# Brain dump on Calb or Thundersky.....???????



## DIYguy (Sep 18, 2008)

So, I'm getting pretty serious about buying some prismatic LiFePo4. In order to best fit my current battery boxes...range "dreams" and voltage desires.... I would like to go with the cells measuring 71 x 182 x 280. This is the size of the "older" T/S 200 Ah cells that were available for a while and also the size of the Calb 180 Ah cells. 

All things being equal...lets say I could buy them both for the same price. 

Opinions?

Pros?

Cons?

I've heard the Calb cells carry higher than specified capacity.
I've heard the smaller 200 Ah T/S may sacrifice life cycle when packed in smaller case....
I've had it confirmed that these smaller T/S cells do in fact have 200Ah capacity.
I've heard Calb have a better reputation?????
I've heard.... They both work....
I've heard the Yttrium formulation (which these small T/S cells have) is better for cold weather and perhaps cycle life.
T/S does claim some higher cycles.....
Is Calb using Yttrium now??? (don't think so.... not sure)

Let's say for the sake of argument that price is 1.25/Ah

My desired pack would be 60 units. That's 10,800 Ah of Calb and 12,000 Ah of T/S. At $1.25/Ah......

Calb = $13,500
T/S = $15,000 

Consider shipping/handling brokerage a wash for time being.

Votes???? 

Other points of interest?

I do like the clamping of the T/S better. how much extra space does each of these clamping systems take??? 

Sorry for myriad of questions.... (brain dump).....


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## PatricioIN (Jun 13, 2008)

I'm right there with you on this! The CALB also claim a higher 4C continuous rating, while TS claims 3C. From what I've seen/read everywhere, they seem to be rather equal, with TS perhaps having a slight edge with the addition of yttrium (not that I know what that does for them). But if you're correct about the yttrium allowing them to perform slightly better in cold weather than CALB, then I'd go with the TS. It will be spring before I jump in with my next project, so I'll keep watching for what you decide.

oh, but keep in mind that CALB now has a warehouse and representative in Pomona, CA! And, he's informed me they have a shipment of 100, 130, 180Ah coming in December. Uh, and they also have a 200Ah cell, pdf info attached.


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## EVfun (Mar 14, 2010)

I would like to point out that the CALB document you linked to is pretty current (2010 document) and it list the maximum discharge rate as 2C for 30 seconds. 

I have a pack of TS cells and I chose them mostly because at the time the documentation was better and also because the allowed maximum charge voltage is higher which makes it easier to manage a series string. The batteries are very near 100% charged at 3.65 volts but can go all the way up to 4 and be within the TS specs.


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## DIYguy (Sep 18, 2008)

Thanks for the reply guys. I knew about the Calb presence in CA and have been in correspondence with Keegan. I didn't know about the 200 Ah cells though. Interesting about the 2C spec.....?? hmmm. 
The 180 Ah size fits my application best.

EVfun, can you tell me how much extra space is required for the TS clamping plates? In other words, how much longer must the battery box be to allow for the aluminum plates...??? Thanks.


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## DIYguy (Sep 18, 2008)

EV, do you have the Yttrium T/S cells?


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## JRP3 (Mar 7, 2008)

I have 100ah SE/CALB cells, they all came in between 110-114ah. I've taken them to 1.77V under load, charged a few to 4.0V, pulled short bursts of 5.5C from them, no issues so far. I've not used TS cells but what I've read from others suggests there may be greater variation in capacity and quality, though those issues may have been taken care of. Jack Rickard has used both TS and CALB and seems to favor the CALB cells.


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## RKM (Jun 9, 2008)

DIYguy said:


> Thanks for the reply guys. I knew about the Calb presence in CA and have been in correspondence with Keegan. I didn't know about the 200 Ah cells though. Interesting about the 2C spec.....?? hmmm.
> The 180 Ah size fits my application best.
> 
> EVfun, can you tell me how much extra space is required for the TS clamping plates? In other words, how much longer must the battery box be to allow for the aluminum plates...??? Thanks.


