dwh
Tail-End Charlie
Nah, get some sleep. I'll study on it and post something maybe later tonight or tomorrow morning.
Blue Sea ACR Wiring Question
- Thread starter Scott B.
- Start date
George, you have a few things confused. The ACR itself can handle 120 charging amps continuous and 200 amps for 5 minutes.
The combine switch is there to handle the combined loads of up to 500 amps. That's the whole point to the add a battery pack. The charge loads from your alternator (or solar) run through the ACR. The very high loads of combined operation are handled by the switch, NOT the ACR.
Spend some quality time with the wiring diagram until you understand how the currents flow in the system. It;s simple and clean and a very good set up.
For DWH - The ACR with the add a battery kit is not the 350 or 500 amp magnetic latching relay you are thinking of. It''s a 120 amp charging relay that does not :combine".
The switch too, is different than what you are thinking. It isn't the 1/2/both/off of a traditional marine switch. Instead it switches both circuits of the charging system on or off, but keeps them separate from each other. But it also has a "combine" setting to combine both batteries. It's pretty cool but look at the wiring diagram. The settings are off/on/combine. The "on" setting is a single throw double pole switch, switching the battery circuits at the same time but independently. The ACR takes care of the combine to charge, but not the combine to self jump or winch.
In many ways, I think the Blue Sea add a battery kit is a superior way to wire up a dual battery system.
Anyway, hard to explain in words but easy if you look at the diagram.
https://www.bluesea.com/products/7650/Add-A-Battery_Kit_-_120A
The combine switch is there to handle the combined loads of up to 500 amps. That's the whole point to the add a battery pack. The charge loads from your alternator (or solar) run through the ACR. The very high loads of combined operation are handled by the switch, NOT the ACR.
Spend some quality time with the wiring diagram until you understand how the currents flow in the system. It;s simple and clean and a very good set up.
For DWH - The ACR with the add a battery kit is not the 350 or 500 amp magnetic latching relay you are thinking of. It''s a 120 amp charging relay that does not :combine".
The switch too, is different than what you are thinking. It isn't the 1/2/both/off of a traditional marine switch. Instead it switches both circuits of the charging system on or off, but keeps them separate from each other. But it also has a "combine" setting to combine both batteries. It's pretty cool but look at the wiring diagram. The settings are off/on/combine. The "on" setting is a single throw double pole switch, switching the battery circuits at the same time but independently. The ACR takes care of the combine to charge, but not the combine to self jump or winch.
In many ways, I think the Blue Sea add a battery kit is a superior way to wire up a dual battery system.
Anyway, hard to explain in words but easy if you look at the diagram.
https://www.bluesea.com/products/7650/Add-A-Battery_Kit_-_120A
dwh
Tail-End Charlie
Okay, the basic problem here is that the kit you have, is not exactly what you need. That kit is setup for a boat. Basically, the ACR is too small and you don't need the switch.
What you really need, is just the 500a ACR. This one:
https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A
But it's not a deal-breaker. The 500a ACR is more expensive, and I dunno if you can return what you've got, or if returning it is even practical.
So...
What I did is just whip up two quickie cave paintings - one "proper" with the 500a ACR, and one to "run whatcha brung" with the 120a ACR.
I did not include the wiring for the ACR controls or the branch circuits from the fuse block. I put in these schematics just the basic power wiring and left the fiddly stuff out so the cave paintings wouldn't be too busy to understand.
Wiring if you had the 500a ACR (click to enlarge, and maybe click again to enlarge again):
Wiring with the 120a ACR you've got now:
What you really need, is just the 500a ACR. This one:
https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A
But it's not a deal-breaker. The 500a ACR is more expensive, and I dunno if you can return what you've got, or if returning it is even practical.
So...
What I did is just whip up two quickie cave paintings - one "proper" with the 500a ACR, and one to "run whatcha brung" with the 120a ACR.
I did not include the wiring for the ACR controls or the branch circuits from the fuse block. I put in these schematics just the basic power wiring and left the fiddly stuff out so the cave paintings wouldn't be too busy to understand.
Wiring if you had the 500a ACR (click to enlarge, and maybe click again to enlarge again):
Wiring with the 120a ACR you've got now:
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dwh
Tail-End Charlie
Reason for doing it the way I did with the 500a:
You can flip the control switch to "force on" (i.e., no longer on auto) for self-jump start, or to supply either winch with power from both batteries + alternator.
