Sunday, May 29, 2011 at 01:08
Hi guys - I have a 120 amp hour (deep cycle) and a marine combined cca & deep 100 amp hour and I wanted to parallel them, but thought I better
check to make sure it was OK to do this.
The outcome was interesting in that, - I could do it, but was advised it was not a good idea as the 120 amp hour could not get charged over the maximum capacity of the weaker battery (100amphr) in the link, ultimately causing the failure of the 120 amp hr battery "probably within 12 months" if I proceeded, and that would then cause the failure of the 100 amp hr battery too! I was advised to buy another 120 amp hr battery.
Anyway I bought another 120 amp hour (note: I was not sold a battery by the battery expert who gave me the advise, so he had no motive to bull me) so now have 2 x 120's (so equivalent to 1 x 240 amp hr now they are connected parallel), and I have not hooked up the weaker (100amp hr) battery.
Michael the point here is if you hook up 2 x 65's with 1 x 120 amp hr the 120 will effectively become a 65 amp hr battery (so you will have 195 amp hrs total and not the 250 you think you will get), and will ultimately fail fairly quickly which in turn will make the 2 x "new" 65's fail fairly quickly after that!
Is this information right or did the battery professional have s__t for brains?
If he was correct "and I think he was" then Michael "I didn't do what you are about to".
Cheers Nigel
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