Fitz’ 2016 Sprinter 4x4 RB 150S Build

[mkkbven]

At the risk of hijacking Fitz’s thread, I finally was able to get a closer look at the wiring of my Blue Sea ACR 7620. It turns out that only the black and red control wires were used. The black of course runs to ground, while the red wire was connected to a terminal block under the drivers seat that provides 12+V when the ignition is on (whether the engine is running or not).

In this configuration the ACR monitors battery voltages and switches opened/closed as designed when the van ignition is off, howewever when the ignition is on, the batteries are forced to combine, essentially overriding the ACR voltage monitor.

This setup has led to some confusion more than once when troubleshooting van power so I will be installing the Blue Sea SPDT switch mentioned in an earlier post to give me a little more control.

Thanks Greg and everyone for your help.

Mark

[Fitz]

Originally Posted by mkkbven

... I finally was able to get a closer look at the wiring of my Blue Sea ACR 7620. It turns out that only the black and red control wires were used.

In this configuration .... the batteries are forced to combine, essentially overriding the ACR voltage monitor.

.... I will be installing the Blue Sea SPDT switch mentioned in an earlier post to give me a little more control.

Mark,

Two data points please:
1. Location of build
2. Year of build

I’m thinking Fresno about 5 years ago. If so, we need someone with a new build from that same location to check their rig to see if anything has changed. Can you post a couple of pictures to make it easy for them to know what to look for?

[mkkbven]

My Sportsmobile was built by Fresno in Dec 2012. I’m currently out of town, but can take some pics when I return on Monday.

[Mer1039]

Hi Tim,
I have a 2016 Sprinter Sportsmobile that was upfitted Feb 2017 in Fresno. Here are a few details on how Sportsmobile wired my 7620.

A Black and Green wire exits the 7620. Both the Black and Green wires are a larger gauge than those on the 7620 and were spliced. Black ran to ground and Green runs to the front of the van under the driver seat. The splices are all taped up so I don’t know exactly which 7620 wire the Green wire is spliced to (I’m assuming it’s spliced to one of the three 7620 isolation wires.

http://www.sportsmobileforum.com/for...1&d=1550346081

Under the Driver seat an inline 15A fuse is attached to the Green wire that came from the 7620. The fuse is marked “15A SEP” (I’m assuming “SEP” for Separator ).

http://www.sportsmobileforum.com/for...1&d=1550346081


The fused Green wire is finally attached to the X145/1 Terminal 3, on the same stud that has a black and yellow wire attached. This is the stud that provides power during ignition (starting).

http://www.sportsmobileforum.com/for...1&d=1550346081

This is all new and a bit technical to me, but if I am understanding my set up correctly, it looks like the 7620 on my Sprinter Sportsmobile is set up for Start Isolation (House battery separated from Start battery when starting the engine).

Ron

[mkkbven]

Originally Posted by Mer1039

Hi Tim,
I have a 2016 Sprinter Sportsmobile that was upfitted Feb 2017 in Fresno. Here are a few details on how Sportsmobile wired my 7620.

A Black and Green wire exits the 7620. Both the Black and Green wires are a larger gauge than those on the 7620 and were spliced. Black ran to ground and Green runs to the front of the van under the driver seat. The splices are all taped up so I don’t know exactly which 7620 wire the Green wire is spliced to (I’m assuming it’s spliced to one of the three 7620 isolation wires.

Under the Driver seat an inline 15A fuse is attached to the Green wire that came from the 7620. The fuse is marked “15A SEP” (I’m assuming “SEP” for Separator ).

The fused Green wire is finally attached to the X145/1 Terminal 3, on the same stud that has a black and yellow wire attached. This is the stud that provides power during ignition (starting).

This is all new and a bit technical to me, but if I am understanding my set up correctly, it looks like the 7620 on my Sprinter Sportsmobile is set up for Start Isolation (House battery separated from Start battery when starting the engine).

Ron

Great pics. Looks like I’m off the hook, because it doesn’t look like SMB Fresno has changed their ACR control wiring in the last 5+ years. Including the green wire running between the ACR and terminal block X145, and the 15amp fuse.

I also thought the green wire was attached to one of the isolation control wires, but found that it was attached to the red one instead. I’ve been told that a positive voltage to the red control wire will force the batteries to combine regardless of individual voltages. (I was also told that combining the two batteries during startup should not be a big deal in a camper van unless you have sensitive electronics like those found in marine applications.)

