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One of the nice things about EV builds is that your setup is modular and agnostic to the rest of the system. If you want to add battery capacity later, you can. If you want to upgrade the speed control, you can. If you want to upgrade the dash, you can.
But it's not, really. At the very least, the system voltage matters to every power-handling component. You can't just swap a nominally 48 volt battery with a nominally 360 volt battery like nothing else (such as the controller) will care. I do agree that once an operating voltage range is established, components can be changed individually to a significant extent.
 

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Discussion Starter · #22 ·
This morning I turned my 460lbs of lead and sulfuric acid into $106 cash at the scrapyard.
122396

Cleaned up some stuff in the citicar as well, and snapped a pic of the motor ID plate. Some surprising specs on here, the motor seems to be designed for 36V and I believe the INT signifies intermittent use. I'm not sure if this is going to change my approach to batteries, I still may go with a 48V pack, but it's nice to know I have some flexibility.
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That's presumably the original motor - it exactly matches an EV Album listing for a "1976 Sebring Vanguard Citicar".

The nameplate values of 98 A @ 36 V correspond to 3528 W or 4.7 HP (input), which makes sense with the 3.5 HP output rating. "INT" suggests intermittent to me, too.

From what I have learned about GE DC motor naming in the past few minutes, the entire "5BC 49 JB 320" string is the model identification, and this plate doesn't have a serial number.
 

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Discussion Starter · #24 ·
The battery bank is 48V nominal, but that means it probably has a max voltage of 60V and a minumum of 40V. You need to know what the minimum voltage cut-off is before choosing your lithium pack, or at least it's a good idea. For instance you might think "I want a 14S lithium pack because that gives me a nominal 48V!" but the lithium can be discharged much further than lead-acid, and most of the lithium's energy is in the bottom half vs the top half of the voltage curve. So the car will shut down at 40V but the 14S lithium pack can still be used down to 35V so there's energy left on the table. In this case you could go with a 15S or even 16S lithium pack and just make sure to keep the maximum voltage to 60V max and end up with more range.
I'll definitely keep this in mind. Ideally I'd like to have easy control over the max/min levels for the pack (what voltage corresponds to 100% vs "0%" state of charge).

You'll likely want a more modern charger at some point though, as you'll have way more capacity than stock to recharge and also probably want the option to use public charge points.
What options are there out there for enabling the use of public charge points? My assumption would be that these types of chargers use standard safety protocols that prevent just anyone from plugging /charging anything.

Luckily a 48VDC car is very similar to golf carts as brian_ mentioned so things like motor controllers, chargers, DC-DC converters, even Sepex motor controllers are all readily available and cheap!
It seems like lots of people go with some sort of golf cart motor controller when upgrading these vehicles. I haven't heard of sepex yet, but from a brief ebay search it seems like they can be had for less then $200 with is great.
 

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@MattsAwesomeStuff yes I was not talking specific voltages but just generally that when considering pack voltage the minimum voltage is just as important as maximum. Probably should have made that more clear.

@xevion to use most public L2 charge points you just need a J1772 plug and a subscription to their service, there is no handshake protocol for those chargers and they put out ~240VAC, same as a home L2 EVSE. Can charge much, much faster than using the 120VAC plug that it has now.

You do not actually need a Sepex controller however, looking at your motor you want a "series" motor controller which is also commonly available.
 

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Discussion Starter · #27 · (Edited)
I've got my eye on these 48V 2.2kwh LG server rack modules from battery hookup. $100/kwh is pretty sweet, and if I disassembled them into two sub-modules I bet I could squeeze them under the seat, but I'll have to take some better measurements. I'd probably grab 2 or 4 of them, depending on how much space I have.

They do seem pretty degraded, and might need to be reconfigured to work well though...
 

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What options are there out there for enabling the use of public charge points? My assumption would be that these types of chargers use standard safety protocols that prevent just anyone from plugging /charging anything.
True, but you can buy equipment to work with the SAE J1772 standard for AC charging of EVs, which is used at both public charging stations and home charging points for production EVs.
 

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It's either amusing or sad that these are described as "48 V", given that according to the specs provided in the listing they are 14S in something other than LFP, and as a result have a nominal voltage around 53 volts.

... if I disassembled them into two sub-modules I bet I could squeeze them under the seat, but I'll have to take some better measurements.
It looks like they readily break down into 1S2P cell groups with bolted connections between them so they can be configured as desired. The length of the group fits into the width of the housing, which fits in a "19 inch" rack, which is actually 17.75 inches (450.85 mm) between the vertical rails. Two groups end-to-end would fit in the battery compartment, but if you can only get two groups per layer you could only fit in two modules worth (4 times 7S2P, which could be rewired as 14S4P), which wouldn't be much energy (4.4 kWh as listed, 6.2 kWh nominally if they still had 30 Ah capacity per cell).
 

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@xevion to use most public L2 charge points you just need a J1772 plug and a subscription to their service, there is no handshake protocol for those chargers and they put out ~240VAC, same as a home L2 EVSE.
There is a simple handshake, as there needs to be, under the J1772 standard. It uses signals on the pilot and proximity terminals of the plug.
 

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I just saw this project, I recently bought one and am restoring it. This one looks in really good shape. There are two main facebook groups(C-car and Vanguard Citicar Registry) were there is a lot of good information or if you have any questions. A lot of people have been using 48V chevy Volt Modules and running 4 in parallel. Lastly just as a good rule, before you start driving it, but real tires and not just trailer tires even though they are about 1/4 the price this will greatly increase drivability and comfort.
 