Gary,

I'm working from memory here. I believe the the aluminum is about .370" plus the thickness for the strap and head of the machine bolt. You'll likely need a bit over .5" per end.

Rob


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## DIYguy (Sep 18, 2008)

Thanks JRP, I appreciate that real world experience. I remember you having the Calb cells. Tell me, (not sure where u live) but have you had experience with them in the cold temperatures? Also, if u use the OEM clamping method, how much extra room do you need for these end channels used for compression?? thanks a lot.

Hi Rob, thanks for chiming in. I always appreciate your input. Thanks for the feedback on end space requirements. I was reading about your cooling fans actually coming on fairly regularly.... good info.
Our climate is an interesting challenge to get best out of these. How are the Farnam heaters working? If I recall, you just use these on AC when parked...yes?
Also Rob, are you using any BMS? Did you read all of the Rickerd stuff on top vs bottom balance etc.???

I have to say, it seems obvious about the impending cell destruction at bottom ..when top balanced. 

Did you ever calibrate your CA with a clamp meter? (sorry guys for hijacking my own thread...lmao...) 
Gary


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## EVfun (Mar 14, 2010)

The end plates are up to 7mm thick at the ridges plus up to 4mm more for the screws if they placed a washer under the strap to make it tighter. That means you should leave an extra 22mm for each row. I have a nice block of 40, 60 amp hour TS cells in a 19.75 by 22.5 inch space under the hood.

My cells are Yttrium cells made in February of this year. I have been hitting them with 5C peak discharges and they seem to be happy.


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## JRP3 (Mar 7, 2008)

The CALB strapping hardware sucks, plain and simple. I used cargo straps with a threaded turnbuckle to tighten them down and 1/4 inch plywood end plates:










I've used the cells down to about 30 degrees F so far, uninsulated and unheated, range on a full charge has gone from 50 miles at 85F this summer to around 40 miles in the cold. Voltage sags so amp draw is higher, resistance increases so voltage is driven higher when charging which shuts off the charger prematurely. I've been experimenting with charging to slightly higher voltages in the cold for that reason. Normally when a few cells get to around 3.46 the smallest ones will start to shoot up quickly to 3.5 and above, but in the cold it doesn't happen till about 3.48 or so. Once they start dumping salt on the road I won't be driving it anyway so I'm not going to bother with insulation or heating. I don't use a BMS.


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## tomofreno (Mar 3, 2009)

I think the clamping issue is overblown. I am using the clamps that evcomponents sent with my CALB cells. Just one, about 3/4" wide steel U channel bar, on the middle of each end of a group of cells, tied together with one ss threaded rod on each side. That's it, because that is all I received. In about one year operation I have overcharged a couple cells, one up to 3.9V, another to only 3.7V and not seen any sign of swelling. Both cells still work similar to the others. It seems you have to seriously overcharge them to make them swell.


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## DIYguy (Sep 18, 2008)

Thanks for the pic and info JRP. That strapping looks like it is better than the OEM which concentrates the force in a smaller area. Also, good to know about the effect of the cold temps..... 

Hey Tom, yes I often wondered about the need for clamping. I guess it is pretty much done by everyone...??? I wonder what the correlation is between overcharge and swelling actually is. I don't recall every seeing anything on that...... hmmmm. Thanks...


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## DIYguy (Sep 18, 2008)

At this point, I'm leaning away from an automated battery management system. I'm pretty convinced that one good bottom balancing will protect my cells when coupled with a limited top end charge. (no flaming please) the only reason I mention it here is because perhaps the Calb cells are better matched. Seems there are several reports of better consistency in resistance and capacity. ????


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## PatricioIN (Jun 13, 2008)

DIYguy said:


> At this point, I'm leaning away from an automated battery management system. I'm pretty convinced that one good bottom balancing will protect my cells when coupled with a limited top end charge. (no flaming please) the only reason I mention it here is because perhaps the Calb cells are better matched. Seems there are several reports of better consistency in resistance and capacity. ????


