Need a simple test for ACR...

[Rowglide]

I am currently re-wiring my boat and in the boxes upon boxes of electrical supplies (All appear new, most still sealed in packages) that came with the boat is a Blue Seas SI-ACR.
Using one of these is part of my plan so it is great that I already have one... if it works.
Is there a simple way to test its function or do I need to wait until it is installed before I discover whether it works or not.

Maybe I am overthinking (very tired)... I run my windlass off the start battery. Let me paint a scenario...
Spend a few days on the hook. House batteries get below say 12.5V. When I start the engine, the alternator will charge the house batteries but not the start battery until the house is over 13v. I would like to have the start battery receiving a charge while using the windlass. With an ACR will I have to wait till my house is charged before running the windlass?
Jim

[john61ct]

Depends on the setpoint and your battery chemistry, but

Full battery one side, light bulb on the other should go on. If not, put a charger on the battery, voila.

Take charge off, light goes out. If not, put more load on the battery or just wait if it's a strong light, at some point goes off.

With a voltmeter you can verify the combine/isolate setpoints.

Fancier solutions, you can set it to your own custom voltages.

May be a delay, or a gap between open/close voltages to minimize "chattering" on and off.

[john61ct]

With the last bit, put the alternator output (and sensors) wherever you want.

Usually best on a big House bank, but fact is, a Starter barely drops at all, ACR should open very quickly in either case.

[Rowglide]

So putting alternator output on Start battery side of the ACR really guarantees a full start battery first then house second instead of the other way around. Any reason that would not be preferred.
BTW. Thanks for your insight. Test makes sense I can try that tomorrow.
Jim

[john61ct]

Yes, starter rarely depleted significantly, best practice as I said pump the big amps where they're really needed.

ACR likely drops voltage, may be amp-limiting, put the puny starter load other side.

But it can be made to work either way if you need to keep alt on starter.

[smac999]

the alt is better to house battery. consider putting the windlass off the house.

if you have a decent size alt it should not take long at all for the ACR to kick in. like 1 min. if you have a tiny undersized alt or a huge drained house bank it could take a while. but in this case you don't want to put the alt on the start because then you get ACR cycling.

if you want to test it. you need to hook up power to both sides. could be from same battery for testing. and ground. under voltage no light on, charging voltage light will go solid and you'll hear it click.

[smac999]

Originally Posted by john61ct

Depends on the setpoint and your battery chemistry, but

Full battery one side, light bulb on the other should go on. If not, put a charger on the battery, voila.

Take charge off, light goes out. If not, put more load on the battery or just wait if it's a strong light, at some point goes off.

With a voltmeter you can verify the combine/isolate setpoints.

Fancier solutions, you can set it to your own custom voltages.

May be a delay, or a gap between open/close voltages to minimize "chattering" on and off.

this won't do anything on a blue sea ACR. you will just get a flashing light for low voltage lock out. it needs power on both sides.

[Rowglide]

Originally Posted by smac999

the alt is better to house battery. consider putting the windlass off the house.

if you have a decent size alt it should not take long at all for the ACR to kick in. like 1 min. if you have a tiny undersized alt or a huge drained house bank it could take a while. but in this case you don't want to put the alt on the start because then you get ACR cycling.

if you want to test it. you need to hook up power to both sides. could be from same battery for testing. and ground. under voltage no light on, charging voltage light will go solid and you'll hear it click.

Thanks for the input. The main reason I would rather run the windlass from the start battery is distance. it is another 10 ft+ (X2) to the House batteries. The windlass existing correctly sized cables end near the start battery. Could you explain ACR cycling?

[boatbod]

An ACR doesn't wait for a battery to become "full" before combining. It works strictly on voltage and will cut in whenever the set point is reached. Batteries therefore charge in parallel as long as there is sufficient charge current to raise the terminal voltage.

[john61ct]

Originally Posted by Rowglide

Thanks for the input. The main reason I would rather run the windlass from the start battery is distance. it is another 10 ft+ (X2) to the House batteries. The windlass existing correctly sized cables end near the start battery. Could you explain ACR cycling?

Cycling: The volts dropping causes open/isolate, which allows volts to rise, causes close/combine, which. . .

Can happen quickly enough to call chatter.

Delays and/or gap in the setpoints reduce the frequency so not damaging, but a bit, spaced out not a problem.

If the windlass is a significant load relative to the starter capacity and runs a long time, that is deep cycling and requires the right size bank or you'll murder it quickly.

Nothing too wrong with two big DC banks and one of them happens to be also used for starting. Alt goes on the one getting depleted more regularly.

But better to increase the House if needed, leave starter small, run alt and All big loads off the House.

#3 many have a dedicated windlass bank.

[Rowglide]

By using house bank (my windlass is a 1200W unit) will the sudden draw drop the voltage and cause my instruments to cut out?

[Chuck Hawley]

I have an ACR connected between a Group 24 AGM battery (starter) and three Group 27 AGMs (house).

There is a time delay in the ACR circuitry that keeps the solenoid from switching rapidly as the voltage rises and falls. It makes it a tiny bit more complicated to understand its operation, since you can misinterpret the ACR's operation by simply referring to a voltmeter. I think the time delay is 30s, but it might be 45s.

In my case, I have the alternator running to the start bank so the voltage rises pretty quickly. If the house bank is low (say 12.0V), the ACR will connect, the alternator will labor causing the engine to lose rpm, and the ACR will disconnect in 30s or so. Just as it is supposed to do. Note: This is not ideal, but it works for me.

The ACR SI has terminals which allow you to force it to connect (sort of like a remote battery switch) and to force it to not connect (override its normal operation). I don't use those terminals, but they might help you diagnose its operation.

Chuck

[blueazimuth]

I use my house bank - don't have a dedicated windlass battery in the bow - and always start my engine, having it at high idle - 1200 rpm on my tach - while using windlass.

[mitiempo]

Originally Posted by Rowglide

Thanks for the input. The main reason I would rather run the windlass from the start battery is distance. it is another 10 ft+ (X2) to the House batteries. The windlass existing correctly sized cables end near the start battery. Could you explain ACR cycling?

The best way to guarantee a start battery is charged and ready at all times is to use it only for starting the engine.

With an ACR all charging sources should go to the house bank. This is both the largest bank and the bank that needs the most current to charge. As posted above the ACR will chatter if charging is wired to the smaller (start) battery. As the start battery comes up to set voltage the ACR closes - the current then rushes from the start battery to the house bank lowering the start battery voltage so the ACR then opens. This can happen for a while if the house bank is low. Blue Seas also recommends that charge sources be wired to the house bank for this reason.

[dw1979]

Another great use for the ACR-si is protection of sensitive electronics from DC spikes. Properly configured starter motors and electric windlasses (to name a few) can be isolated.