# comparing Thundersky vs Sky Energy... comments?



## dtbaker (Jan 5, 2008)

I am getting down to brass tacks in deciding WHICH batteries to use. Both Thundersky and Sky Energy now seem to be widely available, and reasonably priced at a couple places. I am probably going with a total pack of 120v nominal, and 100 or 120aH cells.

Reviewing available docs it looks like the TS cells have a higher range than the SE, but so far I have not seen whether the 'flat part of the settled voltage curve' is different. I think the TS cells settle down to about 3.4 or so for most of the usable capacity, tru? can anyone verify that?

How about the SE cells.... do they actually settle to the same despite lower v range published in documentation? Looks like charge curves might be significantly different enough to require different settings for charger/BMS.

Any other comparative comments pro/con for one over the other? How about sources? Best price/delivery I have noticed is from evcomponents.com ... any other recommendations?


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## Lordwacky (Jan 28, 2009)

I don't have much to offer on this but my 2 cents....

I currently have Sky energy 180 Ahr batteries and I have also seen first had a lot of different sizes of sky energy and thunder sky side by side. my comparison is going to simply on fit and finish etc as I haven't yet finished my build.

in general I think the thundersky's are better as far as fit an finish. The appear to be a higher quality package and have a MUCH better strapping system then the thundersky batteries. The Sky energy strapping system is a complete joke and you might as well as throw it away when you get it.

I chose to go with Sky energy because at the time they were offering higher discharge rating and were more energy dense then the thundersky offerings. The 180ahr sky energy has the same foot print as the 160ahr thundersky's. However this has all changed since I believe that thundersky has upped thier specs to match the sky energy specs and they also have a new 200ahr battery in the same foot print as the sky energy 180ahr battery. 

If had to do it over again I think I would go with thundersky for the reasons I have listed above, but in reality they are esentialy the same battery and I think that they are going to perform very similar if not identicaly, but I have no hard data to prove that statement. 

On side note, make sure that you are getting you order filled with new stock and not some stuff that has been sitting around, that way you are sure you are getting the newest and best material. I'm not sure if there are physical differences between old spec'd material and new spec'd material, but if there is you'll definitly want to get the newest spec'd material.


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## brainzel (Jun 15, 2009)

Six month ago I was thinking about exactly the same decision.
At his time, there were so much differential informations around, that I was very confused.
Looking at the hard facts, I have chosen SkyEnergy cells and I haven't regret the it yet.
Unfortunately I can't give you much real life experience feedback, work is still in progress, but have a look at Jacks blog http://jackrickard.blogspot.com/2009/12/ok-here-it-is-sag-voltage-more.html and although his Videos about the differences and advantages of those batteries. He has tested and maltreated them and could give you a better view on this issue.

I bought at EVConmpnents and the cells came directly out of the chinese factory to germany, so this was no "insipid" ware 

At this point, I would choose SkyEnergy again, but maybe I would take an other size. One that is more common, to get a quick replacement, if a cell quits. Perhaps 100AH or 160AH (seems to me more widespread than the 120AH that I got) but certainly the guys from EVComponents could give more informations about that.

Whatever you will choose, you can't go absolutely wrong with one of this two cells. Anything would be much better then lead acid


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## JRP3 (Mar 7, 2008)

I also agree that the SE strapping system is basically useless so be prepared to come up with your own. The SE cells may perform better in the cold, though the newer TS cells may have removed this difference.


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## EVComponents (Apr 20, 2009)

JRP3 said:


> I also agree that the SE strapping system is basically useless so be prepared to come up with your own. The SE cells may perform better in the cold, though the newer TS cells may have removed this difference.


I agree. The ThunderSky strapping hardware is much more user friendly.

The quality of the cells is the same or so close as to be negligible. ThunderSky is slightly less expensive at this time. About 5% less.


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## dtbaker (Jan 5, 2008)

so.... do some number of terminal straps and bolts come with the cells? Some number of bands to bind blocks of cells together?

Can someone post a close-up of the Thundersky banding system?


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## JRP3 (Mar 7, 2008)

Here is a closeup









For my SE cells I'm using small cargo ratchet straps with a threaded turnbuckle. I'll probably end up using aluminum plate for the ends unless I can find something else.