Again, I'm right there with you. I do not intend to use a BMS when I go lithium.


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## DIYguy (Sep 18, 2008)

PatricioIN said:


> Again, I'm right there with you. I do not intend to use a BMS when I go lithium.


what are you planning to build next Pat?


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## EVfun (Mar 14, 2010)

DIYguy said:


> At this point, I'm leaning away from an automated battery management system. I'm pretty convinced that one good bottom balancing will protect my cells when coupled with a limited top end charge. (no flaming please) the only reason I mention it here is because perhaps the Calb cells are better matched. Seems there are several reports of better consistency in resistance and capacity. ????


I want to point out that everybody is using some type of battery management system. You are leaning toward making YOU the management system.  

These newer TS and CALB cells seem to work pretty good with that but you need to do your part. I recommend you mount them so that you can easily read the voltage of each cell. That way you will do it once in a while when charging to make sure they stay in line. Trust, but verify (I heard that somewhere once )


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## DIYguy (Sep 18, 2008)

EVfun said:


> I want to point out that everybody is using some type of battery management system. You are leaning toward making YOU the management system.
> 
> These newer TS and CALB cells seem to work pretty good with that but you need to do your part. I recommend you mount them so that you can easily read the voltage of each cell. That way you will do it once in a while when charging to make sure they stay in line. Trust, but verify (I heard that somewhere once )


Thank EV, I like the feedback. However, not everyone is using BMS... and as time goes on, I suspect fewer and fewer will be. I have to say, Jack Rickard has me convinced (have you looked into it...?, he pretty much proved it) ... and there are others around to verify like JRP (hope u don't mind me throwing ur name in there). I realize I'm the minority....for now. But I have studied it for quite some time now. It just makes so much sense to me .... to not top balance, as BMS's tend to hang their hat on. Economics is a whole other issues. It's been beat about in other places, so I hope to not do too much of it here 
I have full access to all my battery boxes. I put 3 under my box ( it tilts up easily) and 3 smaller ones in under hood.


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## JRP3 (Mar 7, 2008)

Once I learned which cells were my smallest I just check those 4 once in a while when charging, but only if I want a full charge. Most of the time I just under charge and don't check at all. If you have the option it would make your life easier if you could specify cells within 1 amp hour of each other or so. No reason they can't be sorted that way in a production run, even if you have to pay a little extra for the service. The best answer to the BMS issue is closely matched cells.


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## EVfun (Mar 14, 2010)

DIYguy said:


> Thank EV, I like the feedback. However, not everyone is using BMS...


Please go back and reread my first couple of sentences again. I'm betting you are not just blindly charging and driving. I would guess you have put the DMM to enough cells often enough to make some informed choices on charger and discharge settings. I'm thinking YOU are your Battery Management System.


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## jeremyjs (Sep 22, 2010)

I wonder how no BMS will work out over the lifetime of the cells; since no two cells are exactly the same when some age faster than the others will it make a BMS more of a necessity?


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## JRP3 (Mar 7, 2008)

If for some reason you have cells losing more capacity than others and getting out of whack you should probably replace the cells, not try to limp them along with a BMS.


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## jeremyjs (Sep 22, 2010)

What about the fact that you end up using slightly more capacity on the smaller cells than larger cells; which over time will cause them to degrade slightly faster. I don't know that it will cause you problems many years down the road, but see how it might. It was more a question about how much of a difference over time it will make and whether or not it would eventually be an issue when not using a BMS over one to two thousand cycles.


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## PatricioIN (Jun 13, 2008)

DIYguy said:


> what are you planning to build next Pat?


I haven't decided what yet.. I picked up a Warp 9 on ebay for cheap recently though. My garage isn't heated, so whatever it is, it will have to wait until spring!


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## JRP3 (Mar 7, 2008)

jeremyjs said:


> What about the fact that you end up using slightly more capacity on the smaller cells than larger cells; which over time will cause them to degrade slightly faster. I don't know that it will cause you problems many years down the road, but see how it might. It was more a question about how much of a difference over time it will make and whether or not it would eventually be an issue when not using a BMS over one to two thousand cycles.


