Lara's Lego H-015 Sentry Droid

[kresty]

Thank you very much for the detailed information. Your battery is rather expensive, in particular, as compared to lead-acid batteries like this one: http://a.co/j4ocSk1. But it has probably much less weight, and that may be worth it.

Yea, weight was a concern when we chose that battery. (L3-G0 is closer to 30kg than 100kg ) But, like I said, I'm not particularly recommending it. Partially we were lied to about it's Ah rating. (The car/motorcycle battery replacement industry has an "equivalent" rating that they do some math based on the CCA, but somehow end up with crazy numbers. It's about a 6Ah battery IIRC, but they marketed it as an 18Ah battery).

In London, Oliver loaned us a 12V NiMH pack for Lara's mouse and we really liked how that behaved (though we realized part of that was that we didn't run the LEDs on her mouse, so part of the reason we felt it lasted forever is we weren't drawing as much power.) So we have some NiMH batteries that we haven't assembled into a pack yet.

Anyway, from your description it seems more like the motors would be helpful, battery probably doesn't matter so much. The 30:1 gear ratio does make some noise though. And I still need to figure out how to get the omniwheels securely mounted to the motor's D shaft.