Voltage to High on 1988 Johnson 70 or is it?

[mac_sr]

I have an 88 Johnson 70 and have I have multiple devices (GPS, radio and stereo) hooked up to a separate board then my bilge pump and engine. They all run off the same battery but are on different circuits. Recently I added a fish finder with a voltage meter and a high voltage protector on it. The fish finder works and when the engine is turned off the volts read 12.5 or so. As soon as I turn the engine on the volts start climbing and when I give it gas the volts shoot up as high as 16 volts at which point the fish finder shuts off. I thought the voltage meter on the finder was bad but the other day the main fuse (20 amp) on the board blew so I imagine there is a problem with voltage regulation. I have read some posts here that say voltages as high as 18 can be normal on unregulated systems. I am wondering if that is actually true and if it is then how do I go about regulating so that I can run my fish finder. Also, if it is normal then why would a 20 amp fuse blow.

 

[12Footer]

Re: Voltage to High on 1988 Johnson 70 or is it?

Welcome to iboats. Yes, it is normal. Unfortunately, many outboards, even the ones built today, have sorry regulation. 20AMP is way to high for the fishfinder. 5 AMP should be plenty.<br />If you know the current draw of each device, you can build a regulator for it. Some folks have tried to retrofit thier boats with auto type regulators, but this is risky...They are not regulated well for many reasons,one I'm aware of, is the stator windings melt.<br />Others have installed 2-battery systems, and switch the batteries over as the voltage climbs up,to prevent cooking them. You need to keep an eye on water levels in the battery,also .The high charge voltage boils-off the water.

 

[mac_sr]

Re: Voltage to High on 1988 Johnson 70 or is it?

Thanks 12footer for the info and the welcome. This seems like a great forum. I have have been searching for one like this for a long time. Anyway back to the battery thing. I have thought about the switch idea before. Do you see a problem with putting the electronics on one battery and the engine, bilge and lights on the other. That way when the electronics needed more juice I could just switch over to the all position. And one other thing ... how hard is it to make a regulator and am I right in reading into your response that you don't think that a regulator is a good idea because it can cause damage to the coils? Thanks again for the input