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## dtbaker (Jan 5, 2008)

very interesting.... thanks for the picture!

I am wondering why they are using multiple extruded sections rather than just a plate plate... and also wondering why they are using straps that basically are not 'clamping' the cells together. Seems like to minimize vibration and stress on the terminals it would be important to clamp them as tight as possible with a turnbuckle, ratchet, or screw mechanism....

I am thinking that a couple cheap poly ratchet straps may be better as they could be threaded through the battery box itself and double as hold-downs to 'clamp' the cell blocks up against the battery box?.... true? or am I missing the point?


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## JRP3 (Mar 7, 2008)

The extrusions allow them to use thinner lighter material than plate for the same stiffness. The multiple extrusions let them use one size and stack them for taller cells. My guess is the cells don't need extreme clamping, just enough pressure so that they don't swell, and I guess these straps provide that.


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## brainzel (Jun 15, 2009)

To compare the TS with the SE, here comes the strapping picture of SkyEnergy cells:


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## EVComponents (Apr 20, 2009)

dtbaker said:


> so.... do some number of terminal straps and bolts come with the cells? Some number of bands to bind blocks of cells together?


You receive all of the hardware included. When we order in bulk we always make sure that we get the copper connectors and hardware inclusive in the price.

If you know the grouping that you want, they can be arranged that way before shipping. Groups of 4, 5, 6 cells, etc. That is for ThunderSky cells. Sky Energy just ships a bunch of loose hardware that you have to put together.


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## dtbaker (Jan 5, 2008)

EVComponents said:


> You receive all of the hardware included. When we order in bulk we always make sure that we get the copper connectors and hardware inclusive in the price.
> 
> If you know the grouping that you want, they can be arranged that way before shipping. Groups of 4, 5, 6 cells, etc. That is for ThunderSky cells. Sky Energy just ships a bunch of loose hardware that you have to put together.


great info.... I guess I will spend some time to layout in available space to pre-group cell blocks. Allowing for a little air and access to strap hardware at the ends. 

I am wondering what the 'usual' way is to clamp the blocks of cells together so that rigid terminal connections can be used... or if it would be better to use 2/0 cable and connectors between strapped blocks to allow for a little flex and vibration?


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## pgt400 (Jul 12, 2008)

EVComponents said:


> If you know the grouping that you want, they can be arranged that way before shipping. Groups of 4, 5, 6 cells, etc. That is for ThunderSky cells. Sky Energy just ships a bunch of loose hardware that you have to put together.


Can the TS cells be mounted on their side? I've heard some say no but I have seen several (Bikes) where they lay them down?


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## EVComponents (Apr 20, 2009)

pgt400 said:


> Can the TS cells be mounted on their side? I've heard some say no but I have seen several (Bikes) where they lay them down?


I have heard that people do it with no reported problems. Dave Kois (one of our owners) did it with his EV with no problems. The fact that people have done it with no problems does not mean that the factory endorses that strategy.


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## EVComponents (Apr 20, 2009)

dtbaker said:


> I am wondering what the 'usual' way is to clamp the blocks of cells together so that rigid terminal connections can be used... or if it would be better to use 2/0 cable and connectors between strapped blocks to allow for a little flex and vibration?


It likely depends how how solid the space is for the batteries. What are you dealing with for your EV? Is there a lot of wiggle room for the cells to shift around?


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## dtbaker (Jan 5, 2008)

regardless of orientation, I would plan on strapping down the blocks a tight as possible to prevent stress and vibration on terminals. I am just looking at packing options to take a little less vertical space if I could avoid cutting a hole in floor to save time.... but if it makes cell inspection WAY harder, it wouldn't be worth it probably.


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## Doctorbass (Dec 12, 2008)

I was thinking the same way about the stress on the battery post... they MUST be correctly thightened together to avoid stresss on the post... The Ts i just worked on today had the original metal strap that was loosen even though the little screw was installed properly... 

A question: what is the REAL delivery time for the TS and SE to Canada from the moment we pay our order to Evcomponent?

