out of fear of diverting the LiFePO4 for the Z-20... discussion away from DonCristobal's original question, ive created a new topic.
I was asked how i got 16x lfp40aha to fit in my emax. i put the batteries in this arrangement originally with the 15 cells. However i discovered today that i could get away with 16 cells if i add one to the front. unfortunately i only had 11 cells to test with.
In real life the cell positioning looks like this:
and with the covers on:
you might notice the cutouts in the seat, i needed these for the bms modules.
just have to find a way to seal the seat to the other covers better. New:
old:
now you could fit 20, to do a full time 60v mod, however you may notice i was able to leave one of the old batteries behind. Now if you don't care about these batteries, you can pull 15AH out of them per charge. enough to go 20km at 60v, 60-70kmh throttle wide all the way. at least according to my drain brain. rewiring the contactors to switch alternatively for 48 or 60v could be a longer term solution.
once done with running the old batteries into the ground for the 60v mod, i would buy these as a longer term solution:
http://www.evpower.com.au/-Lithium-Ion-Batteries-for-Electric-.html
for me this would take a while as i have 12 spares. i used to have 16, however 4 were destroyed when one of my chargers failed...and overcharged them for 8 hours:
boyo do they stink when they fail.
Matt
Yesa makes a 50AH "high rate" LiFePo4 of the dimensions 70 mm by 80 mm by 145 mm.
Because a pair of these will fit in the space of one of the eight old 20AH cells, they appear to be drop-in replacement for the old e-max battery arrangement.
Four of these could be added under the seat for a full-time 60 volt operation. For now due to cost considerations I will likely just keep the separate, independently charged Pb-Acid booster under the seat for intermittent use.
I assume that you saw my switchable 60-volt rewire setup back here: http://visforvoltage.org/forum-topic/motorcycles-and-large-scooters/201-e-max-accelerating-over-40mph
hi usatracy,
are the dimensions for the yesa cells wrong? a cells of that size does seem rather small.
the silicon batteries are 181x166x76, so by looking at dimensions alone they should fit. Is the reason they do not fit due to having to add a battery management system?
the thundersky cells are 210x116x46, which made them a lil tricky to fit, and impossible to go 60v.
regards,
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
Hi PJD,
yes i did see your contactor rewiring trick, albeit some time ago. rats....and here i was thinking i as being all original:p its a good idea though.
regards,
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
In his old post, usatrcey was talking about different cells.
PJD,
do you have a link to the cell you are refering to?
while i was looking for thundersky alternatives, i did come across a vendor with drop in replacements, however they did have a bit of a price premium:
http://www.evpower.com.au/-Lithium-Ion-Batteries-for-Electric-.html
and would require bank charging (ive already changed over to this anyway).
usatracy,
how big are the 50AH cells you could not get to fit in the emax?
im currently assessing how to go about a full time 60v mod. im currently running full time 60v with 5 of the original batteries in series, the rest removed. ive become quite used to the extra power, and dont want to go back.
the only option that would fit i have come across is 4 (2 of this special) of these batteries in parrallel:
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=3867
needless to say im still looking for other options.
regards,
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
Matt,
The 50 AH Yesa battery I'm referring to is the YLH7080145 ("high rate 50AH")here:
http://www.yesa.com.cn/product_cells.asp
Two of these fit in the space of each of the original batteries, allowing a drop-in installation for 48 volts. For full-time 60 volts, the four additional cells could fit in the bottom of the under seat storage, with still a fair amount of storage space left - although not quite enough for a helmet.
My main consideration is improving range, but if shorter range isn't a problem, and if you are happy with 5 x 20AH SLA's this is probably the case, then I'm sure twenty lower-capacity cells could be fit into the battery boxes. However, you may run up against the maximum discharge rate for the smaller cells.
At any rate, "Sam" has yet to respond to my request for a price for these cells and a BMS, I starting to suspect that some of them are vapor-products...
