Planing CanView and BMS+ conversion with lithium

I agree, even with having 72 resistors to shunt each cell takes up a lot of room for the resistors themselves and their cooling. Space which could be better used for more cells. Sometimes it is better not to have a balancer specially if it is dodgy. You may get by with just manually balancing once a year. I would be interested in knowing how often Mr Plug-in would need to manually balance? I guess it comes down to how well the 72 lithium cells are matched and put together, wether each cell comes from the same production batch or not or whether each cell has the same internal resistance value and how well their internal resistance stay matched over many charge/discharge cycles.

 

ok thx
so 3600-3700 dollars for the pack.. a 9kwh pack.
what miles/km do you get of this pack? and do you use 80%or more like the OEM ~40/50% of the pack.
the PIP with a 4,4kwh pack can go 10miles, for me 18miles would be perfect and i do not need more ( only added weight )
so maybe i start thinking about a smaller pack..
but then i have smaller AH cells and what about the discharge.... can those handle the amps ( c ) .. maybe have a shorter lifespan...
maybe the 40ah are the smallest you want to go ... but then i am stuck at almost 4000 dollars....
and even better, dont see any below 40ah ;-)

 

I guess when you look at a 10kwh http://www.pluginsupply.com/ pack at $10995 it just seems to be a blatant rip off. Or $5500 for a PIS 4kwh kit.

 

well 10k yes but the 5k dont now because chargers and stuf is also included and the build so 10k is way to high and 5 would be OK ;-)

looking at you A123 cells now.. intressting

dont these cells just like any other also need to be compressed so when getting hot during charging less change of damage?

i geuss this is just for testing the bms

 

...

 

I have only known pouch cells to expand when they are being overcharged. Hopefully with a good BMS this should not happen. And generally when they are very overcharged they will swell and become punctured/split and leak fluid. No amount of compression will stop this from happening.

 

i dont go for hope i want to be sure.
you dont want to spent your time during charging side be side to the cells or do you?
even if one time go's good thats not to say something else can go wrong because over time the cells housing, cable etc etc ..using it wil show design flaws that will cause a overcharge or anything else you can think of.
with a compressed cells and also ( i would add ) temp. sensors hope is less of a factor ;-)

it also looks better then in tupper ware boxes.

 

If your cells become overcharged due to a faulty BMS you may as well kiss them goodbye. There are no certainties.

 

overcharge = heat ( a lot of )
heat ( a lot of above a shutoff temp ) = shutoff charger ( using a simple temp relay board total of 3 sensors )

then second ( also a second board, not the same system for redundancy ) to that 3 prius OEM fans starting to work at a temp below that charger shutoff.

and the last thing is that in my case the Nimh batterys have a V cutoff voltage ( forget the name...delta v? ) moment where the charger senses that packs are full and stopss charging by it self

that how i used to have it working on my NIMH oem add packs
worked great.

not a lot of hope there just pure science facts

o there is one luck ;-) that you dont realy need a BMS with the oem Nimh cells
but in my case i measured then any way .. just to be sure

 

NiMH is a different chemistry. You are comparing apples with oranges.
What happenened with your NiMH add on packs? Are you still using them? Are you thinking of converting to Lifepo4.

 

is overcharging and heat not the same with these cells?

i no longer have those packes installed because in my case it did not do me any good.
short trips i try to use the bike and longer trips the packs are just added wieght and more fuel...

but ~50kilo installed for the A123 you are using and the price and the longer range next to that things changed for me with distance day to day travel ( just on the border of not taking the bike ) YES i am thinking about it.

i hope you open a topic to show your personal road to a A123 setup

 

No. If they were you would have a fan to cool down the Lifepo4 pack during normal operation.

My personal road to A123 cells will stay in this topic. You could also consider using Headway cells. It looks like these Headway cells do not need compression fittings. The PIS website shows a video of a Headway pack with Dimitri's distributed miniBMS.

 

I agree with lopezjm2001 answer. A123 20Ah are sealed pouch. Pressing on these pouch is like pressing on a ballon. Under a load nothing appends, just a little thickness reduction, and over the pouch opens. That's worse. Some gas may be breathed. But you would need a huge load to break the pouch. A123 thickness is about 7mm. I already saw a balooned one. Thickness was more then 20 mm and remain sealed.

These A123 are very different from Panasonic Nimh.
During charging just check each cell voltage and final amperage.
Temperature can be monitored just to stay in the normal range in summer.

With box, wires, contactor, fuses, bms, bms+... total is 41 kg for 4,55kWh

 

are the A123 bags not t he same used in the volt? and the volt pack is temparatured controlled

no i am not going for those cylindric cells
this needs to be cheap as it can be within my own reasoning... so with safety controlles ;-)

41kg is NCIE NICE NICE thats half of the OEM packs i have and double the kwh..
even better i guess those a123 have a wider range to use to..

would like to see more pics of you planitaire.. your french website only shows me 1 or 2.. ;-)
and i am not that good at french to figure out more haha

edit: :
mm i have been out of the loop for some time haha.(i did my OEM nihm BMS+ build back in 2008 and a part of 2009 ) its not A123 that provides the volts cells...


edit2:
the LG chems cells from the volt look the same as the A123 bags
http://www.green.autoblog.com/2009/...truction-of-new-battery-plant-in-south-korea/

 

I added 2 pictures in my post

Yes volt use LG cells. And Volt cells have to handle 111kW, really more then our Prius.

 

any you made of when you build the battery case?

 

Pretty good for the added power weight and volume density. It's far better than some commercial kits.

 

Hi Planetaire,

I did not see these two photos until now. It looks really neat. It appears that each battery bank has to slide in sideways to engage two plugs. Did you make your own PVC enclosure? It looks like perspex or polycarbonate sheeting.

 

Exactly.

Perspex (pmma). Polycarbonate would be better for the thinner.
There are 3 pieces. 2 thick and one ployed using some hot wire. Of course this hot wire as been connected to A123 cells
I heat a little too much so there are very small bubbles inside the pmma.
That's not good. It would probably be better preheating the plate in an oven.
All screws are outside the box. No nut at all. No metal piece can fall in the box (that I cover after the pictures)

But I plans adding this winter 70 cells more and will build other boxes, using pmma (because I have some) and aluminium.
Probably 7 boxes with 20 cells each, always keeping some place behind in case of a rear impact.

These cells are small. 70 could take the spare tire housing: