1977 Johnson 35 HP 35EL77H-Rectifier and starting battery recommendation?

[jitterbug127]

I have a 1977 Johnson 35 HP outboard with Electric start that runs great. Pushes my boat really well and has been a joy to use. I have restored my boat this fall, and its time to get a new cranking battery. I am considering 3 battery types. I'm having trouble deciding on best option.
1. Lithium Ion 20 ah cranking battery. Weighs 9 lbs but costs $200
2. U1 lawnmower starting battery. Cheapest and weighs 16 lbs.
3. 24 size lead acid battery traditional. heaviest weight middle pricing

I'd like to use this battery to start my motor and run my fish finder off the back of the boat. Questions I have.

1.Is it possible to install a rectifier (any other necessary components) to my 35 Hp motor to be able to charge my battery while i use motor?
2. Can I successfully use a u1 battery to start motor and run fish finder? Would it die too quickly?
3. Is rectifier compatible with lithium batteries?

I have a 100 ah lithium trolling motor battery at the bow. I could run a cord to fish finder on back of boat if necessary, but I'd like to avoid wires if possible.

Thanks for you time and have a blessed day!

Rob

 

[jitterbug127]

 

[saltchuckmatt]

I have a 1978 so I'll send you pictures. The short answer is yes. Rectifier, bus bar, then maybe something under the flywheel.

Lithium wont work....not compatible with the charging system.

Others on here love their 4 stroke lawn mower batteries. I'm using two 27 series on my 16 lund with an 1985 30hp Johnson.

Bare min in my book is that 24 series lead acid battery.

Life jackets, oars, lots of fuel and redundant batteries....but I go places!

 

[saltchuckmatt]

 

[jitterbug127]

Awesome! Thank you for video super helpful! I’m going to do more videos with my posts from now on. I’ll do some price matching on charging system vs just a lithium battery. Love this forum.

 

[saltchuckmatt]

The charge kit is labeled under accessories. Here it is.

Finding a used cheaper stator will be your goal.

https://www.marineengine.com/parts/johnson-evinrude-accessories/index.php?year=1977&model=Electrical+1977&section=Battery+Charging+Kit+9.9-15%2F25-35&yid=34200&mid=34201&sid=36114

 

[jitterbug127]

Agreed! I just looked at those prices for the stator. More than I paid for the motor.

 

[cyclops222]

Your motor has a E in the code and is electric start. My 30 hp electric start has a rectifier coil dedicated to recharging a battery. We should be able to find a parts print of the battery charging circuit parts on www.crowleymarine.com