Hi all,
Since purchasing our boat I've had intermittent issues with our Raytheon ST5000+ autopilot (stern drive) unit rebooting. This is most common when I hit +10 a couple of time to tack, or if there are strong seas and pressure on the rudder. I've always assumed that maybe the wiring was bit undersized and needed to be updated, but had not gotten around to that project.
This past week we did a sailing trip, during which I saw a marked increase in the number of random restarts, even when the system wasn't really being taxed. At one of our ports-of-call I dug in a little bit. In troubleshooting through I noticed that the reboots were most common when my refrigeration kicked in. When I turned refrigeration off then failures were few/far between. We recently added Starlink, so the overall electrical load has increased by a bout two amps, which I am guessing is why I saw the uptick in failures.
I have some ideas on ways to solve this, but wanted to bounce them off the group before I made any commitments to one approach over the other.
A quick outline of the system (in use while sailing/motoring -- obviously we have other electrical draws, but they're typically off when using autopilot):
First, while I think this is probably a voltage drop with the increased amp load, this isn't TOTALLY making sense to me. I did see failures even when the motor was running and the alternator was powered. My Balmar would show 13.5+ Volts, so while I could see some Voltage drop, I guess I was a little surprised that it dropped enough to blink the autopilot. Then again, the Balmar is measuring at the battery, so perhaps the wiring to the DC panel is not keeping up (all told I was seeing about 10-12 amps on the DC panel meter with the fridge running when the autopilot was not performing any big maneuvers, so perhaps as high as 15-17 amps for a hard turn). I'm sure I'm not exceeding the wire size capacity (its at least 10 gauge which IIRC is theoretically good to 30A, the run is about 10 feet), but maybe am outside of the tolerable voltage drop margin with the higher amperage.
With my instrument configuration I didn't have multimeter access to measure voltage on the back of the ST5000+ head end, so I don't have any hard numbers there (I really didn't want to tear apart the console mid-trip).
I have two ideas as to how to solve this I'm wondering what others think:
1. Increase wire size between the battery and the DC panel. I may also need to increase wire size between the DC master switch and each of the breaker bus bars.
2. Pull the Autopilot off of the DC panel, give it its own independent switch wired right off of the battery.
The pros to the first option is that I get to keep the system wired as is, the con is that I'm not sure how easily the wiring run/connects will accept a larger wire size (I may even just consider adding a second wire to each leg, IE adding a second wire of identical gauge).
The pro to the second option is I can bypass the whole DC panel, which may be a little tight for adding wiring, the con is that I'll need to add the new switch and possibly re-pull (or use butt-splices) to extend the existing wire run to the switch, in addition to pulling wires to the battery.
Does this analysis feel like its on the right track? Any other considerations as to possible solutions (or additional troubleshooting/causes if you think I'm missing something)?
Thanks!
Doug
Since purchasing our boat I've had intermittent issues with our Raytheon ST5000+ autopilot (stern drive) unit rebooting. This is most common when I hit +10 a couple of time to tack, or if there are strong seas and pressure on the rudder. I've always assumed that maybe the wiring was bit undersized and needed to be updated, but had not gotten around to that project.
This past week we did a sailing trip, during which I saw a marked increase in the number of random restarts, even when the system wasn't really being taxed. At one of our ports-of-call I dug in a little bit. In troubleshooting through I noticed that the reboots were most common when my refrigeration kicked in. When I turned refrigeration off then failures were few/far between. We recently added Starlink, so the overall electrical load has increased by a bout two amps, which I am guessing is why I saw the uptick in failures.
I have some ideas on ways to solve this, but wanted to bounce them off the group before I made any commitments to one approach over the other.
A quick outline of the system (in use while sailing/motoring -- obviously we have other electrical draws, but they're typically off when using autopilot):
- 1 200AH 4D Lead Acid battery. 4 years old, but mostly not abused (the Balmar says SOH is 100%, FWIW)
- Stock Yanmar/Hitachi/shunt configuration
- 300W of solar through a Victron charge controller (tests were performed on a sunny day while the Victron provided power)(wired to the house battery)
- ST5000+ Stern Drive autopilot (wired through the DC panel)
- Starlink Mini (wired through the DC panel)
- Standard array of instruments (Axiom chart plotter, VHF radio, Raymarine speed/depth, Quark AIS receiver)(wired through the DC panel)
First, while I think this is probably a voltage drop with the increased amp load, this isn't TOTALLY making sense to me. I did see failures even when the motor was running and the alternator was powered. My Balmar would show 13.5+ Volts, so while I could see some Voltage drop, I guess I was a little surprised that it dropped enough to blink the autopilot. Then again, the Balmar is measuring at the battery, so perhaps the wiring to the DC panel is not keeping up (all told I was seeing about 10-12 amps on the DC panel meter with the fridge running when the autopilot was not performing any big maneuvers, so perhaps as high as 15-17 amps for a hard turn). I'm sure I'm not exceeding the wire size capacity (its at least 10 gauge which IIRC is theoretically good to 30A, the run is about 10 feet), but maybe am outside of the tolerable voltage drop margin with the higher amperage.
With my instrument configuration I didn't have multimeter access to measure voltage on the back of the ST5000+ head end, so I don't have any hard numbers there (I really didn't want to tear apart the console mid-trip).
I have two ideas as to how to solve this I'm wondering what others think:
1. Increase wire size between the battery and the DC panel. I may also need to increase wire size between the DC master switch and each of the breaker bus bars.
2. Pull the Autopilot off of the DC panel, give it its own independent switch wired right off of the battery.
The pros to the first option is that I get to keep the system wired as is, the con is that I'm not sure how easily the wiring run/connects will accept a larger wire size (I may even just consider adding a second wire to each leg, IE adding a second wire of identical gauge).
The pro to the second option is I can bypass the whole DC panel, which may be a little tight for adding wiring, the con is that I'll need to add the new switch and possibly re-pull (or use butt-splices) to extend the existing wire run to the switch, in addition to pulling wires to the battery.
Does this analysis feel like its on the right track? Any other considerations as to possible solutions (or additional troubleshooting/causes if you think I'm missing something)?
Thanks!
Doug
