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Author Topic: electric motor test question....  (Read 931 times)

Offline jim gilmore

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electric motor test question....
« on: October 20, 2011, 09:31:50 AM »
I have been hesitant to purchase stuff because I'm a little concerned about battery charging here at my mom's apt.
But I was thinking the other night(always a dangerous thing to do) That I my not really need to use lipo's.
Since I'm looking to try out some motors and a simple esc and timer. Maybe it could be just run with a standard pack of AA's that get recharged in a wall socket ?
hat do you think ?
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Offline Tim Wescott

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Re: electric motor test question....
« Reply #1 on: October 20, 2011, 10:18:28 AM »
A lipo charging sack and a windowsill should be enough.  Or go to Goodwill and get a crock pot or other pottery container with a lid to put the batteries in, put it on the stove with the fan running. 

I've never, ever, had a lipo burst into flame, so as long as the thing is vented to the outside in case bad things did happen then you should be OK.

Barring that -- I'd see if there's still NiCd packs available (I think the car guys are still changing over).

ESC's have "low battery" shut down, so you'd need to use one that can understand that it's connected to a NiCd pack and not LiPo.
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Offline Crist Rigotti

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Re: electric motor test question....
« Reply #2 on: October 20, 2011, 10:38:02 AM »
You could also look into A123 cells.  They are used in portable drills.  You wouldn't hesitate charging one of those would you?
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Offline Tim Wescott

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Re: electric motor test question....
« Reply #3 on: October 20, 2011, 10:59:10 AM »
Quote from: Crist Rigotti on October 20, 2011, 10:38:02 AM
You could also look into A123 cells.  They are used in portable drills.  You wouldn't hesitate charging one of those would you?
Consumer equipment battery packs with LiPo (or LiFePO4 cells) in them come with protection circuitry built in, to prevent the sort of abuse that leads to them bursting into flame later.

Model aviation battery packs are generally just a bunch of cells in series, with only whatever thermal cutouts, overvoltage cutouts, undervoltage cutouts, etc., that might come built in to the cells themselves.

Which really means two things: one, if you don't think about what you do with your LiPos, then you're safer with that A123 drill pack; two, if you do take reasonable care of your packs, you're safe.
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Online Dennis Toth

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Re: electric motor test question....
« Reply #4 on: October 20, 2011, 04:46:41 PM »
Jim,
When I first started in electric I was very nervous about the Lipo's and did the A123 pack which at the time you could get fully assembled. That suppler stopped selling the, there is one supplier for them but you need to do a search under "A123". However, you will still need a good charger and this is very important. SPEND your MONEY on the CHARGER! That is the way to keep things safe. The reason they had trouble with the Lipo's in the beginning was they overcharged like it was a Nicad - you can't do that to the Lipo's. A good charger is intelligent and controls the charge process. One thing though you can't just plug them in and let it charge over night. You have to charge when you can disconnect once charged. Do this and you will not have any problems with whatever battery pack you choose.

Best,             DennisT
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Offline Fred Cronenwett

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Re: electric motor test question....
« Reply #5 on: October 24, 2011, 07:43:07 PM »
check out this web site for safety tips regarding charging lipo batteries, some of the videos should scare you, it scared me. But I also learned what I should do correctly so that I don't end up with a problem.

http://www.rchelisite.com/lipo_battery_charging_and_safety_guide.php

What I found interesting is that when the Lipo went bad it did two things, created toxic gas and caused one heck of a fire. I would follow what they suggest on the web site and you will probably be ok. They have several items that we should never do when charging a battery. Read the article and then watch the videos.

Good luck,
Fred C.
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Offline Andrew Borgogna

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Re: electric motor test question....
« Reply #6 on: October 25, 2011, 11:41:51 AM »
Fred
Thanks for the link, it contains some very interesting information.  One thing I noticed is the statement not to store the batteries below 0C or above 50C. 0C is 32 degrees F I keep my fridge at 36F and I was told to store my batteries in the fridge.  The implication of the safety notes is just store the batteries at normal temps say 50 to 80 degrees F.  Am I wrong here?
Andy
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