Tetrx Minibot Battery Charge Cycle during Regional Play

[Hugh Meyer]

Al,

Attached is the discharge curve comparison you requested. One curve shows a discharge rate of 2 amps and the other shows a rate of .9 amps.

It seems there is not a big difference.

-Hugh

[Chris_Elston]

Originally Posted by Hugh Meyer

Chris,

Here is a discharge curve I did on one of ours. It shows good response down to about 1.6 AmpHrs, then below that it starts down hill. It looks like any calculations for life should us 1.6 AmpHrs as the useful life. This is with a discharge rate of 2 amps.

It looks like it will be important to carefully manage battery usage. We will likely top them off between matches and alternate batteries.

-Hugh

That's pretty impressive that this battery hangs on to the voltage for that long in the upper 12 volts. That should keep the minibots pretty consistent in the race to the top even on a so-so charge. Nice work Hugh!

PS: We've been wanting to get one of those CBA II analyzers ourselves. This year might be the year...

http://www.batteryjunction.com/western-cba2.html

[chemipanda]

How long should it take to charge the battery for the first time?

[Bill_B]

Originally Posted by chemipanda

How long should it take to charge the battery for the first time?

Ours took 4 hours to charge when new from the box. that was when the charger light turned green. The battery pack was warm at 3h45m and warmer at 4hours.

BTW, I taped a piece of clear plastic with a small hole for the slide switch over the indicator and switch area of the charger. This will keep the small slide switch from reaching the 1.8amp charge rate position by accident.

[MikeE]

I'm attempting a synthesis of this thread and the dynomometer test results reported on this thread.

A >14V supply gives 40-50% extra power output compared to a 12V supply.
So while the flat 12.5V profile between 0.4 and 1.0Ah is nice, keeping the battery at less than 0.1Ah discharge seems to be the best competitive policy.

Caveat: My knowledge of battery technology is limited, so corrections are welcome.

[IndySam]

Originally Posted by Chris_Elston

That's pretty impressive that this battery hangs on to the voltage for that long in the upper 12 volts. That should keep the minibots pretty consistent in the race to the top even on a so-so charge. Nice work Hugh!

PS: We've been wanting to get one of those CBA II analyzers ourselves. This year might be the year...

http://www.batteryjunction.com/western-cba2.html

A CBA II is one of the best investments we ever made. We haven't had a battery related issue since we got it. We test and rank all our batteries before every competition.

[Al Skierkiewicz]

Chris,
I bought mine at West Mountain Radio, the manufacturer. Of course they are a great source for Ham Radio stuff too. I hope they get a lot of business and stick around.