There is a thread covering this topic here: power pack or second battery? (ausfish.com.au)
I would suggest that any of the jumper kits marketed for cars will suffice for that engine.
I'm looking to add an extra level of redundancy to my dual battery system by purchasing one of those small Lithium power packs to be able to jump start my motor if necessary. Does anyone have an idea of the minimum capacity CCA rating for these units I would require to jump a 1999 115HP 2 stroke Yamaha? Also, any recommendations on good quality brands would also be appreciated.
There is a thread covering this topic here: power pack or second battery? (ausfish.com.au)
I would suggest that any of the jumper kits marketed for cars will suffice for that engine.
Dunno a lot about electrics. But a number of years back I jump started my boat from a spare battery. It somehow spiked and destroyed my sounder and radio. An expensive exercise.
Gunna when u hooked it up u may have made a 24v battery
Some 3-4 cylinder cars require a battery as small as 380cca, the battery i bought a few months ago is 380cca and it starts my 90hp efi mercury 4 stroke which is a 1.7 litre engine tho it starts my engine it wouldnt crank over say a mercury v6 200hp
My batterys cca is bottom of the line at 380cca some cars go up to 1200cca i believe
I have something around the 720-850cca range that starts my v8 ford car
Having 2 batteries you don't need the power pack unless you are out for a couple of days. My starter battery decided to die on Tuesday and I used the second battery for the day and no issues. I guess 6 years out of a 730CCA is pretty good going, the electric winch does pull some power which doesn't help.
I got by by starting the motor with the house then switching it over and using the power from the motor on the winch.
But in saying that I am still looking at another battery to run my deep dropping rigs.
Having redundancy for redundancy is kind of over the top, the chances of both batteries failing in a twin battery setup is not worth the trouble of carrying a third option.
I'm not sure whether you need more cca's with a comparable size 2 stroke vs. 4 stroke motor.
I just checked my batteries, one is 730cca and the other 680cca, probably overkill in terms of the cca necessary to turn over my Yamaha 2 stroke, loosely based on your experience turning over a 90hp motor on 380cca. So maybe i should shoot for a Lithium power pack with a minimum of say 400cca subject to any further comments offered here by members. Always a trade-off, generally the higher i go the more weight I introduce.
Thanks for the link
You can look up the owners manual on the mercury web site most manufacturers have these online ifu look yhru the file it will tell u the required cca
Mercurysowner manual for my engine said i needed from memory 620cca but my little 380cca battery has cranked it over without starting for a good 2-3 minutes with a short break while i couldnt get it started
Try this its on yhe yamaha aust web site a bit hard to find itsabout 5 clicks in from the home page
This isthe cv 115hp 2002 (i didnt download the file)
https://library.ymcapps.net/library/...6726&langId=02
Well you can use them on your car as well, plus they are not that expensive and don't take up much room. 2 batteries may not 'fail' at once, but they can go flat. Especially on a cold morning with a hard to start 2 stroke. Mine saved me from having to turn around and go home one day in that situation.
G'day , I run a small 28ah Century U1R MF (just under 8 kilo) in my small tinny and have used it to start a 115 4 stroke Yamaha. You are only looking for a light backup not a full time crank battery?
4 strokes do start easy so a temperamental 2 stroke may be a bit more of a drain but it is only a 300cca battery and worked fine. To put in context the bigger boat with the 115 had been sitting in yard with old batt's that had lost their love for starting things so we grabbed the tinny battery to kick her over. Yammy 115hp I think is around 2014 model.
Personally, I think if you have 2 batteries, a house and starter, and they are correctly isolated you should be ok, if you really are worried about it and the condition of your current batteries, buy a new starter battery and put your mind at ease. If overtly safety conscious (paranoid :-) ) buy a mobile battery pack or the lithium pack as you mentioned that you can put to other uses and get some value out of, like cars. camping etc, get something with usb and cig lighter plugs to charge phones or run lights etc.
My concern with those small lithium battery jumps are, if you don't ever use them, the day you want to it may not work... and you will be forever charging it for that peace of mind you are looking for.
Cheers
Muz