10-04-20, 03:32 PM
(09-04-20, 12:15 PM)Gnasher link Wrote: [quote author=unfazed link=topic=26060.msg312157#msg312157 date=1586427128]
That battery is a standard lead acid on and is ok to charge it with a car charger, but with the red cell caps off.
No, if it's a intelligent charger, type that can detect the charge AMP/voltage and cycle charge like CTEK for example yes. Your standard low/high charge rate charger will bugger it. I lost count of the amount of owners who've buggered their batteries in this way, red caps off or not.
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You are correct, however since Farmboy81 does not have either an Optimate or Ctek charger then the car charger can be used with care. The biggest issue with using car chargers on old style lead acid batteries is they were being left on for 24 hours or more mostly because a lack of understanding of how they and batteries worked. I have seen many garages leave them on for a few days to give the battery an extra boost which you and I know was totally false economy and destroyed many batteries.
If you use a voltmeter to measure the open circuit voltage of the battery (Open circuit voltage is the voltage of the battery with no load or disconnected from any circuit). It is important not to charge the battery before you test the open circuit voltage. In relation to Farmboy81 Battery, it is a 12v 8ampere hour
In simple terms it would take 8 hours at 1 amp to charge the battery plus about 15%, to allow for the internal resistance but I am not going to go into the full method of how to charge
If the voltmeter shows a voltage reading of 12.2 volts then the battery is approximately 50% charged.
I his case 12.32 volts does not mean the battery is dead.
Generaly a lead acid cell is:
Fully charger at 12.6 to 12.7 volts
75% charged at 12.40v
50% charged at 12.2v
25% charged at 12v
0% charged as 11.8v
Again Farmboy81 battery has a charge of around 60% and his charger would charge it fully in a few hours at a 2 amp rating.
It would be vital for Farmboy to user the charge set to its lowest charging rate which is normally 2amps
All the above of course is not relevant if you have an Optimate or Ctek intelligent charger