E-Trike Project

[Storx]

Well i think i pretty much made up my mind, i am probably going to order the Mac Geared Hub motor w/ 10t setup in a 48v x 26" wheel configuration.. I need to figure if i should upgrade controllers or not.. but i did pick up some laptop batteries yesterday and today i broke them apart, i have checked them over with multimeter.. all were above 3.0v except 3, so untill i test capacity of them to figure out if any are weaklings, i have around 78 cells already for my pack build.. I also ordered tonight an Imax B6 Mini Pro V2 w/ 108watt power supply off amazon for $44... i did a lot of shopping around and it was the cheapest i could find on any Genuine Imax... This one is coming form SkyRC themselves, so i expect it to be the real one, plus after reading about the different models i learned the mini pro can be connected to the PC and Phone through wifi and android app and see the actual graph of the discharge current from the cells and the new mini v2 is suppose to have the 0.1 more accurate resistor mod on the balance circuit that is commonly modded on the other models straight from the factory...

I plan to check out a few more stores to try and double my cell count, so i can have more cells to choose from on building the pack..Here is what i got today from the batteries...

 

[Jonathan in Hiram]

The B6 is going to be ~very~ slow discharging your cells, they do discharge but it is limited to just five watts total. If you have five cells in series for about 20V then you can discharge at 5w/20v or 0.25A which will take roughly ten hours to discharge the 5 cell pack. An 18650 cell holds 7-10 wh usually so count on two hours discharge time more or less per cell.

I ran into this myself, bought a IMax B8 thinking to use it to match cells and found out quickly it can do the job but so slowly it's very annoying.

A Cellog 8s, a wattmeter, a switch and some 12V automotive lamps will make you a much faster discharger for testing batteries.

One other point about a slow discharge, it's hard to find the cells that have a high internal resistance that way and those are the ones you want to weed out of your pack. You really want about a 1C discharge rate on old laptop cells for testing purposes, you'll likely find a number of them that get hot and have a higher voltage drop, they are unsuitable for your purposes.

 

[Storx]

The B6 is going to be ~very~ slow discharging your cells, they do discharge but it is limited to just five watts total. If you have five cells in series for about 20V then you can discharge at 5w/20v or 0.25A which will take roughly ten hours to discharge the 5 cell pack. An 18650 cell holds 7-10 wh usually so count on two hours discharge time more or less per cell.

I ran into this myself, bought a IMax B8 thinking to use it to match cells and found out quickly it can do the job but so slowly it's very annoying.

A Cellog 8s, a wattmeter, a switch and some 12V automotive lamps will make you a much faster discharger for testing batteries.

One other point about a slow discharge, it's hard to find the cells that have a high internal resistance that way and those are the ones you want to weed out of your pack. You really want about a 1C discharge rate on old laptop cells for testing purposes, you'll likely find a number of them that get hot and have a higher voltage drop, they are unsuitable for your purposes.

Actually, i thought about this... i bought the new gen 2 Imax B6 mini, it is a higher 60w/6a unit and its discharge capacity is up to 2amps over the original unit.. and from what i understand after my reading is if you hook 6 batteries up to it through the balance port, in the computer software you can set it to discharge each cell in the 6s configuration.. so you set it to do 6 and let it be while you do other stuff in the room....

Also, the mini model has the 25 second internal resistance tester feature the older ones dont have also, should i check them all through this process first before looking at capacity?

 

[Jonathan in Hiram]

The B6 is going to be ~very~ slow discharging your cells, they do discharge but it is limited to just five watts total. If you have five cells in series for about 20V then you can discharge at 5w/20v or 0.25A which will take roughly ten hours to discharge the 5 cell pack. An 18650 cell holds 7-10 wh usually so count on two hours discharge time more or less per cell.

I ran into this myself, bought a IMax B8 thinking to use it to match cells and found out quickly it can do the job but so slowly it's very annoying.

A Cellog 8s, a wattmeter, a switch and some 12V automotive lamps will make you a much faster discharger for testing batteries.

