Anchor Light drains battery before the night is over!

[samoss]

We have an '83 Ericson 38 with what we believe is its original masthead anchor light. The anchor light drains our battery so quickly that it doesn't even last through the night... we also seem to go through bulbs rather quickly. We have always chartered in the past and have never run into this before. Is it a "feature" of older boats? If so, can we replace the bulb or light housing to something newer and avoid this? Could it be a short or some other electrical issue? Thanks...

[PBzeer]

I'm not an expert, but it sounds like you have a short somewhere in that circut. I've seen a anchor/tri-color LED setup, that had a price of $227 at a local marine store. You might look into something like that.

Regards,

[SteveCox]

Could you give us the rating on the bulb that you are putting in the fixture? It doesn't sound right. It should not drain the battery bank that fast unless the batteries are very weak or not fully charged. The fact that you think you are going through bulbs quickly would point to something being wrong in the circuit but there could be many issues all along the system and without more info it is very difficult to troubleshoot. Do you have a multi-meter? If you do could you measure the voltage on the circuit when the bulb is turned on? Also, what is the voltage across the battery terminals. If this sounds like Greek, you either need to get someone who knows boat electrical systems or you need to learn how to troubleshoot electrical circuits yourself (highly recommended).

[Goodnewsboy]

I think you have a short.

Disconnect the light At the base of the mast and use a multimeter to check the resistance of the circuit from wire to wire and from each individual wire to the mast. The readings will probably reveal whether the problem is at the light or somewhere in the wire run that goes up the mast.

Quite possibly you have a wire with chafed insulation that is grounding out to the spar.

No single bulb light should be able to drain your battery overnight.

[sailingdog]

Yup... sounds like you have a short in the circuit someplace. I have an LED tricolor/anchor light...and it rocks. One other question, what is the size and age of your battery bank?? I doubt that a single light will drain a well-maintained battery bank.

[TrueBlue]

A quick preliminary check can be done as follows:

After a good run on engine power to fully charge battery banks, turn off all 12vDC electrical switches while at anchor. This can also be done while plugged in at dock - but switch off shore power. Check your battery voltage using the helm-mounted voltmeter - fully charged battery banks should read just over 13 volts.

If less, perhaps your battery cells are at fault, or there's an open circuit somewhere. As said above, it's doubtful a single bulb of the size of an anchor lamp will draw more than 1-3 amps.

Now, with all accessories still off, see if voltage drops significantly when switching on the anchor light. If so, you may have a short circuit.

[NickL]

Originally Posted by Goodnewsboy

I think you have a short.

Disconnect the light At the base of the mast and use a multimeter to check the resistance of the circuit from wire to wire and from each individual wire to the mast. The readings will probably reveal whether the problem is at the light or somewhere in the wire run that goes up the mast.

Quite possibly you have a wire with chafed insulation that is grounding out to the spar.

No single bulb light should be able to drain your battery overnight.

where is the goodnews in that?

[Parley]

I'm betting you either have a short or your batteries are completely shot. Very simple to find a short. First check your voltage at the battery (across the posts). Make sure they are fully charged. Turn every thing off, EVERYTHING. Next, disconnect the negative battery cable. Connect a simple test light (available at any auto parts store very cheap) to the end of the negative cable and touch the business end of the light to the negative battery post. If your test light is lighted, you have a short. To take this a step further, you can start popping fuses until the test light goes out. The fuse that causes the light to go out is the circuit with the short. Then comes the real fun part: locating that short in the circuit.

[sailingdog]

If the batteries aren't shot yet, they will be soon by being drained so low by the short in the anchor light circuit.

[pigslo]

I had a new battery that kept boiling off water or so i thought. Turned out to be a crack in the case.