What amperage to charge a dead 8d?

[mike davis]

The digital charger that I bought has a charge percentage of the battery and a voltage.  Both batteries charged up to 64% within an hour or so.  But it took the last 6 hours to get them to 67%.  Any idea on what could cause this?

I'll give you some math
Each cell in the battery charges to 2.1-2.3 volts So a fully charged battery is some where between 12.5 to 13 volts All electrical equipment has a +/- 10% tolerance built into it  If it is designed to run on 10v it is designed to run without any loss  of preforming between 9-11 v It might make a little heat dew to resistants 

so if 12.5 V. is charged Your battery is somewhere between 8-9??? v. now But that does not tell you the state of the batterys capacitances (I think that is the right word It has been 25 years since i got out of collage For H,V,A/C )


  mike   

[TrevorH]

I am pretty sure there are 8 cells so using your voltage that would put the battery at 16+ volts.  Is this correct?

[JackConrad]

12 volt battery has 6 cells (each battery cap is a cell)  2.1-2.3 X 6 cells = 12.6-13.8 volts 
6 volt batteries have 3 cells 2.1-2.3 X 3 cells = 6.3-6.9 volts  Jack

[mike davis]

12 volt battery has 6 cells (each battery cap is a cell)  2.1-2.3 X 6 cells = 12.6-13.8 volts 
6 volt batteries have 3 cells 2.1-2.3 X 3 cells = 6.3-6.9 volts  Jack

jack
       your right
                    I through some "field math" in it. I should explained that If your getting between 12.5-13V. The battery is ok, not new but ok for voltage But that does not tell the hole story of the battery


                              thank you

                                             mike

[Reddog]

I would think that the 60% (+/-) that the charger shows is a percent of the batteries storage capacity, not necessarialy the voltage. i have seen lots of batteries that have 12-13 volts, but not enough reserve amps to light the headlights, much less turn the engine. Doug