Help needed - lighting circuit

nippynorman · 02 December 2003, 21:11

I would like to instal a lighting circiut to run from my yamaha 8 hp motor. It has a power take off but the bullb blow when I rev the engine. Can I fit a battery - do I need to fit soem kid of battery controller/ charging circuit or will the outboard do this for me?

I'd quite like to be able to chage my hand held VHF if fitting a battery is possible. Thanks in anticipation

Norman

chrisallse · 03 December 2003, 00:24

fitting a battery will regulate the voltage and stop it from blowing bulbs. You will then be able to charge your radio etc. The size of the battery will determine how much power you have in reserve when the engine is not running but unless you anticipate needing a lot of reserve IE. for an anchor light a motorcycle 12v battery should do the job.

jwalker · 03 December 2003, 00:35

The lighting circuit output will probably be AC. You'll need to rectify it before connecting to the battery.
A similar problem was answered here last week. I can't remember the name of the thread. Do a search for 'bridge rectifier'.

nippynorman · 03 December 2003, 16:06

thanks for the advice - I'll search for Bridge Rectifier

norman

nippynorman · 03 December 2003, 16:46

I have looked through the post - Seems like I need a recitfier - Maplin did someone say, a motorcycle batterys and case - Towsure only had big ones - any suggestions and can I buy a connectoranywhaer to go into the Yamaha outlet for the power circuit - didn't know it was ac.

Norman

gavin · 03 December 2003, 16:49

You must if a/c rectifiy it to dc and also regulate it to allow a correct charging voltage for a battery it needs to be above 12 volts 3 or 4 volts should be enough

tue · 03 December 2003, 17:35

If the power take off is original then it should already be rectified. It is designed for charging a battery hence when reved the bulb blows. If you fit a battery first it will then keep this charged and you can run your circuit off it. Also the the power take off should also be regulated if an original kit.

chrisallse · 03 December 2003, 21:04

You dont need to regulate it, the battery will limit the voltage to about 13.5 v max

Nickytynick · 03 December 2003, 21:32

Norman,

You must fit a batttery. Remeber if youre out at night and your engine fails youre almost invisible!
I would be tempted to seek advice from a professional 'cos you cant afford to get this wrong!

Good Luck!

Nick

jwalker · 03 December 2003, 23:14

You haven't specified the series of engine or it's year so we're all guessing a bit.

Read your handbook before you start. It should tell you.

If you are really stuck:
It is possible it is already recified. Follow the cables back from the connector. If they end up under the flywheel, it's likely ac. If they enter a wee pack of some sort and the exiting cables go up to the flywheel it's likely dc. Alternatively, set a multimeter to dc at a safe voltage and connect it to the output. If the output is ac, it'll read low or, if a digital meter, it wont settle. If the output is dc, then you should get a fairly steady highish reading.
If you conclude it's ac, as a final check, set the meter to ac and you should get a highish reading - guessing about 15-18v.

If it proves to be dc, then, as suggested, you need a battery.

It would be easier to phone Yamaha and ask them!