Battery Discharger?

 

I'm looking for a battery discharger for testing my golf cart
batteries for capacity.  Golf cart and charger companies make them for
on the order of $500, but it's just a (resistive?) load, a low voltage
disconnect, and a clock to give runtime, so I can't imagine that there
isn't a far less expensive one available that I just don't know about.

Anyone have any sources for this kind of thing for less than the cost
of a new set of batteries?  8*|

Thanks!

 

Kind of low tech but I know a guy who used a car headlight and a Trace C-30
(???) and used the LVD
feature.

 

<William P. N. Smith> wrote in message

Easy.  This will take just one afternoon, plus recovery time.

Take the cart to a large, privately owned area with lots of flat spaces for
driving.

Find a big portable stereo with your favorite tunes.

Strap a keg of beer to the back, and run a hose from that to the driver's
seat.

After that, your on your own.

Seriously, though the above sounds like fun, I doubt a discharger is going
to do much to tell you how much capacity you have, as far as drive time, in
a golf cart, unless it's used for commuting and such.  If your using it for,
say, golf, or something else which requires frequent stops and starts,
finding out how long the batteries last with a steady current draw isn't
going to do you much good.  All the other factors, such as weight of
passengers, temperature, speed, grade, amount of stops and starts, wind,
turns, use of lights, and speed you wish to go are all factors that a fixed
load on the batteries won't take into account.

I'd take the batteries to a mechanic and have him test them.  That at least
will give you some idea of their condition.

Pagan

 


The golf cart industry uses a standard 75-amp current drain, so
batteries can be tested and compared using a common specification.
I'd really like to have taken measurements when the carts were new, so
I can compare to what they are now, and schedule battery replacement
for convenient times.


Our local mechanic doesn't have the discharge tester either, and
specific gravity tests show the batteries to be in fine shape when
fully charged, they just don't seem to last as long as they did when
new.

I suppose I could build something, anyone have any thoughts about 75A,
V loads?

Thanks!

 

William P. N. Smith wrote in


   hi,
  The easy   (and cheapo) way to make a hi capacity load tester is to
scrounge steel strapping material used to strap heavy loads to pallets,
drill a hole in the strap ends , mount with bolts and use a continuous duty
solenoid (if you want to switch off and on) and battery cables to hook up,
experiment with lengths and maybe different thicknesses of strapping to get
the load right. I could not see any point in a timer as you will shorten
the life by running a test too long.
  The hardest part about this method is building a case that won't restrict  
airflow and is not conductive or flammable ( the load straps may get red
hot). I would venture a  good starting point to be  a cheap metal case box
fan with discharge pointed up and the load cell on top fixed to the metal
case with plumber's strap and maybe porcelain insulators from a electronic
supply house (antenna insulators maybe?). fan could help keep straps from
drooping from too much heat, buy some mechanic's safety wire (it is hi temp
stainless) to tie load strap to insulators to support it.
  You wanted cheap, the most expensive part of this setup would be the
meter to measure current draw.
   This is likely to evoke a lot of criticism from onlookers until you tell
them how much the alternative costs. As the saying goes, screw 'em if they
cant take a joke.
  Good Luck
  Scott