# Calb Battery discrepencies?



## todayican (Jul 31, 2008)

Can anyone shed some light on the discrepencies on the CALB spec sheets?

This one found at Current Ev Tech, and most of the other sites have something roughly similar:

http://www.calibpower.com/ProductDetails.aspx?p=2&id=3

This one on Calb's own site:

http://www.calibpower.com/ProductDetails.aspx?p=2&id=3


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## Tahoe Tim (Feb 20, 2010)

Your links appear to be the same. However, one doesn't open. 

Please describe the discrepancies in your post. I doubt many will print out and study both spec sheets to play "where's waldo".


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## todayican (Jul 31, 2008)

Duh, sorry about the link mistake:

Here is the other one: http://currentevtech.com/Lithium-Batteries/CALB/CALB-100ah-cell-p30.html

The differences include a massive indescrepency over constant C output.


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## Tahoe Tim (Feb 20, 2010)

I happen to have a set of these on order. From everything I could dig up, the 4C rating is correct. 

Most EV designs that I have looked at tend to size the pack for 1C constant discharge without issues. No one really knows the true life of the pack at a given C discharge. I looked at AGMs and lead and quickly came to the conclusion that even at a 1000 cycle life, Lithium beats lead all day long. A 100 AH cell is about equivalent to the most popular AGM capacity when figuring in the relative voltage sag of lead.

We will see soon enough!


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## todayican (Jul 31, 2008)

I couldent agree more Tim, im buying Batteries in the next 30 days (Need to get over the shock of spending 2500 on the rest of the drive system first) 

But is is sort of disturbing to see the "mother ship" revising C rates..


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## ElectriCar (Jun 15, 2008)

If you want to get long life out of them you need to size the pack appropriately. High discharge rates=short life or so I've read. Thus the recommendation of 0.3C discharge. I'm sizing my pack to operate normally on flat ground at 0.3-0.4C, with hills and acceleration going to 1, maybe 1.5C for a few seconds. 

My truck will weigh about 3450Lbs with the new pack and use about 350wh/mile or so. The voltage I'm increasing to about 168V for extra range AND to lower the C because higher voltage = less current for a given Kw.


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## JRP3 (Mar 7, 2008)

My pack is sized that normal driving is around 1.5C with bursts to 5.5C when I'm feeling frisky  Since I take the car off the road in the winter and don't normally discharge below 50% SOC I don't expect to see any ill effects show up for many years if ever.


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## ElectriCar (Jun 15, 2008)

OK JRP, how many miles you got on it now and what battery you running?


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## JRP3 (Mar 7, 2008)

SE/CALB 100ah, about 5K miles.


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## DIYguy (Sep 18, 2008)

todayican said:


> Duh, sorry about the link mistake:
> 
> Here is the other one: http://currentevtech.com/Lithium-Batteries/CALB/CALB-100ah-cell-p30.html
> 
> The differences include a massive indescrepency over constant C output.


The 12C is "burst" or about 5 msec. The other one, (which I think may be different for different size cells) is 5.5 (for 180ah) to 8C (for these 100's) or so for 10 seconds.


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## Tahoe Tim (Feb 20, 2010)

8C for up to 10 seconds? I was going to set my controller for 4C max. I'm going to be at 1600 to 1800 lb total weight so I shouldn't need more than 4C except for going up and down to mountain passes. I live in a bowl at the lake and the only way out is over a mountain pass in any direction. 

Are any of you guys aware of a cheat sheet of EV formulas. I should have written them down as I went along. How about a list of EV formulas in the FAQ?​


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## ElectriCar (Jun 15, 2008)

What formulas you referring to?


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## Tahoe Tim (Feb 20, 2010)

Never mind. I went back to the posted wiki and made a quick cheat sheet. I rewrote the battery sizing formulas backwards to allow me to plug in different wh/mi numbers and solve for range for a given battery rating. 

I am using 1C instead of .4C for my battery amps. It seems to be pretty conservative. Agree?


