Headway vrs Thundersky?

pgt400

pgt400

1 kW
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Jul 1, 2008
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Location
New Jersey,USA
Anyone ever compare the new Headway cells to the equilivent capacity TS cells? For exampl 4P of new Headways to a TS-40 ah ?
The published ratings look similar at 3c. The going rate for Headways looks to be around $20 each, Elite wants $68 for a single TS-40.
 
pgt400 said:
Anyone ever compare the new Headway cells to the equilivent capacity TS cells? For exampl 4P of new Headways to a TS-40 ah ?
The published ratings look similar at 3c. The going rate for Headways looks to be around $20 each, Elite wants $68 for a single TS-40.
Click to expand...

Headways all the way. The Thundersky cells do not have the discharge rates that Headway has. The negative to getting Headways is paralleling them together and the BMS. Nobody knows the real life expectancy of these cells yet.
 
I just had a look at the thunder-sky TS-LFP40 datasheet to see how they would compare to headway cells.

From the meager discharge curves available (only goes up to 1C!), the 40Ah cell looks to have just a bit over 11mohms internal resistance. Compared to headway's <10mohms for their 10Ah cells, this is pretty darn bad looking (like about 4 times worse!). Much worse than Ping's cell's internal resistance even, about 2.5 times worse. This means greater voltage sag under load, more cell heating, and thus shorter life under the same operating conditions.

This is going by their discharge curves, and I haven't seen any independant testing for these TS cells so far, so we have yet to know how they really perform.
 
I just wired in 2 TS-LFP60 cells in my 72 volt pack to bring up the voltage. Hot off the charger I'm now 88 volts right at the ceiling of my Kelly controller

I will report my finding with the TS-LFP60 cells over the next week

Mark
 
I haven't finished running the TS40 or the Headway cells I have. The TS40 is running a internal resistance survey now. So far, three hours into a 20hr discharge to 2.5V, DC IR is running between 16 and 18 mOhms. This cell only has six cycles on it so isn't fully broken in.

The headway cells tested at 26 to 28 mOhms. PSI 40138 cells run 2.9 to 5.8 mOhms.

All three batches of tests done on the same LaMantia tester, at 2A and .5A in the same room with the same test leads.

Andy
 
AndyH said:
I haven't finished running the TS40 or the Headway cells I have. The TS40 is running a internal resistance survey now. So far, three hours into a 20hr discharge to 2.5V, DC IR is running between 16 and 18 mOhms. This cell only has six cycles on it so isn't fully broken in.

The headway cells tested at 26 to 28 mOhms. PSI 40138 cells run 2.9 to 5.8 mOhms.

All three batches of tests done on the same LaMantia tester, at 2A and .5A in the same room with the same test leads.

Andy
Click to expand...

Andy - Your headway cells must be the old ones, and not very good ones even at that (all the new ones I've seen tested so far are around 10mohms per 10Ah cell). Please let us know which ones they are. Thanks!
 
The lasts Headway 38120S cells i tested from dimitrib had 9miliohms each at 5A(0.5C) discharge after 3.00minutes of discharge.

The first headway without the screw tab(the 38120L or P had like 6 miliohms but they was not constant and had some problems..

Doc
 
Doctorbass said:
The lasts Headway 38120S cells i tested from dimitrib had 9miliohms each at 5A(0.5C) discharge after 3.00minutes of discharge.

The first headway without the screw tab(the 38120L or P had like 6 miliohms but they was not constant and had some problems..

Doc
Click to expand...

The old Headway cells without the screw tabs had about 16milli-ohms per cell, I am quite sure. But it is true that they had very bad quality control problems that seem to be resolved now. Anyways, between the thundersky cells and the headway cells, I would take the new headways any day. The 4 times higher internal resistance of the TS cells per equivalent Amp-hour is pretty darn crappy. Of course the TS cells are a bit cheaper, and they do make really large ones (up to 200Ah) which would make building a pack easier I guess...
 
I think the price is about the same? Elite sells the 40ah TS for $68. Victoria has been quoting $18 per cell and I bought 4 recently at $22 each. Now I only need 92 more! I've been waiting to hear how the yahoo group buy-ers made out.......but they still havn't gotten their cells. Still time, I don't plan to buy till spring.
 
markcycle said:
I just wired in 2 TS-LFP60 cells in my 72 volt pack to bring up the voltage. Hot off the charger I'm now 88 volts right at the ceiling of my Kelly controller

I will report my finding with the TS-LFP60 cells over the next week

Mark
Click to expand...

Hi Mark,

Have you had a chance to test the LFP60 cells yet?

Thanks
 
Frank said:
markcycle said:
I just wired in 2 TS-LFP60 cells in my 72 volt pack to bring up the voltage. Hot off the charger I'm now 88 volts right at the ceiling of my Kelly controller

I will report my finding with the TS-LFP60 cells over the next week

Mark
Click to expand...

Hi Mark,

Have you had a chance to test the LFP60 cells yet?

Thanks
Click to expand...

I tried to test them but my controller didn't like 88 volts. Every time I tried to brake with regent the controller shut down. I ordered a new 120 volt Kelly controller this week and should have it tomorrow (ouch on the price). So will report back shortly after I get the controller

Mark
 
I have made a little comparative between Ts and headway cells.

I have a friend from Quebec who is making a GSX1100 conversion using a kelly controller and and a DUAL ENERTRACK 602 motor.
 

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Nice chart Doc. Seeing as these numbers are from EVE can we trust them?

Also am I reading it wrong. It looks like the smaller 8Ah cells have less resistance allowing for a higher C rate? I would have thought the 16Ah cells being larger and able to dissipate heat better would be able to sustain a higher C rate.
 
Pure said:
Nice chart Doc. Seeing as these numbers are from EVE can we trust them?

Also am I reading it wrong. It looks like the smaller 8Ah cells have less resistance allowing for a higher C rate? I would have thought the 16Ah cells being larger and able to dissipate heat better would be able to sustain a higher C rate.
Click to expand...


Yes, the 38120P ( 8Ah) is the Power model so the internal resistance is lower

The 40160 cell is confusing... i tried to find info but not succeded

I used the EVassemble website for the pricing information only

Doc
 
Ah good to know. Thanks!!
 
Thundersky is one of those chemistries where it depends what you think is acceptable. I had 24s on the 20AH and it did 2.5-3c but it sagged like a mofo to 2.75-2.8v a cell. I charged to 3.7 or 88v soooo 3.2...3.3 is OS voltage so it rested at 77v after surface charge and it technically was a 66v system under load. In large or voltage config its either you run a voltage to compensate for the sag or go up in AH and so you can get an acceptable C rate for the cell. 2 cells in parallel reduce the IR by half supposedly and C rate. Small scale they suck.. large scale they are awesome. When I was giving my 20AH the business they delivered 19.6 before kicking the bucket. so you dont loose much capacity at high C rates... I was impressed with the 90AH my friend has going in his solectra AC induction geo metro.
 

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