DIY Electric Car Forums banner

1 - 20 of 31 Posts

·
Registered
Joined
·
2,494 Posts
Discussion Starter #1
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....;):D
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).....
 

·
Registered
Joined
·
893 Posts
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.
 

Attachments

·
Registered
Joined
·
2,222 Posts
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.
 

·
Registered
Joined
·
2,494 Posts
Discussion Starter #4
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.
 

·
Registered
Joined
·
8,106 Posts
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.
 

·
Registered
Joined
·
292 Posts
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
 

·
Registered
Joined
·
2,494 Posts
Discussion Starter #8
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...) :eek:
Gary
 

·
Registered
Joined
·
2,222 Posts
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.
 

·
Registered
Joined
·
8,106 Posts
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.
 

·
Registered
Joined
·
2,318 Posts
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.
 

·
Registered
Joined
·
2,494 Posts
Discussion Starter #12
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.:confused: Thanks...
 

·
Registered
Joined
·
2,494 Posts
Discussion Starter #13
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:p) 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. ????
 

·
Registered
Joined
·
893 Posts
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:p) 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.
 

·
Registered
Joined
·
2,222 Posts
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:p) 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 :eek:)
 

·
Registered
Joined
·
2,494 Posts
Discussion Starter #17
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 :eek:)
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 :eek:
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.
 

·
Registered
Joined
·
8,106 Posts
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.
 

·
Registered
Joined
·
2,222 Posts
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. :D
 

·
Registered
Joined
·
370 Posts
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?
 
1 - 20 of 31 Posts
Top