# Andy's VW Polo 99 build!



## polobear (Nov 13, 2012)

hello everyone!

Always wanted to convert a car to electric, been researching heavily for the last 6 months and finally on sunday i bought my donor vehicle for a grand sum of £600, a VW Polo mk 3 on ebay!it had to be a v dub my other car is a lupo. 

Wanted to get a car with simple electrics and not too many warning lights and fancy diagnostics but the problem with older cars is obviously rust.First i got to sort out the bodywork, drivers side door and rear right arch has some rust. sills and underneath is all mint. The car sounds like it has a cluth release bearing on the way out (scratching sound when clutch is depressed) but luckily i'll be going clutchless. The engine is perfect, hopefully i can claim back some money for that and the exhaust (which is new)

I'm pretty much set on this set up, im on a strict budget - getting married next year!

D&D ES15-6 series wound motor
Alltrax 7245 AXE 450 amp controller
Lead acid deep cycle (probably 12x 75 or 100 AH - 6 in parallel with 6)

Originally wanted to sink a battery box under the rear seats but im now paranoid of not passing an MOT on some structural issue. so i think as many in the engine bay as possible then the rest in the back, might take out the rear seats if i have to.

I know a lot of people on here preach lithium but if treated right and looked after i think lead acid is perfectly practical. I'm not expecting any sort of performance, 45 - 50 MPH tops and a range of 30 miles on the odd occasion i'll be happy with.work is 6 miles round trip. i currently have a electric moped with 30AH which gets about 50 - 75 Wh/mile

what sort of c rate can be drawn from a LA without suffering from peukerts effect too badly?

The electrics shouldn't be a problem, im an electrical engineer and commission VSD's and related instrumentation and control daily.

This week ill be sorting out bodywork then i should start ripping the dirty beast of an engine out.


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## Yabert (Feb 7, 2010)

polobear said:


> what sort of c rate can be drawn from a LA without suffering from peukerts effect too badly?


1/20C, or discharge your car in 20h (not practical!)
So, for an half hour ride, your 75Ah lead acid battery is more like 37Ah.
72v x 37Ah is only 2.6Kw of usable energy (I guess 10 miles at 30-40 mph).

I would suggest to change your motor selection for a bigger one. Overall performance will be better with a motor who don't suffer of inefficiency each time you will pass many amps inside.
You can also try to find cheap used forklift motor.

Alltrax AXE 7245 if you find used, but Alltrax SPM 72400 or 72500 if you buy new one.

Welcome to the forum.


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## MalcolmB (Jun 10, 2008)

Hi Andy,
Lead acid can work well if you treat them carefully, i.e. only discharge them partially. They're generally rated at 1/20C discharge rate, so over a 20 hour period. When you discharge them at 1C, over a one hour period, you generally get at best 60 per cent of the capacity . See table 3 on page 8 here: http://www.odysseybattery.com/documents/US-GPL-AM-003_0906.pdf

The motor you've picked is well matched to the Alltrax, but like Yabert I'd also suggest going for something beefier. If you want to upgrade the car later, or sell it in the future, it's well worth investing a little more considering the amount of work it takes to install the motor in the first place.


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## polobear (Nov 13, 2012)

Finally had a chance to post an update, been pretty dam busy, at least 2 hours work on the car after work each day!

First i sorted out a badly rusted door and some other bodywork

Took the front bumper, lights,radiator and fan and structural cross member out. then dropped out the front section of the exhaust including the cat. started the job of stripping the engine of all mechanical and electrical connections to the body. Surprisingly for someone who's done minor car maintenance and certainly never taken an engine out of a car, it really wasn't difficult just time consuming!squashed up under a car isn't great though!

dropped the fuel tank and rest of the exhaust out. dropping the fuel tank is a horrible sh1t job, dont ever want to have to do that again!

doing all this stripping makes you realise the quality of your tools, broke a 3/8 socket, 3/8 extension (twisted like a piece of cheese) and also a ratchet! All these tools obviously only designed for very light use.

before getting the engine out i disconnected every single electrical connection to the sensors just to see what would happen. surprisingly if a sensor wasn't connected the relevant light just didn't show up and no pre flight check of that system was done - BRILLIANT, makes my job a lot easier as in the UK any warning light is now an automatic MOT failure. This was counter intuitive to me, as an ee the systems i usually work on are failsafe, which would require you to bullshit the system into thinking the sensor was connected.