I've just meet two guys from canada today that waited more than 4 month to get their TS cells.. They had problem with emails, communication and some shipping issue...

What is the best way to get them really FAST to CANADA? (TS or SE)


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## Korben_Dallas (Feb 27, 2009)

That depends on who you ask? It's also a matter of warranty. Some dealers will have you sign an escape clause if you install them other than upright.
What is evcomponents's view on this?

Christian


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## etischer (Jun 16, 2008)

I placed an order with EV components. The first check was cashed 9/14, batteries arrived at my door in California 12/31. So, about 3.5 months wait. 






Doctorbass said:


> A question: what is the REAL delivery time for the TS and SE to Canada from the moment we pay our order to Evcomponent?
> 
> I've just meet two guys from canada today that waited more than 4 month to get their TS cells.. They had problem with emails, communication and some shipping issue...
> 
> What is the best way to get them really FAST to CANADA? (TS or SE)


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## etischer (Jun 16, 2008)

Where did you find those sweet post covers?



Korben_Dallas said:


> Christian


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## dtbaker (Jan 5, 2008)

yeah, those post covers look really nice! source?


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## Korben_Dallas (Feb 27, 2009)

Took a while to find it again.
Here's the company's website
http://www.enginer.us/products/conversion_kit.php

You'd have to inquire where to get those caps.

Here are more pics:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MESELX:IT&item=200344551230

Ciao, Christian]


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## etischer (Jun 16, 2008)

Enginer.us didn't know where to get them, I emailed ThunderSky and surprisingly I got a quick response!

Hi Eric,

Thanks for your inquiry. This is Joanne from the sales dept. to answer you.

Yes, we sell the terminal post cover. It is US$0.5/pcs for LFP100AH cells.

We could also make the copper bus bars to connect 100Ah Thundersky cells side to side, it is US$2.5/pcs.

Pls note the above price quoted is just ExWorks price, which doesn't include the transportation fee. For this small goods, it is cheapest to be shipped by express. When order, pls provide your Fedex/DHL/UPS accounts so that we could arrange the express. If you don't have any express account, we could use our Fedex account to send it to you, but the express fee would have to be prepaid together with the goods.


best regards,
Joanne
Thunder Sky


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## JRP3 (Mar 7, 2008)

Maybe you could see if EVcomponents could have them toss some in their next shipment, essentially free shipping since they weigh almost nothing compared to a shipping container.


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## EVComponents (Apr 20, 2009)

etischer said:


> I placed an order with EV components. The first check was cashed 9/14, batteries arrived at my door in California 12/31. So, about 3.5 months wait.


We are trying to order every 4 weeks at this point. 
In the past it was every 6-8 weeks. So hopefully this will lead to reduced waiting times for people.

Most people get their batteries within 6-10 weeks of ordering.
If it is a small order of just a few cells, we often have extra cells in the warehouse. 

Larger orders typically require waiting until the next container, unless you happen to get lucky with an order that fits with a cancel from someone else. It happens sometimes.


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## EVComponents (Apr 20, 2009)

We had a customer change his order at the last minute. 
As a result, something very unusual has happened at EV Components. 
We actually have a lot of Sky Energy cells in the warehouse available for immediately shipping. 

We have 130 cells of the Sky Energy 180 AH size. 

http://www.evcomponents.com/ProductDetails.asp?ProductCode=SE180AHA

You might notice the price for Sky Energy cells has changed to $1.25 per AH. 
This is because Sky Energy (now renamed to CALB) has raised their prices. 

However the cells in our warehouse were purchased under the previous price schedule. 
So we will sell them at $1.15 per AH. 

Sky Energy 180 AH = $207 each 
The new price for orders after these overstock cells are sold will be $225 each.


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## MN Driver (Sep 29, 2009)

Does the CALB acronym stand for anything? I noticed the change to CALB on the site when I was looking at things this morning. Are there any differences to their cells or updates to the specs or is this primarily a rename? I've noticed that as far as the specs listed on the site, things have been the same except some Ah size availability changes that I didn't notice before.


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## EVComponents (Apr 20, 2009)

MN Driver said:


> Does the CALB acronym stand for anything?
> 
> or is this primarily a rename?