Reason for doing it the way I did with the 120a:
When running either winch, the voltage on the engine side of the ACR will drop, causing the ACR to disconnect (untie) the two batteries. Still, the winch (either one) will have the power from the engine battery + alternator, even though the aux battery has been untied.
You can flip the control switch to "force on" (i.e., no longer on auto) for self-jump start, or to supply either winch with power from both batteries + alternator.
Reason for doing it the way I did with the 120a:
When running either winch, the voltage on the engine side of the ACR will drop, causing the ACR to disconnect (untie) the two batteries. Still, the winch (either one) will have the power from the engine battery + alternator, even though the aux battery has been untied.
dwh
Tail-End Charlie
But only for 5 minutes, it's rated at 350a continuous.
Yea, I studied all the specs and diagrams for both ACRs and that switch.
I don't really see the smaller ACR + switch as a superior setup. I see it as a cheap solution - 100 bucks less than just getting the bigger ACR. So it's a workaround that can get the job done for a lower price.
The reason a workaround is needed is that the 120a ACR doesn't have an "always on" bypass control - it always operates automatically. With the bigger ACR, you have the control switch and the option to prevent a disconnect.
With the smaller ACR, any load on either side which is big enough to draw the bus voltage down far enough (12.75v for 30 sec. or 12.35v for 10 sec.) will cause the ACR to open the circuit and untie the batteries.
So they toss in a manual switch to force tie the two batteries when needed and end up with a kit that can get the job done, but is cheaper.
Okay fine, but it isn't needed to begin with.
A winch can run just fine off a single battery + alternator, so the extra complexity (and all around pain in the butt) of wiring in that manual switch, just to be able to keep the batteries tied during winching is not something that most people would even need on a light truck.
Sure, he could add the switch to get the self-jump capability. But he'll probably never need that. Even if he did, he could just run some jumper cables when that once-every-someodd-years problem crops up. I don't see the self-jump capability as being worth the extra PITA of adding that switch.
So I got rid of the switch and simplified the setup. It'll still get the job done unless George is planning to run his winches all day long. If he just let's 'em cool off between pulls (which he should anyway if he's working them that hard), the alternator will keep replenishing the engine battery, and he won't need the aux battery to help with the winching anyway.
dwh
Tail-End Charlie
George,
There are two alternative ways to rig the wiring with this setup.
1. The 2/0 that feeds the rear winch: Instead of connecting it to the front battery, you could connect it to the front winch. Might be easier to work with or just less messy under the hood doing it that way. Doesn't matter. You can't run both winches at the same time regardless, and the wiring to both winches is protected by the same fuse anyway.
2. The ground from the aux battery to the front battery: You could ground the aux battery to the frame instead of running a #2 all the way to the front battery. I wouldn't - it can cause induction noise in the radios, but it would work fine to carry the 75a from the alternator, or the 100a from the aux fuse block.
2a. Or you could run the ground from the aux battery to the rear winch, and piggyback on the rear winch's 2/0 ground. Again, I wouldn't - same reason, induction induced noise - but it would work.
(If you have two wires, one hot and one ground - the further apart they are from each other, the greater the chance of induction, and the greater the chance of radio noise. Best to always run them together as a matched pair and not even use chassis grounds.)
(And no, you can't use the frame to carry the 300a load of the rear winch, you'll have to run a dedicated 2/0 ground for that big of a load.)
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dwh
Tail-End Charlie
(And I was scheduled to be up half the night (or maybe even all night) doing some work on a server halfway around the friggin' planet as a favor for someone - so no, it was not any problem at all to deal with this while I was up and on the net anyway. But now I'm done and I will be sleeping late. 
)
EDIT: And one last thing I almost forgot to mention...
In the 120a wiring diagram, the only wire that is missing that you will absolutely need, is the ACR's ground wire with the 10a fuse. Any wire #16 or bigger would work for that.
You can ignore the starter isolation wiring crapola - you don't need that. When you turn the key and engage the starter, it will cause a voltage drop, which will cause the ACR to automatically untie the batteries if you do it for longer than 10 seconds. The starter isolation setup just makes it untie the batteries as soon as you turn the key, to protect any sensitive stuff you might have connected to the aux battery. For instance radios on a boat. Which you don't have.
If you ended up blowing either of the 100a fuses that protect the #2 wire (if the starter sucks tons of power from both engine AND aux battery), then yea, you'd have to go ahead and hook up the starter isolation. You can if you want, it won't hurt, but I don't think you'll need it.
