Raymarine st4000+ Low Batt warning

[ramblinrod]

Originally Posted by Jd1

There are tons of internet postings about this error on these units. There are also lots of people who have sent in the circuit board, received a replacement and all was well. How you can claim that a display head fault is unlikely is absolutely mind boggling to me!

Based on the symptoms described by the OP, the problem is most likely due to weak batteries, too small wiring, or a poor connection.

[belizesailor]

Originally Posted by ramblinrod

Based on the symptoms described by the OP, the problem is most likely due to weak batteries, too small wiring, or a poor connection.

All normally likely suspects, but these units generate these warnings even when none of the above is the case. Ive seen them across multiple boats and mine does it too (where I know the install is good)...even under power with batteries at 14.2V.

[Jd1]

Originally Posted by ramblinrod

Based on the symptoms described by the OP, the problem is most likely due to weak batteries, too small wiring, or a poor connection.

Although all those are good candidates for the problem, in my experience and with my issues, neither weak batteries nor too small wiring are issues. If you include possible bad solder joints on the pcb in the poor connection category than yes, that might be an issue. I reseated the connectors and that didn't change anything but have yet to go over the solder joints.

[gregjp]

Originally Posted by ramblinrod

When you sit at the dock, are you connected to shore power with the battery charger on? (This will be supplying 14Vdc + to the battery terminals.) Try the same issue at the dock with the battery charger off (and 12.8 Vdc or less at the battery terminals). Bet you have the same problem.

Again, the most likely problem is either low voltage at the batteries, or voltage drop between the batteries and electronics.

Ramblin Rod
Certified Raymarine Installer / Service Provider
www.sheenmarine.com

I did try to simulate actual conditions so while at the dock shore power was disconnected. Since this experiment the wheel drive unit has been replaced; it had had some very funky repair work by PO. Now everything works fine except for the Low Batt warnings. They do not occur everytime I use the autopilot, but they were very frequent on a recent 7.5 hour motor on a very hot day. Warning comes on, unit continues to navigate in Auto, and then warning goes away in a few seconds. Unit never drops out of Auto. As senormechanico suggested in this thread it could be a solder problem. An electronics engineer I know concurs, so that's going to be my next step.

The house batteries are 1 year old AGMs. This problem existed before they were installed and still continues. I'm certain they are not the problem.

[gregjp]

Ok, I may have to eat crow on the last reply. Since I hadn't used the ST4000+ since the 7.5 hour trip I mentioned I decided to check it's operation one more time before pulling the unit to have it re-soldered. I made sure shore power was disconnected. When auto was engaged it repeatedly dropped out to Standby mode. No low batt warning, it just showed 4000 Wheel, Response 1, and went to Standby. So I plugged in shore power and did the same test and all was well, it turned +10, -10 again and again with no failure.

So now I'll be re-checking batteries, connections, terminal voltages, etc. and see what shows up.

[senormechanico]

Make sure the spade lug terminals (especially the + and - connectors on the back of the display are tight. After disconnecting them from the display, squeeze them with a pair of pliers just enough to make sure they're tight when reconnecting them.

I HATE these types of connectors! My whole boat was originally wired with them and I replaced every damn one of them in the original wiring loom with ring connectors.
Long story, but they're NOT dependable in the long run. Just so you know...

[DeepFrz]

Contact cleaner might come in handy while you are checking all of your connections.

[Sailcraft]

Hi Richmatt, I had a similar issue on a home made catamaran and after 1000 miles found the problem (some have touched on voltage drop) but maybe it is a lack of AMPs. When the issue happens you could start your engine or genset (send charge to battery) and see if the alarm turns off (while the pilot is under load and on Auto). If this works I would suggest the cable from your power supply to the autopilot motor may be too small, ( issue on a big cat with a long cable run). Hope this helps.

[ROY HIGGINS]

I have also (in 2016) experienced this problem with the ST4000+. It is not, however, unknown to Raytheon, as they issued a Technical Update on 06/06/1997 Issue No TU 016, Subject: type 100/300 Course Computer D25 Failure. Raytheon are suggesting adding a 1N4001 Diode across two points shown in an illustration.

