1987 johnson 25 ?(AC lighting)?

[JohnJamesSimpson1987]

Hi I recently bought an ex army Johnson BJ25BALCUR, I have found very little info on this model. However I have worked out its model number and found that it includes AC Lighting,
Does this mean that I can still run fishfinders, Bilge Pumps, Electric start etc. and charge a 12 volt battery?? And also How do they wire up, For example do I go from the outboard socket - to the battery - and then wire from there? any help appreciated, John

 

[Vic.S]

Re: 1987 johnson 25 ?(AC lighting)?

The engine is in fact a recreational model ,not a military one, but it is not listed in the BRP parts catalog. I suspect because it is Belgium made.

I think you have your AC power coming out at a special 3 pin plug socket on the lower cover.

To use that for battery charging and your instruments you will need a special rectifier to produce DC from the AC.

There are there ways forward:

1. Obtain the charging kit which plugs into the above socket, part # 582105.
It costs around $77 but it is the simplest solution.

2. Obtain a 4 wire rectifier and terminal block to fit on the motor under the cowl to convert it to the same system that is used on electric start models. You wont need the full $92 kit because you already have the stator coil. . It'll be cheaper than option 1 but you'll need to know a bit more about what you are doing.

3 if you were a bit of an electronics buff you could make what is in effect a 3 phase full wave rectifier from 6 suitably rated diodes.


The circuit diagrams below show how AC lighting should be connected and the circuit for a rectifier.

 

[steelespike]

Re: 1987 johnson 25 ?(AC lighting)?

I know nothing about the details of the motor but being a ac supply you would have to convert it to DC and you may be able to do that by simply adding a bridge rectifier. A square block (not a cube)with 2 ac in terminals and + and - dc output terminals
Whether you can use this to charge a battery I don't know.Surely would not
charge much and wouldn't need to be regulated.The experts probably can help with more details. A little late as usual.
If the bridge rectifier will work it surely is a simpler hook up.It will need to be bolted to a mount plate or portion of the motor that will help dissapate heat.

 

[Vic.S]

Re: 1987 johnson 25 ?(AC lighting)?

simply adding a bridge rectifier

Trouble is it requires a 6 diode rectifier like a 3 phase one.

If there were just two wires out from the stator a three wire rectifier would be the part required or a suitable rated ordinary rated bridge rectifier from Radio Shack etc.

Once fitted with a rectifier battery charging is possible but you are right you don't get a lot of juice. 5 amps maximum. Really intended to recharge the battery after starting an electric start model not for running pumps etc

 

[steelespike]

Re: 1987 johnson 25 ?(AC lighting)?

Trouble is it requires a 6 diode rectifier like a 3 phase one.

If there were just two wires out from the stator a three wire rectifier would be the part required or a suitable rated ordinary rated bridge rectifier for Radio Shack etc.

Once fitted with a rectifier then battery charging is possible but you are right you don't get a lot of juice. 5 amps maximum. Really intended to recharge the battery after starting an electric start model not for running pumps etc

Ah ha now I understand.So there isn't just 2 wires at the socket you could use ?

 

[Vic.S]

Re: 1987 johnson 25 ?(AC lighting)?

Ah ha now I understand.So there isn't just 2 wires at the socket you could use ?

Well you could. You could use either the yellow and the yellow/gray or the yellow/blue and the yellow/gray but then you'd only get half the available power.

6 diodes as in my diagram is the way to do it if you want to make up a rectifier.

 

[tx1961whaler]

Re: 1987 johnson 25 ?(AC lighting)?

The 3 phase rectifiers are pretty easy to find:
http://www.virtualvillage.com/3-pha....html?utm_source=googlebase&utm_medium=shcomp
http://www.denniskirk.com/jsp/product_catalog/Product.jsp?skuId=21578&SR=sr3_43963058_go
http://parts.digikey.com/1/parts/433081-3-phase-rectifier-bridge-vuo82-16no7.html

 

[Vic.S]

Re: 1987 johnson 25 ?(AC lighting)?

Well you don't need 75 or 88 amp 1000 or 1600 volt ones but the one in the second link would do nicely I expect.

 

[JohnJamesSimpson1987]

Re: 1987 johnson 25 ?(AC lighting)?

cheers for all the input folks, will be put to use

 

[JohnJamesSimpson1987]

Re: 1987 johnson 25 ?(AC lighting)?

Could I convert ac to dc by wiring a car battery charger mains wires to the engine output and then using the dc wires to power things?

 

[Vic.S]

Re: 1987 johnson 25 ?(AC lighting)?

Could I convert ac to dc by wiring a car battery charger mains wires to the engine output and then using the dc wires to power things?

No!

 

[JohnJamesSimpson1987]

Re: 1987 johnson 25 ?(AC lighting)?

No!

Without sounding dumb, Why?
Because my dad has being running a 12 volt motor from mains using a battery charger to convert the electric to 12v dc to power the motor. and this is working well.

 

[Vic.S]

Re: 1987 johnson 25 ?(AC lighting)?

Two reasons:

The mains battery charger requires the mains volts input to operate it, 230 volts or 120 volts depending in what part of the world you are located.
Your outboard AC output is only low voltage, 16 volts or just a little more.
I doubt if even modern switch mode chargers will accept that and still give 12 volts DC out

Your engine has, I believe, a three wire output (similar to a 3 phase system) Your battery charger will only have the two wire input ( excluding the earth/ ground) of a single phase system.

 

[JohnJamesSimpson1987]

Re: 1987 johnson 25 ?(AC lighting)?

The engine is in fact a recreational model ,not a military one, but it is not listed in the BRP parts catalog. I suspect because it is Belgium made.

I think you have your AC power coming out at a special 3 pin plug socket on the lower cover.

To use that for battery charging and your instruments you will need a special rectifier to produce DC from the AC.

There are there ways forward:

1. Obtain the charging kit which plugs into the above socket, part # 582105.
It costs around $77 but it is the simplest solution.

2. Obtain a 4 wire rectifier and terminal block to fit on the motor under the cowl to convert it to the same system that is used on electric start models. You wont need the full $92 kit because you already have the stator coil. . It'll be cheaper than option 1 but you'll need to know a bit more about what you are doing.

3 if you were a bit of an electronics buff you could make what is in effect a 3 phase full wave rectifier from 6 suitably rated diodes.


The circuit diagrams below show how AC lighting should be connected and the circuit for a rectifier.

cheers for the information pal, Much appreciated
The engine is ex army and not just recreational, as it is army green, internally andexternally, plus it came with an army carryall full of bits, and controls look ex army to

 

[Vic.S]

Re: 1987 johnson 25 ?(AC lighting)?

The model number checks out as a recreational model. I hope it has not been modified to the point that the normal parts don't fit if you need any.