Chaos upgrade - 72v 20ah LiMn

Ypedal said:
After posting that picture, i realized my tape job sucked... :shock: I had to remove it and redo it with paralell lines... i'm such a prick somedays.. Don't they have pills for this behavior ?
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You've already got the "prick pills" -- you just need to start riding that new lithium pack and all self-concern over your behavior will evaporate like the glaciers.

http://www.rxlist.com/cgi/generic/lithium_ids.htm
rxlist.com said:
Lithium carbonate is indicated in the treatment of manic episodes of manic-depressive illness. Maintenance therapy prevents or diminishes the intensity of subsequent episodes in those manic-depressive patients with a history of mania.

Typical symptoms of mania include pressure of speech, motor hyperactivity, reduced need for sleep, flight of ideas, grandiosity, elation, p.o. judgment, aggressiveness, and possibly hostility. When given to a patient experiencing a manic episode, lithium carbonate may produce a normalization of symptomatology within 1 to 3 weeks.
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Bottom glued in !

I had an old tube that i tested, it kept going rubbery but not hard plastic type.. so this tube tested much better.. no going back.. I'm going to let the bottom sit and cure then do the top..

Once the bottom and top are done, the end pieces will be re-inforced with extra layers for support, then capped in metal.
 

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Alright.. update:

Box 1 all glued up except the end caps.. looking good so far

Box 2 was not quite right, it was slightly taller and too wide to hug the pack tightly.. :x


A long time ago, i had the idea that scroll sawing would be a cool hobby, so i have a dremel scroll saw station, and a mastercraft bench top Belt/Disk sander combo machine.. !!!!!


The belt sander works AWSOME at shaving polycarb into perfect shape !!!

Sanding edges, and glueing box 2 tonight before bed..
 
Wow, nice work!

What sexy packs you have, you must work out!

Would your batteries like to meet me sometime for a little pick-me-up? Maybe a little hot lithium-on-manganese action?
:D
 
xyster said:
Wow, nice work!

What sexy packs you have, you must work out!

Would your batteries like to meet me sometime for a little pick-me-up? Maybe a little hot lithium-on-manganese action?
:D
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Is that with or without duct tape?
 
Nice bending job. How did you bend the sheets?

My experience is that polycarbonate starts to bubble and burn at about 2 degrees higher than the temperature it takes to make it soft. It's extrememly difficult to maintain an even temperature across the entire length of the bend unless you have a really fancy plastic bender.
 
Can't polycarbonate be cold-formed? Wouldn't just a little heat make cold-forming easier without risking bubbles?
 
Hehe.. you can cold form 1/8" stuff.. but FORGET bending 3/8 unless you took your morning steroids... if you had access to a very large industrial press break. mabe.. but i don't got that.

Process used :

-Mark your line where you want the bend to be, then mark another line 1/2 inch away, above or below, depends on the bench vice you have.. .

-Put both pieces of angle iron into a HEAVY AND SECURE bench vice, I used 2 large 3" x 3" angle iron segments with the flats facing eachother to support the sheet all along the edge...

-clamp that sucker with all your might, you want the line taht's a half inch away from your bend to be flush with the metal edges of the angle iron.

- using a 1500w heat gun with a round tip, heat up the sheet at the edge, keep moving or you get bubbles as fechter mentioned.. heat up both sides of the sheet until you can notice the sheet softening up, it will not go soft.. but just " softer " .. then grab the sheet ( 4 hands are helpful here ) and HEAVE-HO... hold it in place while it cools for a few minutes and it keeps it's shape !


Yes, i did bubble the edge in one spot, but Shhhht... it's under the pack over the rear wheel.. no one will know.... :)
 
Ypedal said:
Hehe.. you can cold form 1/8" stuff.. but FORGET bending 3/8 unless you took your morning steroids... if you had access to a very large industrial press break. mabe.. but i don't got that.

... :)
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What's the thinnest sheet you think would work well for a fairing, or body panels?
 
1/8" should be fine for fairing, i have both on hand, and used the thick stuff for the packs as the glue edge was wider and the packs are heavy...

