La Crucero Rubia de la Playa

[pwbset]

I got my Steveo™ brand controller in today! Whoot! This gives me enough basic spare parts to begin construction of my 2nd ebike project for my girlfriend that I'm going to name La Crucero Rubia de la Playa (The Blonde Beach Cruiser)... the aptly named sister to my own ebike El Escalador de Montaña Rojo (The Red Mountain Climber... and no, I don't know any Spanish at all... Babelfish mangles it I'm sure).

The battery pack I'm building for this eventually will be 51.8v nominal (58.8v hot) 6ah konion pack so Steve put 63v caps and 75v fets (I think.. PNF75NF??) so that should not be a problem. Also a CA connector, LVC and Speed pots etc. Nice work Steve... can't wait to try it.





The donor bike is just a generic, no-name off white beach cruiser (I have a matching one in black). We ride these all summer long. I tried to convince her to let me do a mountain bike build, but she said no... the cruiser is her baby. *shrug* The cruiser has steel drops, but there isn't much metal there so dual torque arms will be installed. There are also very crappy brakes so I'm going to do a rear plug brake and try to get some front V-brakes on there at the very least.



I'll be resurrecting my rear 4011 for this project so that should provide plenty of power for the hills around here, but probably max out around 32kph at 51.8v so won't be too fast. Steveo's controller has a 47amp shunt so this setup should peak over 1,500watts pretty easily even with the anticipated sag at only 6ah, which is plenty of power for her and she only needs about 8km range daily.



And... there is nooooooo hurry to get this project done. :wink: :|



I've been itching to get another build going! Now all I need are a couple 100 konions for my ebike and hers and we're all set for next summer.

 

[pwbset]

Got in the VT cells from Marty for the girlfriend's ebike cruiser. She only needs to go a couple miles max so the VT pack is going to be 14s3p/42 VT cells and about 155wh nominal, which is plenty for a couple miles with the 4011. The VTs will handle the higher C rate better than the Vs so she can crank it with the 4011 on the hills and still be okay. Top speed with 51.8v nominal/sagged will be about 28-30kph with the 4011. Good enough for boating around town for sure.

Slow going opening the packs, but with 5 packs left to open (20 more potential good cells) I've got:

4v+ - 4
3v+ - 22
2v+ - 8
<2v - 3
0v - 5
<0v - 1

At 26 very good cells already, but the very high 2v cells I think will revive. I need 42 cells total so it could be close! :? Interesting to note that a couple packs must have had their boards fry or something as all 5 cells were at 3.5v+ and I saw 1 cell at -.42v so it had reversed... neat. I'm finding some packs incredibly hard to remove the cells from the black foam/rubber backing without tearing the green coating. At least 3 packs had tons of sand in them... amazing. Makes me wonder where they come from etc. Fun.

 

[pwbset]

Some of these packs are bugger hard to get the cells off the backing... will have to shave them down with an exacto or something. You'd think battery companies could invent a cell can sidewall that isn't conductive. That green stuff is just way too fragile. I spark these things all the time when trying to peel off the tab welds... despite my very best efforts I assure you. :|

 

[marty]

X
Slow going opening the packs, but with 5 packs left to open (20 more potential good cells) I've got:
X
I'm finding some packs incredibly hard to remove the cells from the black foam/rubber backing without tearing the green coating. X
X

To remove cells from plastic shell. Try my hammer idea. One gentle smack is all you need.
Jaws of clamp are 4 inches apart. 2 pieces of wood nailed to floor would work just as well.

Ypedal say my hammer idea is bad. I think he is wrong. Go here to read.
Battery pack construction using the Makita cells (Pics)

 

[pwbset]

I should have been more specific... it's only slow going because I just don't have much time to work on the packs right now is all. I can get a pack torn down to raw cells in less than a minute though so that part is easy. A small flathead screwdriver will pry out the cell pack easily without damaging them and then you just "roll off" the tab weld stuff with needle nose pliers. Having said that I'm not really opposed to hammering on things if it's fun or necessary. :wink:

What I really need now is some sort of clamp/spring charger for these little single cells to connect them to my banana plug LiMn chargers... once torn down there is nothing left to crimp onto to charge. :lol:

 

[pwbset]

What I really need now is some sort of clamp/spring charger for these little single cells to connect them to my banana plug LiMn chargers

Problem solved. I scrounged around and thought... wait a sec... these Makita packs are perfect for creating a single cell charger holder-type thinghy.

Bits and baubles.


Dremel some screws.


Add some spring parts and screw it all together.
View attachment 2

And bam... a single cell charger setup for two cells at a time.