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## ElectriCar (Jun 15, 2008)

1C is much better than a lot of folks are using. I think most of that is probably due to people buying a smaller pack to save money, which is an issue no doubt, but prismatic batteries really aren't capable of doing hi C discharges without deteriorating the cell somewhat. 

Calb, regarded as the best cell on this board I think, recommends discharging at 0.3C. If it were ok to run at 2C or more continuously don't you think they would post that? They don't because they want you to conserve the battery for longer life so they don't have to warranty cells I imagine. 

I suspect 1C is fine as they probably have a built in cushion above the 0.3C for added measure but how much is anyone's guess.


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## Mr_tim (Dec 13, 2010)

OK, I'm confused a bit. I was looking into getting a CALIB 180AH pack for my truck, 48 for a nominal voltage of 144V. The recommended discharge rate is .3C? That's only 54 amps. The spec sheet does say it can do 1000A for 10 seconds. My lead acid truck weighs in at 4000 pounds right now, it'll lose about 1300 pounds if I switch, but 54 amps isn't going to be moving me around fast enough to be useful. I had my limit set to 250 amps on the lead and it had OK performance, I was under the impression it would get allot better with lithium. What is a "reasonable" discharge limit for these cells that will still make them last?
Thanks,
TiM


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## ElectriCar (Jun 15, 2008)

They will do 500A easily BUT if you want to maximize live for your $11000 investment you would want to keep it as low as possible. 

Just an FYI, I'm ordering their 200Ah and they are just a tad shorter (180 I think) on the long side than the 180's (185?) so they will fit in the space of a lead battery easier. 

My existing rack is made for 7.25" X 10.25" batteries. In each space left by a lead battery I'll be able to squeeze in two 200's with space left over. I think it's about 5 in place of two lead batteries. In any event I'm able to get 50 in my existing racks that now hold 22 US2200XC batteries.

I think they aren't selling so many 200's because they don't push them but they do fit better in existing racks than 180's.


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## JRP3 (Mar 7, 2008)

I can't say how it will effect longevity but I don't know of anyone running .3C. .5C-1C seems to be the norm.


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## tomofreno (Mar 3, 2009)

The general rule often heard for "prismatic" or "large format" cells (in contrast to smaller Ah cylindrical cells like Headway or A123) is no more than 1C for cruising, no more than 3-4C briefly during acceleration. This is not based on many years of data on cell lifetime versus discharge rate (we all wish!), but just what people think seems reasonable based on the manufacturer's spec's and some very spotty anecdotal data. So by this guideline, if you want to pull 250A in normal cruising you should use about 260Ah cells or larger. But 200 Ah cells would likely work without much hit on lifetime, but who knows?


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## Tahoe Tim (Feb 20, 2010)

Tim,
Besides following all the li cell powered cars, I actually based my cell size on lead cars out there. I ran the calcs on the best AGM including all the derating factors in the FAQ. It showed that a typical lead cell was really about 100AH of usable capacity. That's why I am using 100's.

For your heavy lead truck, a set of 100's will give you equal performance, anything bigger will improve range or will improve acceleration if your controller can take the extra amps. 

I also picked 100's because it's my first build and I consider it half of the pack I really want. Once I get it running, I may double it up with another set of 100's.


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## ElectriCar (Jun 15, 2008)

Tahoe Tim said:


> Once I get it running, I may double it up with another set of 100's.


That was my thinking about a month ago when I was really mulling this thing over. After considering lifetime issues I decided to take the plunge and go for the 200. My cruise will be about 20-50A I suspect on nearly level roads. For hills I have seen nearly 300 trying to maintain 50mph. However losing 18% of my total curb weight after ditching the lead, upping the voltage & lowering sag, I'm *hopeful *to see a decline to maybe 200A or less on those hills. 

My operating voltage will go from maybe 110-120V due to sag at 300A to maybe 150-160V with the 50 new Calb batteries at 150-200A.


