I tried looking some in line without getting an answer (that I understood anyway), but if you have 2 12 volt batteries connected in parallel does this make the cranking amps the sum of both batteries? I know it does this for the reserve capacity but didn’t know about cranking amps.
when you put batteries in parallel,you double the amps,when batteries are wired in series,you double the voltage but the amps remain the same as what one would be.
example two in parallel at 1200 amps equals 2400 amps at 12 volts.
two batteries in series,24 volts,1200 amps.
if you really want to complicate things,start wiring them series/parallel,in other words triple voltage double amperage,but thats a lesson for another day.
Iowa is exactly right in his reply.
I’m wondering what are you trying to accomplish? By referencing cranking amps, I’m left to wonder if you’re trying to apply parallel batteries as starting batteries?
And I have no idea why you’d want to do that. Any decent marine starting battery has more than enough amps to start any engine out there. I have dual batteries on my pleasure boat, but that is for redundancy and safety. The engine fires up easily on one battery.
Grouse
Right now I’ve got a battery for electronics and a dedicated outboard battery (and trolling batteries). I think this will be the electronics batteries last season, just pondering the idea of getting two dual purpose batteries and hooking in parallel. Double the reserve capacity, plenty of cranking amps and the outboard can spit juice at both when running accross the water.
Leaning more towards staying with a starting battery on the outboard and replacing electronics battery with a 27 series deep cycle though.
poomunk,you have a good idea,but,your outboards alternator doesnt have the ability to charge that set-up.at best,most outboards alternators are rated in watts,and at the most 30 amps if memory serves me,and,if one battery is only slightly weaker,the alternator will keep trying to top the weaker battery off regardless of the other batteries performance,and it WILL fry your alternator,rectifier,and regulator,if you want two batteries,use a switch that will allow you to select one battery at a time. good luck!!!
be careful of two cranking batteries….. its twice as hard for your outboard to charge them….. make sure your charging them on a charger when shes resting after a long day of fishing
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