openinverter forum

Hey all,

I am currently building a sportscar with an LDU in. I am really struggling with the battery choices. Obviously the Tesla 90 battery pack is an easy install with the BMS, thermal managements and of course the density is great. The Tesla 3 batteries are just too long for my build so they are out.
People have also said the LG Chems will also give a much bigger punch per lb. Is that academic or would this be noticeable in the real world.
The spec on the Renault Zoe 41kwh packs seem good weight with the LG Chem battery, but not sure about the thermal management.
Obviously everyone rants about the Chevy volt batteries...…
Do any of the others give a better punch than the Tesla

Please can someone shed some light.

Many thanks to you all

Take a look at the EIG C20 cells (on sale here: viewtopic.php?f=12&t=216) they are rated for 5C continuous and 10C for 10S. They come from a racing car developer surplus stock. They are a bit heavy for energy density but really good for power density.

I can imagine you want a sportscar to be light. Have a look at ZeroEV's build of a Porsche Boxster on youtube. They use 12 Tesla/Smart modules. 350V and 36KW at 250kg.

tmotion wrote: ↑Thu Mar 26, 2020 8:35 am I can imagine you want a sportscar to be light. Have a look at ZeroEV's build of a Porsche Boxster on youtube. They use 12 Tesla/Smart modules. 350V and 36KW at 250kg.

That is a Small Drive Unit (SDU) not Large Drive Unit (LDU)

Batteries that have been in the Zero-EV Skyline:
-Chevy Volt Gen1
Pros
1. Cheap
2. Watercooling built in
3. Reuse OEM BMS Slaves
4. Limited Sag at peak draw of 1400-1500 amps
5. Small Weight

Cons
1. Low energy density - 15-16kWh
2. Large Bricks

-Chevy Bolt Pack
1. Limited Sag at peak draw of 1400-1500 amps
2. Low profile modules (110mm height if im correct)
3. Energy - 55-60 kWh

cons.
1. Large foot print
2. No available BMS
3. No integral water cooling


Other batteries you can consider are the 16S LG chem modules used by EV west and the like. You would need 12 of these (6S2P) but these lack integrated cooling.

It will just all end up coming down to balancing your requirements:
1. Money, how much are you willing to spend
2. Space, how much usable space is there
3. Weight, how much additional weight can the car handle
4. Energy, how much range do you want to have
5. Cooling, how long do you want the performance for

Did anyone try using a pack from an e-Golf yet?

Thank you so much for the responses guys. Lots to think about.
I just looked at the E Golf batteries, but these seem to be very heavy.

Forgot to say it seems very hard to get Chevy batteries over here in the UK especially newer spec.
Would a Tesla pack sag that badly under full load compared with the LG?

Yes a Tesla pack sags quite hard under load, it all comes down to what sort of load you can put on it and how full it is ect.

If you want large range go Tesla. If you want low weight and do not care about range go with LG Chem 16S modules.

Thanks Tom.
What does anyone know about the Zoe 41kwh batteries as they are LG and seem to come in at around 200kg. Would they be the same as the Chevy batteries?

I have a Zoe 40kwh pack in my E46 touring. Will be doing some driving testing soon.

Clanky wrote: ↑Thu Mar 26, 2020 5:58 pm Thanks Tom.
What does anyone know about the Zoe 41kwh batteries as they are LG and seem to come in at around 200kg. Would they be the same as the Chevy batteries?

I think the most they can manage is 350A. I belive this is according to main fuse. Does anyone have better info?

Fab thanks. What’s the thermal management on them and are they the same as the Chevy volt?

Clanky wrote: ↑Thu Mar 26, 2020 5:58 pm Thanks Tom.
What does anyone know about the Zoe 41kwh batteries as they are LG and seem to come in at around 200kg. Would they be the same as the Chevy batteries?

Thing is LG is not LG, people use a brand to represent a whole range of cells NOT correct.

No they will not be 200 kg for 41 kwh, it weights 305kg in a pack : https://insideevs.com/news/332275/renau ... isualized/

The ZE 40 pack uses the LG e63 https://pushevs.com/2019/02/10/renault- ... ery-specs/

Article also shows great info on degradation

Thing to note the E63 is rated by LG for a 2.5-3C discharge so a 44Kwh pack could output 132Kw.

Even at these rates the cell can sag to 2.5V which would be a real limit you want to use, and keep in mind this on 'datasheet values' so with an aged pack this is alot worse.

Busted again.
Looks like it’ll be the Chevy volt/bolt or the LG used by EV west.

Does anyone have a good place to get the Chevy stuff in the uk?

Cheers again all

Clanky wrote: ↑Thu Mar 26, 2020 6:34 pm Does anyone have a good place to get the Chevy stuff in the uk?

You know right the Chevy Volt is the Opel Ampera / Vauxhall Ampera.

Just look for anyone breaking them.

Thanks Tom.
Yes I do, but still no joy yet

tmotion wrote: ↑Thu Mar 26, 2020 8:35 am Have a look at ZeroEV's build of a Porsche Boxster on youtube. They use 12 Tesla/Smart modules. 350V and 36KW at 250kg.

I am researching my EV conversion with the LDU also, got the new board, trying to work out Battery option. My question is that the LDU on Model S is 350V, each Model-S battery module is 22V, if I want to use them, I have to string 16 in series to get 350V. Using 12 would only give 264V. Would that limit the capability of the motor? or am I missing something here?

I am looking to build enough range for around 150miles. The way I see it now looks like LG chem's 60V battery would have enough flexibility for serial / parallel combination for the high voltage and range needed.

Anyone know a good resource for the Volt / Bolt battery specs?

Maverick441 wrote: ↑Thu Mar 25, 2021 5:11 am I am researching my EV conversion with the LDU also, got the new board, trying to work out Battery option. My question is that the LDU on Model S is 350V, each Model-S battery module is 22V, if I want to use them, I have to string 16 in series to get 350V. Using 12 would only give 264V. Would that limit the capability of the motor? or am I missing something here?

I am looking to build enough range for around 150miles. The way I see it now looks like LG chem's 60V battery would have enough flexibility for serial / parallel combination for the high voltage and range needed.

Anyone know a good resource for the Volt / Bolt battery specs?

264V will limit you a good bit, if you don't need all the LDU power it *should* be fine, but if you don't want all that power no reason to use LDU.
Zero-EV's build uses slightly different batteries, that's how they run with 12.

LG Chem's 60v batteries are very popular for good reason; excellent power output, generally good price, etc. but they are becoming harder to find.

Maverick441 wrote: ↑Thu Mar 25, 2021 5:11 am Anyone know a good resource for the Volt / Bolt battery specs?

https://github.com/kerrymann/EVbatterie ... mmary.xlsx