Large EV battery pack.

[dougnutz]

I just purchased a 99 Ford ranger which has been converted to electric. It’s a nice conversion but the previous owner used flooded lead acid batteries. I think it was a simple matter of batteries were one of the last things he bought and after spending nearly 10k on the conversion he took the cheap option on batteries. From the discussions on http://www.diyelectriccar.com it seems like a lot of people choose lead acid solutions. Anyway the batteries are nearly shot and I bought the vehicle knowing that the batteries would need replaced. So I’m looking at building a large battery pack. The current pack is 144v 140ah (more like 14ah now) with a 500 amp controller. For my use I am thinking about going with Thundersky ( thundersag yes I know)or Calb. I can get an 80Ah pack for about $4000, which rivals the price of the lead acid pack.

View attachment 1

Higher end cells like a123’s are 3 and 4 times as expensive. It’s a given they outperform the thundersky and calb cells but given that I need watt hours more than amps it seems better to go with these options. Or consider staying with lead acid or AGM batteries. What are your thoughts?

I’m asking this question on ES because of the sheer volume of mental horsepower on this site, don’t be afraid of telling me I’m doing it wrong

 

[heathyoung]

Lead cranks out the amps, no question. Is the whole pack shagged or is it one single battery thats dropping the bundle?

Before throwing the baby out with the bathwater, so to speak, I would be having a good look at the whole pack, determining which battery is sick, checking the state of balance (if they are being equalised properly - they are flooded so you can replace the water when you equalise, unlike AGM). Find the odd one out. Ie. specific gravity of each cell. Has it been equalised (ever?) - Equalisation is the lead equivalent of balancing for those unfamiliar with the term.

If they are all tired, then consider what sort of capacity you need for the distances you are travelling, and what the peak currents are so you don't murdur the expensive lithium.

CHL is a brand that is starting to gain some momentum as well - they have a lower voltage droop under load vs thundersag and sky energy too.

I'm putting in AGM's in a vectrix at the moment (because they were free, weigh 30Kg more than the original NiMh battery(120 vs 90kg), and because they are free) but am also thinking of using some exotic chemistry lipo to combat the sag - I think GGoodrum or Fetcher had an EV1(?) that he did this with. All depends on the money situation at the moment.

 

[liveforphysics]

Any form of Lithium you can afford to put in there will be a massive improvement over any lead.

If you're looking for thundersag/clones, make sure you get the yttrium doped version. Much lower resistance.

 

[dogman dan]

I would think you'd be looking at closer to 200 ah of thunderskies to have any real range. Not sure how it would perform with 80 ah, you'd be needing to limit amps to 160 or so.

That's the pretty high volt, pretty high amp controller, Mabye it would perform ok ish with less amps and volts once you dump the weight. Mabye go 100-120v and 200 amps? Then 100ah of lifepo4?

Perhaps a good strategy might be to get new lead, and then pop for a bit of lifepo4 to paralell with it?

I dunno, I always figured it myself, that a lifepo4 pack for a heavier conversion like the ford would cost at least 15,000.

 

[Gordo]

I just purchased a 99 Ford ranger which has been converted to electric. For my use I am thinking about going with Thundersky ( thundersag yes I know)or Calb. I can get an 80Ah pack for about $4000, which rivals the price of the lead acid pack.
What are your thoughts?
I’m asking this question on ES because of the sheer volume of mental horsepower on this site, don’t be afraid of telling me I’m doing it wrong

I think you need a 180-200Ah pack.
Randy has built many Ford Rangers;
http://www.canev.com/

 

[dogman dan]

I haven't kept up with what is going on with car conversions. I wanted one really bad, then was looking at motorcycle conversions, then could afford a bike. Now I just love the bikes too much to think a lot about a converted car.

But it seemed to me, that the truck conversions had the advantage of carrying a pile of lead easy, but the disadvantage of a lot of weight to begin with. The result was a need to carry even bigger batteries. like 200 ah for a truck.

But wouldn't it be possible to get similar range out of 100 ah of lifepo4, simply because you can discharge to 80% instead of wanting to stop at 50% if you run lead? That leaves just the problem of the high amp controller pulling too hard on only 100 ah of TS. I still think perhaps that 500 amp controller needs to go.

 

[mihai_atanasiu]

A 500 A controller with 144 V equal 72 kW; about 90 HP;

 

[dougnutz]

I haven't checked the specific gravity I just tested the voltage across each battery after the charger signals "CC" Each battery was exactly 13.45 volts. I don't really think that means much for lead though. Anyway current range is about 3-5 miles and the batteries all drop to about 10 volts resting so I am pretty sure the pack is a gonner. But like I said I expected to buy a battery.

From looking at what others are reporting and from various online calculators the truck should use about 480 w/mi to cruise at 55. My goal is to start with about 60Ah of lithium. And use the truck for short range hops. Most of my trips are less than 4 miles round trip on 35 mph roads. I think the pack will do ok at this level. I can then work on things and save up some money to increase the pack size (add another 60 AH) maybe next spring. Most of the feedback I got from the people on DIYelectriccar seemed to think 100Ah would be enough. And I would love to have the extra capacity but... for now 60 should work for short trips and getting the kinks out of the build.