CALB = China Aviation Lithium Battery

It is primarily a rename to create a new identity more removed from ThunderSky.


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## JRP3 (Mar 7, 2008)

The price increase sounds like another reason to choose TS instead. CALB may be pricing themselves out of the market, unless TS ups it's price as well.


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## dimitri (May 16, 2008)

JRP3 said:


> The price increase sounds like another reason to choose TS instead. CALB may be pricing themselves out of the market, unless TS ups it's price as well.


Yes, but they make "Aviation" battery  , so they are opening a whole new market for electric airplanes


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## EVComponents (Apr 20, 2009)

JRP3 said:


> The price increase sounds like another reason to choose TS instead. CALB may be pricing themselves out of the market, unless TS ups it's price as well.


I agree and we told that to Sky Energy. In the future, they will not be competitive on our website when customers are seeing ThunderSky and CALB next to each other.

However, elsewhere in the world CALB and ThunderSky charge higher prices. So the price difference is not so obvious. Most websites don't even provide a price publicly. You have to contact them for a quote. EV Components is sort of changed that model by displaying the price and being so low.

CALB (Sky) has always regretted selling to us at the price they were charging at the beginning and has been trying to raise prices on us for the past six months. ThunderSky is fine with our current pricing arrangement because we bring them so much volume.

So in the future, with ThunderSky having an even larger price advantage over CALB (Sky Energy), I think everyone will just go with ThunderSky.

But for now, we have these Sky Energy 180 AH cells at the previous price. They are available for immediate shipping.


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## EVComponents (Apr 20, 2009)

dimitri said:


> Yes, but they make "Aviation" battery  , so they are opening a whole new market for electric airplanes


I think they sell most of their production to the military in China. There are airplane applications for lithium cells. 
Dow Kokam (sponsors White Zombie) designed their cells for the F 22 fighter jet. Then that jet was cancelled, so they are now making it commercially available.


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## AndyH (Jun 15, 2008)

dtbaker said:


> Reviewing available docs it looks like the TS cells have a higher range than the SE, but so far I have not seen whether the 'flat part of the settled voltage curve' is different. I think the TS cells settle down to about 3.4 or so for most of the usable capacity, tru? can anyone verify that?


I can't speak to things like longevity, warranty, or cycle life, but am working thru a side-by-side of the Sky Energy, Thunder Sky, and Shandong Hipower 100Ah cells.

I was surprised to see the flatter curve from the SE cell. Internal resistance was a touch higher, but temperatures were pretty close.

Internal resistance was measured at 50% SOC at 20ºC, after the cell was stabilized 24 hours from the discharge. The HP4328A milliohmmeter is in current calibration. TS 100 .30 mOhm, SE 100 .37 mOhm, and the Hipower .88 mOhm.

Discharges were done with a West Mountain CBA II using their Pro software, an additional positive sensor wire for more accuracy, and their 500W load amplifier.

I bought all three cells from EV Components and received them earlier this month (Jan '10).

Enjoy your build!
Andy

Rechargeable Lithium Power


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## pgt400 (Jul 12, 2008)

Great data Andy! Thanks for sharing.


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## JRP3 (Mar 7, 2008)

AndyH said:


> I was surprised to see the flatter curve from the SE cell.


That is what has been previously reported so shouldn't be surprising. As was the poorer performance of the Hipower cells. Nice to have more verification.


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## tomofreno (Mar 3, 2009)

> TS 100 .30 mOhm, SE 100 .37 mOhm, and the Hipower .88 mOhm.


 Nice to get a data point, but of course with a sample size of one from each population, and no data on standard deviation of the population, it is of very limited use in estimating differences in the population means i.e. "average" differences between cell types.


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## dimitri (May 16, 2008)

tomofreno said:


> Nice to get a data point, but of course with a sample size of one from each population, and no data on standard deviation of the population, it is of very limited use in estimating differences in the population means i.e. "average" differences between cell types.


For what its worth, all 40 of my TS160AH cells have IR between 0.32 and 0.39. This data was provided by manufacturer based on serial number of each cell.

I can see now why HiPower cells are considered as junk by many people, if they all have 2-3 times IR compared to TS cells, they must have really nasty voltage drops at 3C.