Paul
jdh2550_1,
im not sure if my cells arrived doa, were (my supplier and i) are still figuring that one out. after doing the first charge, they were all dead, with high internal resistance. this failure mode is similar to what you would expect from an over charged cell, where lithium metal has plated out resulting in high internal resistance. on the first charge, the charger did not cut out when it was supposed, so the bms halted the charge. in theory, the bms halted the charge before any damage could have been done, as it monitors the voltage of each individual cell. All the cells are dead, and all need replacing. i have sent 4 samples back on friday to verify that they are indeed dead, so im waiting on my suppliers reply. since the emax charger terminates at a higher voltage than expected, when i recieve conformation of warranty replacements, ill buy an extra cell, so hopefully with the new pack, the bms wont have to step in again.
in the mean time im running on 5 of the standard batteries.
usatracy and PJD,
yes a high capacity cell is exactly what im after, as i want it to be wired inline with my 40AH TS pack, when it arrives. im looking for something at 12v, that delivers 20AH or more at a discharge rate of about 60A, 100A peak, that will fit in the space of an original battery. with the LiPo cells i mentioned earlier, they meet that criteria, but are Li-ion, and only have a 500 cycle life or so. obviously i wont be buying until my TS pack is here, and ive destroyed all my remaining silicon batteries.
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
Matt,
have you arranged for pressure on the cell side walls? That was the main challenge for me, when fitting LCP-50AHA cells (which btw, I believe are similar in size and weight to the LFP-40AHA).
I used steel bands, of same type that is used to strap hoses or rubber tubes, but that can be bought in 5 m lengths and cut.
From what I have gathered, you must put pressure on the sides, to prevent TS cells from swelling. The cell walls alone are not rigid enough to keep the electrodes and electrolyte in place. (Note, this applies to TS cells only.)
Rolf
Rolf,
How are the Thundersky cells working? I am surprised that anyone here is considering TS cells. I don't want to sound blunt, but I had heard nothing very good about them.
Maybe the QC has improved?
Paul D.
Rolf,
no i must admit i have not added pressure to the cells. this could be a contributing factor. ill have a chat to my supplier to see if it could be a problem. I cant remember if the lfp200 installation i saw has pressure plates.
Im assuming your using a pressure plate setup similar to Victor at metricmind? Or are you using the steel bands without a plate on the end?
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
Matt,
yes I used the plates that were shipped with the cells. The cells were delivered strapped and under pressure, two rows with seven cells each, so I had plates for 4 side walls. I installed 2x5 cells in the large (bottom) battery box, using these plates. Then I squeezed 4 cells into the top (rear) box and that was a challenge. I made pieces of wood that are pushing on the top part of the batteries (sticking out of the box), and other pieces pushing on the outside of the battery box. This part is not 100% perfect, and I guess it causes one or two of the top box batteries to deviate up to 0.05 V from the rest. (The others are perhaps within +/- 0.01 V.)
Paul,
after 6 months and about 2500 km the TS cells are holding up well. I will make a summary of my experiences soon.
Rolf
PJD,
Like you I have heard more bad than good about the TS cells. Unfortunately the nature of the communication channels are that bad press gets more play than good press. A couple of reasons I am considering TS cells are:
1) They're the cheapest LiFe option I can find. It may be a false economy but at least it gets me into the LiFe game such that I can gain some experiences.
2) Even bad LiFe's are likely better than good SLAs.
3) A couple of respected sources have done real world stuff with TS cells: (a) The aforementioned Victor at Metric Mind and (b) Todd at electricmotorsport.com. That's got to count for something.
I'm still not decided whether I'll take the plunge or not - but just thought I'd share some of my thinking about why even consider TS cells.
John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.
There is a manual on the Thundersky site http://www.thunder-sky.com
Go to Tech Support, then click Instruction Manual on the left.
There are pictures of typical pressure plates and instructions on how to install pack and avoid swelling.
If you only read this board that would explain why you have only heard bad things about thundersky batteries. I know two people that bought them over 6 mos. ago and have been quite satisfied with them. They both use them on custom scooters of their own design powered by etek motors and easily reach 50 mph and range of at least 30 miles.
If any of you subscribe to the thundersky list on yahoo then you know that many people around the world have been having plenty of success with thundersky batteries.
Just not here.
The missing piece so far (for me) is plug and play BMS. That's what I'm waiting for. I'm not technical but I love riding electric scooters. Even my cheap plastic piece of crap Xtreme XB500. I've seen well built custom built scooters and these Chinese ones don't even come close in terms of solid, well built machines. They work and if you know what your doing you can keep them running but I think I'm qualified to make my judgment of these as cheap plastic pieces of crap. You obviously don't have to agree and most of you don't but I would appreciate if you don't delete my comment this time for daring to slander xtreme. I own one. I know what it is.
