# Austin Mini - Conversion



## sparkey (Dec 8, 2008)

As a major gas guzzling owner (Landrover Discovery TDV6) I've been prompted to look at buying another (not replacing!) car for the wife to use. She has just started a new job that also involves going to college 1 day a week, involving a 30 mile round trip.

So I was thinking I could kill 2 birds with 1 stone as it were. I been itching to buy a fast toy for some weekend fun so got to thinking how about combine them both.

I really hate the dreadful souless modern small cars, so am kind of set on using a classic mini (a van if I can get one) as the donor car.











Are there any decent UK suppliers for the kits and batteries or is it an import job ?

In terms of performance I would like 7 sec 0-60 and a range of around 50 miles. Ideally a method of switching the car from performance for fun and miser mode for commute, is that is at all possible.

I know bugger all about engines, but am competent with electrics.

cheers

Sparky


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## dtbaker (Jan 5, 2008)

the combination of 'high performance', range over 40 miles, and very limited space means you will have to go with Li and probably have to do a fir bit of suspension work to carry more than stock weight (even w/ Li) to get the voltage for performance and total energy for your range..... and its going to be pricey because of the Li.


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## Sutitan (Feb 23, 2009)

Check out this build
http://www.evalbum.com/2407

His website is down, but i still think you can find a video or two on youtube about it. I remember that it was a pretty quick car.

Here is a link that I managed to find
http://www.youtube.com/watch?v=g9BL0qtt8Gs

50 miles would probably require Lithium. they would also probably satisfy your performance needs, granted that you get a large enough controller and motor. Your build could be possible with LA, if you drop your standards a bit. Im just now learning about LA's since they have become a possibility for my build, but from what ive managed to gather is that AGM's are more suited for performance and floodies are better for ranges. Its your choice 

Edit: Found his youtube page w/ all his videos!
http://www.youtube.com/user/phillalex82#p/u


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## Woodsmith (Jun 5, 2008)

You can also join the Battery Vehicle Society in the UK for local information in suppliers and parts. Their forum is a lot slower moving then here though but most of their members are within reach for direct assistance.

I am off to meet some of their members tonight.


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## John (Sep 11, 2007)

Obviously with a classic Mini it would be difficult to use the original gearbox as it is basically in the sump of the engine. This will complicate the mechanical side of the conversion by having to adapt another gearbox to the car. On the plus side the car is very light and has unassisted brakes and steering. I wouldn't be too keen on the van. I had one for a few years and the body would flex due to the opening in the back for the doors. The panels either side of the back door cracked in the corners due to the continual flexing of the body. Problems like this would also make the vans quite rare.


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## dtbaker (Jan 5, 2008)

John said:


> Obviously with a classic Mini it would be difficult to use the original gearbox as it is basically in the sump of the engine.


explains why that other chap used a Swift tranny....


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## sparkey (Dec 8, 2008)

Thanks for all the replies. The Li-on look good but are soo expensive.

It's going to have to be traditional batteries. I need to find out of there is a recharge point at the collage as this is the longest trip (38 mile round trip). So this could help with the range issue.

What about old forklift motors, worth looking at ?

Lastly does all the electronics gubbings under the bonnet need sealing against the wet ?

Sparkey


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## dtbaker (Jan 5, 2008)

sparkey said:


> ...the longest trip (38 mile round trip).
> What about old forklift motors, worth looking at ?
> ...all the electronics gubbings under the bonnet need sealing against the wet


with a small car; (12) 8v golf cart batteries for a 96v system might just get you 40 miles, but not at 'high performance'. (12) 12v golf/sweeper batteries would, but I don't know if you have the room or suspension for it. 

I would stick with a new 8" motor if you want performance and highway speed... and very few of the electronics need to be 'enclosed.' You might wanna check my build site for what I put into my 'component' box which I constructed from battery box material (polypro). The motor should be protected from direct splashes into the brushes....


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## MalcolmB (Jun 10, 2008)

Hi Sparkey
I reckon the original Mini is a great choice for conversion partly because of its timeless appeal and partly its low weight. That's why I'm planning to convert one myself. Having said that I think it would be a shame to load down such a sprightly car with a load of lead acid batteries. A Mini van would have the load space, but they're like hen's teeth – very difficult to find – a good one is likely to cost you at least as much as a decent-sized lithium pack plus motor.