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## tomofreno (Mar 3, 2009)

> For what its worth, all 40 of my TS160AH cells have IR between 0.32 and 0.39.


 Dimitri, are your 3 "weak" cells the ones with higher IR, or no correlation there, just difference in capacity?


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## dimitri (May 16, 2008)

tomofreno said:


> Dimitri, are your 3 "weak" cells the ones with higher IR, or no correlation there, just difference in capacity?


No correlation between weak cells and "original factory reported IR", but those cells didn't start as weak, so I am sure they have higher IR now, but I have no way to measure it at this time. However, in my pack, 5 out of 40 cells are from different production batch, and weak cells are all from that batch. I'm sure I just simply have few subpar quality cells, thats all. I will eventually replace them, but for now they don't bother me much.


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## pgt400 (Jul 12, 2008)

When is the March delivery, order for TS cells ending?




EVComponents said:


> FYI... we just did an inventory count of our in stock cells that are *available for immediate shipping*. These are leftovers from customers changing orders or various other reasons.
> 
> 107 Sky Energy 40 AH cells
> http://www.evcomponents.com/ProductDetails.asp?ProductCode=SE40AHA
> ...


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## EVComponents (Apr 20, 2009)

pgt400 said:


> When is the March delivery, order for TS cells ending?


January 31st. We are trying to close each container on the final day of each month.


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## pgt400 (Jul 12, 2008)

EVComponents said:


> January 31st. We are trying to close each container on the final day of each month.


When ordering thru your web site can I specify how I want the cells bound? Such as 4 groups of 6 cells? Total 24 cells.


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## EVComponents (Apr 20, 2009)

pgt400 said:


> When ordering thru your web site can I specify how I want the cells bound? Such as 4 groups of 6 cells? Total 24 cells.


You can send me an email and we can arrange that.

[email protected]


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## AndyH (Jun 15, 2008)

tomofreno said:


> Nice to get a data point, but of course with a sample size of one from each population, and no data on standard deviation of the population, it is of very limited use in estimating differences in the population means i.e. "average" differences between cell types.


Absolutely - 'one in a row'. Internal resistance was only part of the 'data sheet sanity check'.


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## Tiger (May 24, 2010)

Gentlemen
I have read a lot of things here, and each and everyone of the points each of of you have made is valid Me , I am a consultant designing and building electric vehicles. I have tried almost a dozen different brands, from Valance, to ping, to TS, and SE,
TS just did a major reformulation, why because they manage to burn down a few buildings, Have used them and tested them, well the answer is yes, but, cold, subject to over charging, well discharging, that was covered, 
I am using SE, why, because they are very reasonable price wise, but, i have not had any problem with them except like all batteries the cold, so i designed heaters, no problem, 
What I found interesting in read here was on the strapping, 
The main reason is very simple, nothing exotic,
They swell when you begin cycling, of of them do, 
Valance stack 4 in a case, with a terminal like a car battery, but you are locked into their BMS and it sucks, but the case works, 
I am shipping to my client anywhere from 1 to 3 containers a week of ATV, and UTVs but, I placed everything into my own battery case which will number from 4 - 6 cells per case, so all the swelling occurs in the case,
I also do not worry if the cells are lose that there is undue pressure on the terminals from the swelling with the series connectors,
Tiger


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## 88aero (Jul 27, 2010)

I don't suppose I could get the data files that generated the three plots of the 100Ah comparison? Assuming they are in Excel; yes?


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## AndyH (Jun 15, 2008)

88aero said:


> I don't suppose I could get the data files that generated the three plots of the 100Ah comparison? Assuming they are in Excel; yes?


They're not in Excel but can be transmogrified. I can put them on the ACEAA group list as well if you'd like. 

Andy


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## 88aero (Jul 27, 2010)

Thanks! Whatever is easiest for you; several ACEAA members are looking at converting to LiFePO, so we would definitely all benefit. I am saving $s for 55 of the Sky Energy 100Ah units for my MR2. Still looking at Soliton and a new charger though. I think I have the $s for the LFPs, but that Soliton is still out of reach right now..


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