Sanity Check on Wiring Plan

[Target9000]

I had read a few threads over on sailnet where a bunch of guys advocated just starting off the primary bank and having the other battery as "backup" in case the house bank drained down. I suppose keeping the three switch system in place would make for a truly dedicated starter batt.

[btrayfors]

I agree with Don and mitiempo re: complete separation of the starting circuit. I do not agree with those who say, "just use the house batteries"....for the reason Don cited and others as well.

By the way, in the 3-switch setup if you wire the emergency switch to the LOAD side of the other two switches, as opposed to the SUPPLY side as shown, you can then have a very flexible system which will allow you to completely isolate either battery bank simply by leaving its switch OFF.

Don't forget the fusing....very important!

Bill

[Target9000]

How is this then?



I know the fusing is very important. I still need to look into grounding, fusing, and everything else. :P I figured the high level overview would be a good place to start planning though.

[Kettlewell]

Looks good to me, but I would prefer an EchoCharge or something similar. Your starter bank will generally require very little charging, and you can get bad cycling if the house bank is really low, you turn on the engine, the ACR opens up and the start battery dumps its load into the house bank. Also, if you get a fault in the house bank, which does happen, the ACR can allow the start bank to lose its charge into the house bank and then you are left with nothing.

[donradcliffe]

Originally Posted by Kettlewell

Looks good to me, but I would prefer an EchoCharge or something similar. Your starter bank will generally require very little charging, and you can get bad cycling if the house bank is really low, you turn on the engine, the ACR opens up and the start battery dumps its load into the house bank. Also, if you get a fault in the house bank, which does happen, the ACR can allow the start bank to lose its charge into the house bank and then you are left with nothing.

According to the description of the EchoCharge and the ACR, they pretty much do the same thing, except the ACR lets a lot more current flow between the batteries. There is no way that the start battery is going to dump its charge into the house bank with the ACR when you have the charging sources hooked to the house bank. It takes 13 volts for the ACR to connect, and the voltage on the starting bank will be less than that (unless it has just been charged, in which case the surface charge will bleed off in a few seconds). In addition, the ACR has a protective circuit which does not allow a connection in the event of a fault in the house bank.

I would probably compare prices, including the heavier wiring you will need with the ACR with its 100 amp circuit vs the 15 amps for the EchoCharge.

[goboatingnow]

I think its important to note that many people mean Echocharger in a generic sense, I do. That is a DC to DC battery charger. Sterling make ones. They are not some sort of upmarket relay. but a proper charger just powered from DC.

[Kettlewell]

The ACR is different than the EchoCharge. The ACR basically opens up at a certain voltage and combines the two banks, meaning there can be a two-way flow creating the cycling I was talking about. Read what Blue Seas says about it here. The EchoCharge is a "charger" that starts working when one side receives a high enough voltage, and then it starts providing a charge to the other side, but there is not a two-way flow. In other words, the charge only comes from your bank receiving the input and goes to the other bank at up to I think 15 amps max.

[goboatingnow]

Sterlings battery to battery charger is a proper mult-stage intelligent charger, thats what I would use as an "echo charger"

dave

[Stu Jackson]

1/BOTH/2/OFF Switches Thoughts & Musings - SailboatOwners.com
and
http://c34.org/bbs/index.php/topic,6604.0.html

[knottybuoyz]

My 2 cents worth Target.

IIRC the BlueSea ACR gets hooked to the starting battery side. Don't worry though it's in the instructions. There are issues with externally regulated alternators and ACR's but that's covered in the instructions as well.

You don't normally have to draw in the negative circuits on your schematic, they're a given. Use a good quality marine busbar and plan to run all your grounds to it. Pretty easy actually.

Hope it all goes well with your project.

[Stu Jackson]

Originally Posted by knottybuoyz

My 2 cents worth Target.

IIRC the BlueSea ACR gets hooked to the starting battery side. Don't worry though it's in the instructions.

Yes, the rftm really does work!

http://bluesea.com/files/resources/i...tions/6330.pdf

Looks to be in the + wiring for this model.

I concur, good luck with your project.

[mitiempo]

Originally Posted by knottybuoyz

My 2 cents worth Target.

IIRC the BlueSea ACR gets hooked to the starting battery side. Don't worry though it's in the instructions. There are issues with externally regulated alternators and ACR's but that's covered in the instructions as well.

You don't normally have to draw in the negative circuits on your schematic, they're a given. Use a good quality marine busbar and plan to run all your grounds to it. Pretty easy actually.

Hope it all goes well with your project.

The ACR is wired to both battery banks equally - it doesn't have an in and out specifically, just 2 connections labelled A and B. It is dual sensing.

I would run the alternator directly to the house bank rather than to the start battery side of the ACR as in post #18. The house bank needs the most charging.

[zeehag]

what i can see is you didnt hire someone else to do it so ye could KEEP yer sanity, if you still have any .....

[knottybuoyz]

Originally Posted by mitiempo

The ACR is wired to both battery banks equally - it doesn't have an in and out specifically, just 2 connections labelled A and B. It is dual sensing.

I would run the alternator directly to the house bank rather than to the start battery side of the ACR as in post #18. The house bank needs the most charging.

Hooking it to the + on the starting battery allows it to recharge first which ensures you can always restart your engine then it falls over to charge the house bank when the starting battery is fully charged. On mine (VP AQ291A) it takes all of about 60 seconds to replace the starting charge before it switches over. Doesn't get any more idiot proof than that!

[btrayfors]

Originally Posted by knottybuoyz

Hooking it to the + on the starting battery allows it to recharge first which ensures you can always restart your engine then it falls over to charge the house bank when the starting battery is fully charged. On mine (VP AQ291A) it takes all of about 60 seconds to replace the starting charge before it switches over. Doesn't get any more idiot proof than that!

I think you DID just make that up :-)

Depends on which device you're talking about. ALL devices connect to both the house bank and the start battery.

If it's a sort of relay -- ACR, "battery combiner", etc. -- then most of them are dual sensing and just serve to make essentially a physical connection between the house and the start batteries. Doesn't make much difference how you connect them....the bank which needs charging the most (usually the house battery bank) will get the most benefit of charging initially and until the voltages rise.

If it's a voltage follower device, like the Xantrex EchoCharge or the Balmar DuoCharge, then they must be connected correctly to get the maximum benefit, since each of them has a significant limit (15A and 30A, respectively) on the amount of amperage it can pass from one bank to another. And, they're ONE-WAY devices. Naturally, you want to have the most amperage going into the house battery, and use the pass over function to top off the start battery, which generally needs very little charging.

If you were to connect these backwards and have the charging source going to the start battery only, you'd only get 15A in the case of the EchoCharge or 30A in the case of the DuoCharge going into the house batteries. This, clearly, is not desirable.

Bill