There is a lot of misinformation about this burn test... the most important thing to remember: You are NOT testing the batteries in "real time", so the number of minutes of burn DOES NOT relate to the time they will last under real conditions.

The purpose of the battery test is to create a base-line graph of how the batteries discharge over time. If you use a brand-new set, then the graph you come up with should represent the optimal discharge curve FOR THAT SET OF BATTERIES. After 20 use-cycles, you could run the burn test again and see a very similar discharge curve, one that probably will be a bit lower in volts, and a bit shorter in time, but essentially little changed from the original. However, if you see a dramatic change in the curve, then that is an indication of something going wrong inside the battery.

Also, if you start having problems with your scooter, then -- assuming you have a base-line curve already -- do a burn test and eliminate the battery as being the problem before you start replacing circuit boards and such. Probably 60% of the time that a scooter owner thinks the motor brush is skewed, or a reed switch needs replaced, it turns out to be a bad cell in a battery or some other battery problem.

Another very common problem is running the battery down too low. If a 12 volt battery is run below 11.8 volts (11.5 for the test), then you are shortening the life considerably. So, you might have a "new" set which you think CAN'T be the problem, but if you ran them down to, say, 11 volts several times in a row, they may simply be worn out, and they ARE the problem. (With a 24 volt system, the voltage shouldn't drop below 20 volts for the test, and not below about 22 volts in real life.) [Note: Don't walk away from a burn test! If you do, and the voltage drops below a certain point, you might as well trash the batteries.]

Unfortunately, as you can see, dealing with batteries is more art than science --- well, actually, it's a LOT of science, but you have to be religious about taking care of the batteries. Hmmm, how about that, I got art, science AND religion all rolled into this conversation! <g>

Hope this helps. Remember, you might get 45 minutes on the burn tester, but you may get 90 minutes on the scooter. If you take careful and frequent notes about each set of batteries, their discharge curve, their burn time, their voltages after a run of x minutes, and so on, then after a while you'll start to get a feel for it.