Outboard Charging connections

[Pkewish]

Hi, I have a little 6HP outboard which has a 'lighting cable'. I believe the idea of this is to run nav light but not much more. I know they only supply little current but I want to use it to run my lights and maybe instruments in an emergency when the main battery of flat. Also can I use it the charge the battery.

If so, how do I connect this to the boats wiring system. Do I have the go thought a 'little black box' or can I just plug it in as is?

Cheers Pete

 

[RobF]

You're unlikely to cook your battery with the output from a 6hp outboard, so a charge regulator is (in my opinion), not necessary. I would feel comfortable connecting the charging system straight to the battery (obviously, with fuse protection).

I'm sure someone else will come along and suggest that, for the cost of £40, a charge regulator would be highly advisable!

 

[Tommyrot]

If it's a "Lighting circuit" it'll probably be an AC output, you'll need a rectifier in that case.
From my experience of charging from outboards, unless you keep the revs fairly high, you'll get very little current.
That's the main reason I've not bothered connecting mine to the battery , plus I use the engine as little as possible.

 

[Pkewish]

I've just put a multimeter on it and it is AC. so there goes the 'director connection' theory - shame. As for high revs, the boat hardly moves unless revving high so that shouldn't be a problem. It's only in case of emergency really, just in case I get caught out and need nav lights and depth sounder beyond the battery's capability. Thanks guys.
Peter

 

[VicS]

You dont say what engine !

Make, year, Hp, model number and/or serial number would enable some information to be found.

However

If it is just an AC output for lighting you can probably buy a battery charging accessory for your engine.... For £xx

Check with a multimeter to see if its AC or DC if you are in any doubt

Provided there are only two wires ( not three) You will able to use a simple, suitably rated bridge rectifier from Maplin or RS ( a 3 wire output requires a special rectifier) for a fraction of the cost. Get one with spade terminals for convenience of connection.

Engine output to the AC terminals probably marked ~. DC out put from the + and - terminals.

I did that with one of my outboards ( the current one has a rectifier as a standard fitting.)

I mounted it on a small square of aluminum that served as mounting bracket and heat sink.

A regulator will not be necessary unless you are only using a very small battery. But fit a fuse close to the connection with the battery +.

 

[Pkewish]

Its an '86 Suzuki DT6.

 

[John the kiwi]

When i bought my boat it had a 15 HP Honda with a nominal 6 amp battery charging output. Only problem was no output. Quick check with multimeter showed that there was AC as far as the rectifier mounted on the engine and nothing thereafter. Quick check on Honda spare parts price followed. When i came around from the shock i did some more research and discovered that "blowing" the standard rectifier was as easy as disconnecting the cable while the motor was running. Given the way the plug was retained on the outboard, this was more likely than not to happen.
Rectifier cost me $8 NZ at electronics shop which is approximately free in Pounds sterling. A friend provided a large capacitor which protects the rectifier from the disconnect inductance. I run the AC into the electric box in the cabin and have the rectifier mounted there where it is all dry and warm. I dont use my engine a lot, but figure any charge amp is a good charge amp so may as well have it. No I dont have a charge controller, the voltage and maximum current dont warrant it.

 

[VicS]

................ i did some more research and discovered that "blowing" the standard rectifier was as easy as disconnecting the cable while the motor was running. Given the way the plug was retained on the outboard, this was more likely than not to happen.

This may be why my current engine has the battery lead permanently wired to the rectifier while the basic version of the same engine with just a lighting coil but no rectifier has the connection made via a plug and socket.