Hi this is my first post and i am wanting to do a EV conversion using a 95 Holden Barina(Corsa model)but i am still wondering about what is the best way to keep my power steering and Aircon. I have not purchased any parts yet I am still in the planning stages. What i was thinking of using is a 1HP 12Volt electric winch motor(holds 2000 pounds)is this a good or bad idea. I have been reading a lot of the posts on the forum and i have not seen anybody talk about using one so i am thinking its a bad idea.
I plan to use a Warp9 motor which has a double shaft but i did not want to take power away from the motor buy using the second shaft to run power steering & aircon or am i being a idiot. Any thoughts or info would be greatly appreciated.
Powersteering and Aircon
Sat, 12/20/2008 - 02:14
#1
Powersteering and Aircon
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Using any type of winch motor would not work. The reason the motor can handle 2000 Lbs is because of gearing. The motor turns fast enough but with the gearing the output shaft would turn way too slow for either Power Steering (PS) or Air Conditioning (AC). I have no experience but I have read a lot about this because I have a Smart Car I want to convert. I will not need PS but I do want AC. I have read a little about PS and in most cases you can get an electric assist motor made for PS. I have read more about AC and most use a separate electric motors for AC. The AC drive motor only needs to run when the compressor is in use. On an ICE there is an electric clutch on the compressor to turn it on and off. This same signal can be used to turn on and off the electric drive motor. When this is done the electric clutch is replaced with a normal pulley so you don't have to draw power to keep the clutch energized, saves some battery usage. It most cases a small motor rated at the battery pack voltage is used. The control signal is sent to a contactor with a 12-volt coil. A contactor is a relay with large contacts designed to carry the current requirements of a large inductive load, i.e. motor. The reason for this is a DC to DC converter will be used to get 12-volts. A DC to DC converter large enough to run the motor directly would be very expensive because of the heavy load imposed by the motor. So a contactor could be switch with the 12-volts at a very low current draw allowing the use of a much smaller DC to DC converter. The DC to DC converter will also need to drive many other accessories on the vehicle. It would not be a good thing for your headlights to go dim every time the AC kicked in. That could make night driving an adventure. I have not seen much information about auto conversion here on VisforVoltage but that could change in the near future I hope because I will be needing some help as well. BTW the Warp9 is a great motor choice. Keep us posted on your progress. I am sure we will be able to help with your project.
Grandpa Chas S.
Thanks Chas, you make a good point about the DC-DC converter coping with the load, i didnt even think about that.I will look into a motor that i can run at a larger voltages.
what system voltage are you running?
for my conversion i plan on running a 208v 2kw induction motor behind a vfd for my A/C (i dont have pwoer steering) for my 288v conversion, thats the cheapest way to do it.
a separate motor would be the *ideal* solution in my mind, but also the most expensive.
depends how much you feel like spending, using the original clutch and the second shaft would be the cheapest way to go.
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
Hi Matt,
You should visit these sites:
http://www.diyelectriccar.com/
http://www.evconvert.com/
ive been reading www.evconvert.com for quite some time.
i still have a browse though diy aswell.
i spend most of my time on http://www.aeva.asn.au/forums/default.asp partly because im a moderator.
the EVDL is also a treasure trove of ideas.
a few other ideas for power steering is to use the power steering module off an sw20 MR2, or the new mazda2.
both are already electric.
for aircon, you could have a crack at reverse cycle. know any refridgeration engineers?
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
I was wondering about using something different for the AC. What would happen if you took a refrigerator and removed the compressor and coils from it an used that as you AC? You could use a small inverter to get 120 VAC to power the compressor and use the blower fan to force air across the coils on its way to the cars interior. This could be more energy efficient and you could turn on the AC on a hot day, with the battery charger still connected, before you get in to drive.
BTW thanks for the links, I'll check them out for my conversion.
Just a thought,
Grandpa Chas S.
Hi Matt
I plan to have use 120v maybe 144V depends on weight. I plan to use AGM 12v 120AH Deep Cycle batteries so thats why i am bit worried about weight and have a charger per battery instead of a bulk charger. I have also found out that the Holden Astra from 2006 onwards and the Holden Zafira both use electric power steering so i might go and check out some wreckers over the break and see if i can find a working one. I keep you posted. A/C i can live with out but summer days can get hot in Melb i still have the option of running it from the second shaft will wait and see once i start the project.
Thanks for your comments
Vince
yes, using an inverter to run a 120vac compressor could work, but the inverter wont be small or cheap.
you will need sine wave (THD less than 3%) and it will have to do 3kw continuous, with at least 10kw surge rating since it will be direct online starting. not cheap.
if its operating off a vdf, then there is no surge. a 3kw vfd costs around $US300
being able to pre-cool your car is a definate benefit.
Vince,
i see you are in melbourne, i can probably put you in touch with an AEVA member near you.
feel free to come to the next meeting.
a single charger per 12v battery is the best way to go.
however, make sure they are still temperature compensated. thermal runaway is still possible at 12v, though still less likely since theres no chance for imbalance.
have you decided on what battery your are using?
have you priced it out? what price have you found?
one of our members has a pallet of optima 55AH yellow tops here in Perth, so you might be able to get them cheaper than new, though shipping would be a pain.
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km