It's a shame the Australian guy with the Suzuki Swift conversion seems to have dropped out of sight as this looked like a good setup and he was originally talking about selling conversion plans. Does anyone know what happened there?

As for parts availability in the UK, the only place I know where you can buy most of the components you need is here: http://www.avt.uk.com/
Last time I looked prices were very expensive and I'd recommend comparing them with the prices plus shipping from a reputable US supplier such as: http://www.evcomponents.com/


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## vpoppv (Jul 27, 2009)

Do you mean the Holden Barina? (I had to look that up because I thought it was a Geo Metro!). I think he's just driving it:

http://www.youtube.com/user/lpgas1

I'm envious of his awesome coupler and adapter plate!


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## MalcolmB (Jun 10, 2008)

Not seen that one before. No, I meant the Mini conversion with the Suzuki gearbox that's linked to in post #3, this one: http://www.evalbum.com/2407


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## vpoppv (Jul 27, 2009)

Wow! Interesting choice. Probably light, cheap, small, and plentiful; however, those transmissions are not known for durability. Of the 5 Metro 5-speeds I own, only one has a non-problematic transmission. But then, there are a lot of Metro transmission kits for EV use.


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## sparkey (Dec 8, 2008)

Thanks for the links, everything-ev sell a kit for the old Rover Metro which should be pretty similar to the mini. It uses AC motor at 96V and incorporates regenerative breaking.

My concern is this is too low a voltage to expect decent performance. From what I've read it seems 120+ is needed.

The kit, excluding batteries is £6000 which does seem expensive.

I guess what I need to find out is what voltage/amps I will need to make a loaded up mini do 60 in around 7 seconds and have a top speed of at least 80 for safe motorway use. And then see what the range is like!

Any calculators that can do this ?

Also checking battery prices, £285 for a 12v 100AH Lead Acid http://www.everything-ev.com/odyssey-12v-100ah-pure-leadtin-dry-battery-p-233.html

Or $120 (yes dollars) for 3 x 40AH Lifepo4 http://www.evcomponents.com/ProductDetails.asp?ProductCode=TS-LFP40AHA

Am I comparing apples with apples in terms of power rating and capacity ?





thanks


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## dtbaker (Jan 5, 2008)

sparkey said:


> It uses AC motor at 96V and incorporates regenerative braking.


at 96v the performance will be good, but more like 12 sec to 60 mph I bet. you'll want 120v, and still may not get 7 sec. The AC will increase range in urban driving maybe 20%, but cost a lot more, and require a few more parts (like invertor and cooling) that you may not have room for in a mini unless you completely give up all cargo space.



sparkey said:


> Any calculators that can do this ?


try this
http://www.evconvert.com/tools/evcalc/



sparkey said:


> Also checking battery prices, £285 for a 12v 100AH Lead Acid http://www.everything-ev.com/odyssey-12v-100ah-pure-leadtin-dry-battery-p-233.html
> Or $120 (yes dollars) for 3 x 40AH Lifepo4 http://www.evcomponents.com/ProductDetails.asp?ProductCode=TS-LFP40AHA
> Am I comparing apples with apples in terms of power rating and capacity ?


...not really. with Li you wire some in parallel and then block in series usually to get the voltage you want. Also important that the aH of a block of Li also limits your MAX draw without damage. i.e. 3x rated aH is ok for short burst, but not extended drive. you probably need 100aH blocks to allow 300a-500a max, and 100a for extended driving at highway speed.
The Li is going to cost 3x-5x as much, and further complicate as you need a good BMS and a really good charger to prevent damage.


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## sparkey (Dec 8, 2008)

thanks for the reply, I am a little confused on the batteries though.

I was assuming 3 LifePO4 connected in series would give 12.75V 120AH 'single' battery for the cost of $132 or less than half the cost of a 100AH Lead Acid.

What am I missing ?

cheers


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## dtbaker (Jan 5, 2008)

sparkey said:


> thanks for the reply, I am a little confused on the batteries though.
> 
> I was assuming 3 LifePO4 connected in series would give 12.75V 120AH 'single' battery for the cost of $132 or less than half the cost of a 100AH Lead Acid.
> 
> ...


