Test for unconditioned NiMH batteries

[plo]

Over the years, I've acquired many sets of NiMH batteries. Because I primarily use NiMH in my daily routines, I've noted how their behavior changes over time. When I first get the batteries and use them, they've been idle (but on a charger) for a long time, and not surprisingly they act a bit funny there first few times out. They'll drop their first few bars quickly making you think you're only going to get 5 miles out of them. I think this might be an indication of "unconditioned" batteries.

I tend to recondition these batteries twice immediately when I get them. Then I make sure to recondition them every month, and I cycle them into the line up for a weeks worth of active use. By the third month, they're performance has dramatically improved. Now after charging they'll only drop half a bar after 3 miles.

I don't really think the range is improving dramatically, but the battery indicator shows much more comfortable behavior. Or maybe Blinky is just beginning to trust these batteries...though my weekly switches should leave Blinky quite confused. Oh, one more thing...I tend to drain my batteries at least half way (and often to the last bar) before charging. I'm not saying folks should do this necessarily. Also, after a few months of a rigid reconditioning regimen, I tend to switch off to reconditioning every 2 to 3 months. I've noticed no significant change in the batteries discharge rates, but remember, I cycle them in one week per month for active use.

ps - In the interest of keeping fact and fiction separate, I'll ask that Tom not respond to this thread despite all the years of experience he has with NiMH in a demanding tour operator environment. I'd like to keep the misinformation about this topic (such as a new reconditioning method that gets you say "15 mile range") to a minimum!

[Timezkware Tim]

Whenever I take the batteries off, as I do when we play the 21st century's hottest new sport (OPTA moment), I always put them back in a different order (front-back). Does this have any effect on overall battery life? Does it help balance the conditioning effect?

Tim

[plo]

Originally Posted by Timezkware Tim

Whenever I take the batteries off, as I do when we play the 21st century's hottest new sport (OPTA moment), I always put them back in a different order (front-back). Does this have any effect on overall battery life? Does it help balance the conditioning effect?

All my comments apply to the older i-series. The newer i2 and x2 cannot use stock batteries from the older i-series, so nothing below relates to these newer models.

It can't hurt to swap them IMHO, but I have nothing to base that on. If your segway is off for very long periods of time (on the order of weeks), then one of the batteries (rear?) is going to be drained more quickly than the other. My understanding is that this occurs because while "off" the segway continues to monitor the key port. If the batteries are Li-Ion without the more recent protection circuit, this can be a significant problem.

Daily usage will load the batteries much more than sitting unplugged, and supposedly draining done during normal operations is done in a balanced fashion.

Now with that said, recently I did a series of battery tests, and I was very careful to mount the batteries in the same location (front vs rear) so as not to introduce any possible variations. So I had the same concern as you, but I tend to think it's unfounded.

[Timezkware Tim]

Thanks, plo. I'm sure bystander and hellphish can provide more info when they stop by.

Tim

[plo]

As I continue this latest round of tests on unconditioned batteries, I found "topping them off" (where you unplug fully charged batteries, wait 10 min, plug back in and start a drastically shortened charging cycle to shove just a bit more juice in) didn't change anything. The first two bars still dropped off in the first 2 miles.

Interestingly enough the last 3 bars took even longer to burn through. And when I got to work this morning, these batteries had performed almost as well as my best set. So even though these "unconditioned" batteries showed the same quick drop off, they did accept the extra power (and utilize it the next day) from the "top off".

What this means is a seller probably can't hide how they've failed to condition their batteries by doing a short half hour long "top off" procedure.