Running on 1 battery VS 2?

[Bfun220]

You are correct. The alternator is not connected to the switch. The rely is wired between A and B battery. Your alternator goes to battery A. Once battery A is charged above 12.9 volts (I think) it closes the rely. Once closed your batteries would be combined at this piont. Battery A while being maintain by the alternator would then charge battery B.

In the video they run the relay back to the switch because it is a shorter distance to wire. It would be the same as going back to the battery.

[Driller]

As long as Battery A does not go bad. If Battery A goes bad, neither gets charged? The relay will isolate when either battery goes below a certain low voltage.

[Bfun220]

Only if Battery A is bad and drawing down the 14-15 volts your alternator is putting out.
Only isolates when A battery falls below voltage. If it isolates when B is low, then B would never charge.

[Driller]

Agreed. I think the "new fangled" system is better and should be more reliable if everything works as designed. I like the option of charging both batteries most of the time any the operation is much simpler.

[Driller]

Volvo also makes a system which as you would expect is a lot more complicated and I'm sure an order of magnitude more expensive, but is can selectively direct the alternator charging directly to either battery while still maintains isolation.

Will install on ECM or non-ECM setups.

http://volvopentabatterymanagement.com/ ... 940_US.pdf

[Driller]

Page 18 has the 2-battery setup with the optional remote control.

[Bfun220]

That looks like a nice set-up and im sure it comes with a nice price.

[Driller]

Can't find any details on the price online. I have no spare arms or legs, but I'm curious.

[notstock4long]

Volvo also makes a system which as you would expect is a lot more complicated and I'm sure an order of magnitude more expensive, but is can selectively direct the alternator charging directly to either battery while still maintains isolation.

Will install on ECM or non-ECM setups.

http://volvopentabatterymanagement.com/ ... 940_US.pdf

I looked into this. I want it, but not bad enough to drop about $1500 on the setup. The damn battery monitors alone that mount on the negative battery terminal are about $280 each.

It would sure be cool though!

[notstock4long]

Can't find any details on the price online. I have no spare arms or legs, but I'm curious.

I found pricing on most of the parts on a couple foriegn sites that sell Volvo Penta parts. It was something like $600 for the BCM, $280 per battery monitor, $400 for the remote stuff, and a bunch of cables at ~$100 each. The display is another $400 or so, but I think I could bring it into my existing EVC display.

When tearing into the boat I found that they put one of the Multilink distribution panels right behind the dash, so it would be easy to bring the info into the network.

[notstock4long]

You are correct. The alternator is not connected to the switch. The rely is wired between A and B battery. Your alternator goes to battery A. Once battery A is charged above 12.9 volts (I think) it closes the rely. Once closed your batteries would be combined at this piont. Battery A while being maintain by the alternator would then charge battery B.

In the video they run the relay back to the switch because it is a shorter distance to wire. It would be the same as going back to the battery.

I did quite a bit of reading on the ACR over the weekend after I had an issue.

It looks for voltage on either battery to rise to a charging level. If 13.6V or higher, it closes the connection between batteries after 30 seconds. If 12.9V to 13.6V, it closes the connection after 2 minutes. It senses the charging voltage on battery A or B. It does not care which one. However, if the battery not connected to the alternator drops below some specific voltage, it will isolate that battery to prevent draining the good battery into a bad and/or severely depleted battery, since that could potentially suck voltage from the good battery faster than the alternator could keep it charged, leading to both batteries being dead.

I learned about the isolation feature after running the house battery too low while tinkering around. The radio and GPS gave me a low voltage warning, but I figured once I got out on the water the alternator would charge it back up and all would be good. It didn't, so I was worried until I got to reading about the ACR. I then charged the battery back to normal with a battery charger, and it worked fine next time we were on the water. I'll be wiring in my onboard charger/maintainer this week, so at least I won't need to wheel my big charger over to the marina if it happens again.

The ACR also has a terminal to power a remote LED. Just like the LED on the ACR, it just illuminates when it has combined the batteries and goes off when they aren't combined. I'm thinking about putting an LED somewhere on the dash for this.

[Driller]

I would really like the Volvo system also, but hard to justify vs the $160 Blue Sea. Lots more info and the ability to selectively charge the batteries on the VP. Hmmmmm

[Driller]

Can't find any details on the price online. I have no spare arms or legs, but I'm curious.

I found pricing on most of the parts on a couple foriegn sites that sell Volvo Penta parts. It was something like $600 for the BCM, $280 per battery monitor, $400 for the remote stuff, and a bunch of cables at ~$100 each. The display is another $400 or so, but I think I could bring it into my existing EVC display.

When tearing into the boat I found that they put one of the Multilink distribution panels right behind the dash, so it would be easy to bring the info into the network.

Well, if I dropped the remote then it might be more tolerable. I don't know if I would use the remote that much. Still hard to drop the price below $1000.

[Ytmsn]

Man I really admire you guys that understand wiring. Every time I have ever tried to learn electric, I blow something up or catch it on fire, so my subconscious has decided to "tune out" wiring or anything with the word electrical. I can change flashlight batteries. The rest is Latin..

[notstock4long]

Man I really admire you guys that understand wiring. Every time I have ever tried to learn electric, I blow something up or catch it on fire, so my subconscious has decided to "tune out" wiring or anything with the word electrical. I can change flashlight batteries. The rest is Latin..

I'm an electrical engineer, so don't worry...the running joke is that every electrical component inherently has some amount of smoke kept inside of it. You just happen to let some of it out more often than most people it sounds like

I accidentally shorted a 480V circuit at a machine shop the other day. It crashed a half dozen CNC machines and fried a few hundred dollars worth of big fuses.