ST 4000 (Low Battery)

[Don Crowther]

OK here's the story.

I was working on the boat listening to the radio with the vhf on and no other electrics on. I put in new house batteries 2 wks ago and they were fully charged before installed.

I finished up early and decided to go out for a couple of hours. Since I was going alone I was planning on using the auto-pilot to make my life easier.

I motored out on to the lake about a 10 min run on the motor.

I turned on the a/p and was going about the boat getting things set up and check on everything since this was the first trip out of the year.

The a/p was working great for about 10 mins. the it started to beep. I went back to check on it and the LOW Battery alarm was going off. Then the a/p went into standby mode.

So now here's my question. Would the a/p run the 2 house batteries down that quickly? Or after running for that amount of time would the wiring warm up and cause more resitance and cause the voltage drop. Or?

I don't have a battery monitor and I didn't get down to check the battery voltage with my meter. To busy single-handing woth out the a/p. Even after starting the motor and trying the a/p again it still showed low battery and would go into stby.

I did see on the archives that these a/p draw about 4 amps when engaged. I don't think it's the batteries since they are new. But it could be them.


Any help would be great
thanks again
Don

 

[Don S/V ILLusion]

Don
It wouldn't draw down fully charged batteries that quickly. Absent any other issues, it would almost certainly have to be a bad electrical connection

 

[kloudie1]

Don is correct.. if you are seeing "Low Batt" when the engine is running and the engine spun fine for start, ya have a bad connection to the autopilot head. Those little slip on connectors at the bottom of the head are notorious for corroding and/or slipping off. The 4 amperes of draw is when the motor is actually running into a pretty good load.. The pulses of motor probably draw that, but the average draw, if your sails are trimmed well, is considerably below that number..

 

[Don Crowther]

re-connection

Thanks for the quick replies.
So do you think that the connection gets more resitence as the wires warm up?
And this is what causes the low battery warning?
Or maybe just a loose connection but then wouldn't it happen as soon as I turn on the a/p?
Next time I'm down at the boat I'll take some contact cleaner and spray the connections.
Do you think i should do a resitance check on the power lead?
Thanks
Don

 

[kloudie1]

Turn it on, and while the connection cover is off, wiggle the wires and press 'em home to make sure the spade connectors are all OK.. Make sure the spade is actually engaged and not slipped so that the insulating cover of the spade connection itself is sorta holding the connector against each other. If that doesn't work, best to take a voltmeter and measure the voltage at the control head power input. While looking at voltage, turn on the unit and make the motor run. Get to and measure voltage at all the connections in the power wire, even back to the breaker box if ya have to, to find where the voltage drop is.. You will not see a significant voltage drop unless the motor is running or trying to run. One test for a shorted or jammed motor would be to unplug the motor and see if the LOW BATT warning goes away.

 

[Don S/V ILLusion]

Those bayonette connections on the head are notorious for corrosion - sometimes simply removing and re-connecting them does the trick. To do a resistance check will probably not be conclusive as you won't know what the nominal resistance should be and you'd have to remove the connections regardless. While you are at it, closely inspect all crimp connections for corrosion and replace any which are suspect. If that doesn't do it, the ponly other likely cause is a problem with the supply voltage connections which you should be able to easily pinpoint with a simple voltage check (while under load).
Sorry to dupe what K said previously - bad timing..

 

[SoSound]

Don't forget the battery end of the circuit...

You said that you had just replaced batteries... Check all of the connections at the battery end of the circuit. Are there multiple leads, or leads to multiple locations with connections to a post or other multi-connection point? If you worked on the batteries recently, and something electrically related that you haven't touched isn't working correctly now - go back and recheck your recently finished work and start your troubleshooting from there. That's how I find most of my mistakes and oversights (some of them quite emberassing )

Dave

 

[Steve Dion]

Don:

1. How do you know that they were fully charged?

2. Have you checked your connections at the charger & batteries. What about your ground.

3. You are correct about new batteries being bad, but your engine did draw a lot more power than the AP.

Be sure to remove the connections and clean with a wire brush or something to make very good connections. You are going to check voltage so that should give you some idea too.

I like the idea of checking the ST head. Those little connectors can easily get bent or even corrode.

Good luck!

 

[Don Crowther]

Steve;

I guess I can't be sure the batteries are fully charged since I didn't check them I just made an assumption that they were. But wouldn't the altn. on the engine provide enough power to run the ap?
I think batteries are wired to a fuse/switching panel below the entrance and the ap gets it's power from the nav station switch/fuse panel. From there they go to their respective/switched items which include vhf,radio,chartplotter/loran, and instruments. Could there be a bad ground that would effect just the ap.

