Mercury Classic 50 - Blowing Fuses

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Kier
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Mercury Classic 50 - Blowing Fuses

Post by Kier » 26 Feb 2017, 22:47

Had a real nice 70 degree day and took out my boy and enjoyed the boat. Water temp was 50 degrees. No issues with blowing fuses. Going camping and fishing in a couple weeks. Will put it through the torture test then. I replaced the battery with a new group 24 lead acid battery. I am still getting readings of 16 volts on my fish finder though. Any advice on that issue?

Xtremeboats
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richg99
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Mercury Classic 50 - Blowing Fuses

Post by richg99 » 26 Feb 2017, 23:10

Is the voltage reading from the fish finder only? Did you test the output with a separate voltmeter?

A 12 volt battery won't put out more than 12 volts.

If you get that reading while the engine is running, you may be seeing the output of the engine's own alternator. Even that shouldn't be 16 volts.

If you are just seeing the erroneous voltage reading on the fish finder, and a separate voltmeter shows 12 volts with the engine turned off.. the fish finder is faulty. I wouldn't worry about it. You can buy a separate permanent voltmeter for under 10.00

Richg99

Kier
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Mercury Classic 50 - Blowing Fuses

Post by Kier » 28 Feb 2017, 16:32

My old fish finder Lowrance elite 4xhdi and my new one Hummingbird helix 5 both showed 16volts. I have not tried testing with a multimeter. I know the older mercury motors dont have a regulator to stop charging the battery when full. They just assumed the battery would regulate it. I am just concerned it will fry my fish finder.

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richg99
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Mercury Classic 50 - Blowing Fuses

Post by richg99 » 28 Feb 2017, 18:47

I am just concerned it will fry my fish finder.

At 16 volts, I'd be concerned also. Suggest you just call your Fishfinder manufacturer and see what the maximum voltage is for your unit.

I'm sure that you could google up some kind of cheap voltage regulator. Your FF probably only draws 3 or 5 amps. I'd check an auto supply store and see what they have. They have to deal with 12-volt batteries and alternators/generators.

richg99

Kier
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Mercury Classic 50 - Blowing Fuses

Post by Kier » 28 Feb 2017, 22:57

I contacted HumminBird via email. The automated response said they would get back to me in 2-3 days. I looked through the manual and the only over voltage information I could find is under troubleshooting.

Problem: The control head loses power at high speeds

Possible Cause: If the power output of your boat's engine is unregulated, the control head may be protecting itself using its over-voltage protection feature. Make sure the input voltage does not exceed 20 volts.


Well I don't I have that issue, but my boat engine is unregulated. Maybe it is not an issue at 16volts.....???? I will post what I find from the HumminBird.

Kier
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Mercury Classic 50 - Blowing Fuses

Post by Kier » 01 Mar 2017, 22:40

I got the email back from HumminBird.

This is what they said.

"Thank you for contacting Humminbird. We appreciate your interest in our products. The power input is 10.8 to 20VDC for the HELIX 5 SI GPS."


So I assume the 16 volts should be fine and not damage the unit?

nccatfisher
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Mercury Classic 50 - Blowing Fuses

Post by nccatfisher » 01 Mar 2017, 23:48

richg99 wrote:Is the voltage reading from the fish finder only? Did you test the output with a separate voltmeter?

A 12 volt battery won't put out more than 12 volts.

If you get that reading while the engine is running, you may be seeing the output of the engine's own alternator. Even that shouldn't be 16 volts.

If you are just seeing the erroneous voltage reading on the fish finder, and a separate voltmeter shows 12 volts with the engine turned off.. the fish finder is faulty. I wouldn't worry about it. You can buy a separate permanent voltmeter for under 10.00

Richg99
Most fully charged 12volt lead acid batteries at static will show 13.6 volts

Kier
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Mercury Classic 50 - Blowing Fuses

Post by Kier » 02 Mar 2017, 00:45

I have a 1985 Mercury 50HP and it charges the battery when it runs. Unlike the newer motors it does not have a regulator. So it sends a charge to the battery even though the battery is fully charged. At full throttle the motor produces ~6amps of charging. The newer motors have a regulator that stops charging the battery when it is fully charged and turns the extra charge into heat. It is possible to buy a regulator for these older engines but I am trying to avoid it if possible.

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richg99
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Mercury Classic 50 - Blowing Fuses

Post by richg99 » 02 Mar 2017, 09:54

Most fully charged 12volt lead acid batteries at static will show 13.6 volts

You are 100% correct. I should have clarified that 12 volt batteries do not produce 16 volts....but..they do show more than the nominal 12 volts after a charge.

Thanks richg99

nccatfisher
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Mercury Classic 50 - Blowing Fuses

Post by nccatfisher » 03 Mar 2017, 01:03

richg99 wrote:Most fully charged 12volt lead acid batteries at static will show 13.6 volts

You are 100% correct. I should have clarified that 12 volt batteries do not produce 16 volts....but..they do show more than the nominal 12 volts after a charge.

Thanks richg99
Gotcha, I would be a little worried if it was showing 16V. Especially if he made any long runs with it. That could fry a battery or some sensitive electronics.

Kier
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Mercury Classic 50 - Blowing Fuses

Post by Kier » 03 Mar 2017, 10:28

Just as you charge a 12 volt battery and the volts raise to 13ish, the unregulated charging of the older outboards is causing my battery to raise to 16volts while it is charging. I checked with an eletrical engineer friend of mine and he said if the specs for the fish finder are for 10 to 20volts and it should not matter if it gets 13 or 16 volts supplied. I am going to run with it and see what happens.

nccatfisher
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Mercury Classic 50 - Blowing Fuses

Post by nccatfisher » 03 Mar 2017, 20:51

Kier wrote:Just as you charge a 12 volt battery and the volts raise to 13ish, the unregulated charging of the older outboards is causing my battery to raise to 16volts while it is charging. I checked with an eletrical engineer friend of mine and he said if the specs for the fish finder are for 10 to 20volts and it should not matter if it gets 13 or 16 volts supplied. I am going to run with it and see what happens.
Do as you wish, when you start over charging a lead acid battery it really starts generating gases (hydrogen sulfide) all it will take is a random spark and you have a problem.

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