A BMS can't prevent you from using a greater percentage of capacity of a smaller cell. If you pull 90 amp hours from one cell that's 110 ah and another that's 114 ah it's always a greater percentage of the smaller cell. Obviously not much of a difference though. All a BMS can do is top balance your cells and protect an individual cell from over or under discharge. Staying conservative in your DOD and charging does the same thing and actually should increase the cycle life of the cells more than using a BMS to push the envelope.


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## jeremyjs (Sep 22, 2010)

Not making myself clear. They'll still do more or less the same thing with the BMS, but over time will a BMS be needed more as the cells age differently. Basically after the cells are through half their cycle life more or less will the ever increasing variation in the cells make them harder to manage without a BMS?


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## DIYguy (Sep 18, 2008)

jeremyjs said:


> Not making myself clear. They'll still do more or less the same thing with the BMS, but over time will a BMS be needed more as the cells age differently. Basically after the cells are through half their cycle life more or less will the ever increasing variation in the cells make them harder to manage without a BMS?


Experience from some is not showing this. In fact, cells seem to become more balanced when not influenced with top balancing. BMS's can actually cause you to loose cells. When top balanced, and you hit bottom of the weakest one, you drive hundreds of amps through it driving it to 00 volts and killing it. This has been done and repeated for verification. With bottom balance and undercharge, you don't push them at the top (where incidently, very little energy is stored) and if you hit bottom, it tends to be when they are all @ bottom and you are not pounding high current through one low cell. 
So, yes.. until recently you theory seems to be the popular one... but, I'm not going there. Read Rickard's stuff on it. 
Thanks again!


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## DIYguy (Sep 18, 2008)

EVfun said:


> Please go back and reread my first couple of sentences again. I'm betting you are not just blindly charging and driving. I would guess you have put the DMM to enough cells often enough to make some informed choices on charger and discharge settings. I'm thinking YOU are your Battery Management System.


Yes, you're right! Sorry about that.


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## jeremyjs (Sep 22, 2010)

DIYguy said:


> Experience from some is not showing this. In fact, cells seem to become more balanced when not influenced with top balancing. BMS's can actually cause you to loose cells. When top balanced, and you hit bottom of the weakest one, you drive hundreds of amps through it driving it to 00 volts and killing it. This has been done and repeated for verification. With bottom balance and undercharge, you don't push them at the top (where incidently, very little energy is stored) and if you hit bottom, it tends to be when they are all @ bottom and you are not pounding high current through one low cell.
> So, yes.. until recently you theory seems to be the popular one... but, I'm not going there. Read Rickard's stuff on it.
> Thanks again!


Interesting. Thanks. I'll read into it.


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## dimitri (May 16, 2008)

DIYguy said:


> BMS's can actually cause you to loose cells. When top balanced, and you hit bottom of the weakest one, you drive hundreds of amps through it driving it to 00 volts and killing it.


I really try to stay away from these arguments, since I am biased, but above statement is simply false, so I want to point it out...

I am not saying that you must have BMS, many certainly go without if they know what they are doing, and long term verdict is still out since we don't have 5-7 years of data....BUT lets not repeat idiotic statements made by people who don't bother themselves with facts and logic.

Above statement is ONLY true when simple shunts are used for top balancing, but lets not call that a BMS, because its far from it. Real BMS must at the bare minimum have *cell level HVC and LVC actions*, which will effectively prevent damage REGARDLESS of top or bottom or not-at-all balancing scheme.


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## DIYguy (Sep 18, 2008)

Ok... fair enough.... Thanks for the clarification Dimitri.


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## DIYguy (Sep 18, 2008)

Check this out guys.... http://www.diyelectriccar.com/forums/showthread.php/anyone-purchase-powerscaner-yeti-46890.html

I bumped it up and made some interesting comments.....


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