Engine cut out with winch?

[Larry Backman]

Weird one yesterday which leaves me scratching my head.

QSM 11 with a pair of 8 D batteries, one house, one starting. We went squidding yesterday and I sat on the hook for 4 hrs with the engine off and all my electronics on. When I went to start the engine the DVMs read 12.2 on the house battery, 12.4 on the engine battery. It started normally, and both DVMs jumped to the usual 13.1.

I immediately went to pull the hook with my electric windlass and heard the engine stutter as if fuel started, then stumble and die about 20 seconds later.

I realize I need to debug my windlass circuit and find the electrical leak but – can a huge amperage drain possibly affect the QSMs ECM and temporarily kill fuel flow?

Topic

[Tony Athens]

“OK I’ll bite”

Remember if you do end up going this direction, you’ll need to be sure you have a 3-wire alternator with remote sensing….

You may already–I’d have to see it–How to ID one in in “Tony’s Tips”…

Tony

[Stephen Oliver]

You can remotely disable the 7610, all acrs require a negative, so by switching the negative you disable it. This is what I have automated on mine so that when shore power is present, the acrs are not active by switching negative off and can’t combine the 3 charger banks and let the magic smoke out. Just another option for you..

Steve

[William Walter]

Ecm power

Was reading the thread and looked at 12 volt schematic .I noticed power to ecm coming from engine bank.on my boat both ecms are powered from house bank.thinking my engines wouldn’t start if I killed that bank but I do have cross over capabilities.

[Larry Backman]

Got it

I had read the same thing yesterday either before or as I posed the original question. That software and delay before combining explains another situation I had a few years back when I drained the house battery accidentally at the dock, started the engine off the engine battery and one minute later had the engine cut out, presumably because when the ACR combined both batteries the dead house side pulled the engine battery down.

Now that I understand it, it’s less intimidating but I will rewire this winter. I don’t like the fact it’s completely out of my control in a critical situation.

[Rob Schepis]

Software

There is definitely some “software” going on in that 7610 – see attached. That’s why I mentioned the 7622 because it would be an easy direct replacement offering the manual control..

[Rob Schepis]

No, that is different than what I was explaining. Tony’s diagram includes a diode battery isolator – basically a current”check valve” — do some Googling on it..
N.O. = normally open switch
N.C. = normally closed switch

[Larry Backman]

OK, I will bite

Found your schematic on DC power distribution for a single engine, three battery system which is pretty close to my needs. I got some work to do this winter!

Typical DC Power Distribution Example

Can you explain to me what I need to buy and do in the upper left hand corner coming off the alternator? Is that the manual Blue Seas 7622 Rob is referring to?

Also, on the various breakers, what does NCand NO stand for?

[Tony Athens]

This is my answer to your “not able to sort it out”….

We never use any type of battery combiner ( AKA VSR’s) that uses some type of “software” to control relays when batteries are to be combined, no matter how smart they advertise they are..

Why?/ For the exact reason you are here.. Not a clue what is going on or how to find the issue.. My thoughts on how to wire DC battery power distribution on a boat are well documented in at least 50 posts on the subject over that last 10 years ..

Good luck is all I can say until you really want to do it right and then it’s “hands-off” for the long term..

Tony

[Rob Schepis]

What makes you think it’s hard-wired? Have you put the battery selector switch to OFF and the windlass still operates? If it does not operate with the selector switch OFF then you can just use the switch to figure out which battery the windlass is wired to.

[Larry Backman]

Thanks Rob

I’m thinking through one further test first which is to go out to 60’, drop the anchor with the engine off, the DVM’s both below 12.5 volts which will in theory cause the charging relay to separate the batteries and then carefully observe using the DVMs which battery actually drains when the windlass is engaged.

It’s a twisty maze of wires and the thick windlass wires run aft from the breaker to somewhere! For all I know the windlass is hardwired to battery 1 which is my starting battery!

I do like the idea of an “off” switch for the combiner but what to fully understand my boats wiring first.

DVMs Are worth their weight in gold!

[Rob Schepis]

I think you’ve proven that unless YOU are in control of a device it will not always perform as it should in every situation. I would never install an ACR that did not have a manual control feature. I run the older Blue Seas 9112 to which I added the optional manual control switch and LED. Your 7610 model does not have the option to add a remote switch. Consider switching it out to the 7622 model which includes the manual control switch. Here’s the link. Between that and your new spiffy DVM’s you’ll always be 100% “in the know”……

https://www.bluesea.com/products/7622/ML-ACR_Automatic_Charging_Relay_with_Manual_Control_-_12V_DC_500A

[Larry Backman]

Yes but…..

They are isolated by a 1-2-all battery switch but….I have an BlueSeas ACR 7610cbarging relay with start isolation which combines them. I did some diagnosing today as well as reading on that relay.

When I started the engine yesterday the batteries were isolated, as soon as the ACR sensed 13.5 volts on the starting battery due to the alternator input it would have combined them 2 minutes later.

My guess is that I was bumping the windless up before the ACR combined the 2 batteries and when the ACR combined them, that is when the engine stutter and stall occurred.

I did verify that when the engine is started the ACR has isolated the 2 batteries and that there is a roughly 2 minute latency as the manual says. During that time I have 13.7 or 8 on the starting battery and 12.4 on the house battery.

Is there an instant when the charging relay switches from isolated to combined and the 2 batteries are at different levels where high amp load on the house from the windless could pull down the start battery for an second and cause the ECM to stutter?

[Corey Schmidt]

Larry, is your engine battery completely separate from your house battery (other than common ground)?

The engine battery should be 100% isolated from any other power source and therefore not be affected by anything you do external of the engine…

[Author]

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