still mucking about with the idea of a lithium conversion.
I guess this is a question for mik, but the vec techs out there could probably weigh in as well.
From Mik's posts, it seems the whole battery is 230 wide 330 high and 700 long.
How much extra space is there, length, width and height to play with?
There is practically no leftover space.
A little bit of space in the frame in front of the battery could be used for a BMS. That is the space where the water ingress causes problems with the front battery temp sensor board, if the holes are not taped over.
Otherwise, the cables, connectors and small boards for the M-BMS are the maximun that can be fitted in without hindering the coling air flow.
One of the rainbow cables was not perfectly tied down early on, and when the impellers started to run during driving, with my bbum depressing the seat a bit, the edge of the rear impeller cut into the cable! That's how close it is! It took ages to fit it all in, many attempts until I got it right.
Click picture for details:![//i281.photobucket.com/albums/kk217/Mr_Mik/Vectux/Battery/Battery%20Rework%208%20M-BMS%20with%20Freddy%20access/th_DSC01287.jpg)](http://i281.photobucket.com/albums/kk217/Mr_Mik/Vectux/Battery/Battery%20Rework%208%20M-BMS%20with%20Freddy%20access/th_DSC01287.jpg)
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There is always a way if there is no other way!
How does the cooling airflow go?
It looks like it is ducted from the inlets to either side of the battery at the bottom edge, sucked through the holes in the battery top cover, through the plenum and out over the motor controller, is that right?
In addition to the inlets there are several other air entry points on an unmodified Vectrix VX-1. That could be important when you try to prevent further cooling of a cold battery in winter by blocking the inlet grilles. It also lets water in at the two holes at the front of the battery cover. Other entry points are the hole through which the front battery temp sensor harness enters the frame, and the many small gaps around cable-ties and cable entry points through the thin plastic (white) cover on the sides of the battery.
There is also a certain amount of re-circulation, if by design or by accident I am not sure. The triangular gaps at the rear end of the battery housing cover (impeller housing box) do allow some air to blow onto the MC board, and then re-circulate through the bottom of the batteries. This can be important as it will allow some cooling of the MC board when it's dedicated fan is not running. It could also allow to equalize battery temperature without increasing or reducing of the battery temperature, like when parking in the sun in hot ambient temperatures, or when charging in very cold areas. If you block all entry points, you could keep the hot air outside and keep the cells perfectly balanced despite the radiant heat penetrating from the top of the battery down, by closing the air inlets and running the impellers. Or keep the precious warmth in your battery in cold winter climates.
A smoldering incense stick can be used to figure out the airflow patterns.
This information may be used entirely at your own risk.
There is always a way if there is no other way!
if lithium has a wider range of use in way of temp
and do we really need to keep all the gubins that goes with the cooling fans cooling fans and tubing and shrouding that incases the fans .
i/e if all gone more space + more batterys + more range ??
but would the cooling be a probblem .i have spoken to a electric scooter company its on a previus blog of mine .
and they said that they used lithium ion cells but they found gp cell get very hot and unreliable ? but they said they have liquid cooled cells on scooters ??
to be truth full i took what they said with a pinch of salt ..
SO really to cap it up...
CAN WE USE LITHIUM CELL WITH OUT COOLING SYSTEM ?????????
KEV
I guess how much cooling you required would depend on maximum abient temp, how hard you are pushing the cells and their individual characteristics.
compare the temp changes in these graphs
http://www.zeva.com.au/tech/LiFePO4.php
I reckon if the phet cells started at 40 deg C ambient and were discharged at 10C with no active cooling, they'd be toast. the A123 cells might survive but would probably be damaged to some degree.
I'll be cooling, probably air
i have yet to see *any* EV with a LiFePO4 battery that has a cooling system.
on my emax, when i pulled 1.4C cont, with 4C peaks, heat was never an issue. The high discharge currents probably were.
a vectrix with 42 x 40Ah cells would see 4-5C peaks (amps limited by sag) and 2C (9200w) at 100kmh.
a TS pack wont last long at that discharge rate.
a 42 x 60Ah pack would see 4-5C peaks (amps limited either by sag or 275A bus limit) and 1.2C(9200w) at 100kmh
at that sorta discharge rate, my old cells got 500 cycles to 80% capacity remaining
the newer cells do better apparently, time will tell.
the 42 x 100Ah pack i did want to put in the vectrix would be 2.75C peaks, and 0.7C (9200w) cont
but fitting that in requires to much modification.
the extra weight would also improve the handling due to better sprung/unsprung mass ratio.
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
yeah, it is probably overkill. But I think it is worth doing.
Some form of packaging needs to be used for the pouch cells. Made out of aluminium and with a bit of extra finning, it'll would sink heat away from the cells.
TS prismatics and cylindrical cells all have surface area on each cell exposed to air. These pouch cells won't have even that little bit of cooling
13.3 kwh... over 220 km of range...
hi.
did i see correct 220 klm RANGE
now you have me hooked tel me more......
kev
He's dreaming :)
he's talking about squeezing these in http://www.evworks.com.au/index.php?product=BAT-LFP100AHA
but his bike is not the TARDIS :D
42 x 90Ah cells would weigh 126kg cells only.
you would have to lose the under seat storage, and all the cooling impellers.
220km range would still be at a slow speed (~60kmh).
at 100kmh, you would have more like 120km range.
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
120 km range compared to a practical 40km limit of the factory bike is awesome.
I've been trying for a while now to find some cells tha would fit inside the existing battery dimensions AND could handle the demands of the Vectrix.
A123 20Ah pouch cells look like the business, but I chickened out on those. I can only order a complete set and I don't know yet how to successfully connect or package them.
A 42s5p pack of Headway 10Ah screw terminal cells seems more doable. I am a bit nervous about their current handling capacity, so riding like a granny might be in order. :)
interesting new product
http://www.lifebatt.com/prismaticcases.html
210mm x 312 x 165 for a 24V 40Ah pack
modular aluminium cases and integral BMS (needs master control unit for this stack of batterys)
4 on their ends and 1 in the fan space might fit
This thread has been added to the Vectrix Collaborative Handbook, please stay on topic!
This information may be used entirely at your own risk.
There is always a way if there is no other way!
I wonder how many cells are in a 24V pack.
8 x 20AH cells 4s2p would be my guess
very light, less weight than TS or SE equivalent and it includes BMS and packaging
I wonder what the prices is...
http://www.lifebatt.com/cellspecs.html
it looks like uncased cells in 2 9x7 layers would fit inside the standard battery dimension
42s3p 60AH! AND high rate nanotech cells AND weigh the same as the 40Ah pack I have bought for my bike.
I bet we are looking at about $8k AUD.
ooh, and if you really wanted to get carried away and do some battery box mods to cope with something like a 420mm high stack, then 3 layers of 10 x 7 cells 42s5p would give you a 100Ah pack, almost in the stock battery space....
It'd just about be worth it to make a bike that's verging on the side of useless into a really good machine. The sort of thing I'd be interested in, however, would need to use the existing control system....even though I can see I might have to give two charge sessions to finish the charge by the sound of it. or I might be completely misunderstanding everything I read here, of course.
I often do 40km round trips with bits on 80kph roads.....but doing those without having to even THINK about the charge would be a welcome relieve.