Blue sea automatic charge relay

[cutlass]

I was recommended to use an automatic charge relay rather than a battery isolater to split my starter and house bank. Is this the right thing to do?

Anyone have experience with the blue sea models?

Thanks!

[colemj]

We have those ACR's. They work as advertised and are a better solution than an isolator.

Mark

[Dustymc]

I have one. My "oh crap that was really stupid" battery stays charged without me ever thinking about it.What more could I ask?

[Albro359]

I use a FET isolator from Victron...almost no voltage drop and nothing to go wrong. I had a BEP automatic charge relay and it died shortly out of warranty.

[rebel heart]

I have a blue sea acr. I'm amazed more people don't use them.

[goboatingnow]

if your starter and house are similar batteries, then a really is fine , otherwise a diode splitter is better.

[Dustymc]

Originally Posted by goboatingnow

if your starter and house are similar batteries, then a really is fine , otherwise a diode splitter is better.

Explain please?

My "start" (backup) battery is a Wal-Mart special El Cheapo "Marine" G27 battery. My "house" (which I start with 99% of the time) is 4 T-105s. My charger, alternator, and solar all treat the "house" side as if it's all that exists, and the ACR keeps my "start" battery happy without me having to ever think about it.

My two sides are about as dis-similar as possible, my system is flippin' awesome, and the ACR works perfectly for me. Right?? What am I missing?

[sabray]

Used the acr blue sea for 5 years works simple and great. Same battery types so charge voltages are the same. Having lead acid and Agms would be a problem as the lead acid would be getting a higher then specked voltage or the Agm lower. That's why people get the other options. I have Agms through out and have no issue. Very happy with it.

[cal40john]

If you have something like a Balmar 612 regulator the bulk charge voltage limit is set higher than the acceptance voltage limit. With a large house bank the voltage output could be at 14.8 volts during bulk charge when your start battery had already charged up resulting in gassing and heating your start battery.

If you have an internally regulated alternator or a smart regulator that doesn't go above 14.4 volts in bulk then it doesn't really matter.

John

Originally Posted by Dustymc

Explain please?

My "start" (backup) battery is a Wal-Mart special El Cheapo "Marine" G27 battery. My "house" (which I start with 99% of the time) is 4 T-105s. My charger, alternator, and solar all treat the "house" side as if it's all that exists, and the ACR keeps my "start" battery happy without me having to ever think about it.

My two sides are about as dis-similar as possible, my system is flippin' awesome, and the ACR works perfectly for me. Right?? What am I missing?

[barnakiel]

I used one ((the older type, read explained below). It was very good. It is a relay type so no drop voltage as with a diode isolator. Now I have a plain relay which is equally good except the blue wave thing had a remote reconnect and a diode that said when it was on/off.

Later I found there is a newer one - a voltage sensitive that dis/-re connects depending on the voltage and on which battery is doing what. This one I did not use, but I read the specs and I think it is a very smart piece of equipment.

b.

[goboatingnow]

Originally Posted by Dustymc

Explain please?

My "start" (backup) battery is a Wal-Mart special El Cheapo "Marine" G27 battery. My "house" (which I start with 99% of the time) is 4 T-105s. My charger, alternator, and solar all treat the "house" side as if it's all that exists, and the ACR keeps my "start" battery happy without me having to ever think about it.

My two sides are about as dis-similar as possible, my system is flippin' awesome, and the ACR works perfectly for me. Right?? What am I missing?

the relay parallels the batteries ( banks), it is not good practice to parallel banks of widely differing capacities or age or type. nor when one bank is significantly lower SOC then the other,

Dave

[Dustymc]

Originally Posted by cal40john

If you have an internally regulated alternator or a smart regulator that doesn't go above 14.4 volts in bulk then it doesn't really matter.

Hu. Why didn't I think of that? I have a stoopid alternator, but I just added a fairly large solar array on a MPPT controller, and tried out the equalize function for the first time a couple days ago, having never had such capacity before. Looks like I may be shopping for a new non-sealed "backup" battery fairly soon....

Thanks!

[sabray]

The unit I have disconnects house from start when they hit a fixed voltage. Think it's 12.8 but not sure. Then the house discharges until a charge is applied or everything is turned off and the panels start catching up. At 12.8 volts I think the relay comes in and the banks are connected and topped up. Same age batteries all Agm group 27 on the start and 2 4ds on the house. Maybe not perfect but it has worked well for 5 years now.

[westsail42]

I prefer using an EchoCharge on the starter battery when charging from the alternator. You wont suffer the dissimilar battery problem. And, your starter battery should never be so deeply discharged that it needs three stage regulation (if it is, you have a problem, or are not using it as a starter battery).

The problem with paralleling charging devices on widely dissimilar capacities, is that you risk one battery never fully charging because paralleling will change its "appearance" to the regulator. The starter or house bank can "bring down" the other depending on it's charge state and condition.

I tried this on my system once. After hours and hours of motoring on windless days, the house bank would never fully charge (according to the battery monitor). Replaced the parallel switch with an echocharge and it has been working great for seven years with the same batteries.

[RUSTYNAIL]

I've put several ACR relays on vessels, especially when they get a new engine with a serpentine belt, and no place for a second alternator. For boats with similar batteries in both banks, it's a simple/easy fix with no problems. Adding the Blue Sea digital voltmeter with an adjustable hi/low alarm setting will take a lot of guess work out of the charging for the banks. The ACR wont parallel the banks until one of the banks comes up to 13.3VDC or so, with a short time delay to eliminate any cycling. Great device.