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## DIYguy (Sep 18, 2008)

The Alibaba page on Calb 180's indicate a 4C continuous discharge rating.... who really knows... http://cali-battery.en.alibaba.com/product/220762247-200593204/SE180AH_Vehicle_Battery.html


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## Mr_tim (Dec 13, 2010)

I didn't see the 200s listed on their products page here . I was looking at the 180s Vs the 400s. The 400s would give me over 100 miles easy, but out of my price range. The 200s would be doable. That would put me at about a 60 mile range. I think I'll take a run over to their Pomona place and see what they have in person. I called and was trying to get the strapping requirements. I think It'll be easier to see them in person. Keegan told me he had the 180s in stock....

TiM


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## MN Driver (Sep 29, 2009)

400Ah cells would be physically fairly large as well for most EVs and although they are lighter than lead acid, 400Ah cells would be heavy, especially with a set of, say 40 or 50+ of them. I'm not sure of anyone using anything larger than the 260Ah cells and those bigger cells are being used in a small quantity of 36 cells.

Back to the 100Ah and doubling the pack later, remember that there is a certain amount of weight and size that gets wasted in the plastic and terminal connections(both internally and externally). If you are thinking to double it later, be sure to measure everything out and be sure you will actually be able to do it. You might find that cells in the 160-200Ah range would fit and a doubled up 100Ah pack might not.


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## JRP3 (Mar 7, 2008)

DIYguy said:


> The Alibaba page on Calb 180's indicate a 4C continuous discharge rating.... who really knows... http://cali-battery.en.alibaba.com/product/220762247-200593204/SE180AH_Vehicle_Battery.html


I don't think that is correct. When they say "continuous" they really mean longer than a few seconds. I think most places list CALB's as 4C for 30 seconds "continuous." That mostly relates to internal cell heating beyond spec I think. They will certainly put out more for longer periods but you risk overheating and damage.


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## MN Driver (Sep 29, 2009)

Jack Rickard did a test on 4C discharge, I think he went at 5% intervals at 400 amps on a 100Ah cell at 4C, he ended up pulling them beyond the max heat they should have been pulled to and continued even when voltage dropped to well below spec. He was basically trying to kill them. He succeeded in venting the cells and I think he destroyed all but one or two if I remember right. It's on one of his evtv.me weekly videos on his site.

Based on the numbers including heat and the voltage profile it looks like pulling 4C for an extended period would probably be fine if you generally did it above 70% depth of discharge, that last 30% when the voltage took a dive and heat started to rise much quicker should have been the signal to stop IMO. I don't think this should be used for design though as ambient would have to be a controlled temperature which is a vehicle environment, it really isn't ever controlled well.

I think these are plenty capable of the 10 second max ratings from the en.calb.cn site, of course you would have to have a stop period and not continue with a continuous discharge to allow cooling if you did the max 10 seconds and I think the continuous number was to develop an ideal discharge rate for cycle life testing. I doubt that 1C is a challenge for them and I think 2C continuous wouldn't be much of an issue. Extreme cold temperatures will limit what you can really pull from them due to the internal resistance being higher in the cold and if the cells overheat, that is when you have issues, but I don't think 2C would overheat a CALB cell unless it was baking in the back of a car in Nevada all day or somewhere else hot like that before driving.


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## JRP3 (Mar 7, 2008)

Yes Jack did that test and some cells vented and ended up with reduced capacity, though they did take another charge. What we don't know is what sort of localized internal damage might result from extended 2C or higher currents. That might add up over time to reduced capacity and cycle life.


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## ElectriCar (Jun 15, 2008)

Here's the data Keegan sent me on the 200A cell. "For the dimensions of 200Ah cell, 180mm x 98mm x 279mm. I also attached the specification for your reference."

When I spoke to Keegan he told me he was going to bring in 50 additional SE200AHA cells when he ordered mine. I think that is what he said anyway. They do make them but he doesn't stock them. He sent me a PDF spec sheet on them I could email to you if you're interested. 

If people start asking for the 200AH cells he'll start stocking them I suspect.


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