I'm not great on electrics and I havn't run though the wiring diagrams to figure out where or how the wires run. I'll have to get that done nexted trip down.

Thanks
Don

 

[Don12364]

Low Batt - High Batt?

I had been motoring along for several hours one day when my autopilot began to bleep.
It is an Autohelm 6000 but probably uses similar circuitry to the 4000.
The display said "LOW BATT".
I went below to discover my batteries were up to 18.5 volts!!
Fortunately they seem to have survived

The field wire on the alternator had shorted to ground and put the alternator on 55 amps charge rate regardless of the regulator.

The point of the story is that Raymarine's circuit monitors both high and low battery voltages but the display only reads LOW.

Suggest you make sure you know whether it was low or high voltage.

 

[Don Crowther]

Re: Low Batt - High Batt?

I'm pretty sure it's low because it happened the first time when i had the motor off. and only running on battery power.

 

[Steve Dion]

....but Don, you engine started! A starter is anywhere from 40-80 amps (very short period of time) so why would this "really" be the problem.

The point is you just need to start a one end and go to the other and the batteries are a quick and easy way to start. Be sure to check those connections between the ST4000 head and the autopilot as well as the connection at the breaker panel.

We had a '85 Hunter 31 from 1987 (purchased as new) until 2006. It was a great boat and had very few problems (compression post).

 

[Don Crowther]

Thanks Steve

I guess instead of sitting here stewing about it and trying to fix it from afar i will just make a trip down to the boat. It's the little things that sometimes get blown out of proportion. So lit's gotta be a bad connection somewhere.
thanks again to all

Don

 

[catsailor]

The ST 4000 is much more voltage-sensative than the engine starter.

....but Don, you engine started! A starter is anywhere from 40-80 amps (very short period of time) so why would this "really" be the problem.

The point is you just need to start a one end and go to the other and the batteries are a quick and easy way to start. Be sure to check those connections between the ST4000 head and the autopilot as well as the connection at the breaker panel.

We had a '85 Hunter 31 from 1987 (purchased as new) until 2006. It was a great boat and had very few problems (compression post).

Although the manual states the minimum voltage is 10v, I swear mine cuts out at ~ 11.5v. I suspect, at peak draw, the resistance through the connectors and small wire drop it to that, for a just moment. It will come back, only to drop out when engaged.

 

[sailingdog]

If you had the boat sitting on the dock without a shore power-based charger plugged in, the self discharge would have dropped the batteries some during the two weeks, then the radio and VHF dropped it some more. A 10 minute run on the motor is enough to raise a large surface charge on the batteries, but not enough to significantly change their charge state.

You may have had enough power to start the motor again, but that may not have been enough for the autopilot to register as having sufficient voltage. IIRC, many engines can start with as little as 10.5 VDC, but that is well past the point of 0% charge on a 12VDC system, which is usually about 11.6 VDC.

Whether the batteries are new or not doesn't mean much if they're not being charged properly.

OK here's the story.

I was working on the boat listening to the radio with the vhf on and no other electrics on. I put in new house batteries 2 wks ago and they were fully charged before installed.

I finished up early and decided to go out for a couple of hours. Since I was going alone I was planning on using the auto-pilot to make my life easier.

I motored out on to the lake about a 10 min run on the motor.

I turned on the a/p and was going about the boat getting things set up and check on everything since this was the first trip out of the year.

The a/p was working great for about 10 mins. the it started to beep. I went back to check on it and the LOW Battery alarm was going off. Then the a/p went into standby mode.

So now here's my question. Would the a/p run the 2 house batteries down that quickly? Or after running for that amount of time would the wiring warm up and cause more resitance and cause the voltage drop. Or?

I don't have a battery monitor and I didn't get down to check the battery voltage with my meter. To busy single-handing woth out the a/p. Even after starting the motor and trying the a/p again it still showed low battery and would go into stby.

I did see on the archives that these a/p draw about 4 amps when engaged. I don't think it's the batteries since they are new. But it could be them.


Any help would be great
thanks again
Don

 

[Don Crowther]

It's been awhile since I updated this post. I was out this weekend and used the auto-pilot for over 3 hrs in following seas and on tacks. I had been out a couple of weeks ago and cleaned all the connections on the auto-pilot as well as tightening up the battery grounds that seemed a little loose. It would seem that all is well with the auto-pilot and it was just some poor contacts.
Thanks again to everyone for getting me looking in th right direction.
Don

 

[Ron20324]

It would seem that all is well with the auto-pilot and it was just some poor contacts. Don

Ahhhh... If people would just start with the basics....