I would bet that EACH of the cells is $132.... so $396 for a 12v block for comparing to a single 12v battery, plus $25 per cell for minimal 'volt-blocher' BMS.... so more like at least $471 per 12v block.

Lowest price I've seen around is roughly $1.10 per AH per cell plus BMS. which still adds up to 2.5x cost of FLA for equiv aH, although far less weight, and (perhaps) 2x or maybe 3x the life.


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## sparkey (Dec 8, 2008)

Well their website says $44 per cell http://www.evcomponents.com/ProductDetails.asp?ProductCode=TS-LFP40AHA

Now I am confused!


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## efan (Aug 27, 2009)

first i want to say that i am just an enthusiast not a professional..so if i am wrong please correct me but...

4 (TS-LFP40AHA) in series will give you 12.8v and 40AH.

if you want to build the amps up you need to wire them in parallel

4 (TS-LFP40AHA) in parallel will give you 3.2v and 160AH,
which I think is pointless since you can just go with larger cells say TS-LFP100AHA, and wire them in series until you get the desired voltage.


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## dtbaker (Jan 5, 2008)

sparkey said:


> Well their website says $44 per cell http://www.evcomponents.com/ProductDetails.asp?ProductCode=TS-LFP40AHA
> 
> Now I am confused!


efan has it right I think..... the three cells in series give ya 12v nominal, but only 40AH. A good FLA will give ya closer to 100ah at 75amps. so you need to compare apples to apples for a given aH and voltage.

for your example, note that the cost per aH is right around $1.10, but you need enough cells in series to get up to desired voltage. You would want to go with 100ah or 120ah cells rather than parallel the 40s together.


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## Sutitan (Feb 23, 2009)

You almost had me confused for a second there. the cells your are looking at are rated at 3.2v and 40ah. you would need 4 of these cells in series to have 12.8v 40ah or 38 of them in series for 120v or 45 in series for 144v if you wanted a system of 144v 120ah you would need 135 cells in a s45p3 configuration. at 44 dollars a cell thats 5940 which ends up being about 6600 shipped to you. I am however pretty sure that this pack would meet your needs, if not surpass them.


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## sparkey (Dec 8, 2008)

ok I understand, in series you do not get an increase in AH.

So I would need 3 x (3x40AH packs) a total of 9 cells to give a single 120AH unit. This would cost $270 which is still a hell of a lot cheaper than a single Lead acid 100AH at £285.

Obviously it is better to use the larger sizes to keep the weight down. Still I was expecting Li to be much more expensive rather than on par or cheaper than Lead Acid. At least in the UK.

Now to find a more local source for the LI to cut down the freight costs....


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## efan (Aug 27, 2009)

sparkey said:


> ok I understand, in series you do not get an increase in AH.
> 
> So I would need 3 x (3x40AH packs) a total of 9 cells to give a single 120AH unit. This would cost $270 which is still a hell of a lot cheaper than a single Lead acid 100AH at £285.
> 
> ...


I dont really know how you get your numbers...but 9 cells @ $44 = $396 (this is just for the cells BMS not included)
in addition you should use 3.2v per cell when doing your calculations:
3cell in series will give you 9.6v not 12.8v.
I am not trying to convince you to use Lead Acid vs Li or anything...just trying to help


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## MalcolmB (Jun 10, 2008)

To get a mini with 50 mile range using lithium you'll need a battery pack with a capacity of at least 10 to 15 kilowatt hours, probably closer to 15 if you enjoy pressing the go pedal.

The cheapest currently available cells that will fit your needs are Thundersky or Sky Energy. As a minimum, I'd suggest using 40 Thundersky 100Ah cells wired in series to give a 120 volt (nominal) 12 kWh pack. This would cost $4,400 plus shipping + battery management system + charger (from evcomponents – I haven't found any cheaper).
(Just a side note about lithium phosphate cells – for calculation's sake they're generally considered to have a voltage of 3V, so it naturally takes four cells to make 12V. One of the reasons is that the voltages are close enough that you can get away with charging four lithium cells with a 12V lead acid battery charger, with some tweaking and cell monitoring). 

I personally wouldn't consider trying to fit enough lead in a mini to get 50 miles range – you would be well past the point of diminishing returns – loading on more lead just to accelerate lead.

