats how its currently set up.

Was this how you had it wired initially?

 

[Ambolorian]

Oops, scratch that middle wire going from the Junction to the House lead.

 

[Bikersmurf]

Thanks for the reply Bikesmurf.
You are correct.. thats how its currently set up.

Was this how you had it wired initially?
View attachment 790347

Initially I essentially had it wired like that less the wire from the junction point to the starting batteries.

In my case I have a single 215 amp Mitsubishi alternator. I’ve read that this 32 pound beast can put out up to 300 amps cold, and the 215 amps 24/7. The big catch is that it’s $950 CDN from Ford, and when I was told that price there was no stock showing in North America.

I found with the initial setup the alternator’s VR read the starting batteries voltage and peaked at +/- 16.5 v for a. split second until the ACR connected the house batteries to the starting batteries. Once combined, the output was reduced to 14.4v. Although the 16.5 likely wouldn’t harm anything for a momentary peak, the Inverter I was running registered over voltage and shut everything off for 20 seconds until it reset and registered the 14.4 v which was below its 15v max limit.

Now it’s connected as shown (less the wire from the junction point to the house batteries. The small (inconsequential) difference is that junction for the alternator to ACR is at the ACR rather than the starter battery terminal. However in the real world, the circuit is the same, and I’d recommend sticking close to how the ambulance up fitters set it up and not making it hard on yourself.

 

[Ambolorian]

Copy that.
I wasn't sure if it was better to begin at the Starter batteries and have the ACR switch to the House or visa versa.
And I think you're right, why re-invent the wheel when Leader already did a solid job with their build.

Thanks a lot for helping me work thru this.. I really appreciate your input.

 

[iggi]

A couple suggestions based on where I'm at with my own ambo build.
I've removed all connections from the starter batteries to the aux power.

My auxiliary / camper panel will be fully independent except for:

a) a DC to DC charger so I my auxiliary lithium battery bank can charge from the alternator. (for AGM the ACR is fine)

b) a 20 amp battery charger connected full time to my starting batteries that is powered either from my inverter or from shore power.
I considered trying to retain the super start relays but it added a lot of complexity and with the size of my aux battery bank I can fully charge the starting batteries if I ever have to, plus I can trickle charge the starting batteries from excess solar.

I'm curious why you're going with AGM instead of a lithium iron phosphate.

 

[Hugh Heifer]

Hey all - I wanted to Bump this old thread (and hi-jack it) since I have the same Leader E350 @Ambolorian had. (He has since sold his.)
I am hoping to get some help incorporating the ACR in my system and am copying @Ambolorian's stuff as best I can. Unfortunately, he never let us know what he deleted under the seat and there are no pics of where he placed his ACR.

Here is a clean schematic of what he ended up doing:



Here is a color image of the underseat wiring and a full explanation from Mike Marcacci who built "Boltline" (another Leader ambo in a very old blog HERE):


B+h (house battery positive) - I had already disconnected this before snapping the photo, but it was connected to the post where the arrow is drawn. This went to the "hot spare" battery bank (the rear two in the side box). We rewired the side battery box so that all 3 are in parallel.

B+s1 (starting battery positive 1) - This connected to the under-hood battery. With our conversion, we replaced the upfront battery with the biggest one we could fit, and this became the *only* starting battery.

B+s2 (starting battery positive 2) - This connected to the front-most battery in the side box, and was in parallel with the under-hood starting battery. Since we wanted 3 batteries in our house bank, we removed this wire entirely.

A - This solenoid is controlled by the module on/off switch above the driver.

B - This is the manual module disconnect switch. [Note: Not all Leaders have this. My 2000 does not.]

We didn't want to power a solenoid just to have the ability to use the house system, so we put these switches in parallel instead of series... and we never really use the solenoid.

C - This is a timer that allows the lights/etc to run for a configurable amount of time after the keys are pulled. Ours malfunctioned and we didn't want it anyhow. I'd highly recommend sending it to the trash.

D - This is actually a battery isolator (2 diodes) but it's being used instead as a huge single diode (notice the bridge). This takes power from the center post (which is connected to the starter battery and alternators), and sends it to the "hot spare" (aka house) batteries without letting electricity flow back the other way.

This kind of setup is only relevant with a "spare" battery bank, and is useless if you want 2 independently functioning systems. You'll want to remove all of this.

E - This solenoid is for "emergency start" and connects the "hot spare" system to the starting system. We kept this, and have used it on several occasions (really cold starts)!
______

@Ambolorian's install was pretty clean behind the seat and I have followed suit:



But there are unaswered questions for me.
As I mentioned above, unfortunately Ambolorian never let us know how exactly he modified his underseat wiring to incorporate the Blue Sea ML-ACR7620, where he put the control switch for the ACR or if he retained the emergency start solenoid (in the pics of his rig the switch is still above the driver's seat). I am attempting the same thing.
The wiring of the house system is pretty straight forward but I am looking for advice about a couple of things:

QUESTIONS:
1) I have not yet removed the timer "C". I suspect that will be easy and I think mine is not working anyway. Does anyone know if I need to watchout for anything weird in this removal?

2) The next question is do I still need to run "D" (The diode/Isolator) with the ACR? I know the ACR allows charging of all the batteries, combining of all the batteries for a cold start and will automatically disconnect the batteries should one side become low (below9.6v) or overcharged (above 16.2v) in auto mode. It reads like it does all the same things as both D and E.

3) And last, if above is correct, can I delete "E" (emergency start solenoid and switch) and then the ACR can take its place (switching to "on" to combine the batteries) in the event of a discharged or cold start issue?

There may be a better place to post all this but I wanted to take advantage of the thread that @Ambolorian already had started.
Cheers!

 

[Bikersmurf]

I have a type 3 but essentially the same wiring. So... I'll explain what I did.

1st off ditch the diode isolator. It'll lead to a quick death of your batteries.

2nd I connected the lead from the center pole of the diode isolator (Alternator) to the house batteries. Long story short, the alternator voltage spiked for a split second and the inverter shut down. Reason, the voltage regulator didn't read the alternator output till the ACR connects, and then the regulator corrects the alternator's output. So, don't do this.

3rd I connected the center lead and starting battery lead to the primary ACR connector. I then connected the house battery lead to the secondary connector of the ACR.
This works perfectly and I've not had to replace any batteries since.**

If your sticking with flooded lead acid batteries I'd recommend a pair of 6 volt golf cart batteries in series. They last so much better than marine "Deep Cycle" batteries that are a compromise between starting and deep cycle batteries... and they do neither as well as dedicated deep cycle batteries.

If you switch to LiFePO4 or other similar I'd recommend a DC-DC charger or disconnect them from the alternator and charge with solar instead.

** Although I didn't have to, I did switched to golf cart batteries and highly recommend it. They last for days vs hours.

 

[Hugh Heifer]

@Bikersmurf - did you also ditch the emergency start solenoid and use the ACR switch for that purpose? Seems it serves the same purpose with updated technology.

 

[Bikersmurf]

@Bikersmurf - did you also ditch the emergency start solenoid and use the ACR switch for that purpose? Seems it serves the same purpose with updated technology.

The Blue Sea ACR I bought didn't have the Start feature. I still have it and use it now and then if the house batteries are very drained and I want to connect them quickly to the Alternator. I don't remember the exact figures, but if the house batteries are too much lower than the starting batteries, the ACR doesn't connect them right away.

I can't remember what the ACR does if the House batteries are dead... I haven't had them get very low since I put 320 w of sollar panels on the roof.