Blue Sea battery link discharging "house" battery

M

mhjackson123

Advanced Member
Joined
Dec 4, 2016
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37
Location
Victoria, BC, CANADA
I have noticed that after I have charged my 92 Ah AGM house battery, my Victron BMV700 tells me that I am charging up the truck battery for a while... (I leave the camper switch off and there is still significant discharge). I would prefer that the truck be able to charge the camper battery, but not the reverse. Does this make sense. It seems as if the battery link cuts out around 12.75 V which is quite a bit less than the camper battery seems to charge up to 12.9 or 13.0 V.
Thanks in advance for any suggestions.
 
What's the problem with having your charge source charging both batteries? I have the same ACR as Hodakaguy, and charge both batteries via shore, alternator or solar all the time.

Or are you saying that when you disconnect your charge source (40W portable panel - if I read your other post aright) that the BMV shows the camper battery flowing current towards the truck battery?
 
Vic Harder said:
What's the problem with having your charge source charging both batteries? I have the same ACR as Hodakaguy, and charge both batteries via shore, alternator or solar all the time.

Or are you saying that when you disconnect your charge source (40W portable panel - if I read your other post aright) that the BMV shows the camper battery flowing current towards the truck battery?
Click to expand...
exactly. I am guessing that the truck battery does not charge to the same high voltage as the camper AGM one. It does not matter if I am using solar or a standard charger to charge the batteries, current always seems to flow to the truck battery.
 
Hodakaguy said:
The Blue Sea ACR is dual voltage sensing and will combine the battery banks if either battery starts receiving a charge. I replaced my factory ACR with a M-ACR that allows full auto or manual control of the ACR.

Here's a link to the Mod: http://www.wanderthewest.com/forum/topic/16457-manual-control-over-the-factory-acr/?hl=hodakaguy

Hodakaguy
Click to expand...
Did you just put a switch in to switch out the original ACR Battery link (7611)? Or did you go to the full M-ACR unit? Can I mod the factory installed one to work? Or just live with a loss of a few Ah after charging...
 
mhjackson123 said:
Did you just put a switch in to switch out the original ACR Battery link (7611)? Or did you go to the full M-ACR unit? Can I mod the factory installed one to work? Or just live with a loss of a few Ah after charging...
Click to expand...
If your running AGM batts in the camper ideally you would run a AGM in the truck as well, then set the solar charger for 14.2 volts and let it properly charge both the camper and truck batt.

You might just add a switch on the factory ACR that will interrupt the ground off the ACR. When you flip the switch and disconnect the ground the ACR won’t be able to sense voltage and should stay in the off state. When you want it back in auto just flip the switch and connect the ground again.

I swapped my factory ACR out for a M-ACR, I like the ability to keep it force combined for extra AH when camping. I’m running dual AGM batts in the truck as well.

If you want a one way unit with no voltage loss from the wiring then install a RedArc DC-DC charger. They are really slick and would give you exactly what you are looking for.

Hodakaguy
 
mhjackson123 said:
Did you just put a switch in to switch out the original ACR Battery link (7611)? Or did you go to the full M-ACR unit? Can I mod the factory installed one to work? Or just live with a loss of a few Ah after charging...
Click to expand...
Switch in the line is cheap and a good temp fix. Current flowing back/forth between the two battery banks is not ideal. Like Hodakaguy says, AGM's in both places largely solves the problem.
 
Thanks Vic, I will look at putting in a switch which I can use to disconnect after I arrive at a site. I can look at replacing the truck battery with an AGM starting battery when it dies...
 
I recently removed the Surepower 1202 battery separator the previous owner installed in my truck and replaced it with an ML-ACR with remote switch located in the dash of my truck.

I have a NAPA 1250 cca FLA in my truck. I have two Lifeline 6v AGM deep cycle batteries in the camper which are typically well maintained with my solar panels and Victron charge controller. The camper batteries are monitored with a Victron 702.

I will next be adding a battery monitor to the truck battery so I can determine its state of charge.

I intend to only enable the ML-ACR when it is needed rather than leave it in an automatic mode
but I'm still not certain how I will wind up using this total system. Once I get some actual use with all of this working together and with the data from the battery monitor on the truck as well as the camper batteries I think it will become clearer.
 
I've always been leery of manual over-rides. Sure as shoot I'll get too wrapped up in where we are and leave it in the wrong position at the least opportune time.

The current going to the starting battery(ies) wouldn't bother me so long as I knew that the solar system could more than keep up and that the charging voltage wasn't damaging either battery bank.
 
I have the Blue Sea ACR 7611 and there are times I want all the solar charge to go to the two camper batteries. The Isotherm fridge alone can use more than 40 Ah in 24 hours. If I pull the grounding wire from the ACR box the ACR light goes out and I assume it is shut down, not allowing current to flow in either direction. Do I have that right?
 
My question above should have been, with the ACR not functioning is the current blocked or can it flow freely?
 
http://assets.bluesea.com/files/resources/instructions/980011740.pdf

Looks like you could test that easy with a volt meter. If the fuse is pulled check the voltage on either side of the blue seas unit. With engine off it should be different as you would be seeing voltage at each separate battery bank. Start the engine and test with volt meter you should see the engine alternator 14 volt something and truck side of the separator be higher. If the led light comes on then the battery banks would be combined. With the fuse pulled the unit should not combine battery banks. Let truck run for a while as it may not combine for a set period of time. You should still see a difference in volts on each leg of the separator.

Turn truck off and put the fuse back in and repeate the above.

The blue seas unit is just a battery separator that has a brain and connects banks of batteries together when needed. Get yourself a volt meter and then you can test and understand what is going on.
 
There should be a breaker or a fuse at both ends of the wire between the camper battery(ies) and the starting battery(ies). Breakers with manual resets are easy, I just pop the one at the starting battery(ies) and then it doesn't matter what the ACR/VSR does.
 
Very good point that there should be breakers/fuse in the system and that would be the easy way to separate battery banks. If he wanted to find out what the ground wire does on the blue Seas 7611 then he should use a volt meter. He can decide if taking on the responsibility of placing a switch on the ground wire and remembering that it is now a manual thing has to remember to do.
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ntsqd said:
I've always been leery of manual over-rides. Sure as shoot I'll get too wrapped up in where we are and leave it in the wrong position at the least opportune time.

The current going to the starting battery(ies) wouldn't bother me so long as I knew that the solar system could more than keep up and that the charging voltage wasn't damaging either battery bank.
Click to expand...
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I agree with you Thom on your earlier statement about manual overrides. If somebody else uses your rig then how is they to know what to do? Yeah... Never push that RED button!!!
 
Disconnecting the ACR ground does shut down the VCR (its green light goes out, indicating the batteries are no longer connected) and the voltage meter confirms this.

I'm not overly impressed with the FWC wiring and what FWC has told me about the wiring isn't the way it was done. The wiring running from the truck battery to the camper has no fuse on the truck end and I find no fuse or breaker on the camper side. The 8 gauge wire running to the camper batteries from the VCR has no breaker or fuse that I see.
 
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