To get close to 0-60 in seven seconds the simplest/cheapest off-the-shelf combination would probably be a 8-inch series DC motor with Synkromotive controller. To be sure of achieving this sort of performance, or achieving it repeatedly without overheating stuff, you're likely to need a 9-inch motor and Zilla Z1k or EVnetics controller, but then you'll also need bigger cells to feed them with enough electrons.


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## sparkey (Dec 8, 2008)

Thanks for the replies, I didn't know that 3v was used as a nominal voltage.

Using Malcolm's example of a 40 batt 120V system, when fully charged at 4.25v per cell this would be a 170V system. Will this effect the electronics at all ?

Also i thought wiring bats in series left you with no AH, so 40x 100AH batts in series would still only give 100AH @ 120V ? This doesnt seem a lot of capacity ?

I'm guessing the controller is the devide that decides how fast you can burn your batteries, can it be programmed to say dump the max it can handle and conversely go into 'miser mode' for trips ?

When 'having fun' 10 mile range would be perfectly fine for example.

Apologies for all the noobie questions!


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## Woodsmith (Jun 5, 2008)

Having 100ah at 120 volts is not a problem. It is the Watt hours that you are interested in.

For example 
120v at 100ah is 12,000Wh
12v at 1000ah is 12,000Wh

They are the same amount of energy which is what you need to know to determine range.

If your car uses 200Wh/mile then at 12,000Wh capacity you will drive 60 miles.

The real difference is the current flow.
At 12v you will draw 10 time the current that you will draw at 120v and high current will give you a lot of heat, voltage drop and energy loos in the system. High voltages will reduce the current and allow cooler components and less losses.


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## MalcolmB (Jun 10, 2008)

sparkey said:


> when fully charged at 4.25v per cell this would be a 170V system


Although the Thundersky data sheets give 4.25V as the fully charged voltage, it seems generally accepted that to maximise battery life it's better to limit charging to 3.7-3.8V. In practice the cell voltage drops quite quickly once disconnected from the charger, to a resting voltage of around 3.35V.


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## sparkey (Dec 8, 2008)

well after some thinking and reading up on others conversions of a mini I think I maybe am being too ambitious due to the mechanical stuff that is not straightforward (gearbox, space for motor etc).

The only other option is a good old MR2.

What do you guys think ?

thanks


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## Woodsmith (Jun 5, 2008)

sparkey said:


> The only other option is a good old MR2.
> 
> What do you guys think ?
> 
> thanks


Have a look at my build thread. I am working on a 1991 MR2 mk2 GLimited so if you go that route I have lots of information for you. Also Samborambo is working on the same in NewZealand.
There is also the Kickngas MR2 and the Jon Cutshall MR2 and Brian's mk1 MR2.

If you join the MR2 owners club it will make their heads spin that there will be two electric MR2 running around!

Where are you based? Maybe we can help each other out.


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## Barry W (Mar 1, 2010)

Sparky

Am interested to find out how you are getting on with your Mini conversion as I have two 1275GT clubmans in the shed. One is completely in parts and the other is a runner. 

I figure that with an auto box it should not be too hard to convert to Electrics and have the box off an 850 but ust new to the Idea of building a round town runner with a dfference.

Can you let me know how thigs are progressing....

ps, pleased to hear about the LandRover owership, have driven these all my working life starting with a series 1 soft top. My last working vehicle was a 110 country 5 door V8 before LR replacements got too expensive. Currently committed to Suzuki.

Regs

BJ


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## Woodsmith (Jun 5, 2008)

Also interested in how you are getting on. Mini or MR2?

I am starting to think the MR2 is overly complex in its standard car electrics. I am starting to wish I had kept my old MGB GT, that would have been easier to convert as it is such a simple car with a decent amount of space.


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## dtbaker (Jan 5, 2008)

MalcolmB said:


> Although the Thundersky data sheets give 4.25V as the fully charged voltage, it seems generally accepted that to maximise battery life it's better to limit charging to 3.7-3.8V. In practice the cell voltage drops quite quickly once disconnected from the charger, to a resting voltage of around 3.35V.


The common 'nominal' voltage used for sizing things up is 3.2v per cell.... so a 120v system is 38 cells.


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