If you're looking for thundersag/clones, make sure you get the yttrium doped version. Much lower resistance.

These are the cells I am leaning toward at the moment. I did see that some of the thundersag specificly mentioned the yttrium but these Calb batteries don't mention it directly. http://www.calibpower.com/ProductDetails.aspx?p=2&id=2

 

[dogman dan]

60 ah + 500 amp controller. I dunno dude. Can the controller be programmed to run say 100 amps?
Might be better off to just get lead, as murder lifepo4. I don't completely understand that chart though, it says recomended 18 amps, but 600 max for 10 seconds. But nothing about what would happen when you are cruising at say 3-4c discharge rate, which is still only 240 amps.

I just think you are going to really need a lot bigger pack of lifepo4, unless they are A123 or at least headways.

Till you get your big lifepo4 pack together, it could make a ton of sense to run that thing on a 72v 240 amp controller. Then you can take your 60 ah and run it as 120 ah. Then 2c discharge rate is there for sure. Sure, no freeway speed but your pack has a chance that way.

 

[dougnutz]

Well I don't think the controller is programmable. But I am purchasing a CA for the truck I'm pretty sure I can tie that into the throttle to limit current. These calib cells seem to be rated at 4C with 10 C max (for 10 seconds)

In what little driving I have done with this truck it seems to pull 100-200 amps normally. I was able to hit 400 amps full throttle up a hill but the voltage sag was horrifying so I didn't do that very long.

I hope I am not fooling myself thinking I can pull 100-200 amps out of these cells for short trips which would be 1.5- 3.33 C respectively. I don't want to kill a $4k battery pack.

I could smash the piggy bank and get 100Ah cells that would drop the normal useage to 1-2C .

Would it be possible to parrallel the two packs as a short term solution? I didn't think it was a good idea to mix chemistries like that...

 

[liveforphysics]

I would advise against this cell:

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


If you're going the thundersag/clone approach, you want this cell:

http://en.winston-battery.com/index.php/products/power-battery/category/lyp-battery

If you go over 100Ah, the next step up is a pretty big one at 160Ah.

Virtually everyone that goes with normal thunder-sag/clones (the non-yttrium ones) has a very sad face and a soggy EV. The Yttrium batteries are really better by a substantial amount.

 

[dougnutz]

I'm wondering if I would be better off going with 64 ah of headways. They have a better C rate so I would be less likely to hurt them until I can afford a larger pack.

 

[liveforphysics]

I'm wondering if I would be better off going with 64 ah of headways. They have a better C rate so I would be less likely to hurt them until I can afford a larger pack.

About 5x more work to make a pack from them, but yes, they definitely perform a large step better than the thundersag/clones.

You could make the upgrade to more fairly painless if you built the pack as rows of busbars, all drilled and ready to mount the additional parallel cells you need, and just populated them with cells as budgeting permitted.

 

[dougnutz]

Yeah, the idea of stringing together nearly 200 cells is not apealing at all (400 connections ugh). Plus the fact that more connectors to come loose increases the chance that it would happen and result in a damaged/melted cell connection.

So if the choice was 64 ah of headways vs 80 Ah of thundersag?

I may crack open the piggy bank to get the extra $$ for 96ah of headway vs 120Ah of thundersag

At somepoint simplicity and capicity is going to win over power. I don't want to be checking 2 connections on 288 cells.

 

[dougnutz]

I would advise against this cell:http://www.calibpower.com/ProductDetails.aspx?p=2&id=2If you're going the thundersag/clone approach, you want this cell: http://en.winston-battery.com/index.php ... yp-battery

LPH help me out. The concensus I get from the Diyelectriccar forums seem to be wishy washy between calib and thundersky batteries. One user pointed me to a direct comparison of the Calib and Thundershy (lifeYPo) the test seems to indicate the Yttrium hurt the cell performance.

http://jackrickard.blogspot.com/search?updated-max=2010-05-14T11%3A36%3A00-05%3A00&max-results=7

here is the test result View attachment 1Cbatterytests.xls

 

[liveforphysics]

Just an an alternate approach, I'm seeing lots of Nissan Leaf's running around (at least in the bay area here they are common). This means they are going to start showing up in wrecking yards.

Plug-in Prius packs are also going to start showing up in wrecking yards.

I almost never see GM Volt's here, but they are bound to start showing up, and they have the best cells on the planet right now in them if you can scavenge one.

 

[Gordo]

If you're going the thundersag/clone approach, you want this cell:

http://en.winston-battery.com/index.php/products/power-battery/category/lyp-battery

If you go over 100Ah, the next step up is a pretty big one at 160Ah.

Virtually everyone that goes with normal thunder-sag/clones (the non-yttrium ones) has a very sad face and a soggy EV. The Yttrium batteries are really better by a substantial amount.

