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Old 03-25-2012, 02:12 AM
bitbox bitbox is offline
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Join Date: Dec 2011
Posts: 5
A newbie question

Hello,

Reading this thread's 15 pages took me all night but was better than a full season of "Heroes" !

Thanks all of you, because after reading all of this, me and a friend decided to jump in and try assembling the thing. First went for batteries at a batteries discount close to where I live to find out that most batteries available nowadays are "Gel"... Nope I need Acid Lead batteries ! So we had to take two motorcycle batteries (12V 12Ah "Nitro" + 12V 9Ah "ACS").

Our next question to the shop keeper was "do you, by any chance, have some dead lead acid batteries"?
He only had one that we took. This one showed only 2.5 V and the vendor says it can't be recharged (though it doesn't "look" old).

Back to the garage, taking appart my pal's kid's radio-commanded electric truck to extract an electric motor. Putting the 2 good batteries in serie... I measure both batterie's voltage (12.5V & 12.2 V) and go for the good neg to bad neg connection. Done !

I decided to now measure the potential between the "bad pos" and "good pos". Thinking that it shouldn't be too high or even zero if it was a "good bad" battery. (am I correct in my understanding here?)

I REMEMBER WELL that finding a "good bad" battery isn't easy, so....
DISAPPOINTED!
I got around 23 V :-(

So here we are... I decided not to go further, as if I got it right, a potential of 23 V would clearly set the motor in motion immediately which indicates the bad candidate is a "bad bad", right ?

We'd appreciate your feedback on this (telling us we got the basics or pointing us back on the track). Although I read that there is no "certified" method for producing a "good bad" bat, but is there "something" we might try to make our "bad bad" closer to a "good bad", maybe some more details about the metal parts addition could help. I'm sorry but I never openend a Lead Acid battery and clearly think that we'd better be carful with that. I noticed there are several "caps" that can apparently be opened on the hopefully bad battery (which is a car battery - no reference cause I left it in my pal's garage sorry), probably one for each cell, but I really don't know...

I must say that, although a little bit disappointed, but not surprised, by the fact that we didn't pick up the Holy Graal, we are both impatient to get back to it. If no other solution exists, I'll even drop by all surrounding car mechanics asking them for their oldest Lead Acid battery.

One last question, regarding the motor. I called a few car parts resellers asking them for "any kind of 12V electric motor"... And it felt like they almost hang the phone laughing !? Didn't get it !
I went to a local electronics store but the last, and only, 12v motor they had was gone (a small one). That's how we found ourselves tearing the kid's truck appart.
I was thinking about going to a radio-controlled models specialist next week, but it's at the whole other side of town and wouldn't want to go there for nuts. I rapidly scanned their website and they seem huge... I'm pretty sure they probably have some kind of 12v (or higher) electric motor that can fit... Is the fact that it has to be permanent magnet and not brushless enough to satisfy the requirements for the assembly ?
Do you have an idea where we possibly could find a motor that would fit if radio-controlled model's motors are all brushless (many seem to be) ?

for sharing all this.

Best,

Thibaut
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