(ET) Charging gel batteries in the Elec-trak

["Markus Lorch" <mlorch vt edu>]

Hi,

in my previous post I mentioned that I have different size
batteries. Larger ones that also drive the 12V and smaller ones
that add 24V to reach 36V for the drive and mower motors. 

The batteries I have a gel, valve regulated batteries. I had 
noticed that the built in charger overcharges and causes the
valve regulated batteries to vent, not a good thing.

In an old post I found that David Roden also used valve regulated
batteries and he helped me to figgure out how to charge best my
unbalanced set of batteries (2x 12V Deka Unigy I, valve regulated,
100ah)
and two 6V Deka Unigy I (not sure about the amperage but quite higher).
 
I looked at battery regulators that would control the voltage made
available to each individual battery but decided against it (following
David's recommendation) as they may not be able to redirect enough
current when the batteries are full and the time controlled built-in
charger is still humming along. 

The solution is to use individual chargers, which will charge and 
control each of the batteries individually (actually for the two 
6V I group them together into one logical 12V). 

I have charged them individually with a 12V charger for gel batteries
the last two days. One time I gave them a 1.5 hour boost with the 
built in first and then topped each one off with a small 1.25 amp 
"Battery Doc" charger. 

I just ordered three "smart" soneil 3 Amp 12 V chargers. I will
report on how they work. The best deal I could find was here: 
http://www.batterymart.com/battery.mv?p=ACC-1206WB I intent to 
permanently mount them in the ET. 

I also have a "smart" Schumacher 12V charger (for $40 at
Walmart), its 2,8 or 12 Amp and I thought of using three of these
as they have a voltage meter built in and show how far along they
are in the charging process (in percent). I loved the thought
of having a display for each battery. The reasons for not
doing so are the following:
1. they are regular transformer based and are relatively large and 
   heavy (so they can't be mounted permanently somewhere in the elec-
   trak without casing modifications)
2. they default to flooded lead-acid batteries and require pushing
   a button to select gel batteries. This would prevent me from  
   using them in a plug-in and forget kinda manner.
3. the volt-meter doesn't work when the charger is not plugged
   in, so I can't control the battery voltage and charge status
   while using the ET. What I would like to have is a display
   that tells me how far each battery is discharged.

I hope this information is also useful for others. I'll report on
how well teh Soneil chargers work and how long they need to
recover the pack from various discharge states. 

Markus