In my case, I connected the Control Unit directly to the Positive battery terminal, with a multimeter coupled in parallel. This showed an input voltage of 13.5v at the same time as the "Low Battery" sign showed. Hope this info will be of some help. Issue TU 016 can be downloaded.

[Jd1]

Originally Posted by ROY HIGGINS

I have also (in 2016) experienced this problem with the ST4000+. It is not, however, unknown to Raytheon, as they issued a Technical Update on 06/06/1997 Issue No TU 016, Subject: type 100/300 Course Computer D25 Failure. Raytheon are suggesting adding a 1N4001 Diode across two points shown in an illustration.

In my case, I connected the Control Unit directly to the Positive battery terminal, with a multimeter coupled in parallel. This showed an input voltage of 13.5v at the same time as the "Low Battery" sign showed. Hope this info will be of some help. Issue TU 016 can be downloaded.

Thank you for posting this tidbit of information!

I quote from the bulletin:
This problem can easily be recognised by seeing the ‘LOW BATTERY’ alarm when the pilot is in Auto mode and the absence of clutch and motor drive.

A lot of people (me included) see the 'low battery' warning without the associated loss of motor drive function (not sure what clutch drive refers to)

I have always looked at this issue to be caused by the ST4000+ rather than the control unit. Maybe my trouble shooting should be expanded to the course computer unit.

Here is the link:
http://raymarine.ning.com/forum/atta...dedFile%3A3516

[gregjp]

In my case sometimes I got the low batt warning and sometimes not but in either case the ST4000+ would drop out of Auto and into Standby. Finally traced the issue to poorly insulated butt connectors. The PO had brought the 12v power up to the pedestal on #12 wires but then carried the power through open air wire loom to a separate housing holding the ST4000+. Unfortunately, once I removed the wire loom wrap the #12 wires had been butt spliced not once but twice to #16 wires which carried the power to its final destination. These were not heat shrink butt splices nor were they treated with any anti-corrosion grease or film, and lo and behold, all the connections were heavily corroded.

I cleaned the ends of the #12 power wires and butt spliced new #12 wires to carry the power to the ST4000+. All wire ends were coated with dielectric grease and sealed in heat shrink. Now, after numerous sails all continues to work well.

[ROY HIGGINS]

I had the "Low Battery" problem. Checked all connections and wired a voltmeter in parallel to supply direct from the battery, and still got "Low Battery" when it patently was not the cause. I then sent the control unit to The Service Centre in Wareham, UK, Service Repair Marine Electronics | The Service Centre | Home Index vie their ebay site, where I paid £79.94 up front, and they gave me an estimate of an extra £27.00 for the replacement component. It arrived back with me an hour ago.

I spoke to the Centre and they advised that they cannot deal with USA due to the high insurance cost. However, it shows that this unit can be repaired and surely there must me a service operator in USA who can do the same repair.

Hope this helps, but it is essential to eliminate all other possible causes, such as poor connections etc.

[HappyMdRSailor]

Welcome to CF Roy !

Good info, thanks for posting ...

[Down2TheC]

I've occasionally seen the low batt warning, but the more critical issue of blanking out and waking up in STANDBY is clearly a voltage issue. Mine has been progressing for years. First only when the helm requires a lot of force to move, then a bit more frequent, until now it lasts about a minute under sail (when batts aren't charging at 14V.) It always blinks out when trying to move the wheels so I'm guessing it's the electric motor aging poorly such that when it moves the wheel, it's drawing down the voltage below the minimum needed to keep the head unit alive. I'll be doing some testing and looking into rewinding the motor if the resistance readings back up my theory. (or replacing it outright if the part exists.)

[senormechanico]

Imho, it's not the motor, it's excessive resistance in the supply wiring.
Could be anything or several things from a corroded connection to a loose terminal screw.
The low batt warning is just telling you the input voltage to the autopilot is too low.
It's up to you (or an electrical guy) to find the location of the drop.
If it's been gradual as you say, I'll bet you will find what I described above.
Check all of both positive and negative wiring from the unit all the way back to the battery.

Also possible, the battery could be on its last legs.