What is my motor? + amp hour question

[StudentEV]

Hi guys, this forklift drive motor is going to run my EV conversion.

Any ideas as to whether it's DC series wound or not? The controller I'm looking at requires this info.



TTL160C
48V S2 60min
98 A 3.9kw
1920 min-1 max: 1000 min-1
(the 'max' figure might have another 0 after the 1000, hard to tell as there's a scraped off part of the label)
Class H

Regarding amp hours, I used the range calculator at: http://www.evsource.com/battery_calculator.php , this gave me an estimated range of almost 30 miles with a 48 volt pack using 90ah batteries. This seems unrealistic to me, but I might be wrong?

So my question is, with a 48 volt, 90 ah pack, what range can I realistically expect from the vehicle? Assuming I get this controller which is rated 24-48V and 400 amps. Remembering that the vehicles curb weight as an ICE was less than 600kg.

Ideally I'd like more thank 20km range to get me to work and back.

I'm asking because I haven't been able to get a hold of any used batteries, and the four 12V 90ah batteries will come in only a little over budget.

Thanks
Tom

[BigMouse]

It's a bit hard to see, but it looks like there are 4 terminals on the motor. Normally, two of those would go to the brushes (and armature) and the other two would go to the field. This means you could wire it up as either series or shunt (or switchable, or sepex with the right controller).

Regarding range:
Your pack is 90*48 = 4320 w.Hr
30 miles is 48 km,

So if you got the full capacity out of your batteries (100% depth of discharge and neglecting the peukert effect), you'd be getting 4320/48 = 90w.Hr/km, which is probably pretty close. I'd expect something closer to 110 for a small, light car with that battery pack and non-EV components.

At 110 w.Hr/km, you'd use 110*20 = 2200 w.Hr of energy. With your pack, this should be feasible after peukert effect and a reasonable depth of discharge. You'd even have some buffer left over (for a year or two at least).

[Richo]

Did you skip reading your own build thread?
Didn't you figure out you could click "ask a question about this motor"?

http://jwarfieldelectric.com/home?page= ... .tpl&pop=1

Hope those batteries are Gell cells or similar.
Don't forget you'll still need a demister, contactors and fuses etc to be roadworthy.

[StudentEV]

Did you skip reading your own build thread?
Didn't you figure out you could click "ask a question about this motor"?

Aha! Yes I entirely missed that, thanks for the link and sorry for my ignorance of that, I thought it was just a page you could buy the motor from. Which it is. Thought a pic might help anyway.

As far as I know they're just lead acid deep cycle, the guy was pretty rushed on the phone so I didn't get too much info out of him, I will find out if they're sealed or wet.

Yeah we've since upped the budget to an undefined amount after working out that things are a lot more expensive in Australia than the US - the cars we are basing ours on was made there. I guess however cheap we manage to do it will be the benchmark for a student budget in Aus.

[Richo]

Click the link and ask the question - is it series or shunt...
You can also find out how much it's worth at the same time

Please don't use wet cells.

I would still suggest more than 48V as this will really limit your speed.
My estimate is 48V would get you ~55kph continuous assuming your gears were optimum.
And it's most likely the ratio will be somewhere around 4th gear.

Next time you go for a drive think how quick/fast you can go with 1920RPM as an RPM limit.

96V may get you to ~90kph for short periods but around 60-70kph cont.

[StudentEV]

It's a bit hard to see, but it looks like there are 4 terminals on the motor. Normally, two of those would go to the brushes (and armature) and the other two would go to the field. This means you could wire it up as either series or shunt (or switchable, or sepex with the right controller).

Regarding range:
Your pack is 90*48 = 4320 w.Hr
30 miles is 48 km,

So if you got the full capacity out of your batteries (100% depth of discharge and neglecting the peukert effect), you'd be getting 4320/48 = 90w.Hr/km, which is probably pretty close. I'd expect something closer to 110 for a small, light car with that battery pack and non-EV components.

At 110 w.Hr/km, you'd use 110*20 = 2200 w.Hr of energy. With your pack, this should be feasible after peukert effect and a reasonable depth of discharge. You'd even have some buffer left over (for a year or two at least).

Yes there are 4 terminals. So it's just a matter of how it's wired up as to what motor it's classified as? That's good news, means I can get this controller and then the batteries.

Thanks for the equations, this electrical speak is starting to make a lot more sense to me now. So you're saying we'd probably be OK for 20km range? Which is excellent. I guess it's just an issue of the speed that the car will reasonably travel at as to whether it'll get me there and back without serious honking from other drivers.

