PSI -- LiFePo4 -- Testing.. 1 ... 2... Testing..

ZapPat said:
So Ypedal's nice BMI cells will display voltage sag half as much as the newest headway cells, or about a quarter of my ping battery. Thus, my Ping battery's voltage sag is just over 1V per 10A, or just over 110milli-ohms resistance for a 16-cell pack.

Also, internal resistance changes as the battery discharges, and better quality cells will keep a lower internal resistance for a longer time (ie down to 90-95%), letting you get better power almost right down to the end of discharge.
Click to expand...

Since internal resistance changes as the battery discharges, does the Ping pack begin to trip the LVC at 50% DOD?

If a 48v 10Ah BMI/PSI pack cost the same as a 48v 20Ah Ping pack, which would you buy?
 
I would choose a pack that suited my performance needs. If you need low discharge rate and long range, the ping pack is your best friend. If you want a higher discharge rate, lighter, and lower range pack the BMI is what you want.
 
Hi Gaston,

It just occurred to me that you might be reinventing the wheel to some extent.

PSI makes excellent cells. Their inclusion of the copper bars show that they want to help customers assemble their cells into packs. Their "Lego Blocks" show that they are putting a lot of thought and effort into this. They might supply complete packs. I'm pretty sure they help and support customers who are building their own packs.

You might want to contact Raymond and:
  • 1. Ask him if they have any instructions or generic advice.
    2. Ask him any questions you have as they come up. You could even send him links to some of your posts on this thread or email him the pictures with any questions you have.
    3. Even if you don't have questions show him what you are doing and ask him if he would do anything differently.
BTW as of now there have been 3403 views of this topic and you might want to point that out to him. So it would be good advertising for him to jump in on the thread with help and advice.

You are welcome for the NuVinci. Enjoyed working with you :!:
 
I think I would agree with Mitch, that with the new "Lego" blocks, I'm not sure you need anything more, from a construction point-of-view. I think glueing the cells may be overkill. None of the LiFeBatt/BMI designs ever used anything to lock the cells together, besides the studs.

-- Gary
 
miro13car said:
Ypedal,
what happened to your PSI cells testing, any results, any pack construction details?
MC
Click to expand...

Cells in regular use, holding up very well, currently only using 16 cells but working on my plan for the " Grin Reaper " 2009 bike..

72v 10ah PSI cells = check
4110 fet modded clyte controller with 80amp limit = check
X5303,4,5 = check ( unsure wich i want to use at the moment )

The pack build is still undecided, it's either i order up some Lego blocks from PSI, have some plates CNC'd or i make my own molds.. but since winter has arrived i have time on my hands to figure it out..

Rest assured i will document it all !! :wink:
 
A cheap and easy solution for mounting plates is to use thick polypropylene sheets like I'm doing. It's easy to mill, can be drilled out using standard wood bits on a regular drill press, is lightweight, and relatively cheap. Since it's a softer plastic, it will also help cushion the cells without having to worry about damaging the cells from rubbing.

http://freckleface.com/shopsite_sc/store/html/polypropylenesheet.html

.
 
michaelplogue said:
A cheap and easy solution for mounting plates is to use thick polypropylene sheets like I'm doing. It's easy to mill, can be drilled out using standard wood bits on a regular drill press, is lightweight, and relatively cheap. Since it's a softer plastic.
Click to expand...

The polypropylene looks like "kitchen cutting" boards, is this so?
 
Ypedal said:
miro13car said:
Ypedal,
what happened to your PSI cells testing, any results, any pack construction details?
MC
Click to expand...

The pack build is still undecided, it's either i order up some Lego blocks from PSI, have some plates CNC'd or i make my own molds.. but since winter has arrived i have time on my hands to figure it out..
Click to expand...

Hi,

Unless you are short of time and the Lego's will take to long to arrive or the Lego's are very expensive or you are absolutely sure you can come up with something that is going to work much better I would at least order the Lego's and give them a try.

If they are not satisfactory (which seems unlikely) the cost and time involved will not be very much.

On the other hand if they work well they should save you a substantial amount of time, probably be a little cheaper and possibly work better than a DIY solution.

Besides someone needs to review the Lego Blocks :wink: :lol:
 
Ypedal,
what glue, silicone would you use to glue them together.
I took apart my LifeBatt pack and I am redoing all pack into entirely different enclosure which is going to attached to the bottom of frame.
I am wodering what glue can stick to such glossy plastic of cell wrap?
Miroslaw
 
The RC modelers use hot melt glue to glue the packs together.