Luke;
I find all manner of contradictory information. Such as Winston "purchased" ThunderSky. Winston is ThurderSky, etc.
And from Winston's website;
""Originally founded as "Thunder Sky Green Power Sources Co., Ltd" in 1998, based on his invention of lithium-ion vehicle battery technology, Mr. Winston Chung has since built the Winston Industrial Park, containing manufacturing plants for rare earth LiFeYPO4 cathode material, LiFeYPO4 vehicle batteries, rare earth permanent magnet synchronous motor/controller, as well as assembly plants for lithium vehicle battery production equipments and pure electric vehicles.""

Are they two companies or now one?

EDIT;
This site lists Winston, Thundersky and Calb all as branches of the same company.
http://www.lithiumstorage.ch/index.php?option=com_content&view=article&id=19&Itemid=49

 

[liveforphysics]

I would advise against this cell:http://www.calibpower.com/ProductDetails.aspx?p=2&id=2If you're going the thundersag/clone approach, you want this cell: http://en.winston-battery.com/index.php ... yp-battery

LPH help me out. The concensus I get from the Diyelectriccar forums seem to be wishy washy between calib and thundersky batteries. One user pointed me to a direct comparison of the Calib and Thundershy (lifeYPo) the test seems to indicate the Yttrium hurt the cell performance.

http://jackrickard.blogspot.com/search?updated-max=2010-05-14T11%3A36%3A00-05%3A00&max-results=7

here is the test result

Interesting test. Our 40Ah thunder-sag samples with the LYP part number rather than LFP are really a big improvement in resistance. Jack doesn't know a battery from a cinder-block, it's entirely possible he never did a few cycles to complete the formation charge process before testing the cells.

 

[dougnutz]

Jack doesn't know a battery from a cinder-block, it's entirely possible he never did a few cycles to complete the formation charge process before testing the cells.

LMAO good to know.

The wrecking yard is an interresting idea, but I'm a little worried about the condition of the pack after an accident that totals the car. Given the mass of the battery it seems like it could easily distort it's case and tweak the cells. Maybe that doesn't matter.

 

[scotticeberg]

I thought dow/kokam cells in the leaf were superior to the lg chem cells in the volt? Are they both lithium nmc?

 

[Gordo]

Jack doesn't know a battery from a cinder-block, it's entirely possible he never did a few cycles to complete the formation charge process before testing the cells.

LMAO good to know.

I didn't author this one, but I agree. Jack is a guy with a lot more BS than brains. He continues to confuse wealth with smarts. He pays an idiot to wire things up which burn and then blames the component.

 

[liveforphysics]

I thought dow/kokam cells in the leaf were superior to the lg chem cells in the volt? Are they both lithium nmc?

Leaf uses NEC brand cells which are NMC chemistry.

Volt uses LG NMC cells, which are the best EV cells in the world at the moment. That said, they are over 2 years old now, meaning LG all ready will have secret cells that are much better.

 

[dougnutz]

what would you do?

245 ah of trojan floodies for about 4k delivered.
or
120 ah of thundersag lifeYPo for 8K delivered and in another year add 4k more for a total of 180ah (12K total)

1. The truck already has floodies so the swap would be simple.
2. With the LifePo I would need to limit the controller to about 250 amps to keep from hurting the batteries.


I can already hear the chant "lead is dead" but I would hate to murder a set of 8K batteries by over discharging, thus the 250 amp limit. But that effectively make the truck a 45-50 hp truck.

 

[Gordo]

what would you do?

245 ah of trojan floodies for about 4k delivered.
or
120 ah of thundersag lifeYPo for 8K delivered and in another year add 4k more for a total of 180ah (12K total)

1. The truck already has floodies so the swap would be simple.
2. With the LifePo I would need to limit the controller to about 250 amps to keep from hurting the batteries.


I can already hear the chant "lead is dead" but I would hate to murder a set of 8K batteries by over discharging, thus the 250 amp limit. But that effectively make the truck a 45-50 hp truck.

I will assume you would use 40 cells? Therefore 40 X 120Ah X $1.40 = $6720 40 X 160 X 1.4 = $8960
Once again I recommend you call Randy and you will find he has vehicles with 5 years on their LiFePo4 and still going strong. You would be very fortunate to get 2 years out of lead in the same conditions, so do the math and the initial cost does not look so bad. The weight saving is huge, which changes the performance too. The TS cells I purchased last year were at $1.35 per Ah, but I imagine there has been an increase.

 

[auraslip]

I used to drive a converted ford ranger for AAA battery installs. It only had probably 20-30 12v automotive batteries in the back at a time, but it was still a boat. Almost flipped it taking a turn too fast when some awesome wheel shake kicked in. Scared the hell out of me. Also we had to upgrade the suspension... and the airbags we installed blew out multiple times.
Can't imagine 140v140ah of lead! Would not like dealing with that.

That being said, have you looked into goodrums nano-tech "stiffie" packs? He had good results with his GEM. Lot less sag, and a lot better range because of less pekuert effect.
Seems like a cheap way to get some of the benefits of lithium. Hell, it might be good to do with lifepo4. Been thinking of throwing nano-tech packs in parallel with cheap packs myself.

BTW, what sort of wh/mile is expected from a full size conversion going 40-50 mph?