Battery modules

Batteries are one of the most important component in any conversion.
These make up most of the cost of EVs. 

Batteries are also heavy.

To contain costs I did look into using recycled second hand batteries from vehicles that have been in an accident and written off.
I'll also consider to limit my range so fewer battery module would be required. 

Battery type of interest I've encountered are:

• BMW i3 modules - Samsung SDI
• iPace Jaguar - CATL 
• Land Rover / Jaguar / VW - Samsung SDI
• Nissan leaf - (LG?)
• Tesla - Panasonic

I've discarded Tesla batteries as they are overpriced and the configuration of these module would be difficult to arrange in the limited space of my Classic Fiat 500.

Size, weight, and power

BMW i3 modules Samsung SDI cells
28 Kg - 41cm x 32cm x 16cm
44v  60, 94, 120 Ah (there're various Ah options)

CATL 1p4s
11-13 Kg - 26.6cm x 23.6cm x 17.7cm
12.8v  202Ah

CATL 1p6s
12 Kg - 35.5cm x 15.5cm x 11.5cm
21.9v  110, 120Ah

Tesla modules (6s74p - 444cells Panasonic)
26.3 Kg - 68.5cm x 30cm x 7.5cm 
22v  232Ah

Where to find batteries

Ebay is probably where you can find cheaper batteries if you can wait and offer below advertised price.

Car breakers yards like evbreakers.com seem to have good deals too, a little more expensive option could be looking on secondlife-evbatteries.com .

I guess there will be plenty more as more EV and hybrid vehicles start to come to market.

My choice

I have now settled for SDI modules from i3 BMW and I have managed to source 2 modules for just 1 K GBP mark.

The battery chemistry is nickel-manganese-cobalt, the cathode contains also lithium hence is also referred to as lithium or Li-ion battery.

At some point I was considering CATL 1p4s 12.8v 202Ah or 1p6s 21.9v 110Ah (or 24v 120Ah).

Why ruling out Tesla modules? The price, and the configuration, 22v per module I would have needed 4 to get close to 96v supported by my motor. It would be a squeeze to load them on a Fiat 500.

Other places where to source batteries

Evlithium mainly CATL batteries.

Sunray CATL batteries.

Gn-batteries CATL - found advertised at Made-in-china.com - they were offering me 4 modules for 1950 USD including taxes and shipment (35-38days).

    ☝These aren't recycled batteries, so bear in mind the gains for the environment will be lower.

TIP: Looking for failed EV conversion projects may lead to find cheap components.