I have also used a good thick double sided sticky foam tape. the cheap stuff from the dollar store won't cut it because the glue won't survive our cold Canadian winters.

rick
 
Thanks Rick,
I have some challenges with re-building pack in different box mainly , because I abandoned original factory plastic cell craddles.
They provide spacings between cells for cooling, I draw just below 50A on my TForce , newer more for just couple of seconds and there is no need for any cooling.
I will do research about melt glue, but I am still concerned about strenght of such hot melt glue jonts,
Rick , any particular brand from where - Rona, Can Tire, others?
How about RTV silicone?
Miroslaw
 
I've used two way carpet tape on coroplast which is shiney pastic like your batteries and it's amazingly strong. You can purchase the industrial equivalent two sided tape at any sign maker shop, very strong and almost impossible to pull apart without damage.
 
the sign makers tape is good. the stuff i got was weather proof.

for the sticky foam tape i bought a roll of 1/8" thick 3/4" wide stuff from Brafasco Industrial supplies. their catalog # FT3418. on most surfaces you will destroy the foam before the glue separates. just make sure the clean the surface of the plastic well before applying. use a mild solvent like tri-chlor-ethelene.

maybe it was the brand i used but RTV did not stick well to the surface of the shrink tubes used on my lifebatt cells. it worked more as a cushion. it did not really stick the cells together well.

i also tried a structural polyurethane foam adhesive. this was the kinf of stuff builders use to glue down a floor or stick wood panels to a cinderblock wall. the stuff stcks to everything. hands, cells, anything it touches. messy stuff. it sticks to the plastic so well that it is impossible to remove from the cells without cutting the shrink wrap off of the cell.

rick
 
michaelplogue said:
A cheap and easy solution for mounting plates is to use thick polypropylene sheets like I'm doing. It's easy to mill, can be drilled out using standard wood bits on a regular drill press, is lightweight, and relatively cheap. Since it's a softer plastic, it will also help cushion the cells without having to worry about damaging the cells from rubbing.

http://freckleface.com/shopsite_sc/store/html/polypropylenesheet.html

.
Click to expand...

Oh man.. you had to go and do that huh.. that site Rocks !! :D .. this is gonna get expensive i can already tell..

I have used this stuff on the Chaos
http://www.ypedal.com/Chaos3.htm

It's easy to work with, strong as hell, you can drill it and screw it, i have a piece left and it's the material of choice if i make my own plates..

The lego blocks are tempting, if/when i order those form PSI i may as well order another round of cells, the finances don't allow for this at the moment.. ( the winter power bills here are harsh.. )

--

Micro.. see page 10 of this thread on the Hot Glue.. as rick mentioned the Hot glue works great .. . instantly sets, stiff, comes off clean if you really have to, I tried silicone but it's flexible and takes for ever to dry, no good.. you want the cell bodies to support each other to prevent the copper tabs from stressing the threaded lugs..

--

I have foam mounting tape, considered it but on round cells it just seems like it would not be the greatest.. i've used industrial double sided carpet tape on square cells and it worked very well..
 
Look what Yesa recently added to their website.
200812418492051158.jpg


They should give PSI cells a run for their money if they are priced accordingly.
EDIT: Yesa quotes US$37 per cell.... I was expecting less :cry:

10Ah cylindrical 40138 8C continuous, 10C peak. Claimed "<=6mohm" internal resistance.
http://www.yesa.com.hk/goods.asp?id=27

I wonder if its a good old "copy job" of PSI cells. Something that mainland China/HK is well known for... :lol:
 
Hi,

Ypedal said:
The lego blocks are tempting, if/when i order those form PSI i may as well order another round of cells, the finances don't allow for this at the moment..
Click to expand...

The total for the Lego's plus shipping and customs shouldn't be that much. If you could use the Blocks now I'd at least get a quote.
 
boostjuce,
those green ones had been on their web site for a while.
nothing recent.
The big question is :
what is it?
I doubt it is PSI/BMI cell.
correct me if I am wrong.
But read specs carefully.
MC
 
YESA says in this cell specs 8C - means it cannot be PSI/BMI.
Check LifeBatt web site for specs and you can see differences.
I would they sell for 37dollars?
MC
 
boostjuice said:
Look what Yesa recently added to their website.
200812418492051158.jpg


They should give PSI cells a run for their money if they are priced accordingly.
EDIT: Yesa quotes US$37 per cell.... I was expecting less :cry:

10Ah cylindrical 40138 8C continuous, 10C peak. Claimed "<=6mohm" internal resistance.
http://www.yesa.com.hk/goods.asp?id=27

I wonder if its a good old "copy job" of PSI cells. Something that mainland China/HK is well known for... :lol:
Click to expand...

These cells have been on the site for quite some time. They are made by PSI - not copies - confirmed with PSI. My test results with these cells are here: http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=6151

Andy
 
Ypedal said:
Got my Hakko 936 today !!!! :p
Click to expand...
You'll be happy with it, I'm sure! I waited too long before buying mine, and I would never, never go back to regular irons now. I even made a copper bar tip ("T" shaped) that can desolder about 14 pins at once - great for IC removal!
 
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