I tested the X145 terminal and found that it had power when ignition is on (engine running or not). Note that when you are testing voltage, you might find around 4volts at the terminal when the ignition is off. That is a control voltage supplied by the ACR. I was scratching my head for quite a while when I saw that!

[Scalf77]

I can only assume that Sportsmobile considered the Blue Sea ACR as a drop in for the Sure Power Unit. Thus they were trying to mimic the same feature of the start assist function that the Sure Power Unit had by continuing to connect the wire to the Blue Sea Unit. It appears that they just picked a circuit for the wrong key position. They appear to have picked the accessory circuit, this will be hot when the key is "Accessory" and "On" "(possible even Start)". If it had been connected to the "Start" it would have worked similar to the start assist of the Sure Power Unit.

Lock: This is the off position. ...
Accessory: In accessory mode, you can listen to the radio, as well as use some other electronics. ...
On: This turns on all of your electronics. ...
Start: Turn the key to this position to crank the engine.

I would just remove the fuse, and it should start acting like it was intended, monitoring the voltages before connecting. It is generally not an issue if the batteries are connected while starting, unless of course you have sensitive equipment. I have found that having the batteries connected while starting somewhat mask a starter battery going bad, and is the primary reason for my dislike.

It is funny how one manufacturer (Blue Sea) went out of their way to design in a start isolation features, and another (Sure Power) did the complete opposite and designed in a start assist feature. My belief is that the start assist feature of Sure Power was more to help keep the contacts clean on the solenoid by ensuring a high wetting current while making contact.

The Blue Sea ACR can be forced open during the start process, hooking up the start isolation line. This would come into play if you had solar charging the house system and they were combined.

I apologies for somewhat hijacking this thread.

-greg

[tlg]

This continues to be one of the most informative threads on this forum. Many thanks to Fitz and all who have contributed.

[Fitz]

Originally Posted by Scalf77

I would just remove the fuse, and it should start acting like it was intended, monitoring the voltages before connecting......apologies for somewhat hijacking this thread.

-greg

Hijacking? Nothing seen here but educating!


Greg, you mentioned you would simply remove the fuse. Mark bought the switch, would we all be correct to assume that removing the fuse is good and that adding the switch is better?


It's amazing to me how things like this get "institutionalized" in a place. Working in a refinery, I always take a much closer second look whenever the answer to a question is "because that's the way we've always done it".

[Scalf77]

Originally Posted by Fitz

Greg, you mentioned you would simply remove the fuse. Mark bought the switch, would we all be correct to assume that removing the fuse is good and that adding the switch is better?


It's amazing to me how things like this get "institutionalized" in a place. Working in a refinery, I always take a much closer second look whenever the answer to a question is "because that's the way we've always done it".

Fitz, you are correct, removing the fuse would be a quick fix to not have the ACR connected when the key is in the accessory setting, adding the switch would give you more functionality and a indicator as to the state of the ACR.

-greg

[Mer1039]

Originally Posted by Fitz

Hijacking? Nothing seen here but educating!


Greg, you mentioned you would simply remove the fuse. Mark bought the switch, would we all be correct to assume that removing the fuse is good and that adding the switch is better?


It's amazing to me how things like this get "institutionalized" in a place. Working in a refinery, I always take a much closer second look whenever the answer to a question is "because that's the way we've always done it".

Thanks all (and a special thanks to Tim for letting me hijack),

With all your inputs I have concluded that Sportsmobile also got creative when wiring my 7620 ACR. Just like Mark's situation, Sportsmobile wired my 7620 ACR "red" remote control wire to the X145/1 Terminal that supplies power when the key is in the ignition position, engine running or not (forcing the Start and House batteries to combine beyond just starting).

So that I can get Start Assist properly wired for my 7620 ACR, I have decided to pull the fuse and order the Blue Sea 2146 SPDT switch. The switch will then allow me to manually control when the ACR combines batteries for Start Assist. Should I need Start Assist before I install the switch, I can temporally put the fuse back in.

Tim,

If you decide to switch over to the 7620 ACR, give me a shout and I can come up the road to let you see how Sportsmoble wired mine.

Ron