EV Motor Durability

Open for any sort of non-technical discussion regarding EVs
Post Reply
Outsidethebox
Noobie
Posts: 2
Joined: Mon, 23 Oct 2017, 18:00

EV Motor Durability

Post by Outsidethebox » Mon, 23 Oct 2017, 18:27

Hi there,
how durable and what sort of life expectancy would I be expected to achieve for a 130 hp (approx) EV motor operating under constant load 24/7. My aim is to run a 240V Alternator off an EV Motor to replace household mains power and increase capacity for other projects i have underway. I had thought to power the motor with multiple battery packs integrated with a charge sensor / switching arrangement to swap packs when a preset charge depletion level was reached - The offline packs would then be charged either by mains or off the alternator and obviously i would require enough capacity to enable 24 hour operation taking into consideration recharge times and battery depletion rate. Given the alternator would have an RPM requirement of 1500 RPM i had also thought to run the motor through a suitable reduction box to achieve the required RPM and greatly increase torque.
Are EV components suitable to perform this task or is the cost : Life ratio not going to work? Any help is appreciated or even a point in the right direction if i'm in the wrong place for this discussion.
cheers

User avatar
Adverse Effects
Senior Member
Posts: 967
Joined: Sat, 01 Jan 2011, 03:30
Real Name: Adverse Effects
Location: Brisbane

Re: EV Motor Durability

Post by Adverse Effects » Mon, 23 Oct 2017, 20:05

what your asking is impossible

you carnt run a electric motor off a battery bank to run a generator to charge the battery bank and stay power/energy positive

am i getting what you are saying correct?
I had thought to power the motor with multiple battery packs integrated with a charge sensor / switching arrangement to swap packs when a preset charge depletion level was reached - The offline packs would then be charged either by mains or off the alternator

Outsidethebox
Noobie
Posts: 2
Joined: Mon, 23 Oct 2017, 18:00

Re: EV Motor Durability

Post by Outsidethebox » Mon, 23 Oct 2017, 21:09

i see where your going with this but i'm trying to stay as far away from perpetual motion arguments as i can and i'm not trying to cheat the laws of thermodynamics. If my alternator needs 120 horsepower to operate at 1500 rpm under maximum load then the driving force (EV Motor and Battery Packs) needs to be slightly greater taking into account mechanical inefficiencies - for the sake of the discussion let's say 130 horsepower.
As in an EV car the power for the motor is supplied by the battery pack - i want to use the same method so the motor is not reliant on the alternator for power but on the battery pack. I want to use additional separate battery packs to achieved sustained operation. Separate battery packs also enabling me to charge the packs not currently in use. The battery packs can be charged off mains power thereby reducing my power bills to a bare minimum.
My original question was whether EV components could sustain the constant operation and what life span could i expect. I hope i have cleared that up somewhat

antiscab
Senior Member
Posts: 2126
Joined: Mon, 26 Nov 2007, 05:39
Real Name: Matthew Lacey
Location: Perth, WA

Re: EV Motor Durability

Post by antiscab » Tue, 24 Oct 2017, 00:11

All motors have a continuous rating, just stay below it. I have a 6.7" x91 motor in my shed that would normally be used in a daihatsu charade size conversion. That's rated to 14kW continuous.
Matt
2008 Mazda 2 - EV Shop convert
2011 Blade Electron mk6
2007 vectrix - 117'000km
1993 Electrolux - needs batt and charger
1998 Prius - needs batt
1999 Prius - needs batt

User avatar
4Springs
Senior Member
Posts: 443
Joined: Thu, 23 Dec 2010, 01:14
Real Name: Christopher Walkden
Location: Selbourne, TAS

Re: EV Motor Durability

Post by 4Springs » Tue, 24 Oct 2017, 04:37

A DC EV motor? Wire it for shunt mode (so you don't need a controller) and keep an eye on it to make sure it doesn't overheat. Should last for a long time.
120 horsepower (90kW) is a huge load. That's 39 10A outlets at full capacity. antiscab's 14kW motor would only do one sixth of that power. Do you have a 240V alternator already? - that would be a monster!
Why an EV motor? Wouldn't an industrial motor suit this purpose better? Get one to match the speed of the alternator so you don't need a gearbox and all the losses involved with that.

The other question is - why not just use an inverter? Much more efficient and (I'd assume) cheaper than the setup you describe. Plus quicker to respond to varying loads, uses no power when there is no load, no moving parts to wear out, can sense the state of charge of the batteries...

User avatar
4Springs
Senior Member
Posts: 443
Joined: Thu, 23 Dec 2010, 01:14
Real Name: Christopher Walkden
Location: Selbourne, TAS

Re: EV Motor Durability

Post by 4Springs » Tue, 24 Oct 2017, 04:43

To give you an idea of the inefficiencies of a DC motor, I ran the DC motor in my car at one point without load to wear in the brushes. 17 hours of running with no load used 15kWh of electricity. Extrapolate that out to 24 hour a day operation gives 21kWh required per day just to keep the motor spinning.

User avatar
Richo
Senior Member
Posts: 3043
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Re: EV Motor Durability

Post by Richo » Tue, 24 Oct 2017, 13:00

1500RPM 100kW would be 636Nm continuous - which is pretty hefty - as you say a gearbox would be needed.

You could so it with off the shelf industrial stuff:
800kW PV solar panel
565V battery pack 3.6MWh
110kW+ Induction 3-phase Motor drive (controller)
TWO(2) x 110kW 3-phase induction motor 6-pole 1000Nm 1000kg

So this would convert solar with a days storage into 3-phase 50Hz 100kW isolated output 24/7.

Are you really sure you want 100kW continuous 24/7?
Help prevent road rage - get outta my way! Blasphemy is a swear word. Magnetic North is a south Pole.

User avatar
Richo
Senior Member
Posts: 3043
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Re: EV Motor Durability

Post by Richo » Tue, 24 Oct 2017, 13:06

The the price on the above would be around $700k.

Motors would last 10-20 years.
Solar 20+ years.
Battery 8-10 years.

But TBH this is enough for 160 regular houses...

:lol:
Help prevent road rage - get outta my way! Blasphemy is a swear word. Magnetic North is a south Pole.

User avatar
Richo
Senior Member
Posts: 3043
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Re: EV Motor Durability

Post by Richo » Tue, 24 Oct 2017, 13:08

Actually it wouldn't...

The the isolated induction motor would need an exciter.
Help prevent road rage - get outta my way! Blasphemy is a swear word. Magnetic North is a south Pole.

Post Reply