Question About Solar And A.C.R.

[xymotic]

Let's say you have Solar, putting about 6 amps into the start battery, which is then connected via Blue Sea's Automatic Charge Relay. The Relay senses the higher voltage of the solar and connects to a house bank that you are pulling let's say 10 amps out of.

What happens then? Does the draw on the start reduce the voltage below 13 kinda by definition and open the circuit on the ACR or is it possible for it to stay closed because it senses a 'charge' and actually deplete the start battery?

[barnakiel]

Read into the manual, the relay is voltage, not amperage, driven. It will connect and disconnect the batteries as per its cut-in / cut-off voltages.

Check how your regulator's voltage set points interplay with relay's behaviour.

b.

[djmarchand]

If the solar panel is really supplying 6 amps to the starting battery, then the voltage is most certainly below the cut in voltage of the ACR relay. Once the voltage rises to its cut in voltage (and tne current drops), then the relay will start supplying current to the house. It might cycle on and off a bit while the starting battery builds up enough charge to let most of the current go to the house.

David

[xymotic]

Thanks fo the replies, but I'm afraid I still don't get it.

if the start battery is full. the solar power has to go somewhere, right? so the ACR will sense 13-14v and open at which point it's connecting to an 11.7v house bank with a larger load.

Does the voltage automagically drop when the house starts to draw off the start and turn off the ACR?

[Sumner]

We will have all charging (solar and alternator) going to the house and the ARC will send charge to the start battery. I was going to go with the solar to the house and the alternator to the start battery, but after others posted on that (Maine Sail and others) saw that it was best to take all of the charging sources to the house and let the ARC take care of the start battery. I'd wire it like that and trust the ARC and not worry about it unless you actually see a problem at some point.

I will be able to start off the house batteries if needed. The starter doesn't/shouldn't actually pull very many amp-hrs from the start battery but does pull a large amperage when it does. Make sure that amperage is not going through the ARC. The Blue Seas can be wired so that it drops out when the starter is engaged and is what we will do. With that wired and an A/B switch you could start off the house if needed.

If the batteries are full then the solar charge controller will stop the charging by just disconnecting the panels,

Sum

[Maine Sail]

Originally Posted by xymotic

Let's say you have Solar, putting about 6 amps into the start battery, which is then connected via Blue Sea's Automatic Charge Relay. The Relay senses the higher voltage of the solar and connects to a house bank that you are pulling let's say 10 amps out of.

What happens then? Does the draw on the start reduce the voltage below 13 kinda by definition and open the circuit on the ACR or is it possible for it to stay closed because it senses a 'charge' and actually deplete the start battery?

You would be best to connect the solar to the house bank not the start bank. When the house comes up to connect voltage you will not get relay cycling and it will remain combined with the start..

Any combiner with small solar current will drop out when a discharged larger bank combines. The larger bank is sucking the voltage back below the combine point because there is insufficient current to support that voltage. It can cycle like this for a loooooong time before remaining connected.

The easy fix is to route the solar to the house bank first...

[xymotic]

Originally Posted by Maine Sail

You would be best to connect the solar to the house bank not the start bank. When the house comes up to connect voltage you will not get relay cycling and it will remain combined with the start..

Any combiner with small solar current will drop out when a discharged larger bank combines. The larger bank is sucking the voltage back below the combine point because there is insufficient current to support that voltage. It can cycle like this for a loooooong time before remaining connected.

The easy fix is to route the solar to the house bank first...

Thank you.

I'm temporarily living 'aboard' a 16' airstream type trailer while I work on the boat on the hard. I've mounted some of the boat's Solar onto my van's roof, and so physically it needs to go to the Van's two "start" batteries (optima AGM)

Then there's a 10gauge wire to the trailer's 'house' two batteries (wet cells). I've measured that link @ 25 amps with the alternator, up to about 10 with solar (200 watts)

I know it's not ideal, but I'm trying to save as much money and effort as possible until I move all of this stuff back to the boat permanently. If I watch TV/internet too long (fall asleep with it on) I can deplete the van to the point where it won't start, so I'm thinking of ways to overcome this. I'm getting OK at physically unplugging it but that's a PITA.

[foggysail]

This was tough to follow so I'll do some guessing. Which battery group do you have your load connected to?

From what I read, the ARC will prevent discharging a charged battery into a discharged battery but you say your start batteries become discharged to the point where the van will not start.

Now again, I said I would be guessing so here goes..... there should be no reason for your start batteries to see anything outer than the vehicle's 12 load normally connected to the start system such as headlights, radio and so forth.

YOur tv along with other powered amenities should be energized from the load bank. Does the load bank discharge along with the starting batteries?

Finally, how many watts does your tv require? I push the heck out of two 12vdc flooded batteries connected for 24 vdc (group 29??) when we are out. The tv, a 27" Sony is on most of the day until after 11pm along with a fluorescent light, the small lamp styles. We never kill the batteries. It takes about 1 1/2 hours to charge them in the morning with our generator. Using the genny is fine because I need a lot of coffee in the mornings. It also heats the water. Our solar as currently connected is mainly for our fridge. Next season I am connecting (at least I think I will connect) both house batteries to 24vdc and purchase another 24vdc inverter, install another 290 watts of solar and finally wire all my solar for 24vdc.

[barnakiel]

Originally Posted by Sumner

We will have all charging (solar and alternator) going to the house and the ARC will send charge to the start battery. I was going to go with the solar to the house and the alternator to the start battery, but after others posted on that (Maine Sail and others) saw that it was best to take all of the charging sources to the house and let the ARC take care of the start battery.(...)

I bet I used a double sensed relay the other day - the start battery took the alternator charge and the house batteries took other sources, the relay connected if either bank hit the assigned voltage(s).

I think this would equal having two relays in the rig, each sensing one bank.

b.