)EDIT: And one last thing I almost forgot to mention...
In the 120a wiring diagram, the only wire that is missing that you will absolutely need, is the ACR's ground wire with the 10a fuse. Any wire #16 or bigger would work for that.
You can ignore the starter isolation wiring crapola - you don't need that. When you turn the key and engage the starter, it will cause a voltage drop, which will cause the ACR to automatically untie the batteries if you do it for longer than 10 seconds. The starter isolation setup just makes it untie the batteries as soon as you turn the key, to protect any sensitive stuff you might have connected to the aux battery. For instance radios on a boat. Which you don't have.
If you ended up blowing either of the 100a fuses that protect the #2 wire (if the starter sucks tons of power from both engine AND aux battery), then yea, you'd have to go ahead and hook up the starter isolation. You can if you want, it won't hurt, but I don't think you'll need it.
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dwh
Tail-End Charlie
And naturally...just as my head hit the pillow...I thought of another alternative way to rig the wire...
Run both the hot and ground from aux battery to the rear winch and piggyback them both onto the rear winch's 2/0. You'd have to put the ACR in the back so it's between the aux battery and the rear winch, and you'd still need a fuse at both ends of the #2 that's between the rear winch and the rear battery, but you wouldn't need to run #2 from the front to the back at all.
Run both the hot and ground from aux battery to the rear winch and piggyback them both onto the rear winch's 2/0. You'd have to put the ACR in the back so it's between the aux battery and the rear winch, and you'd still need a fuse at both ends of the #2 that's between the rear winch and the rear battery, but you wouldn't need to run #2 from the front to the back at all.
Blue Sea 7650 Add a battery --more questions
WOW! I'm at a loss for words! People staying up all night to help me, Come on over, supper and libations are on me!(and a couch to rest up!)
This is going to take a while for me to digest. Thanks for all your time and effort!
George
WOW! I'm at a loss for words! People staying up all night to help me, Come on over, supper and libations are on me!(and a couch to rest up!)
This is going to take a while for me to digest. Thanks for all your time and effort!
George
DiploStrat
Expedition Leader
This would be a slick setup, but I confess that I still prefer using the 500A ACR (see dwh's first diagram) as it allows you to use ALL of your batteries and your alternator when winching. And, at least in my case, my camper batteries are much larger than my starter battery.
In the end, however, I defer to those who know more about winches than I do.
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While I don't disagree that the 500A ACR would work fine, being practical, so would the 120A ACR serve for most needs without the switch. What most people want is 2 batteries and a way to charge two batteries. Combined winching or self jumping are extremely rare (if ever) events, and so really just being able to charge and isolate loads can be done with an inexpensive ACR.
The smaller ACR is cheaper, easier to mount, simplifies the wiring and allows the use of smaller gauge wiring. It seems a superior set up unless you just have to be able to self jump, or if your alternator makes more than 120 amps (or 200 for 5 minutes).
But hey, we're all about overkill here, so break out the 500 amp ACRs and the 4/0 cable!
BTW-Nice seat of the pants diagrams.
The smaller ACR is cheaper, easier to mount, simplifies the wiring and allows the use of smaller gauge wiring. It seems a superior set up unless you just have to be able to self jump, or if your alternator makes more than 120 amps (or 200 for 5 minutes).
But hey, we're all about overkill here, so break out the 500 amp ACRs and the 4/0 cable!
BTW-Nice seat of the pants diagrams.
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dwh
Tail-End Charlie
Nah, it wasn't like that. I had something else I had to do anyway. I just didn't know exactly how long it would take me. But I knew I'd be able to squeeze this little project in at the same time, so what the hell.
Don't thank me, thank The Norns.
Took longer to type it up than it did to actually do it. (Which is the main reason why 90% of all IT jobs are never properly documented.
Documentation would double the cost of the job. At least...)
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dwh
Tail-End Charlie
Or if you want to run a rear winch AND rear battery without running two sets of wires to the rear of the truck - but you just gotta have the ACR in the front.
Ooh Rah!
Thanks. I just use Paint.NET (awesome freebie Photoshop replacement). Start with one layer for the basic components layout:
Then add more layers - one for each different wire plan. Disable whatever layers you don't want at the moment and save as .jpg. Total time - about 5 minutes for each wire plan.
And purely for the hell of it, I also just whipped up the simplified "ACR in the rear" diagram:
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