One other point about a slow discharge, it's hard to find the cells that have a high internal resistance that way and those are the ones you want to weed out of your pack. You really want about a 1C discharge rate on old laptop cells for testing purposes, you'll likely find a number of them that get hot and have a higher voltage drop, they are unsuitable for your purposes.

Actually, i thought about this... i bought the new gen 2 Imax B6 mini, it is a higher 60w/6a unit and its discharge capacity is up to 2amps over the original unit.. and from what i understand after my reading is if you hook 6 batteries up to it through the balance port, in the computer software you can set it to discharge each cell in the 6s configuration.. so you set it to do 6 and let it be while you do other stuff in the room....

Also, the mini model has the 25 second internal resistance tester feature the older ones dont have also, should i check them all through this process first before looking at capacity?

I sit corrected..

Yeah, high resistance cells and cells that leak down significantly should be eliminated before you start capacity matching if you want to save time.. Good to know about the new charger, that's quite a useful upgrade to the old capability.

Charge them all up and let them sit a week, longer is better shorter worse, get rid of any that drop voltage significantly in that time then test the internal resistance of the rest. Getting rid of leakers will save you a lot of trouble with the pack later, questionable cells aren't worth the effort they can entail in troubleshooting. I had the best success not worrying about brand or number but putting together matched capacity banks strictly by measurement, put low cap cells with high ones and low resistance ones with high ones to get all your parallel strings as near matched as possible. Remember to use Ohms law to parallel resistances when matching. 1/Rt = 1/R1 + 1/R2 + 1/R3 +... A little spreadsheet can make it a lot easier to match up the cells, then all you have to do is move them around in the spreadsheet and recalculate til you find something near optimum.

 

[Storx]

So today i scored more cells for my battery build, decided to try dropping in at this mom and pop computer repair shop to see if they had any by any chance and they did, they gave me all they had.. told me it was like 3 years worth of collection lol.. only 11 batteries...This set of batteries doesnt seem to be as healthy via multimeter compared to the other batch, all the red unmarked cells were around 1.9-2.1v, and 4 random cells were at 2.95-2.99v.. so i have a lot of thoughts that the red cells may all be bad...

 

[John in CR]

Why do none of your cells have tabs left on them? Proven factory battery connections are a mistake to give up, because it greatly increases the work as well as pack failure risk.

 

[dogman dan]

Same stuff in like three different threads now.

 

[Storx]

A change of plans happened this morning, another forum member sent me a private message that i was making a mistake buying the imax b6 product if i was only ever planning on using it to test capacity on the 18650, so he linked me a product that can discharge test 4x18650 cells all at the same time at the same 5w discharge rate, so i called amazon and cancelled my order since it had not been shipped by the third party yet.. and placed an order on 2 of them for a total of $64 vs the $44 for the imax and power supply.. The product is called the Foxnovo F-4S, its manufactured by a well known cell phone charger company... so i made the change, this will allow me to charge and discharge up to 8 cells at once instead of the 1 with the imax, this will greatly speed things up during the weeding process, also it allows micro charging cells that are below 2.8v that apparently people have been informing me that the imax b6 with the newer firmwares refuses to charge..

 

[Storx]

Same stuff in like three different threads now.

ya, some of it has kinda bleeded to other post, but those post were more designed to answer a specific question, i think i have most of the answers i have been looking for, for now.. the only thing i am still debating on is spot welding over soldering, many have soldered without any adverse effects.. but spot welding is highly prefered, but i dont know if i could spot weld the lead of the fuse to the battery without it blowing the fuse... i just feel like a cell fuse is very important.. but many sport weld their batteries together and not care about fusing the individual cells..

Do i really not need a fuse and just skip to spot welding them?

A few have mentioned that i could build an easy spot welder with just a 12v lead acid battery and some copper wire attached to a stick with proper spacing..

Another idea kinda floating in my head that would vastly increase the amount of work i think is instead of using soldering or welding, maybe do both to kinda keep the cell fuse idea??
I would prepare the tab/fuse combo by soldering the fuse to the tabs before spot welding them to the battery...

