DIY Electric Car Forums banner

1 - 20 of 34 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter #1
Hi all!

I am converting a lighter car (900kg) to an EV. For the motor I have chosen the Remy HVH250-90S. I also have the AC controller situation pretty much figured out (thanks P&S Power!).

Now I need to think about batteries. The motor will work with 200V - 700V. The maximum I would push it would be 600A at 700V.

Because it is a small car I am limited to the amount of space the batteries could occupy and would like to stay light. Also I do not need a massive range. Somewhere around 100km(~60miles) would suffice. But I sure would like some power too.

If using Li-ion cells that would amount to an enormous number of them if I also want some torque.
I would like to avoid StepUP boost converters.


Any suggestions?:D
 

·
Registered
Joined
·
4,898 Posts
Because it is a small car I am limited to the amount of space the batteries could occupy and would like to stay light. Also I do not need a massive range. Somewhere around 100km(~60miles) would suffice.
By DIY standards, while that is not a "massive" range, it is still substantial. It might take 20 kWh of battery capacity, and while that's not large by current production EV standards, it's still a big heavy box full.

If using Li-ion cells that would amount to an enormous number of them if I also want some torque.
You will be using some sort of lithium battery, since there is no better alternative. By "Li-ion cells" do you mean the individual prismatic cells, such as those from CALB, that were popular in conversions for a few years? The currently popular approach is to use modules salvaged from production EVs, which (in addition to being less expensive) can be somewhat lighter and more compact by having less packaging around each cell.

With any large-format cell (as used by in most production EVs) you still have the challenge that if you want a high pack voltage you need a lot of cells, and that establishes a minimum pack size. The small cylindrical cells can be combined into a relatively small pack with high voltage and low current capacity, but they are not really practical to custom-package.

If you want to run at the high end of the voltage range, one compromise to get high voltage from a small pack is to use modules from a hybrid rather than a pure battery-electric vehicle, because they tend to be smaller. On the other hand, most non-plug-in hybrids have used NiCd cells, not lithium, so they have inadequate energy storage capacity.

Does anyone know what the smallest roughly 360V lithium pack (presumably from a plug-in-hybrid) might be? Two of them in series would be a candidate package for high voltage; one would be a candidate for a shorter-range pack at a typical modern EV voltage. There's the popular Chevrolet Volt battery, but two of them would still be large (even though mfor1000 is jamming two of them into a 911).
 

·
Registered
Joined
·
733 Posts
Looks like 2, 2018 Mitsubishi Outlander PHEV batteries would fit the bill: https://www.mitsubishicars.com/outlander-phev/2018/specifications

Lithium, 12kWh, and 300V. I don't know about other years. The Toyota High lander still uses NiMH batteries?
Although they won't work with this higher voltage build, the Outlander, has both front and rear electric drives available for DIY use. Somebody probably has or is trying to hack the inverter and other electronic components. The Outlander also has DC fast charge capabilities- a nice addition to a build, if it can be included.
 

·
Registered
Joined
·
4,898 Posts
Looks like 2, 2018 Mitsubishi Outlander PHEV batteries would fit the bill: https://www.mitsubishicars.com/outlander-phev/2018/specifications

Lithium, 12kWh, and 300V. I don't know about other years.
The Outlander PHEV is a series design, so the battery should have good power capacity... good for this application.

Although this model hasn't changed much since its introduction, I remember seeing reports that the battery capacity has increased.

The Toyota High lander still uses NiMH batteries?
Yes. I think all Toyota other non-plug-in hybrids use NiMH, too; the Prius Prime has lithium, but may be the only one.
 

·
Registered
Joined
·
4,898 Posts
Although they won't work with this higher voltage build, the Outlander, has both front and rear electric drives available for DIY use. Somebody probably has or is trying to hack the inverter and other electronic components.
Any of the AWD hybrids which have an electric-only second drive axle (typically the rear) are a possible source of a drive unit of moderate power; however, cooling can be an issue because they are not expected to run at significant power continuously. That includes the Outlander, Toyota Highlander and RAV4, Lexus RX, Acura MDX and Honda Pilot, Volvo XC90... The Toyota units are unique to them; the Outlander uses GKN drive units.

Any hybrid which runs primarily in series mode is a potential source of a drive unit for the engine end (the front in most cases), although it may be difficult to separate the motor and transaxle from the engine and generator, especially in designs with a clutch which can connect the engine to the drive axles for a mechanical high gear (Honda Accord, Mitsubishi Outlander). The only completely series hybrid light vehicle sysem (not bus or truck) that I know of is Nissan's e-POWER system (which is not sold in North America)... but even then separating motor and generator would be difficult.

Two rear drive units - one in front and one in rear - might be adequate for a compact car.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #6
@brian_: Thanks for a comprehensive overview of the current situation in the world of EV batteries ;)


I was looking at CALB cells, then found the smaller capacity Winston(WB-LYP60AHA) 60Ah, it is a LiFePO4 variety. Which means a voltage of 3.65V and less under load. I would need 200 of those cells to have a little over 600v:rolleyes:


Then I stumbled upon this: Enerdel NMC

They come in packs/modules with a configuration of 12s2p


10 modules would give roughly 400V. So 15 of them should do it(=225kg). But we are talking about 10kUSD:D



What are my options? With those cells I still have to make a custom BMS etc.
 

