[T3] Re/ Endless Problems etc etc etc

[Jim Adney]

On 10 Dec 2010 at 0:56, J. Jonik wrote:

> Advice was to put battery charger on low...2 amps...instead of 10 amps, to get it up to  over 14.00 volts, or to 14.50,  to solve fuel injection performance problems.
> 
>  Hours ago, when battery was Almost There,  at 13.90 volts (after a day of charging at 10 amps) I turned it down to 2 amps for slower charge to go the rest of the way.
> 
>  Now, hours later, the battery has lost an entire volt.  It's back to about 12.90 volts.
> 
>  How did battery LOSE voltage while on the charger?

The voltage you measure depends not only on the state of charge in the battery, 
but also on direction and amount of current going in/out of it. At the high 
charge rate, you are pushing the voltage up artifically, giving you the 
impression that it's more charged than it really is. The low charge number is 
more likely to be correct. The real number is the one you get with no charging, 
and that number should be somewhere in the mid 12s.

At this point, I think you've done enough charging to do a different test.

Remove the charger and let the battery sit untouched for an hour or more. 
Measure the battery voltage with no charging or discharging going on. If that 
voltage is below 12 V, this battery is dead. 

If it is above 12 V, continue charging at the LOW rate. Leave the charger going 
day and night while you check the voltage occasionally. You should see it 
slowly creep upwards. Keep us posted on its progress. You can quit once the 
voltage has reached 14 V. Never let the voltage exceed 14.4 V.

-- 
Jim Adney
jadney at vwtype3.org
Madison, WI USA