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newnhamrs4's picture


I have been think alot about the power consumption of the robots, in particular the rs media. Unsatisfied with paying so much from batteries, i have been trying to find a solution. One of me friends owns a rc model shop, they have a new type of battery. Its called a lithium-polymer, on the thing, it says it puts out 2200 mah fine, i thought nothing more of it. Until, me friend said that i could pull 44 amps out of it with no problems.

So my question is this do you think the robot would pull what it needs like 3 amps 4 amps, until the thing is flat. If it would we would have a 11 hour run time on one li-ploy cell, the charge time would be about 2 hours to. The other bit of good news is this, the li-poly cells run at 7.2 volts/ 9 volts. So im thinking two in the legs, and we have 88 amps and a run time of 22 hours.

The only problem is they are explosive, not like normal batteries

i mean explosive, see the link.

i no it says from over charge, but its the same if you hit them to hard. what do you think.

Nocturnal's picture

Welcome to batteries 101. The amount of current (ie amps) a battery can supply has nothing to do with the ammount of TIME that it can supply that current for.

1mAh, means that the battery can supply 1mA for 1 hour. 2200mAh means the battery can supply 1 amp for 2.2 hours, or 2 amps for 1.1 hours. Assuming 2-4amp (which would be the max loading, when moving multiple joints, not the load of standing still) load, the battery would last 30-60 minutes (approximately).

If the batteries internal resistance is low enough to supply 44amps of steady current, that means it probably has a much lower internal resistance than a throw away (I have no idea the max current a standard battery can supply). In the event of one of the motors stalling, the amount of current flowing through the RS Media will be higher than the designers intended, potentially damaging your RS Media.

If you want lasting power, you might want to have a look at what Robosapien V2 4mem8 did a while back with 12,000mah rechargables.

BTW, at 44amps, the batteries would last 3 minutes.

newnhamrs4's picture

oh well come on me calculations where not that far out lol