·
Registered
Joined
·
4,898 Posts
... Then I stumbled upon this: Enerdel NMC

They come in packs/modules with a configuration of 12s2p

10 modules would give roughly 400V. So 15 of them should do it(=225kg). But we are talking about 10kUSD:D
This?
ME500-050 Moxie+ Battery Module

Is a maximum of 250 amps - for only 10 seconds at most - the "high current" that you want? It's only 100 kW even at 400 volts, and far short of your 600 amp target.

It looks like they'll sell you 8-module or 14-module complete pack, in a nice box.

With those cells I still have to make a custom BMS etc.
The specs include
Flexible circuits for individual element voltage sensing and 12 temperature zone sensing
So the on-module components appear to be there, but you still need a BMS to use the data from them and manage the battery. The spec sheet might provide more information, but I didn't download it.
 

·
Registered
Joined
·
1,007 Posts
Hi all!

I am converting a lighter car (900kg) to an EV. For the motor I have chosen the Remy HVH250-90S. I also have the AC controller situation pretty much figured out (thanks P&S Power!).

Now I need to think about batteries. The motor will work with 200V - 700V. The maximum I would push it would be 600A at 700V.

Because it is a small car I am limited to the amount of space the batteries could occupy and would like to stay light. Also I do not need a massive range. Somewhere around 100km(~60miles) would suffice. But I sure would like some power too.

If using Li-ion cells that would amount to an enormous number of them if I also want some torque.
I would like to avoid StepUP boost converters.


Any suggestions?:D
Notice on the datasheet for your motor, the S (series wound) version is limited to 300A not 600A.
 

·
Registered
Joined
·
4,898 Posts
The motor will work with 200V - 700V. The maximum I would push it would be 600A at 700V.
I didn't notice this before, but the comment about motor specs made me look at these values again...
600 amps at 700 volts is 420 kW!

Is that really the plan, or did you mean that the motor might be pushed to perhaps 100 amps at as much as 700 volts (at high speed), and at other times to a much higher current (300 or 600 A) at much lower voltage (at low speed)?
 

·
Registered
Joined
·
7 Posts
Discussion Starter #12
The motor is a remy250 but only the cartridge at the moment. It is from the bmw X6 hybrid. Don't worry. I work in a CNC shop, with lots of machines. I will make a housing for it. I may change the hollow shaft with a custom made solid shaft.



The seller told me that he got it to make 175kW at 700v with an industrial inverter and about 63kW at 280volts. I made a mistake with those 600A. That is the maximum current of the IGBTs that I will use with the P&S AC motor inverter/controller.
He also told me that the specs of this motor are not exactly like other HVH250 models, but should be pretty similar to the 90S series. With the stator wired in series.


I would like to run at 600v or more, preferably at 700v for the efficiency and torque - which is dependant on the voltage as I understand.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #14
You could also use 2x Volkswagen Passat GTE battery (9,9kWh, 96s, Samsung SDI high power cells)

or more available: VW Golf GTE battery (also used in audi ..) 8,6 kWh, 96s, Panasonic cells

This seems interesting! Now where to find one for sale. Should I go to a VW dealer? :D
 

·
Registered
Joined
·
4,898 Posts
I would like to run at 600v or more, preferably at 700v for the efficiency and torque - which is dependant on the voltage as I understand.
For a given motor, torque is dependent on current, and the voltage needed depends on the current being driven and the rotational speed.

Higher supply voltage makes higher speeds available (within the rated speed range of the motor), which makes additional speed/torque combinations available for the same power... which may be more efficient than other speed/torque combinations.
 

·
Registered
Joined
·
4,898 Posts

·
Registered
Joined
·
4,898 Posts
The motor is a remy250 but only the cartridge at the moment. It is from the bmw X6 hybrid.
Ah, the classic Global Hybrid Corporation Two-Mode system, co-developed by GM, Daimler, and Chrysler, later joined by BMW. Essentially the same Remy units (two of them) are found in transmissions from all of those manufacturers, mostly in SUVs built for few years starting around 2008. For more specs and any hints for using the cartridge, people working with units from these other vehicles may have information.

Allison started offering this system for buses years earlier, and apparently still sells it as the H 40/50 EPTM Series. They presumably use a larger Remy cartridge, but I've never seen any details. They do run in the higher voltage range of the Remy units.
 

·
Registered
Joined
·
34 Posts
I will be having a similar dilemma in about 3 months time when I convert my E39 (got to get my 'big shed project' out of the way first though!)

I have ordered a nice 320V 25/50KW 45Kg Permanent magnet synchronous motor from china for $1300 delivered and I will be building up the P&S Controller when it arrives to drive it. My current favoured solution which may work for you is to make my own batteries using 18650's. I recently got in touch with a local (NZ) guy who refurbishes balances and tests old batteries for about US$2 each so I will be ordering 400 to do some testing to make a 320V pack then use 9 x 36V (10S40P) Battery packs in series with a simple BMS to power everything.

My current master plan is to use this company Voltaplex and purchase 9 of their 10S20P battery packs which will probably come to around $10K :eek: but should get me the range you are looking for.



Being a small car you are going to be constrained by space and weight, Some government inspectors will not certify your vehicle for road use if it goes over its original designed weight, big motors and big battery packs may do that so its worth taking in to account.
 
1 - 20 of 34 Posts
Top