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Old 03-25-2012, 02:52 AM
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Neight Neight is offline
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Join Date: Apr 2011
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Originally Posted by bitbox View Post

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....
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.


Hello and welcome to the forum!
You might try to run your motor with the bad battery you have already. worst thing that happens is the motor starts right up and you have to recharge the good batteries for a bit. also, if the bad battery is on the edge, this might fix it pretty well instantly, which happened to me once already.

It sounds like you and your friend are on the right track, you just need to find the right battery for B3. You can also make your own B3 with just a couple of bucks and a trip to the store. I made one out of a couple of copper plates and a couple of aluminum plates and some alum mixed in water. It works great, and because it's small, even if it does get charged, it will never hold more than a volt or two on it's own.

There is a 9-18V motor that you can buy at radio shack, which is the same motor I started with. it's pretty small, but it works well enough to see the same results.

You can always make your own motor too. I took apart a hard drive and kept the motor out of it. I taped some magnets to the top and used a reed switch rather than commutators, and it worked to my surprise.
This is honestly one of the most flexible systems I have ever worked with. most of the variables I have tried have produced decent results.

It works with AA batteries as well. I had a couple of alkaline AA's for my good bats, and used a NiCd rechargeable as B3. when I started, the NiCd was reading 0V, which is clearly a dead battery. using the HD motor and the reed switch, That battery fixed itself, and is now holding 1.2V and will run a small 3V DC motor slowly.

If you have an old printer laying around, take it apart, there are usually at least 3 motors in the ones I have scrapped, and they also work well in this system. The most important things to know, you already seem to have right, from there, don't be afraid to experiment around a bit. You never know what you will find, and as I said above, the worst thing that can happen is you have to recharge your batteries a bit for the next attempt (or blow out a motor, which also isn't the end of the world, they will make more )

glad to see you are on board, and hope you can find what you are looking for to make this work. It's pretty amazing to see running, and once you get it in the zone, the results get even better!

The absence of proof is not proof of absence
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