John,
Remember that the Thunderskys being discussed in this thread are NOT LiFePO4's. They are conventional lithium-ion (lithium cobalt oxide) batteries. So, while still a considerable improvement over lead-acid, I don't think they have the (purported) cycle or shelf life or intrinsic safety of the lithium iron phosphate.
But, what are the 40AH Thundersky cells selling for?
Oops! I stand corrected. The LFP series are LiFePO4's. 2000 to 3000 cycle life. Now I am interested!
As far as a seller in the US. I located this "International Battery" which seems to be Thundersky's US "front" for complying with the domestic content laws for US military procurement. With all the money they are making in the M.I.C., I don't know if they will give me much of a price break, or sell to me at all, but I'll give them a try.
And on another note, sorry to say, but after fiddling with the battery dimensions, they seem to be just 5mm in width too big for any kind of assured fit - especially if the pack clamping hardware is included, and Matt's the photos seem to show this out.
Rolf, how are you fitting the cells in your e-max?
The yesa cells certainly seem to fit the same or more capacity in a smaller volume. I'd be skeptical, but some e-cyclyists on the "other forum" are reporting getting the full advertised watt-hours from them.
PJD,
you are correct with the lack of space in the emax. the row of 5 batteries closest to the original one aren't actually perfectly lined up. to get them to fit, i had to align them so that the corrugations in the cell sides aren't aligned and push into each other. with my setup, putting in pressure plates would be difficult. and yes the thundersky cells discussed are indeed LiFePO4.
an update re my cells.
The four that were returned to evpower have proved to be not defective, outputtng 120A at 3v, after being charged. It seems the batteries were merely at a very low state of charge. were still trying to work out why the stock emax charger failed to charge them after being put in my bike, and why the voltage rise was so rapid when charged at only 6A.
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
Well, my got a quote for a 16 cell, 50AH "high-rate" pack - $3,120 sold from the Yesa factory. It includes cheap, 3 amp charger.
Ouch!
Rolf, What kind of improvement in range per charge are you achieving with your 50AH Li pack? A preliminary figure will do fine...Thanks.
The LCP50AHA is 116x190x46 mm, exactly the same size as LFP40AHA. I have fitted 2 rows of 5 cells in the lower box, and 4 cells in the upper, rear box. As I wrote before, the fitting in the upper box is not ideal, it's difficult to get a good mechanical pressure arrangement. It would be better to fit 2 rows of 7 each in the lower box, if possible.
Range is not improved much compared to SLAs, but it is a lot more consistent. Range is about 70-80 km when driving carefully (slow), which is what I got with SLAs when they were new. I guess this translates to 40-50 km in Pittsburg conditions with modified controller. Note that I only charge to 4.10 V. Cells can be charged up to 4.25 V, but it shortens their life. TS now recommend charging to max 4.20 V, but in return claim a longer cycle life (1500 cycles, was 4.25 V / 1000 cycles). Charging to 4.20-4.25 V would increase capacity and range by 10-20%. (I charged to 4.15 V once, but for daily driving 4.10 is enough, I don't even need to charge every day.)
About the LFP cells, I have read worrying reports on the EVDL (EV Distribution List) not long ago. They fulfill all the performance specs, but it seems the electrodes or terminals can corrode and dissolve after a year or two of use. And there have been similar reports for the LMP chemistry before. Only LCP have a consistent record of long term usage, and it was also TS's first chemistry so there is plenty of experience from it. The only aging is that internal resistance increases gradually over the years, until the cells can no longer deliver enough current and must be replaced. Typically after many years. Until the LFP issue has been solved, I would not recommend anyone to buy other than the LCP series.
Rolf wrote:
"Range is about 70-80 km when driving carefully (slow), which is what I got with SLAs when they were new..."
You may want to share this with the Vectrix forum. The Vectrix owners have reported somewhat disappointing range per charge - much less than advertised. One test in Australia yielded only 67 km at a steady speed of 40 kph, so they have been asking for any other electric scooters/motorcycled have better range performance. I would be pretty upset if I spend $11,000 on a cycle that gets poorer range performance than a cheap Chinese scooter.