Then got the starter motor/ alternator and power steering pump off the engine, removed the gearbox and clutch plate/clutch from the engine. the clutch was completely worn to the rivets and now i know what the irritating noise was on the way home - the release bearing was screwed.

Then degreased the gearbox and painted it with hammerite silver and a few bits wire brushed and painted black.rust treated power steering pipes (light rust) and painted power steering servo and pipes. Wire brushed frame rails and underside of the car then rust treated with kurust and then painted with hammerite. No-one will see under the car but its like new again!Hopefully it weill last another 14 years.

Made an adapter plate template, bought a big plastic transparent box and traced the gearbox, i wanted to use perspex but i got angry with B&Q's price for a small piece of plastic i'll use once.now i have a box which i can use with no lid!

today i got my aluminium 10mm plate, traced the template onto the plate and cut it out with my bandsaw, cleaned it up, just have to drill holes.

ordered d&d 15-6 motor, alltrax 7245 controller sw200 contactor precharge resistor and diode from the states on sunday night, scary amount of money! should be here this week, obviously im going to get ripped for customs and import duty.great service from Carl at EV drives so far, pleasure buying stuff from the US as usual, unlike the UK where we have to put up with poor customer service, overpriced and old stock!

put the gearbox back in the car, gear linkage connected and working!only one problem, the gearbox is usually attached to the engine and that is mounted on the left of the engine bay so the left side of the gearbox sags a little (maybe 5 mm), im wondering whether to put in another support for the gearbox (it has 3 rubber mounts) or just attach the motor to the adapter plate and support the motor at the left side mount?

I'm still trying to decide whether to go with 6 x 140ah batteries or 12 x75 or 100ah batteries (same price) but in two banks of 6 for a total of 72v 150ah(theoretical) i figure if i have two parallel banks of batteries there will be less load on each as theyll be sharing the load equally, hopefully there will be less peukert's effect.i need to make the most of lead acid as its all i can afford for now.


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## polobear (Nov 13, 2012)

Just some more pictures!


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## skooler (Mar 26, 2011)

Nice Project!

Check the MOT requirements for warning lights. They have to POST (power on self test) i.e. come on and then go off.

On the lead acid side of things.... My advice: Go lithium! If you must go lead then go for Trojan or propper traction batteries. *DO NOT USE DEEP CYCLE LEASURE BATTERIES.* Have a read of mine and Ace_Bridger's build threads for how Lead Acid conversions can turn out.

I'd also advise you to go for the highest voltage possible.

http://www.diyelectriccar.com/forums/showthread.php/vw-golf-mk2-voltswagon-68852.html

http://www.diyelectriccar.com/forum...-conversion-formally-good-motoriii-61556.html

Cheers,

Mike


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## Yabert (Feb 7, 2010)

Good work Polobear
But I think it's a bit sad than you don't take our advices. Like Malcolm say, all this good work and you will stick with this little, unpowered and not efficient motor (good for a motorcycle).



MalcolmB said:


> like Yabert I'd also suggest going for something beefier. If you want to upgrade the car later, or sell it in the future, it's well worth investing a little more considering the amount of work it takes to install the motor in the first place.


Try to don't overheat this small D&D motor.


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## polobear (Nov 13, 2012)

I've decided to go 84v nominal so should be just under 90v fully charged, because the alltrax 7245 has a max voltage of 90v. The car is going to be 99% a city commuter car, so under 40mph. I've decided to go with 84v nominal simply to get more efficiency out of the system, and avoid the heating effects and wasted energy of low voltage, high current. I cant afford to get a high voltage controller for now, might eventually build my own.

Of course this throws my charging ideas out the window, i was going to go 72v 10a nominal lead acid charger, not many people seem to go 84v, could still go with that charger then charge the other batteries seperately with some cheap 6a chargers.any other ideas?


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## Yabert (Feb 7, 2010)

Good idea about higher voltage for better efficiency.
But: 84v / 12v = 7 battery x >14v fully charge = >98v at end of charge!


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## cts_casemod (Aug 23, 2012)

Keep us posted. 
I believe you are running close to the limits with your motor/controller though.

There is no check engine light on the Polo. Only problems that it may report are coolant bottle level (short the two terminals), Brake fluid level and ABS if it has it.

You may also find something usefull on my conversion http://www.diyelectriccar.com/forums/showthread.php?p=344996#post344996


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## polobear (Nov 13, 2012)

I've been slack with this thread, 4 months with no updates, but that's because i've been so busy with the car  I've averaged about 2 hours a day, after work, since christmas, im exhausted but desperately want to get it on the road now.

Today i reached a big milestone,the first test drive!( only at 48v with scrap batteries from work).... well it was slower than a lazy snail,eventually got up to 20 mph on a private street, didnt have much more space.it was as expected with the reduced pack voltage and i limited the current on the alltrax down to 100A.wanted to go easy on the coupler and listen for noises etc.

I was able to view the current draw with my ah counter (30 pounds on ebay, including 500a shunt!) Unbelievably its calibrateable so i borrowed the injection set from work to calibrate a high and a low amp draw. The car draws full current of 100a accelerating to 20 mph which seemed a lot but hopefully when the voltage is nearly doubled the current will almost half for the same speed/acceleration.

finished all the power wiring for the controller motor and batteries and also control wiring. 

all power wiring is 50mm welding cable crimped with a hydraulic hand crimper.

decided to go with AGM batteries,85 ah each, got 12 of them, theyre going to be wired in buddy pairs for a total of 72v 170ah.

calcium lead is crap and there is just not enough choice for FLA, you just dont know what you're getting here in the UK, they'll tell you its flooded but i just wasn't convinced it was a genuine flooded deep cycle lead acid. The guy at "the battery specialists" - Multicell wasn't very helpful at all, it seems i asked him too many technical questions and he just fobbed me away with marketing bullshit. Technical questions like how many cycles can i expect at what DOD, which is a perfectly valid question when buying lead acid, was answered with a blank stare. nevermind ill go somewhere else!

SO, my batteries are rated at 300 cycles at 70% dod, at least i know exactly what i can expect. I will not often be going more than 50% so im hoping for at least 500 cycles and ill be happy!

for the chargers i'm going with individual 8a 12v mobility vehicle smart chargers, they do absorbtion up to 14.4v which i think? seems about right for AGM.


The car has switches inside the cabin for the vacuum pump, power steering, instrumentation and heater (ceramic heater element - havn't done a full pack voltage test yet but i think i may be paralleling two of these up for lower resistance/ more heat). I've added simple logic to the control relays such as not being able to switch on the heater until thye fan is running - to prevent accidental plastic smells! And not being able to engage the contactor circuit while charging.

still lots more work to go, including battery racks, battery insulation and heating system, and my diy picaxe based information display.

here are some pictures!


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## polobear (Nov 13, 2012)

more pictures!


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## cts_casemod (Aug 23, 2012)

Now that makes me remind my Polo, I had to push it to come out from the brake testing machine at the MOT, as it didnt had enought power to do so!
I also ripped the mounts when I finnaly got the controller ready so take a look at those when you're finished to make sure there is no excess play.

Flooded batteries are quite hard to find and sealed VRLA suffer with equalization charges. I would advise you to get some sort of BMS to shunt aditional current when the first battery gets above 14.4, this way you are always sure that they dont over/under charge. As with people not knowing, remember you are the engineer they know nothing about it. Its quite hard for us when looking at stuff, but you get used to

I've found some older cells start to generate heat if pushed above a certain voltage, so in practice you can take lets say 80Ah out of the battery if you charge it with 100Ah. This makes balancing quite hard because after a few charges the weaker cells tend to dissipate more power as heat, so you end up overcharging the good cells, because their charge efficiency is higher.

Where are you planing to place the batteries? Engine bay or where the fuel tank was?


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## polobear (Nov 13, 2012)

cts_casemod said:


> Now that makes me remind my Polo, I had to push it to come out from the brake testing machine at the MOT, as it didnt had enought power to do so!
> I also ripped the mounts when I finnaly got the controller ready so take a look at those when you're finished to make sure there is no excess play.
> 
> Flooded batteries are quite hard to find and sealed VRLA suffer with equalization charges. I would advise you to get some sort of BMS to shunt aditional current when the first battery gets above 14.4, this way you are always sure that they dont over/under charge. As with people not knowing, remember you are the engineer they know nothing about it. Its quite hard for us when looking at stuff, but you get used to
> ...


Thanks for the reply!

Did you need to give a weight to the MOT guys? they have to work out the braking efficiency of the vehicle, and i guess they usually use a generic weight for your car?

Im hoping balancing isnt going to be a problem as i'll have a smart charger looking after each parallel buddy pair. Im going to use a cell log 8 for monitoring series string voltages, obviously this is a lithium voltage device so im going to have to scale down the voltages (divide by 4) to the input. this is just so i can see the bar graph function and use the alarm function to bring on the battery light on my dash.

im guessing that light comes on when the alternator lead is floating and when it is grounded or 12v the light goes out?

two traction batteries are going in the engine bay along with the accesory battery (38ah AGM) this will all be in an insulated heated box. then there will be 10 batteries where the back seat used to be, disappointed to be losing the back seat but theres no real option if i want to get a long life out of the batteries. i dont want to be discharging the batteries heavily to run around town. most trips wont use more than 20 to 30 percent hopefully!


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## polobear (Nov 13, 2012)

casemod, who are you insured with? i think i will buy tax for petrol car then insure and mot it then apply for dvla tax exemption, is this what you did?


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## cts_casemod (Aug 23, 2012)

polobear said:


> Thanks for the reply!
> 
> Did you need to give a weight to the MOT guys? they have to work out the braking efficiency of the vehicle, and i guess they usually use a generic weight for your car?
> 
> ...


 
I havent, they used the standard weight. Mine weights 80Kg less on the front, everything else being the same, considering a full fuel tank. The margin they have is quite large, I think you only fail if less than 50% efficiency.

In that case you should be okay, just make sure the charger is fully isolated, some models share a comon earth and may cause you problems.

The alternator light is the second leg of a bulb conected to the positive of the battery, so it will be on if the voltage is lower than the battery (say maximun brightness when switched to GND and off if left floating or attached to the positive of the battery (ie 12V).). I will be using mine for the DC-DC and precharge circuit.

Bare in mind that if not using a DC-DC converter (say using a separate battery for the 12V) you'll end up with 11V on the 12V line instead of 14 and the brightness of the headlamps is about half (10V to the bulb). I found this to be unaceptable for me.

You can cut the place where the spare tyre is and fit a battery box. Takes a bit of work, but its the best option in terms of space. You can also cut over the gas tank and fit a few more in there. I will be doing that to mine in future as I need the space in the front for a generator and a second inverter.

Insurance, the only one I could get to insure my Polo was pluginsure. Send some photos of the car to start the coverage and theill cover you to the MOT. Or you can also go to the MOT without insurance (They wont cover you in case of an acident anyway), in any case pre-book with them and have the paper with you in case the Police stops you and explain that you can not get insured/taxed because you've done a conversion that needs to be MOT checked.

After that pop into your local DVLA office, again with photos, invoices, MOT and insurance certificate and a letter saying that you require the change of fuel and the taxation class to electric and they should give you a new tax disk. Also advise about the change in seats.


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## polobear (Nov 13, 2012)

hello everyone!i guess i never got round to updating this forum - the car passed her MOT after failing the first one for corroded power steering lines, so the guy said why bother with power steering!!! After all that work he didnt care if the car didnt have power steering like it did out the factory - i would have had strong arm steering from the beginning if i had known!

Apart from a few failed chinese chargers, totally trouble free motoring for about 5000 miles! Sadly (and expected) two batteries in the string have started to fail so the range has dropped. I was going to upgrade to lithium at this point...

Unfortunately i cant look after two cars and an electric scooter so sadly i have to say bye to my little electric polo.

I'm never going to be able to afford to upgrade to lithium, which i always planned to so im selling the polo for someone else to enjoy a great project

Hopefully i someone buys her i can get lithium for my electric scooter, rather go BIG on a small project than go half ass on a huge project!

Have a look - if youre interested or have any questions give me a call!

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=141284002209


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## cts_casemod (Aug 23, 2012)

polobear said:


> hello everyone!i guess i never got round to updating this forum - the car passed her MOT after failing the first one for corroded power steering lines, so the guy said why bother with power steering!!! After all that work he didnt care if the car didnt have power steering like it did out the factory - i would have had strong arm steering from the beginning if i had known!
> 
> Apart from a few failed chinese chargers, totally trouble free motoring for about 5000 miles! Sadly (and expected) two batteries in the string have started to fail so the range has dropped. I was going to upgrade to lithium at this point...
> 
> ...


Curious how much you pay for insurance with adrain flux. They never acepted to insure mine for God knows what reason.

Whats the maximun speed you can reach? I mean reasonably not going down hill 

Going lithium may not be as expensive as you may think. I spent about £800 for my first battery pack with also 15 miles range.

And at 72V is super easy and cheap to fit a BMS (hence my interest).

Kind regards


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## polobear (Nov 13, 2012)

The insurance was about 400 i think, not cheap but then again it's "modified" even though its less powerful or dangerous than a petrol equivalent car....

Top speed - i got it up to 50 once, on a full charge on the flat but had to change into 3rd gear, but i think it likes to cruise at 30 in 2nd gear


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