1992 Johnson 115HP

[FirstRealBoat]

I have looked all over the internet and just can't find what I'm looking for or maybe I'm just not looking in the right place or asking the right questions. So to the forums I come running.

I have a 24' Pontoon with a 1992 115 HP Johnson outboard (J115TLAND). I am wanting to upgrade the wiring and electrical to fit my needs better.

What I am wanting to know, does the motor charge the battery? If so, what is the amp output?

I would like to put three batteries in parallel and then have one stand alone. Using a selector switch I would start the motor on the stand alone and then move all other power needs to the three other batteries. Once they got drained, I would start the motor with stand alone and switch the switch to bank 2 and effectively charge the battery bank while motor is running.

My goal is to be able to have a cranking battery for the motor, keep it charged (if motor does in fact charge batteies while running). Then have the option to charge the battery bank for all the other stuff. Nav lights, fishing lights, bait tank, trolling motor...ETC.....

Currently I have all batteries separated from the main motor except Nav lights. This is a pain, I have to remove batteries to charge them at the house. On long camping/fishing trips 5-7 days, this isn't an option and I will need those batteries.

Suggestions, comments and ideas are needed.

Thanks

 

[sam am I]

Yes the motor charges the batt (Carb'd = 20A Fitch = 35A, both regulated) either way, going to take long time to charge up 3 flat'ish batts....Hours in fact but, sometimes, in a pinch its better to charge one at a time when time and current are limited as in your case.

For example and with rough numbers, say you have 3 same'ish type batts that are all 40% discharged and say it's possible (by the rough numbers) to charge ONE at a time back to 100% up in around 4 hours at your boats 35 amp rate but, instead you elect to tie all 3 40% discharged batts in parallel to charge them all at the same time and of course, your thinking in that same 4 hrs and of course with the same 35 amps rate. NOPE, In 4 hrs you'll then have 3 battery's that only are charged up only 1/3 above the 60% level or 73% (40/3 + 60).

You multiplied your charge time by 3 by dividing the charge current across 3 batts by paralleling them.......It'll now take 12hrs @ 35A (4hrs * 3) to get all 3 back to 100%

So, decisions, decisions......Sometimes life during war time warrants that after 4 hrs, it might be perhaps better to have one at 100% then 3 batts still at only 73%.

BUT, nothing is gained at the end of a linear half life, either way, one at a time or in paralleled, it'll be 12 hrs to have 3 full batts, 1 at a time or 3 at a time, 3 full batts = 12hrs

I run 3 batts (1 motor, 2 acc) and have only have a 40 amp alt and installed a auto management isolator that charges them one at a time but, once each in turn is topped off, then and only then, does it go into paralleling all 3.

 

[FirstRealBoat]

I run 3 batts (1 motor, 2 acc) and have only have a 40 amp alt and installed a auto management isolator that charges them one at a time but, once each in turn is topped off, then and only then, does it go into paralleling all 3.

What is this little device you speak of? I might be interested in something like that then.

 

[sam am I]

http://www.promariner.com/en/products/proisocharge-series

https://www.amazon.com/s/ref=nb_sb_n...tery+Isolator+


Ran one now going on 4 seasons, run perfect and works well for my needs.......