Hi All
Happy New Year to you all
Had some starting issues over Christmas so thought l would leave batteries on charge for a few days with Mastervolt 24 charger and popped back yesterday> Then left for 4 hours isolated each battery and tested. Now a bit confused.
All 6 showed respectable volts corresponding to volt meters on boat and the fact the charger had gone on float for the last 24 hours. Engine still refused to turnover well checked all connections and no voltage drop.
Tested and recorded 12.5-12.9 volts min on all.
2 Starter Batteries CCA dump test showed fault failed test and battery bad even when volts still above 12 and sg of each cell was below .05 so why would it fail to pull enough amps.
One of the doms failed dump test and even with good volt the SG between cells was way out--bad battery and l understand that.
2 of the doms good volts even with slightly variable SG and achieved 800 CCA without dropping below 10.3 volts so OK??
Other 2 checked out with SG, volts and CCA test so good :
My main query is how can a battery with good volts good SG still be bad on CCA??--can it just be old age?
and a good battery with slightly variable SG still pass with flying colours on CCA test---should l chuck it anyway when SGs vary by .03-4max my instinct is to keep using it.
All answers gratefully recieved
Simon
Also if l am using 24 volt starting setup with 2x 12v batteries does that double the CCA eg 640 at 12 volt is 1280 at 24v or does the CCA remain the same?
edited for this addition