And say what you want about LiFePO4 and how cool it is, but it sure is fun to scrounge around for old Li chargers like this one from a heated vest of all things. A 2p LiMn charger... perfect! If i resurrect my old Sony camcorder 4.2v charger also I'll be able to charge 5 cells at once now drastically cutting down my testing time.

Next project will be to use that casing with some sort of ghetto load to measure cell capacities. Since I gave Steveo my CBA II I'll have to come up with something else that's "relative". I don't really care so much about amp/hrs as how the cells compare to each other. I'll want to design something that pulls about 5 amps and cuts off at 3v. Hmmm.

 

[marty]

What I really need now is some sort of clamp/spring charger for these little single cells to connect them to my banana plug LiMn chargers

Problem solved. I scrounged around and thought... wait a sec... these Makita packs are perfect for creating a single cell charger holder-type thinghy.

Bits and baubles.
View attachment 4

Dremel some screws.
View attachment 3

Add some spring parts and screw it all together.
View attachment 2

And bam... a single cell charger setup for two cells at a time.
View attachment 1

And say what you want about LiFePO4 and how cool it is, but it sure is fun to scrounge around for old Li chargers like this one from a heated vest of all things. A 2p LiMn charger... perfect! If i resurrect my old Sony camcorder 4.2v charger also I'll be able to charge 5 cells at once now drastically cutting down my testing time.

Next project will be to use that casing with some sort of ghetto load to measure cell capacities. Since I gave Steveo my CBA II I'll have to come up with something else that's "relative". I don't really care so much about amp/hrs as how the cells compare to each other. I'll want to design something that pulls about 5 amps and cuts off at 3v. Hmmm.

Like that battery holder. Look like you just using friction to hold batteries against screws? If you would like plastic case to be a little wider to allow some space for a spring? You could use a heat gun to bend plastic shell and make it a little wider. Heat plastic and bend how you want. Wear gloves.

These things might also work for contacts?

Grounding Clips. For sale everywhere.

 

[pwbset]

Look like you just using friction to hold batteries against screws?

Hard to see, but there are a couple turns of spring in there, but yeah.. it's pretty tight fit. Thanks for the idea to heat the plastic! That'll work great.

I had a couple cells last night that have been sitting at around 1.2v. They fully charged to 4.19v, but I'll be curious to see how their capacity is effected. I'm focusing on the runt cells first so they don't have to sit low any longer than needed. I still need to find a 5a discharge method to 3v for capacity measuring. Was thinking of an old toaster or something, but I'll have to measure load first. It's fun trying to think of things to recycle around the house for these projects. Necessity is the mother of all invention after all. :wink:

 

[pwbset]

4v+ - 4
3v+ - 22
2v+ - 8
<2v - 3
0v - 5
<0v - 1

Got all 12 packs opened (60 VT cells + 8 I had from another ES member awhile ago). Final count is:

4v+ - 4
3v+ - 26
2v+ - 13
<2v - 14
0v - 10
<0v - 1

10 of the 2v+ cells are better than 2.5v so I think they will recover okay. So... that gives me 40 "good" cells. I needed 42 for 14s3p so I didn't quite make it. :?

A bit disappointing overall, but I certainly can't complain because the price was so cheap! Thanks again for your generosity Marty! Clearly we're learning your mileage may vary with these packs your getting. Two of the packs had rust and "green" corrosion on the cell tops... maybe salt damage from a marine environment? Thought Lake Erie was fresh water. :wink:

Anyhow... maybe I'll just do a 10s4p pack instead as I already have a 37v LiPo charger, but it'll be slow on the 4011... like 22kph tops. Maybe that'll still be okay for my better half.

 

[marty]

Battery Charger for 18650 Rechargeable Li-ion Batteries
$9.99

Smart charger can charge for 18650 Li-ion batteries, two at a time;
The AC adapter easily folds out to charge and pack away;
Suitable for 18650 Li-ion for 2pcs batteries;
Model: 18650
Input: AC 100-240V 50/60Hz 8w
Output: DC 4.2V
Measurement: ~8.4 x 4.6 x 3.3 cm(L*W*H)
Weight: 72g
http://www.sourcingmap.com/battery-charger-for-18650-rechargeable-liion-batteries-p-11250.html
I know nothing about this.

 

[pwbset]

Battery Charger for 18650 Rechargeable Li-ion Batteries
$9.99

:lol: Well... I think I'm turning into such a DIY tinkerer that it didn't even occur to me to search for an 18650 cell holder... of course there is one. Doh!

Thanks Marty.