"I guess this translates to 40-50 km in Pittsburg conditions..."
Yes, that's about right, but even 40 km, or a bit above, was only possible with the battery pack in it's optimum condition and a very warm day, and no significant hills the last 5-8 km.
"Charging to 4.20-4.25 V would increase capacity and range by 10-20%."
That is interesting. I had assumed the only effect of charging voltage (assuming a CC/CV protocol) was time required to achieve 100% charge, not the state of charge. For lead acid, charging at a lower voltage for a long time still gets the battery to the maximum state of charge.
rgx,
I have changed my initial arrangement of my cells to the same as yours, 11 in the lower rack and 4 in the upper. the 1 extra is in front with the black box holding it in the bottom most batery box fimly. I ended up raising the seat up higher than i was otherwise going to.
as yet i have not yet had a ride with the new cells, im still getting them balanced with a slow charge before i ride anywhere. this will take a few days as the most the BMS can absorb is 0.5A. I cant charge faster than this as some of the cells are already fully charged. Ill report my range when ive finished this.
Do you know if the terminal corrosion of the LFP series is a problem common to the chemistry? or just thunderskys cells? The users of the LFP cells here in WA have yet to report similar problems.
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
The terminal corrosion has only been reported on Thundersky LFP batteries. Some LiFePO manufacturer's products haven't been available long enough for us to be sure though - I wouldn't be surprised if we soon see the same on some of the packs bought off e-bay. Others still have been around a while without problems, for example the 18650 format cells that Tesla will be using.
Note rgx is using LCP not LFP's...
upperleft - why do you think we only read this board? In fact most of the bad press for TS was sourced from other boards. If you bothered to read the posts in detail you might not need to jump to such snide conclusions. Of course, feel free to be cynical - most of us here are up to it...
John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.
I have started to summarise my experiences of LCP in an e-max here
http://visforvoltage.org/forum-topic/motorcycles-and-large-scooters/1197-emax-li-ion-conversion
Matt,
In lieu of raising the seat to accommodate the taller batteries, have you considered shortening the storage well under the seat?
One way to do this would be to cut the seat well in two halfway down, cut narrow, vertical "V" slits in the lower half, telescope the halves together; fasten with pop rivets.
Paul D.
earlier someone asked me why i picked thunderskys. mainly, because they have had a LiFePO4 battery on the market hte longest. long enough for seom users to do destructive testing.
Jukka Jarvinen had this to say (on the email based thundersky forum on yahoo groups):
"
I use 24 pcs of LFP-350 cells in Elcat which has 72V system. You do not
need to charge the cells up to 4,2V. Thou it is ok. It just kills the
cells faster. 3,8V should be fine to stop charging. I have completed now
over 3500 cycles on LFP-30 cell on test bench. Still holding over 50% of
original capacity. If we reduce the end of charge voltage to 3,8
capacity loss should not be this high.
Voltage based balancing will do the trick in your case. So BMS is all
you need. Clampers from Victor can do it. Dennis can easily chain 2
units to get your batteries behave right. Simple an effective.
At least older LFP cells have capacity problems and internal pole
corrosion. Use cells ONLY poles up.
Buy only complete systems if you feel LCPs are the option for you. No
tinkering.
-Jukka
"
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
PJD,
I was actually trying to avoid losing the under seat storage area, as this is where i store my helmet.
For the moment i hav lost the area as i havent permanently mounted the master bms unit elsewhere. i should rectify this soon.
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
Matt,
If you keep the batteries centred the helmet will fit around them under the seat. But if you intend to carry a whole bunch of stuff and the helmet I guess that will not work.
http://www.hotpropertybrisbane.com
Ben,
The batteries span the entire space under the seat. I'll post a picture when i get one, either next time i take it apart again, or when my supplier who remembered to bring a camera, sends me the photos. My setup is now physically exactly the same as that of rgx, i abandonded my the positioning mentioned at the start of this thread at the suggestion of Rod, my supplier.
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
oh wait i get wat u mean....still wont be able to do it, at least not yet....thats where im hiding my BMS master control module. but ill probably do that eventually anyway.
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
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