[cre8tiv]

Hi Everyone,

I just wanted to introduce myself to all. I'm completely new to the forum and looking forward to planning my ev build.

My thoughts are to convert a Mazda RX8. I've been doing some research and there seems to be a few around that have successfully been converted.

My skill level is intermediate I would say. I can sevice aswell as change parts etc.

My fear is with the electricals. I'm hoping this part of the job is not too scary!

I'm looking to find a balance between range and performance. I think I would gravitate more towards range.

Budget wise, I have not set one just yet. I want to be realistic and make it a worthwhile investment. Therefore I'm open to suggestions as I have no idea what would be a realistic figure that I will need for the project.

I've been inspired by Eric Tischer's VW Passat.
http://etischer.com/awdev/
http://www.youtube.com/watch?v=2tFSVniO_Cc
I was really impressed with how much thought he has put in to the project, such as the little details!
So if I can convert the RX8 to have some of the clever features like Eric's car, I'll be a happy chappy!

Parts wise, I've only got so far as considering the electric motor. As so far as I can see, I might be completely wrong about this, but I am hope to get a motor that regenerates the batteries while coasting or braking and as so far as I can see if I get an Electric Motor with AC Brake Motor, that will do the job. But please correct me if I am wrong.

Thats it for now, I've not purchased my RX8 just yet so if anyone is selling one in the UK for a good price, please let me know!

I look forward to hearing your thoughts

Thanks

 

[skooler]

I'd suggest a read of my build thread (in my sig). I'm slowly battling through all of the 21st century stuff. Got the Power steering, ABS etc working, just need to get the dash gauges to work now!

I'm only in Malvern so if you want a go feel free to pop down the M5!

You'll probably find that AC is not quite powerful enough for this heavy car at any reasonable cost. I'd reccomend a 1000 amp controller such as the Soliton1 and a Kostov11 alpha.

I have a 600A controller and 10" milk float motor and performance is reasonable but not great.

If you put a figure on your budget then you'll probably get a few more ideas in. Once I fit my new battery pack, charger etc I'll be at about £20,000, 120-150BHP and 120+ mile range to give you an idea.

Good luck!

 

[Siwastaja]

I'm looking to find a balance between range and performance. I think I would gravitate more towards range.

Hi,

A nice thing in EV "theory" is that you don't balance between range and performance; instead, they go hand-in-hand.

When you add range, you add performance, because larger battery pack can supply more power at higher efficiency.

If you decrease range, you decrease performance, unless you take special measurements to avoid this (this is, use higher power batteries, which are more expensive).

So, increasing range by buying a larger battery pack (of the cheap cells) is the easiest way to increase power that the battery pack can be deliver. Then you can think the extra range as a "free bonus". This is why I find it funny that some people build a small battery pack using expensive "high discharge" cells while they could get the same performance with longer range for the same money. [There are some special cases where minimizing pack weight really makes sense.]

Budget wise, I have not set one just yet. I want to be realistic and make it a worthwhile investment. Therefore I'm open to suggestions as I have no idea what would be a realistic figure that I will need for the project.

For batteries, about $5000 absolute minimum which will get you about 50 km range with usable but maybe not especially good performance. The more, the better.

For motor, controller and charger, between $5000-20000 total depending on performance. Too much for me, which is why I'm DIYing everything except battery cells.

 

[cre8tiv]

I'd suggest a read of my build thread (in my sig). I'm slowly battling through all of the 21st century stuff. Got the Power steering, ABS etc working, just need to get the dash gauges to work now!

I'm only in Malvern so if you want a go feel free to pop down the M5!

You'll probably find that AC is not quite powerful enough for this heavy car at any reasonable cost. I'd reccomend a 1000 amp controller such as the Soliton1 and a Kostov11 alpha.

I have a 600A controller and 10" milk float motor and performance is reasonable but not great.

If you put a figure on your budget then you'll probably get a few more ideas in. Once I fit my new battery pack, charger etc I'll be at about £20,000, 120-150BHP and 120+ mile range to give you an idea.

Good luck!

Hi Skooler,

Thank you for your advice and feedback regarding my project.
I'm chuffed that you are so local! I've been to Malvern before, love the stunning views from the hills!
I'll definitely be up for a visit to see your RX8 and take some notes if thats ok?

Has the conversion been difficult or straight forward?
What speeds are you averaging on a 120 mile range?
How much has the project cost you minus the car?

Many Thanks

 

[cre8tiv]

Hi,

A nice thing in EV "theory" is that you don't balance between range and performance; instead, they go hand-in-hand.

When you add range, you add performance, because larger battery pack can supply more power at higher efficiency.

