Blue Seas ML ACR 7622 questions

[OmegaMan73]

Hey guys I have a couple of questions about the ML ACR. I need a better understanding of how this unit works. Do I need to have the remote switch wired in and installed for this system to work properly? Also can you describe "normal" operation of this unit? Meaning day to day driving, will I hear the latching sound when the starting battery is isolated and it begins to charge the house battery? What position do I need the manual latch to be in if i do not have the switch wired in?

I'm installing this in a 2017 Tacoma. Thanks!

 

[luthj]

The switch is not required for automatic operation. When either battery gets above a certain voltage threshold the relay will close. This makes a single clicking noise which can be fairly loud. When both batteries drop below a certain voltage threshold the relay will open again making a clicking noise.

For automatic operation do not use the manual bypass switch.

Your typical day to day operation will involve the relay closing shortly after you start your vehicle and opening within 20 or 30 minutes of you shutting off your vehicle. If you have solar or other charge sources really will stay closed as long as the charge source is active.

 

[DaveInDenver]

You do not need the remote switch for it to work. You do need to ground the ACR no matter if you use the switch or not. I think it's a black wire in the harness. As long as that is grounded the box will operate automatically and can still be manually overridden.

Daily you may or may not hear it click. This depends on your parasitic loads and condition of your batteries. Mine will stay connected for a day or two, sometimes disconnecting after that when I open the door and the overhead light turns on. With the fridge in the truck it will disconnect after an hour or two usually. But I've had it stay paralleled overnight sometimes and other times it will disconnect almost immediately. Just depends on how good I've been about conditioning the batteries, what loads have been running, what engine speeds have been.

You want the manual position to be fully clockwise, then you'll see the button in the middle pull in or push out depending on the state of the relay. It'll be pulled in when the two batteries are connected. If you turn the dial fully anti-clockwise this is the permanently unlatched position, where the two batteries are held isolated. This prevent loads from draining both but it also prevent both from being charged (assuming you have only one source). Neither the automatic function nor the switch can override this, it's a mechanical isolation.

There's no valid position between the two, you want the manual dial either fully right or fully left. But with it's turned clockwise you can push the center button in to latch the relay and connect the two batteries for 10 minutes. After that the automatic function will revert to the voltage levels to decide whether to stay connected or open again. This is what you'd use to self jump or winch. If you've started the truck then presumable the alternator will be running and it will stay latched, for example.

The remote switch doesn't give you any additional operations that you can't get with the dial & button. It just makes it more convenient to do from the cab. I don't have the switch personally and haven't missed it. Having the status LED might be nice but not essential IMO.

 

[OmegaMan73]

Thanks for the replies guys. Is there any harm if I hooked it up by it did not run the ground in the harness? Because, well, I did that. Oops.

 

[DaveInDenver]

AFAIK it just doesn't work and doesn't harm anything. It's a pretty common mistake.

 

[DiploStrat]

You don't need the switch, but I used to like having a tell tale on the dash, just to let me know what was happening.

 

[snowgroomer]

I just installed and today I never saw the lights on the switch come on it seemed to work the other day does this mean my voltage is not enough to connect.

 

[john61ct]

The docs should give the close / open voltage setpoints.

Run the negative wire directly to the bank negative post, either side. Chassis ground is often not reliable long-term.

 

[DiploStrat]

I just installed and today I never saw the lights on the switch come on it seemed to work the other day does this mean my voltage is not enough to connect.

More likely an error wiring the switch.

N.B. Take a close look at the voltages of you Toyota. Some Toyotas only go up to around 13.9v and that is too low for most AGM and FLA batteries. (One reason why there are aftermarket voltage adjusters for Toyotas and why many Toyota owners use a B2B rather than a relay based system.) The voltages at which the ACR operates are perfect for lead acid batteries, but they still won't charge properly, i.e. fully, unless something takes them up to around 14.4v. If your Toyota won't do it, you will need to add a shore or solar charge source.

 

[DaveInDenver]

The Tacoma alternator is a little low but mine has had no issue with the ML-ACR for a bit more than 3 years now. I run dual Odyssey AGMs with a periodic top off, usually about once a month or two.

Combines after 30 sec @ 13.5 V
Combines after 90 sec @ 13.0 V
Opens after 10 sec @ 12.35 V
Opens after 30 sec @ 12.75 V
High voltage open @ 16.2 V

 

[DiploStrat]

The Tacoma alternator is a little low but mine has had no issue with the ML-ACR for a bit more than 3 years now. I run dual Odyssey AGMs with a periodic top off, usually about once a month or two.

Combines after 30 sec @ 13.5 V
Combines after 90 sec @ 13.0 V
Opens after 10 sec @ 12.35 V
Opens after 30 sec @ 12.75 V
High voltage open @ 16.2 V

The question is that whether the ACR will work, but whether you will charge your battery.

The voltages are fine for the ACR, the question is whether the Toyota gets to and sustains a voltage over 14v for long enough to charge a large, deep cycle battery.

 

[john61ct]

The voltages at which the ACR operates are perfect for lead acid batteries, but they still won't charge properly, i.e. fully, unless something takes them up to around 14.4v. If your Toyota won't do it, you will need to add a shore or solar charge source.

Or a DCDC charger

 

[DaveInDenver]

The question is that whether the ACR will work, but whether you will charge your battery.

@OmegaMan73 didn't ask that in the original post or his reply. None-the-less, a Tacoma alternator works fine with occasional topping, which is true of most stock charging systems that usually aren't designed to be ideal for AGM. I have pretty much exactly the same charging system as he does, stock alternator, ML-ACR. He can of course refer the volumes to previous posts about care and handling of AGM to be dazzled or baffled.

 

[DiploStrat]

Or a DCDC charger

Isn't that what I said? " … and why many Toyota owners use a B2B rather than a relay based system.)"


Mechman used to sell a nice plug-and-play adjuster for Toyota regulators, but with that off the market, a B2B/DC-DC charger may be the easier option.

Or, of course, you can play the Aussie diode game. See: http://www.smartgauge.co.uk/alt_mod.html

 

[DaveInDenver]

You can also just move the voltage sense out of the fusebox. That's all it takes to get the alternator output to within an acceptable range. There's a significant difference between the battery bus and the stock location Toyota picked to sense in 05+ Tacomas and 4Runner. But no reason to take the simple solution when there's gadgets to be bought or the potential for cooking your batteries by floating them at > 14 V.