Hey Guys i was recently thinking about the new batteries available. Now from what i understand the 7.2V NiMH 2000mAh battery is much lighter then the 3000mAh more “standard battery” the 3000mAh battery is also the recommended battery for competition use. Now it seems silly to me to spend a lot of time and effort into designing a light robot if you are trying to hang if you are going to overlook an easy way to save a decent amount of weight (the batteries). My question to those of you who have tested out the new batteries is this… Do the 2000mAh NiMH batteries provide enough power to run a robot that is using 4, 393’s and lets say 4, 269’s and 2 standard motors for the duration of one match assuming that the robot utilizes a power expander? now i understand that the motor distribution between drive and mechanisms as well as motor load and several other factors play into this but i am just trying to get a general sense here. I feel like the weight you save wold be quite a bit and easily worth the weight savings even if you could only run the robot for one match before recharging.
What has been your experience with the 2000mAh NiMH batteries? (please be sure to give information regarding your motor usage and whether or not you used a power expander)
Right now we have been running a 2-wheel drive robot, using 4 393’s on the drive and 4 other standard motors for other things. (No exact details, sorry.) We have yet to add the power expander, and we are probably going to swap at least 2 of the 393’s on the drive to 269’s, possibly all 4, once we get the 269’s, that is…
So pretty much, the 393’s haven’t caused a problem at all, and we haven’t had a single time out ever, and so I guess teams experiencing those problems were putting way too much of a load on them.
Also we haven’t been able to try out 269’s as we were unable to purchase them before they went out of stock.
Aaahh, very sorry, I must have read through this a little too quickly. We haven’t gotten to try running our robot on fully charged batteries, and run it for an extended amount of time yet, and also we have not yet purchased any of the 3000 mAh NiMH batteries yet, but I could still do some testing for you, today we are doing a robotics demonstration, so I should be able to try out our robot sometime during the day, and I will try running it and see how long a fully charged 2000 mAh NiMH battery takes to make a noticeable difference in robot performance, and also just how long it take for it to be running so that I wouldn’t want to be running it anymore, and would probably change the battery.
But note, I also am not using the power expander yet, so my values would probably be the minimum or even less than the minimum for the time they last, since you will be running two batteries to run the whole robot instead of one.
We haven’t used any 2000mAh batteries since getting HS motors, but I can tell you our experience on using a single 3000mAh (no power expander) and running 4 HS motrs for drive continuously with 6 3-wires on mechanisms.
During a 2hr robot demonstration, we only had to switch batteries 7-8 times, and on a few of those, we were just doing it to make sure our robot wouldn’t stop moving during a bad time.
Concluding, I think if you used a 3000mAh, you wouldn’t need a power expander, which could be just as light, if not more, than using 2 2000mAh’s.
So it turned out, without a power expander, running non-stop for 7 minutes the battery held up fine, after that batteries in the remote failed and screwed up timing, and we weren’t able to test much after that, so I’m sorry, but I hope to be able to do more testing in the next few meetings, and after we get the 269 motors.