 

[leo99]

Hi storx, just in case for you to know paul from em3ev is putting a new version of the mac at the beginning of march so you might want to wait to buy it. it supposed to heat up less fast. well i am waiting for it

 

[Storx]

Hi storx, just in case for you to know paul from em3ev is putting a new version of the mac at the beginning of march so you might want to wait to buy it. it supposed to heat up less fast. well i am waiting for it

He has the new one already on his site for sale from what he told me... if you look he has a separate page for the older model stating that a more updated kit is available..

 

[Jonathan in Hiram]

If you use 33 or 34 gauge (skinny) copper wire to solder to the individual cells from a bus bar they can act like fuses at around 4-6A per cell. It's also so thin it's really vibration resistant since it bends so easily and allows the cells to move a bit without breaking the connection. I wouldn't worry about welding used cells, go ahead and solder, even that is going to take a while and welding with shade tree equipment is going to be frustrating and slow.

Using a bunch of old mixed cells in a high drain environment is fairly hazardous, the individual fusing really helps in the fire safety department, just like a Tesla pack..

What you don't want is one cell in a parallel group shorting out and then the rest of the dozen or however many parallel cells you have dumping their entire charge through that one cell, it's about a guaranteed fire so you put the fuses on each cell so if any one cell shorts the fuse wire blows and isolates that cell from all the rest.

[youtube]JQa5gn-7D74[/youtube]

 

[Storx]

today i got lucky, i was at the university awaiting for class and remembered last semester that the professor told us she couldnt put our grades in because her laptop wouldnt hold a charge or something.. so she had to get the battery replaced by IT, so today i asked around to find the IT section, went and asked them if they had any old laptop batteries i could possibly take for cell salvaging, turns out they had loads of them in the back, asked me how many i wanted and i told them as many as i could get to increase my odds of getting excellent cells... turns out all of them was way more then i was expecting, the guy brought up on a dolley 3 boxes of them, 81 in total for me to have.... took them home and started to strip the units down... didnt get them all done tonight, but im well over 700+ in cells already... i have well over a 100 of the samsung 22F cells, so i may start testing on them, so if i get some good capacity with them i could have a single battery made from the same model of battery.. since i have so many now, i went ahead and ordered 2 more of the Foxnovo F-4S at the $64, the ebay seller contacted me back and mentioned that he had not shipped out my first 2 yet, but because i was buying 4 in total he was drop the price down for me to $28/unit, so he changed the pricing on the 2nd set to make the entire total for all 4 testers/chargers to $112 shipped... figured it sucks to spend $100 bucks on testers for the cells, but i have a feeling im going to have well over 1000 cells when im done stripping them down and the time to test all of those was worth the price of buying 2 more, so ill be up to testing 16 at a time, so i should be able to do like 50 a day easily, since i home alot for study lately..

These are all the ones i broke down tonight so far..

 

[leo99]

the upgraded version has been out for a while now. I am talking about another version. here is a response of his from this January:

"Hi Leo,
There should be a new version of the standard motor ready quite soon, but I can’t give any precise dates. My estimate is maybe late Feb or March until the standard type is ready. Further developments will come after the standard type is ready and being offered, it is a little early to give a timeline on those versions.

Thanks
Paul"

 

[Storx]

My inbox has been blowing up with questions on how i found so many batteries, i managed to get a lot of my batteries from thrift stores, i went down to my local salvation army because the last time i was down there donating there was a couple of laptops in the bin from people donations and after talking to the store manager, he explained that they are not allowed to resale laptops at all due to the possibility of info being leaked to the public from the previous owner, so they seperate the battery and recycle it along with sending the laptop itself off to a company that harvests exotic metals from them.. So they had a recycle bin with laptop, tool, and cell phone batteries in it.. i pulled out all of the laptop batteries was able to take them home with their approval.. The big score of batteries came from my local university, i talked to the IT department and they had a top of laptop batteries in boxes in the back, some looked brand new as if they were never used.. but they let me have all of the batteries i wanted, so i took them all