1979 Evinrude 25952R 25hp charging system? Solar panel as a back up?

Robbyracks

Cadet
Joined
Jun 27, 2022
Messages
26
Hey folks,

Does anyone know if this model has a charging system? It was a remote motor but previous owner converted it to a tiller. If it came with one, is it possible that the system doesn't charge any longer? I'm curious because I am going on a camping trip with this boat and will be motoring to semi-remote campsites. I just want to be sire that the battery (it's a new12 volt lawn tractor battery). We will be using an electric trolling motor too. I've thought about buying a solar panel to trickle charge as a back up. Thoughts?

Thanks!
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,047
Any yellow wires coming from under the flywheel?-----A rectifier mounted on the starboard side of the block?-----At any rate I doubt it can charge enough and a lawnmower battery might be too small !
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,690
An electric start model should have had battery charging
It should have a 5 amp stator and a round 4 wire rectifier .

Measure the battery volts before , during an after starting.

If the battery is fully charged , and not been on charge or used for 24 hours it show show around 12.7 volts.
The volts will fall while you crank the engine but quickly recover once the engine is running and then slowly rise towards 14 volts and above with the engine running at normal cruising rpm. (It is not a regulated rectifier so don't be surprised if it continues to rise to a15 or 16 volts)

You don't say what Ah capacity your lawn tractor battery is but you need to estimate your daily power usage, in Ah, and ensure that you have a battery at least twice size.
You must also be able to replace the Ah used in the length of time the engine is running at an absolute maximum, but probably a lot less, of 5amps.

I am sure you will find your battery is too small and the output from the engine insufficient unless your power use is very small.
I'd say there is little hope of powering a trolling motor as well.
Solar is the best way forward but you need to estimate the size of solar panel you will need.
You will almost certainly need a solar panel controller especially with a small battery. The rules of thumb are that a controller is needed if the capacity of the battery in Ah is less than 10 times the power of the panel in watts or if the panel is larger than 10 watts.

FWIW I get by with a 60 Ah leisure battery and a 5 watt solar panel on my small sailboat. Charging from the engine is insignificant because it only runs for a short while on a good day but at least it's rope starting so a discharged battery is not a major problem.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,047
It may have had an electric start kit installed.------Not all electric start kits include a battery charging coil !!
 

oldboat1

Fleet Admiral
Joined
Apr 3, 2002
Messages
9,598
Mennonite families here use lawn mower batteries and solar chargers for operating the running lights on their buggies and shays. They routinely use state and county roads. For your outboard use, I would opt for a pair of regular batteries, using one for starting only. Charge with your A/C charger when the boat is in your yard.
 
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