please help will my outboard charge a battery

[Dazz]

can anyone help please can anyone tell me how i go about checking if an outboard can charge a battery please i have a johnson 35hp many thanks

[captnjack]

Is it electric start already?

[Poly]

Do you mean (1) is my outboard charging my battery? or (2) is my outboard capable of charging a battery?

1. - First step, measure voltage at battery terminals with engine running.
2. - Does it have two thick (usu. Black and red) wires coming out the front, or a connection point with two reasonable sized holes (usu. on the front with a small cover over it).

[Dazz]

Hi it's an old Johnson 35 with pull start but I want to have electrics on the rib do I just go down the route of just having a battery and keep it charged up many thanks

[whisper]

Does you outboard have the facility to charge a battery?

[whisper]

Have a look at this link and select the year then model, you should see from the parts list if your OB has a charging circuit.

Johnson Outboard Parts

[Dazz]

Whisper that was fantastic just what I was looking for model j35balcts if I am reading correct says ac lighting so should have a 12 volt out is this correct many thanks for your help

[whisper]

I found this on the net regarding your j35balcts model number...

J Johnson
35 HP
BA Belgium, AC Lighting (Rope Start)
L 20 inch shaft
CT 1983 (I-N-T-R-O-D-U-C-E-S corresponds to 1-2-3...-9-0)
S Model Run

[EnglishLes]

Originally Posted by Dazz

Whisper that was fantastic just what I was looking for model j35balcts if I am reading correct says ac lighting so should have a 12 volt out is this correct many thanks for your help

AC Lighting Circuit will need rectifying (to change to DC) and regulating (to prevent the voltage going too high) to charge a battery. The volts will vary with revs.

I have 3 wires on my 15HP, you will need to see how many your engine has.

I believe a lot of people use a motorcycle unit to do this. You will need one capable of handling the amperage.

[Dazz]

Many thanks for the reply guys I now know the way forward many thanks

[9D280]

Just be careful where you mount it - the regulator type ones can run very hot.

(but as I found the "rectify only" type can toasty a battery - the Clamshell only has a rectifier - I measured 19.7V at 1500 rpm. No wonder my batteries weren't lasting!

Now have a rect / reg off a Honda O/B strapped to the side of my air box (to keep it cool!)

[Peter_C]

I converted my 40HP to charge a battery and to electric start. All I needed to do was add a voltage rectifier/regulator. A unit from Ebay fit the bill perfectly and has worked great charging an AGM battery. My motor already had the charge coil installed.

[matt h]

Variable voltage regulators are avail fom maplins and other associated stores

[9D280]

Originally Posted by matt h

Variable voltage regulators are avail fom maplins and other associated stores

I also looked at that option, but with a charge coil throwing out 19+ V, I did some maths on a worst case flat battery, which needed a fairly high current rated one (came out at something like 20A, and a big heatsink.

You might not be surprised to hear by the time you have bought the bits, a used one off a dead outboard was the easiest & cheapest way to go (and one off an old O/B will be a bit more water resistant).