Pics of my final 2100Wh Lithium battery project

[Doctorbass]

Hey guys,

There are many month i have been working hard on these battery pack using Makita LXT pack.

I'm now proud to show you a great part of the results!



(pics above show pack 1 and 2 out of 4 total)

Doc

 

[slayer]

wow looks very professional doc ...bravo ! 8)

 

[stew007]

Very nice 8) very well done, thats one serious battery!

 

[1800vtx]

Can you make me one?

 

[Ben]

Did those all come out of packs from the Makita service centre?

 

[knoxie]

nice work doc!!

Knoxie

 

[Doctorbass]

Thanks guys!


And.. finally... the last one!!! Finished!



Now i really think i can't put more power to my ebike! But..... ... you know me! 8)

Doc

 

[Microbatman]

Nice work

Is that G10FR4 fiberglass you are using?

Where did you get it?

 

[Doctorbass]

Nice work

Is that G10FR4 fiberglass you are using?

Where did you get it?

I got these fiberglass from our local PCB manufactur here un quebec. These are rejected large PCB plate and they have been etched. I used flexible PCB of 0.009" in sandwitch between each of the parallel group to insulate i case of colision or friction with vibration while riding.. then i used 0.060" rigid (etched also) to protect the exterior envelop. Adter that i used duck take to seal all the battery and then heat shrink tube for best looking!

 

[29a]

Doc. wouah très gentil quelle est votre gamme réaliste prévue avec ces paquets ?

http://babelfish.yahoo.com/translate_txt

 

[Doctorbass]

Ah haaa. thanks for trying french

The real energy availlable from each of these pack is 520Wh at 25A continuous rate 100A peak 5% time

that can be translated into 23Ah at 22.2V nominal.

I tested each pack seperatly and they are very balanced forom each others.. so that confirm that the cells matching job i did is accurate :wink:

Doc

 

[Puppyjump]

In your pic, 6th from the bottom I worry about the kapton tape wrapped wires shown crossing each other. I don't know if kapton is durable enough to withstand vibrations and cold flow over time, especially with the added pressure of the final duct tape wrap. I would consider placing small sheets of thicker plastic at the places where the wires cross in addition to the kapton.

Remember it was failed kapton that brought down flight 800 when abraided kapton insulation allowed a spark in the plane's center fuel tank.

 

[Doctorbass]

In your pic, 6th from the bottom I worry about the kapton tape wrapped wires shown crossing each other. I don't know if kapton is durable enough to withstand vibrations and cold flow over time, especially with the added pressure of the final duct tape wrap. I would consider placing small sheets of thicker plastic at the places where the wires cross in addition to the kapton.

Remember it was failed kapton that brought down flight 800 when abraided kapton insulation allowed a spark in the plane's center fuel tank.

No prob.. :?

-My bike dont actually fly

-I have no gas tank

It felf on the concret ground dozens of time and the battery hit directly the ground withiot any throuble.. all Ah are still on

Dont forget that i use fiberglass then shrink.. then foam.. then shrink...

The kapton i use is aerospace grade and is thick too.

But thank for the warn

Doc

 

[efreak]

Man a work of art indeed

great job and thanks for such details and neatness

i could very well be battery pack making 101 .. sticki-fied and copied to basic battery and then some

must read for any one planning on making pack themselves

 

[tartosuc]

cool

maintenant ca prend des phots du pack sur ton vélo!

est-ce toute des batteries récupérées?

 

[Doctorbass]

cool

maintenant ca prend des phots du pack sur ton vélo!

est-ce toute des batteries récupérées?

Oui, ce sont toutes des cell récupérée!

Pour les photos ca viendra.. ce sera aussi des video.. mais pour l'instant personne pour me filmer durant que je suis dessus.. il me faut un cameraman!!

 

[Mathurin]

Meh, that can be arranged...

I got a laptop, so just to plug in that usb camera you have and it should be able to get good frame rates? The batteries are dead but I got an inverter and 2 X 18ah lead slabs, so filming could be done someplace nice.

 

[VRdublove]

Doc,

What made you decide against spotwelding these up with your homemade spotwelder? Mine's about finished, is there anything wrong with spotwelding these?

Also, out of curiousity, what is your final weight for these packs? Lbs/wh?

 

[Doctorbass]

Doc,

What made you decide against spotwelding these up with your homemade spotwelder? Mine's about finished, is there anything wrong with spotwelding these?

Also, out of curiousity, what is your final weight for these packs? Lbs/wh?

Nothing wrong about spotwelding them.

I decided to solder cause for large current i had difficulty to spotweld the 0.020" cooper strip and i anbandoned that. My spotwelder capacitor need to be replaced.. it is a mediem ESR..

My 4 packs weight 4.7kg each and have 520Wh each =110Wh/kg that join the theory of their spec.

AND... STILL STAY BALANCED !

Doc

 

[karma]

doc im working with the same cells, i was wondering what gauge wire did you use to bridge the cells?.

thanks.

 

[Doctorbass]

doc im working with the same cells, i was wondering what gauge wire did you use to bridge the cells?.

thanks.

I would recommand to use at least 12 AWG.. the goad is to find the tradeoff between large wire size that need more heat to solder and less heat transfer on the cell when soldering it. if possible 10 AWG.. but it depend o the max current you would like to draw on the controller...

First, put some stain on the cell pair bridge.. then put some on the cooper wire then join them together. by this way the time that the solder iron is on the tab is shortened.. see what i sent to John in CR about that:

The heat transfered from the solder iron, strip, spot weld and then to the cell tab is low and this path is enough long to dissipate the heat. I mean the trick is to put some solder on the middle of the strip, then on the conductor you want to solder on it and then to heat them together.. by this way, the time you apply the solder iron on the strip is shortened.

Make sure that every cell tab contact are secure and that you have minimal resistance cause that could make dsammage to the cell if that contact heat up due to high current and high resistance contact loss..


Doc

 

[karma]

thanks :wink: