Planning a build...

[Tweety]

Well, I have been lurking a good while now... So I'm finally starting to collect the parts for converting a car to DC...

I'd just though I'd run my ideas by you to see if I got things straight...

I have been reading a lot here especially about the "Electro-Metro", the "Forkenswift" and the Cougar motor controller... I like the idea's and the commitment here to DIY with a small wallet approach... My conversion will defintely be on a tight budget... It's in the beg, borrow and *beeep*, and if that fails, then you buy stuff category as far as budget planning goes...

Unfortunately I won't be able to use the Cougar to start with... To have even the slightest chance of getting the car through inspection here in Sweden every large part needs to be CE certified... Ie a DIY controller is out of the question for inspection...

So the plan is to get the car set up for 8 batteries, run them in buddy pairs for 48V and run either a Curtis or Alltrax controller for inspection and then switch to 96V and a Cougar... Hopefully at that time I will be able to re-sell the controller and make most of my money from that back...

I will need to have some monitoring system for both engine and battery pack as I will be starting with used batteries... I was thinking the LED stacks from Forkenswift would be good, along with an Amperemeter for the batterypack and one for the engine... Would it be redundant to have a voltmeter on the total battery voltage as well? Is there any other instrumentation that would be useful?

Setting up the tacho to give me engine RPM is easy enough, and it seems like usefull information to get me in right gear for optimal engine RPM...

So far the car I'm looking at is a VW Polo, or similar... should come in around 2200 lbs finished which is close to stock weigth...

Should be able to make a battery tray where the fuel tank was for 4-6 batteries and then stick at least 2 batteries in the front where the radiator was, then depending on how many fits in the rearbox the remaining will have to share space under the hood with the rest of the stuff... It's kind of vital that I'm able to keep all the seats and the cargo space... I might be running into trouble getting 4 fullsize (and weight) adult in the car, but two adults and two kids should work fine...

For the motor, right now I have two leads for two forklifts that I can get for free if I haul them of the premises for the prevoius owners, so one of those motors should be good to use... (And I have access to a flatbed and a loader so it should be easy...)

I have 36 used 12V/75Ah marine GEL batteries in unknown condition... The previous owner said some 4-5 of them are basicly dead and that atleast 10 of them had been used less than 12h but he didn't know which one's where which... My price...? Get them and the rest of the junk out of his storage space... Took me 2 hours of sweating... But it beats paying for new...

For charging I haven't really been able to figure out a defintive answer as any charger I buy for a 48V system becomes useless for 96V (or any other voltage) and getting an onboard 48V charger that is CE marked is beyond my budget even to begin with... Five small 12V chargers, one for each buddy pair and one for the 12V battery should work for the initial 48V setup... But 9 of them? there has to be a better solution... Especially since I really need to run this of a 240V 16A fuse, or worst case two of them...

Now I welcome you all to poke holes in my plan and help me improve it...

Yeesh, long post, hope somebody bothers to read it...

[Daox]

Welcome to the site. Its good to see another conversion happening.

BTW, individual chargers is actually a great way to go when using used batteries since it tops each one off individually and deals with some balancing issues.

[MPaulHolmes]

I have no holes to poke in your ideas! Sounds good! Joe has been developing a DIY charger that you might be able to make. I've been using 7 individual chargers, and it has worked really well too. I can't believe you have 36 free batteries! Holy cow you are going to be able to do this thing really cheap!

Please take pictures of your process. This is exciting! Also, some pictures of the mother land!

Cheap DIY adapter plate and coupler isn't the easiest thing in the world. They aren't too expensive though. Ben Nelson went with a very cool and simple coupler that seems super strong. I've been using L-95 lovejoy couplers, which was like $20. It hasn't given me any problems.

[Tweety]

Heh... fabrication isn't really a problem... My father is into restoring old bikes and cars, so I pretty much grew up with a tool in each hand... If I'm not able to weld up or cut whatever I'll need I'll just point where to do what and he'll do it...

I'm on my 5'th? at least I think it's that many customized bike myself (this one has been through a few iterations, an so have a few of the previous, so counting is a bit difficult) and I have stopped counting the cars... My mother has set a non-negotiable limit of maximum 50 projects in the workshop, divided between me, my father and my brother... We keep moving stuff about so she won't figure out the exact amount, but I think there is roughly 60 bikes in parts and 7 cars in running order and 2 in non working order...

I actually convinced her the other day that this one doesn't count against the total, since it's electric...

My reasons for doing this is simple... I enjoy riding bikes which isn't very eco friendly... I go racing several times a year in a 1000 HP Dodge Viper (admittedly running on e85 fuel but still not eco friendly...) My way of balancing is that my "daily driver" during the summer through town is a pedal bike, good for me and good for the environoment... When I'm going further I either take the bike or if I need to bring stuff I have an old clunker standing around... It also comes into service in the winter months when using a 2 wheeled vehicle become a life threatening event...

So for around town driving in the summer when I need to carry stuff around and for the winter daily drives I'm thinking a EV will do the job quite nicely...

Now my thinking as far as cars go have always been a bit different than most around me... I see no real point in having a new super extra deluxe station wagon or similar as a "normal car"... If it has 300 hp it's still a boring A-B car... It's still kinda underpowered when you compare to 1000 hp... And like a lot of people have said... 90% of the time I'm only going across town... Well in range and at a comfortable speed for an EV...

So it simple... If I use an EV for this I kind of balance out some of the things I do for fun... And I believe if more did it this way, the impact of the old or new, but maintained "enthusiast vehicle" won't really have an impact compared to the lazy people commuting alone in a SUV...

[Tweety]

Oh... Back to topic... Yeah the batteries are free, but I'm pretty sure I will have to weed out a few of them that are unusable, so I won't really have 36 of them... I'm happy to get me the 8 I need for my planned 96V and a few spares... I'd gladly pass the rest of them along if there wasn't a big pesky puddle in the way...

There will be pictures, don't worry... But I kind of doubt I can compete with some of your youtube creations...

Oh BTW... And I'm far from rich... All my work on cars and bikes so far has been made mostly with used parts, traded parts for others and building/machining what is needed... With a father that in his life has been both a car and bike mechanic professionally and a CNC operator and a brother that works as a programmer and me being an electrical engineer (circuit designer, RF/MW field) we kind of have most bases covered...

BTW here's a few pic's of my current bike (or rolling project as people keep referring to it... ) First one as I bought it, fairly stock just a few aftermarket parts bolted on, second as it is now (or was, the snow/ice season just started here so it's already in pieces... again...)

SuperHawk Forum - Tweety's Album: Tweety's Firestorm - The beginning

SuperHawk Forum - Tweety's Album: Tweety's Firestorm

[mora]

Hey, sounds very nice project. We're converting a '89 VW Golf to dc electrics. I'm planning to use those led bargraphs like in forkenswift too. I designed a pcb for those, see http://ecomodder.com/forum/showthrea...tor-11064.html for more info. I was able to fit 9 of them on a single 160x100mm pcb. I thought this might help you.

Good luck with your project. Keep us updated with pics

[Tweety]

Unfortunately I do that stuff for a living and I can see a some things in the design that are big no-no's... Makes me cringe... But that's just professional concerns, it obviously works... Sorry, don't mean to put anyone down...

So I'll probably re-do it...

[mora]

Originally Posted by Tweety

Unfortunately I do that stuff for a living and I can see a some things in the design that are big no-no's... Makes me cringe... But that's just professional concerns, it obviously works... Sorry, don't mean to put anyone down...

So I'll probably re-do it...

Hehee, no worries. I'm no designer or electrician, I make those for fun/educational purposes.

[bennelson]

Sounds like you are off to a good start!
I will try to answer any more specific questions once you get going, but yes, individual battery chargers are a good thing. (Just make sure they can all turn on automatically.)

Used batteries can be trouble trying to keep balanced. You will need some sort of individual battery monitoring to weed out the bad from the good.

[Tweety]

Well... So far I have a lead on CTEK copies at $55 a piece... That's going to put a big hole in my budget...

But then again they are proven to work, a friend had two and we hooked up four of my batteries and then tested charging two of the batteries, obviuosly I first checked that the chargers where isolated and would work that way... But knowing in theory and seeing it in practice are two very different things... One thing I don't like though is the 4A max charge... That's going to take a while... There are a larger model at 7A... but that's $87...