We've decided to go with the 48v configuration Richo to try to prove an EV can be converted on a serious budget (it seems as though you are pushing us to go with more power straight off the bat )and get it on the road. If it proves viable for commuting to work and back, great! If not, we'll add more voltage later and you're more than welcome to say 'I told you so'

Could be wrong about this, I don't want to make too many assumptions! Haha!

That said, you do seem to be something of an authority on this stuff, so in your honest opinion, do you think deep cycle will do the job for our modest needs? If not, what batteries/suppliers do you recommend?

ALSO I will switch back to the build thread after this, it seems all questions are answered everywhere on the forum, which is awesome! I am looking forward to having finished the conversion so I can help other people out. Definitely very appreciative of all the help we get on here!

[StudentEV]

Accidental double post, nothing to see here

[Richo]

Ah I plugged the values into my Handi calulator execpt reduced the weight to 500kg.

There are defn more 48V controllers around.
It will mean later that you may need to upgrade your controller.

Another option if you want to stick with 48V is to buy 45Ah cells.
Put two sets in parallel and you still have 48V 90Ah but later if you find the voltage is limiting your speed you can then put them all in series for 96V 45Ah.
It will have the same range either way but at least you don't need to buy batteries again later - just a controller.

[StudentEV]

Click the link and ask the question - is it series or shunt...
You can also find out how much it's worth at the same time

Done!

My internet is being a dog so sorry if my posts are out of sequence.

OK so 1920RPM is the highest 48V will spin my motor at? I will be able to test that tomorrow in an ICE car.

And continuous 55kph sounds golden to me, I live in inner city Melbourne, so top speed rarely goes above 50kph in peak traffic! This is actually one of the reasons we thought a low cost, low power conversion would be possible in the first place! I assume there are much higher average speeds when commuting in Perth...

Another option if you want to stick with 48V is to buy 45Ah cells.
Put two sets in parallel and you still have 48V 90Ah but later if you find the voltage is limiting your speed you can then put them all in series for 96V 45Ah.
It will have the same range either way but at least you don't need to buy batteries again later - just a controller.

That's a genius idea, I guess the cost of the lower amp hour batteries would be considerably lower too, and only slightly more expensive as a pack?

I will definitely look into it.

[Simon]

I understand that you are on an extreme budget, Forkenswift inspired me to consider doing a budget conversion too.
Doing the sums though it became apparent that it was not going to be possible in Australia.
Low budget conversion is possible.. just not on a beer budget unless you can get everything for free.

There are other things to consider if you are planning to go 48V now and upgrade later. Not only the controller but the DC to DC converter, charger and even instrumentation may all have to be replaced when you decide to increase the voltage.

[Richo]

Yeah there are still some roads that I can get to 60kph for short periods.

You might find that the smaller battery is more common and better value.
But most likely to work out about the same $$.
Might be able to ask for discount when asking for 8.

48V@1920RPM@3.9kW
It will spin faster at lower torque levels.
Thats why they will spin really fast (possibly to damaging RPM) when there is no load on the shaft.
It won't help your car though.
You need more power to get more speed.
Increasing current-> Torque gets more power but no extra RPM.
So your still stuck to 50-55kph.
Good for hills though.

[StudentEV]

I understand that you are on an extreme budget, Forkenswift inspired me to consider doing a budget conversion too.
Doing the sums though it became apparent that it was not going to be possible in Australia.
Low budget conversion is possible.. just not on a beer budget unless you can get everything for free.

There are other things to consider if you are planning to go 48V now and upgrade later. Not only the controller but the DC to DC converter, charger and even instrumentation may all have to be replaced when you decide to increase the voltage.

Yes I did think about that. I guess it's one of those decisions that will have to be made. Spend more now or later?

Out of curiosity, how did your conversion go on the 55ah pack? What kind of range were you getting when they were new and for how long?

Also, what was your top speed and average speed on that pack? I'm thinking our host vehicles are very similar and maybe I could get an idea based on your experiences with a smaller car?

[StudentEV]

You might find that the smaller battery is more common and better value.
But most likely to work out about the same $$.
Might be able to ask for discount when asking for 8.

A few searches haven't been very promising but I'll call around later and see what I come up with.

And:

"Hi Tom
This motor is series wound coils and your cost is $1300.00 rebuilt outright.
Motor is in stock."

