I have several Hunter sailboats of various sizes which have TV/DVD players on board. I recently had two of them go bad at the same time and in the same way. It appears the circuit board that drives the screen was damaged by a surge. These TVs are powered by the 12v circuit. There are only two ways I can think of which could cause a surge that might fry a circuit board. 1. Switching batteries while the engine is running. 2. Connecting/disconnecting shore power. (we always shut off the shore power circuit breaker on the boat first, then shore, then pull the plug.) I have searched all over the net for a surge suppressor for 12v with no joy. Does anyone have any suggestions as to how to avoid this in the future. I am hesitant to re-install the repaired TVs until I get the surge problem figured out. Thanks, Pace
TV/DVD fried
- Thread starter pbonner
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Surge Help
I am a Electronics Enigineer and will always help boat owners if possible. My Hunter wiring was completely removed to improve. So I should be able to cure your problem. Just forward as much info as you can. Regards, Rick.
I am a Electronics Enigineer and will always help boat owners if possible. My Hunter wiring was completely removed to improve. So I should be able to cure your problem. Just forward as much info as you can. Regards, Rick.
The shop should be able to tell you
what happened to the circuit boards. Well, maybe not these days - everything is 'plug and play' and black-box. (The US Army trained me as an electronic technician back when tubes were still widely used. *yks Two units on two different boats failed in the same way at the same time? Wow! Were the boats near each other at the time? Was there a thunderstorm in the vicinity? Switching battery banks with the engine running might cause a spike, but I suspect that the batteries would 'eat' the current the way they do if you suddenly run up the voltage on the battery charger. I have dumped 800 amps into a 48vdc battery (a BIG one: 24 cells, each holding 15 gallons of electrolyte) and the voltage never got to 60 volts. Essentially, the more voltage you try to put out, the more current the batteries consume. They are very good at damping transients in the DC system. Your shore power is 120v AC. Barring some very wierd wiring problem (on 2 boats at the same time???), shore power can only get to the DC system through the battery charger. Even the most rudimentary battery charger has rectifying and regulating circuitry to prevent surges or spikes from getting into the DC side. Of course, lightning doesn't follow the same rules that 12v DC or 120v AC do. :-( If you are REALLY REALLY worried about this, go buy a couple of DC/AC inverters. Wire them into the DC system of your boats. Assuming that your TV/DVD players are dual voltage, plug them into the inverters. If you are REALLY REALLY REALLY worried, put a surge arrester between the inverter and the player. And if lightning strikes your boat, none of that is likely to help. You could also get hold of a recording voltmeter (if such a thing is still available... remember, I'm a certified dinosaur [see reference above to tubes]) and hook it up to your DC and/or AC systems and hunt for a spike. Cheers, Bob s/v X SAIL R 8
what happened to the circuit boards. Well, maybe not these days - everything is 'plug and play' and black-box. (The US Army trained me as an electronic technician back when tubes were still widely used. *yks Two units on two different boats failed in the same way at the same time? Wow! Were the boats near each other at the time? Was there a thunderstorm in the vicinity? Switching battery banks with the engine running might cause a spike, but I suspect that the batteries would 'eat' the current the way they do if you suddenly run up the voltage on the battery charger. I have dumped 800 amps into a 48vdc battery (a BIG one: 24 cells, each holding 15 gallons of electrolyte) and the voltage never got to 60 volts. Essentially, the more voltage you try to put out, the more current the batteries consume. They are very good at damping transients in the DC system. Your shore power is 120v AC. Barring some very wierd wiring problem (on 2 boats at the same time???), shore power can only get to the DC system through the battery charger. Even the most rudimentary battery charger has rectifying and regulating circuitry to prevent surges or spikes from getting into the DC side. Of course, lightning doesn't follow the same rules that 12v DC or 120v AC do. :-( If you are REALLY REALLY worried about this, go buy a couple of DC/AC inverters. Wire them into the DC system of your boats. Assuming that your TV/DVD players are dual voltage, plug them into the inverters. If you are REALLY REALLY REALLY worried, put a surge arrester between the inverter and the player. And if lightning strikes your boat, none of that is likely to help. You could also get hold of a recording voltmeter (if such a thing is still available... remember, I'm a certified dinosaur [see reference above to tubes]) and hook it up to your DC and/or AC systems and hunt for a spike. Cheers, Bob s/v X SAIL R 8
For 110V. devices a UPS is the best method
of protection. I'm aware of devices made for 48 V. but not for 12, I've attached website for APC, one of largest makers of such devices. If you can't find what you need on the site call them. Or as soon as one of the electrical wizards on this board sees your post they will tell you exactly what you need. BTW I once lost a TV to a lightening strike on the cable nearby, you could track the damage, there's a resistor that is the first thing in the antennae circuit called a "protector" that blew, but not before the surge finished destroying power supply etc.
of protection. I'm aware of devices made for 48 V. but not for 12, I've attached website for APC, one of largest makers of such devices. If you can't find what you need on the site call them. Or as soon as one of the electrical wizards on this board sees your post they will tell you exactly what you need. BTW I once lost a TV to a lightening strike on the cable nearby, you could track the damage, there's a resistor that is the first thing in the antennae circuit called a "protector" that blew, but not before the surge finished destroying power supply etc.
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