It will scratch easily, and will not remain clear for very long with my usage.. but they sure look good at the moment !! :lol:

I figure if and when they start to look ratty.. i'll paint them up.
 
Ypedal said:
1/8" should be fine for fairing, i have both on hand, and used the thick stuff for the packs as the glue edge was wider and the packs are heavy...
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But since even 1/8" is difficult to form, and sounds very strong, would 1/16" work for a fairing just about as well? The thinner stuff is cheaper too....
 
Got distracted by visitors tonight, but still managed to get one end cap done...

I was going to go with metal end caps, but after some thought, i'm going with a dual layer of poly, one recessed and one over the edge. both glued together.

I remeasured the thickness.. and i got it wrong.. it's not 3/8".. it's 1/4" thick... Still plenty strong.
 
is that the same as perspex?

we did some more ghetto forming when i was younger with perspex - looks to be the same thickness.

The way we did it was to only cut off a bit of the paper at the point of the join, and leave it next to a bar radiator (kind of heater for heating rooms). As it heated in a long line, it allowed you to heat an entire bend line at one time. This meant you weren't worrying about it bubbling in just one spot. What we then did was to wait until it started to really melt. Because the heat was radiated it seemed to not bubble as easily.

I was going to make metal packs for my batteries - i think I'll make polycarbonate/perspex ones now! :)

I'm possibly getting LiFe Packs that have no protection (ie the cells have no covering, and will be shrink wrapping them into one large box to protect it.
 
Are you going to give them some ventilation?

I'd be worried about the strength of the corner joints where the halves of the box are glued. On the other hand, I've never tried polycarb solvent glue.

If they come apart, you could reinforce the edges with some aluminum angle. You could drill and tap into the plastic and use a bunch of short screws (or sheet metal screws).
 
fechter said:
Are you going to give them some ventilation?

I'd be worried about the strength of the corner joints where the halves of the box are glued. On the other hand, I've never tried polycarb solvent glue.

If they come apart, you could reinforce the edges with some aluminum angle. You could drill and tap into the plastic and use a bunch of short screws (or sheet metal screws).
Click to expand...

VERY good idea!: something like this would GREAT!!!1!

productLarge_1244.jpg


I'm very impressed either way! ventilation would be a very good idea! completely agree Fetcher
 
I just got a call from my neighbor, he got his hands on the real deal adhesive for the polycarb.. i'm told with the special stuff it WILL NOT come apart.. ever... lol..

Bigh - What was the picture's source ? those look cool !

Venting.. i considered this, the Li packs do not get hot during use ( so far ) and i considereed the Venting vs Weatherproof situation..

To vent or not to vent.. that is the question.. :?
 
Properly spec'd lithium cells of all types don't appear to benefit from venting, or cooling, as they don't get but a few degrees warmer than ambient temperature. This may not be the case for small packs of LiFePO4 or LiMn run at high current, like in RC vehicles.

This temperature chart for LiMn emoli's is from a pdf I found online.
According to the chart, the temperature at a 4C discharge (for instance a 10ah pack run continuously at 40 amps) will rise about 20F (11 celsius) over ambient temperature. We know voltage will sag more, but I wonder if the operating temperature wouldn't be higher for LiMn packs of with a lower C rating -- suppose it should since increased resistance increases heat.
 
Ypedal said:
I just got a call from my neighbor, he got his hands on the real deal adhesive for the polycarb.. i'm told with the special stuff it WILL NOT come apart.. ever... lol..

Bigh - What was the picture's source ? those look cool !

Venting.. i considered this, the Li packs do not get hot during use ( so far ) and i considereed the Venting vs Weatherproof situation..

To vent or not to vent.. that is the question.. :?
Click to expand...

They're from an electronics shop in australia called Jaycar electronics.

you should be able to get them at ur equivalent shop oveer there - like radioshack or whatever its called.

I'm pretty sure i'm going to be doing a very similar thing with my battery packs!


http://www.jaycar.com.au/productVie...d2=&pageNumber=&priceMin=&priceMax=&SUBCATID= here!
 
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