If you decrease range, you decrease performance, unless you take special measurements to avoid this (this is, use higher power batteries, which are more expensive).

So, increasing range by buying a larger battery pack (of the cheap cells) is the easiest way to increase power that the battery pack can be deliver. Then you can think the extra range as a "free bonus". This is why I find it funny that some people build a small battery pack using expensive "high discharge" cells while they could get the same performance with longer range for the same money. [There are some special cases where minimizing pack weight really makes sense.]

For batteries, about $5000 absolute minimum which will get you about 50 km range with usable but maybe not especially good performance. The more, the better.

For motor, controller and charger, between $5000-20000 total depending on performance. Too much for me, which is why I'm DIYing everything except battery cells.

Hi Siwastaja,

Thank you for your advice regarding batteries. I think I will take your suggestion and go for cheaper ones. I was initially looking at expensive Optima Batteries thinking they will make a difference. They cost on average £250 EACH!!!
http://www.ebay.co.uk/itm/OPTIMA-BT...rElectronics_Batteries_SM&hash=item53e6b28f5e

Should I look for deep cycle gel marine batteries?
How many batteries should I consider buying for my project as a minimum? Would 10 batteries be sufficient?

Many Thanks

 

[skooler]

Hi Skooler,

Thank you for your advice and feedback regarding my project.
I'm chuffed that you are so local! I've been to Malvern before, love the stunning views from the hills!
I'll definitely be up for a visit to see your RX8 and take some notes if thats ok?

Has the conversion been difficult or straight forward?
What speeds are you averaging on a 120 mile range?
How much has the project cost you minus the car?

Many Thanks

Your more than welcome.

The mechanical side of the conversion is reletavely simple, as was the elecrical stuff on the HV side. the problems have all come from from things like CANbus being used for power steering and the dash guages.

To be clear, I don't have a 120 mile range at present, I'm in the process of upgrading from lead to lithium. 120+miles is the estimated range after the upgrade.

I'm curently at about £5,000 plus the car, will be at more or less £20,000 after the battery and charger upgrade.

Hope this helps!

Cheers,

Mike

 

[cre8tiv]

Your more than welcome.

The mechanical side of the conversion is reletavely simple, as was the elecrical stuff on the HV side. the problems have all come from from things like CANbus being used for power steering and the dash guages.

To be clear, I don't have a 120 mile range at present, I'm in the process of upgrading from lead to lithium. 120+miles is the estimated range after the upgrade.

I'm curently at about £5,000 plus the car, will be at more or less £20,000 after the battery and charger upgrade.

Hope this helps!

Cheers,

Mike

Hi Mike!
I think I have seen your video on Youtube of you test driving the car in the unit car park, when I was researching EV RX8's! By Any chance is it Team Mike & Dave?
You are the reason I am choosing to do the RX8! So thanks for that!

Thanks for the heads up about the CANbus issues. I'm sure I'll be hitting that problem very soon
Wow! For £5000 you have a running electric car!?
Are you looking to hold on to your lead acid batteries or will they be up for sale?
I think I will do the same as your self, which is to start off small, and get the basics going and upgrade at a later date.
Thats quite a steep cost for a battery and charger upgrade.
I'm trying to look for the Siemens electric motor that is 90hp, but I can't find one anywhere at all. How many Kw is your electric motor?
What type of distance are you getting at the moment with your current batteries?

Thanks
Shaz

 

[skooler]

Hi Shaz,

Yep fully working. I initially wanted to prove that a modern car could be done for cheap. I kinda failed due to the range issues I am having but other than that its perfect.

I have since caught the bug and want a decent range!

The batteries, and battery boxes could be up for sale as will the charger. The batteries (alphaline DC31 - 125AH * 12) dont quite cut it for EV use. Good for testing and getting into everything but only practical for short journeys.

The battery boxes will fit Trojan Batteries that are much better suited for EV use.

If your interested in any of that then drop me a PM, I'm about to rip it all out and swap for lithium so it'll just end p getting put into storage.

My motor didnt really come with much info. It was an eBay win for £150 with no nameplate!

The previous owner said it was rated for 11KW. I have since cleaned it up, re-varnished, new bearings, etc. and have run about 85KW through it with no heating issues whatsoever I suspect it could handle whatever my Soliton Jr can throw at it!

If you can get the Siemens motor then great! Although it wont be anywhere near as simple as Series DC for a first build and there aren't really that many benefits, especially when compared to cost!

Just an FYI 90HP is about 65-70KW.

Distance is up and down dependent on weather and how it is driven! anything between 4 and 15 miles - hence the lithium upgrade! I think the equivalent Trojan batteries would manage 25-35 miles.

Hope this helps

Cheers,

Mike