Voltage regulator

[HughN]

Hi,

My somewhat elderly outboard doesn't have a voltage regulator. Retro-fitting a Mariner one looks to be a pain in the neck as a different sub-harness would be required and I'm not convinced the space to fit one even exists.

Once it has been topped-up from the exertions of starting the battery isn't interested in drawing any more and the voltage gradually creeps up past 18V or more (at which point the Fishfinder starts to complain then switches off), then the GPS complains and switches off. With even less load being supplied the voltage creeps even higher.

I would have thought that it wouldn't be beyond the wit of man to come up with a box that takes "12V" in from the coils and provides a stabilised 12V at up to 20A on the other side. I'm darned if I can find such an animal - do such things exist, or could I use a regulator from a car / bike / van?

I don't want to have to try and make something.

Cheers
Hugh

[Anchorhandler]

Hi Hugh

You could use a DC to DC converter which will guarantee you a stabilised 12v output but it all depends on what current your looking to put through it as to how cost effective that would be.

Are you sure there is no regulator fitted from new though?

Search the RS website for 'DC DC converter' and you will find quite a few. Most have a 12-36vdc input range and come in various current ratings. Technically though this will only provide you with a stabilised output voltage and not provide you with any charge regulation.

Simon

[HughN]

Originally Posted by Anchorhandler

Hi Hugh
Are you sure there is no regulator fitted from new though?

Thanks Simon.

Yep, I spent ages taking off what I assumed was a knackered voltage regulator - only to find it was the rev limiter (same shape!).

I will trawl through RS.

[doggypaddle]

ask NOS4r2 i think he has used or may know how to use bike regulators. either that us use a 14.7 volt zenner as a shunt regulator? as on ole british bikes.

[HughN]

Thanks.

I'm hoping this will do what I want it to. I may have to add a charge regulator to pamper the battery.

Cheers
Hugh

[Trailer Guy]

I use Barden UK, for my batteries and ancillaries. Not the cheapest (though I do get a decent trade discount on batteries) but the stuff they do is good and they all know what they're talking about in my experience.

Barden UK

I bought a DC / DC convertor the other day. 12v in and 24v out (actually 27.6, because I wanted the charging version) 10A output. Think it was around £120 + vat. Gives you an idea anyway.

[Peter_C]

Without much engine information to go on, are you sure it is capable of producing 20 amps? Seems like a lot for a smaller outboard...or is it a bigger on?

I used a motorcycle regulator/rectifier on my little engine. They are available for PWC's etc too.

[Nos4r2]

What motor is it and how many outputs does the alternator have?

You SHOULD be able to go to the Electrex website and look for a regulator/rectifier unit for a Kawasaki Z750 twin, or another 4 stroke bike with a 2 output alternator and replace the rectifier as well with it.

[HughN]

Originally Posted by Peter_C

Without much engine information to go on, are you sure it is capable of producing 20 amps? Seems like a lot for a smaller outboard...or is it a bigger on?

I used a motorcycle regulator/rectifier on my little engine. They are available for PWC's etc too.

The manual states 16A at 3,000 rpm so 20A was my 'upper guess' (the 25A fuse was a clue also).

Thanks

[HughN]

Originally Posted by Nos4r2

What motor is it and how many outputs does the alternator have?

You SHOULD be able to go to the Electrex website and look for a regulator/rectifier unit for a Kawasaki Z750 twin, or another 4 stroke bike with a 2 output alternator and replace the rectifier as well with it.

Thanks - I will trawl through that. It is a single output system (according to the manual)m but I am sure they will have options.

Thanks. At least I won't have to go back to my O-level Electronics text books!