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A lot of people have been using 48V chevy Volt Modules and running 4 in parallel.
There are no 48 volt Chevrolet Volt modules, but there are seven 12S3P modules in a first-generation Volt battery (plus two 6S3P), all bolted together with other modules. A second-generation Volt battery has four 12S2P modules (plus three 16S2P), again all bolted together with other modules. The cells of the two generations have different capacities, so the 12S modules have about the same energy capacity in either generation.

A 12S module of the NMC-LMO LG Chem cells used in the Volt has a nominal voltage of 45 V, so the operating voltage range is relatively close to that of a nominally 48 volt lead-acid battery.
 

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Discussion Starter · #34 ·
There are two main facebook groups(C-car and Vanguard Citicar Registry) were there is a lot of good information or if you have any questions. A lot of people have been using 48V chevy Volt Modules and running 4 in parallel. Lastly just as a good rule, before you start driving it, but real tires and not just trailer tires even though they are about 1/4 the price this will greatly increase drivability and comfort.
I'll be sure to check out these groups. Upgrading the tires didn't even occur to me, but that makes a lot of sense.
 

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Discussion Starter · #35 · (Edited)
Just picked up two of these modules for this project. Glad to have the largest piece of the puzzle out of the way. Based on my measurements they should fit well, maybe even well enough to fit two more in the future should I want more range. Now I'm on the hunt for a beefy 7S BMS that can handle ~200-300A peak. Anyone have any suggestions? Also I want to start thinking about how I'm going to keep those batteries at a happy temperature under use.

I am having some trouble finding good spec listings for those modules, I can't seem to find examples of others using them, maybe because they are so new.

Anyway, battery tech is just amazing. Those two modules alone should give me nearly the original capacity, at less then a quarter the weight.
 

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Just picked up two of these modules for this project.

I am having some trouble finding good spec listings for those modules, I can't seem to find examples of others using them, maybe because they are so new.
That's one of the three different sizes of module found in the 62 kWh battery of the Leaf+:
  • 7S3P (four per pack)
  • 4S3P (eight per pack)
  • 9S3P (four per pack)
The only example of anyone using the Leaf+ 62 kWh battery that I can think of is Rockcrawler and his race 4Runner:
... although others have discussed the possibility.

Those discussions provide illustrations and dimensions of the modules. That project uses an entire pack, but packages the modules differently.

The 62 kWh Leaf+ battery appears to use the same cells as the current generation base Leaf's 40 kWh battery, just in a 96S3P configuration (split into the listed modules) instead of the Leaf's traditional 96S2P configuration (in the Leaf's traditional 48 identical 2S2P modules). So any specs which apply to the cells of the 40 kWh battery also apply to the cells in these 7S3P modules.

7S of the 96S of the Leaf+ pack is 7/96= 7.3% of the voltage, and the same fraction of the energy (4.5 kWh), and the same fraction of the power. The Leaf+ has a 150 kW motor, so a single module can certainly handle 11 kW for reasonable periods (at least a few seconds at a time of acceleration). That's 14.6% of the pack or 9 kWh and 22 kW, at 52.5 V nominal, for two modules.
 

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Discussion Starter · #37 ·
That's one of the three different sizes of module found in the 62 kWh battery of the Leaf+:
  • 7S3P (four per pack)
  • 4S3P (eight per pack)
  • 9S3P (four per pack)
The only example of anyone using the Leaf+ 62 kWh battery that I can think of is Rockcrawler and his race 4Runner:
... although others have discussed the possibility.

Those discussions provide illustrations and dimensions of the modules. That project uses an entire pack, but packages the modules differently.

The 62 kWh Leaf+ battery appears to use the same cells as the current generation base Leaf's 40 kWh battery, just in a 96S3P configuration (split into the listed modules) instead of the Leaf's traditional 96S2P configuration (in the Leaf's traditional 48 identical 2S2P modules). So any specs which apply to the cells of the 40 kWh battery also apply to the cells in these 7S3P modules.

7S of the 96S of the Leaf+ pack is 7/96= 7.3% of the voltage, and the same fraction of the energy (4.5 kWh), and the same fraction of the power. The Leaf+ has a 150 kW motor, so a single module can certainly handle 11 kW for reasonable periods (at least a few seconds at a time of acceleration). That's 14.6% of the pack or 9 kWh and 22 kW, at 52.5 V nominal, for two modules.
Thanks for all the background info/links! I'm currently looking at the Daly BMS offerings, I think some of there largest ones (14S, 48V, ~250A) might be well suited for my needs. I'll probably make a post in the appropriate sub-forum and see what people suggest.
 

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Discussion Starter · #39 ·
I found a Daly on Alibaba and was able to get a 500A discharge/250A charge BMS from them built to order for exactly my pack config. Been using that site more and more always had good luck as long as I talk with a rep first.





That's awesome, that setup looks pretty similar to what I'd be looking for. How much was it if you don't mind me asking? What had to be customized to fit your setup? Does that BMS include any thermal regulation?
 

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That's awesome, that setup looks pretty similar to what I'd be looking for. How much was it if you don't mind me asking? What had to be customized to fit your setup? Does that BMS include any thermal regulation?
It was $440 including 3 day DHL shipping. It has a thermal protection for the BMS itself, but it doesn't have any input for battery temperature.
 
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