Saturday, July 23, 2011

Robot Batteries

When I was playing with 'Jim-Bob', my toy tank-tread robot, I was appalled by how quickly those little gear motors ate AA batteries! I hate throwing AA alkaline batteries in the trash for so many reasons: environmental, financial and personal thrift. The weight of my first robot, 'Little Jimmy' was nearly 50% gel cell battery. The electric car industry faces similar dilemmas of achieving the needed voltage and capacity at the lowest possible weight and volume (bulk) at a cost people can accept. There are a lot of choices in battery chemistry for secondary (rechargeable) cells: lead acid, gel cells,  nickel cadmium, nickel metal hydride, lithium-ion polymer. They do not come without risk: a few years ago the industry had a rash of exploding lithium lap top batteries. Each type of battery chemistry requires a different charging system. (Batteries in the hands of idiots are dangerous!) Every element of robot design and construction requires research, and batteries are no exception. Attached is a matrix of my research on various battery specs. The conclusions I came up with is that for an Ant-Weight (1 lb) robot like 'Jim-Bob', a 6V NiMH battery pack is a good choice. For a Hobby-Class robot like 'Little Jimmy' (10 lbs) a lead acid gel cell is just fine.

Battery Matrix [Link]

My other interests (Kayaking, plant ID, sea beans, etc. ) [Link]

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