Sweet! My actual cost was $100.

So assuming everything is in working order I've saved $1200. Good tip on emailing them.

[Richo]

I think my estimate was ~$750 for the pack.
Some of the battery recyclers near you might have something.

[Simon]

Yes I did think about that. I guess it's one of those decisions that will have to be made. Spend more now or later?

Out of curiosity, how did your conversion go on the 55ah pack? What kind of range were you getting when they were new and for how long?

Also, what was your top speed and average speed on that pack? I'm thinking our host vehicles are very similar and maybe I could get an idea based on your experiences with a smaller car?

My conversion had about 25-30km (with 8 x Optima D34 55AH AGM) of usable range when they were new. You could eek out another 10km more range but that was tedious and slow, ie feathering the accelerator, 60kph max speed and no using wasteful things like brakes!

The pack only lasted (from memory) about 1.5 years, 9000km before range was no longer useful to get me to work and back (10km round trip).
Top speed was 100kph, average speed would of been mostly 60-80kph cruising.

Lithium batteries made such a difference. Suspension was better acceleration was even better and range doubled for half the weight in batteries.

[StudentEV]

I think my estimate was ~$750 for the pack.
Some of the battery recyclers near you might have something.

All of the battery recyclers tell me they rarely deal with deep cycle and it's even more rare to find a set of similar condition! Really disappointing stuff.

[StudentEV]

My conversion had about 25-30km (with 8 x Optima D34 55AH AGM) of usable range when they were new. You could eek out another 10km more range but that was tedious and slow, ie feathering the accelerator, 60kph max speed and no using wasteful things like brakes!

The pack only lasted (from memory) about 1.5 years, 9000km before range was no longer useful to get me to work and back (10km round trip).
Top speed was 100kph, average speed would of been mostly 60-80kph cruising.

Lithium batteries made such a difference. Suspension was better acceleration was even better and range doubled for half the weight in batteries.

OK cool, so our best estimates on a 48V 100-ish ah pack of a little over 20km range (four batteries lighter than your conversion) and a rough average cruising speed of 50-55kmph, again as a (slightly) lighter vehicle, seem accurate enough for me.

I thought I found a bargain yesterday, 12V 100ah AGM batteries for $160 but it turned out the guy only had one. I'll keep looking. Still have not acquired controller so I'm still open to different battery combinations.

[Richo]

8 x 12V x 55Ah = 5280Wh (96V total)
4 x 12V x 100Ah = 4800Wh (48V total)

4 less batteries but overall about the same capacity and weight.

How about golf cart repair stores.
They probably have some 2nd hand batteries and controllers that might suit.

[Johny]

"Hi Tom
This motor is series wound coils and your cost is $1300.00 rebuilt outright.
Motor is in stock."

That fits with this page that indicates Series wound as well (second motor RMLT3392).
http://www.lehner-industriemaschinen.ch ... azione.pdf
It's not a very powerful motor - rated at 3.9kW, 48 VDC at 95 Amps. Of course you will get more power at higher voltages (higher RPM) so if we assume 8kW cont. at 4000 PRM, then 20-25kW peak may be permissable for short times (comments here from those with more DC motor experience???).
IMO I don't think you will have enough power at 48 VDC to drive the car reasonably - you need to get the Revs up which means more voltage.

[Richo]

It would get you around the inner city at 48V - but not much else.

There are some cheapish 72V controllers but that would mean setting up for 72V to start with.
Not as convenient as changing from 48V to 96V with a paralleled battery pack.

[elmex]

A major consideration during this process is battery chemistry, don't use two different chemistry when connecting in series or parallel. Make sure the voltages are the same, but more importantly the charge rates and capacities are the same to help prolong battery life.

Thanks.

[Johny]

A major consideration during this process is battery chemistry, don't use two different chemistry when connecting in series or parallel. Make sure the voltages are the same, but more importantly the charge rates and capacities are the same to help prolong battery life.

Thanks.

You're not terribly welcome!

[StudentEV]

Haha! Thanks John. That video is still coming along by the way, uni has tied me up a bit!

In other news, picked up some batteries from a couple of legendary Vectrix owners who have converted to Lithium and didn't need their old batteries.

So I am now in possession of a whole bunch of nimh cells that need testing. With boxes and bolts rated to the weight of the batteries, stoked. I'll put some pictures up on my blog and the build thread. Matt in WA helped me hook it up, legend!

It'll go a long way towards us coming in under budget.