Thanks for the detailed explanation Dennis, very helpful in understanding
why the mACR works the way it does.

-Mark

On Tue, Apr 28, 2020 at 9:41 AM Dennis Haynes <d23haynes57@hotmail.com>
wrote:

> Mark,
> I didn't get your original post so hopefully by direct response I'll get
> the future posts.
> I am extremely familiar with the mACR, I install a lot of them. The only
> problem I have experienced with them is that they have both over voltage
> and under voltage lock out. If the voltage for the house battery goes too
> low it will not connect and charge on its own. This is a safety feature and
> it ca prevent a bad day if a battery is discharged, then freezes and then
> you try to charge it. Makes a mess.
>
> The mACR senses voltage from both banks and closes the contactor when
> either bank goes high from a charge source. If using a smart charger a
> typical curve will be to charge up to some voltage and then go to float or
> standby. This could be as low as 13 volts. You want the ACR to stay
> connected. Also, while driving it is common for the alternator output and
> battery voltage to sag under some loads, driving conditions. You don’t want
> the ACR to short cycle and keeping it closed also allows for the house
> battery to provide some support during these conditions.
> And then comes the next point. During charging the battery voltage will
> rise. Just after charge there is that high voltage, surface charge which
> used or not will be lost in a few hours. That top 10% is going to be lost.
> So as you pull into camp, ACR will let you use some of that top power
> before it disappears. The real goal out of the box to charge your batteries
> and prevent the house loads from leaving you stranded. No need to keep a
> cassis battery at 100%.
>
> The mACR does allow for you to disable it. Just install a switch in the
> ground lead. I do this for folks that have dual output charges or different
> battery types that they want to isolate will on storage chargers.
>
> Hope this answers some of you questions.
>
> Dennis
>
>
>
>
> -----Original Message-----
> From: Vanagon Mailing List <vanagon@gerry.vanagon.com> On Behalf Of
> Alistair Bell
> Sent: Tuesday, April 28, 2020 12:18 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: do all ACRs work like this?
>
> Again mistyping.... I mean OVERvoltage at 14.65.
>
> Sheesh
>
>
> Alistair
>
> Mark,
>
> I think I mis typed in my reply. I have the disconnect set at 13.65. And
> voltage setting somewhere around 14.65.
>
> Sorry for confusion
>
> Alistair
>
> > On Apr 28, 2020, at 7:41 AM, Mark McCulley <markmcculley@gmail.com>
> wrote:
> >
> > I have a Blue Sea m-ACR installed in my van, there is one aspect of
> > how it works that I'm not sure that I like. It does not isolate the
> > house battery from the starting battery unless the voltage on one of
> > the batteries goes below 12.75v. When I installed the ACR I thought
> > that the batteries would be isolated whenever they weren't being charged
> but this is not the case.
> >
> > Regards,
> > Mark
>