New user with E-Kart

[QuebecoisSti]

Hello guys,

I am pretty new in here. First, I am not sure if Kart goes in E-Scooter/motorcycle categorie but be free to move the post if it's not o.k.

My dad bought an electric kart conversion from someone. You may have seen it on YouTube, here:
https://www.youtube.com/watch?v=bERjkSTYOdU



Since the kart is in pity condition we are looking to make him nice and achieve around 12 at 1/4 mile

We right now have in hand:

- 300 cells of A123 coming from old DeWalt battery pack (cells are around 8 years old)
http://liionbms.com/pdf/a123/charging.pdf

- Zilla Z1K-HV controller

- DC hydraulic pump motor from forklift vehicle

- Some connectors and mechanical stuff
- A better kart chassis

I sold the old kart frame, I am currently desoldering the battery wiring because it was done not correctly nor safely.

We are not sure right now if:
- we are investing in newer battery or keep the good cells we have (we are considering LiPo, pouch style cell, some pack made by third party)
- buy a newer motor (or do some maintenance on this one we have)
- create/buy/have a BMS for charge/discharge

After the kart idea, we are looking forward for a ATV drag type and later, an EV conversion (we have a Hyundai Accent in hand)

Right now I actually check about 20cells and they look not too bad, around 3.1 to 3.2V each, I am waiting a better solder station right now since mine is not powerful enough to melt tin.
My idea at the moment is to desolder everything and make 5s1p battery pack with all those 300cells. This way I will be able to charge them up correctly using a JST-XH type connector on those.

Feel free to give me some advices or references I should look at,

Thanks

 

[DanGT86]

That is enough hardware to easily power a car! I bet that thing was a rocket!

That should be a pretty fun project. It will be interesting to see what condition the cells are in. Soldering directly to the cells can damage the cells due to the heat. I can't imagine the original builder was able to get that large copper wire to stick without lots of heat. Do you have a method to test the cells for condition and capacity? That might make your decision easier if you knew their general health before investing in a nice bms and all the work of reconnecting them all.

The large DC motor you currently have might be a bit overkill for that platform. Seems like an awful lot of extra weight and extra torque you just don't need on something that small. You could list the motor and controller for sale on DIYelectriccar.com and use the money to get a smaller and much lighter power plant. You could also save the DC motor and Zilla controller for the Hyundai project and start new with the kart atv. If you could find a wrecked Zero motorcycle you could salvage for its parts that would be a more appropriate size and weight for your frame. There are motors combos about half that size and weight that will produce the same power but they are delicate and must be cooled to do so. So motor choice spans the whole range from light and complicated to large and simple like you have. It really just depends on the space and weight constraints and how complex you are willing to make it. I think 30-40kw would be enough to get you 12sec 1/4miles on that thing. So if the other 30kw is just going up as tire smoke at any speed then that is a sign you are carrying extra copper around for nothing.

If you want to keep the setup you have then I don't think the motor would require any modifications to provide more than enough power. I doubt you can crate enough load with such a light vehicle to get that motor hot. It takes traction to use the power. The only real upgrades for the motor I can think of would be brushes. My understanding is that the brush material and hardness should match the voltage you are intending to run because of the speed and the sparking that can occur when you run far outside of the intended voltage that it was built for. But if it works fine than the old saying "if it aint broke, don't fix it" might apply.

Looks fun and super dangerous. That means it will fit in great around here!

 

[QuebecoisSti]

Right now the only way I have for testing the cells is to measure the voltage using a multimeter.
They are around 3.1-3.2V for the 20 i've done yet so it looks good on that side.

I am not sure what equipment to get to test correctly the condition and capacity. My idea is to make 5s1p packs, charge them
up using balancing connector and test how they perform.

We wish to keep the actual setup but we have budget to make it better.
We don't really want to start from stratch (which imply selling the actual setup) . I understand that setup is pretty much overkill for a kart.

I was looking to clean the armature and maybe change the brushes on the motor if they are not in good shape,
I will open that motor soon.

 

[DanGT86]

For testing cells you need some method to monitor the output and a load. You can use a simple watt meter and any load to discharge the batteries. Hair dryers and space heaters can be good tools to discharge a large pack.

The idea is to charge them all up to the same voltage and then discharge to a set voltage while recording the number of amp hours. This will tell you the general health of the cells.

Takes a while to do a large pack but you could do your parallel strings and compare them. This would tell you if there are weak cells in the bunch. If a parallel group gives you its rated capacity then you can assume they are ok in that group.

You can also get an RC balance charger to cycle them and track watt hours. Thats a nice thing to have around for working on packs anyway. Problem there is the discharge is usually low current compared to the size of your large packs. Just takes longer.

Here is a link to an informative post from Dr. Bass about balancing and measuring cells in bulk for pack building. Look about halfway down on page 3 for the pic of balancing lots of cells in parallel.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=28285&start=50#wrap

Here is a link to a member selling a cba 2 battery analyzer for discharging and testing cells.

https://endless-sphere.com/forums/viewtopic.php?f=9&t=70568

You could also cycle the whole pack and see how many amp hours you get. If you get almost the full rated capacity then you wont need to look further. If you get poor capacity from the pack as a whole, then you start searching the parallel groups individually.

Sorry if you already knew all that.

 

[major]

I was looking to clean the armature and maybe change the brushes on the motor if they are not in good shape,
I will open that motor soon.

Hi Queb,

Photos show the commutator (comm) which is part of the armature. I suggest you read up on commutators before cleaning it. Commutators need a film or patina to function correctly. The photos appear to show a decent film. If you remove it or clean it or otherwise contaminate it, you can experience damage under load unless you go through a lengthy break-in period. Likely the best advice is not to touch it, literally. You can take a look at the brushes, but to me, they look good. That is an old, but good heavy duty motor which can tolerate a 1000 Amps.

Regards,

major

 

[QuebecoisSti]

Some update.

@major: my idea is to clean it with special spray stuff and degrease the housing.

I did not know about special film required on it. Most people I saw clean them using stuff and/or sand it on a lathe using soft sandpaper. I may need to gain more infos then.




Here you can see the more decent chassis we have.

 

[Doctorbass]

Salut QuebecoisSti et bienvenu ici !

Je connais bien Jonathan Lamoureux the previous owner of the kart if i remember.

You have to know that there will be a big EV drag racing event ( still unofficial from now) at the Pont Rouge Drag Racing strip for their 50th anniversary this summer! I am one of the organiser. Club Tesla Québec should be there too.

I will for the true first time test my 32kW 2WD ebike and also if i have time my ultra light weight drag racing motorcycle.

I also hope that Yabert from diyelectriccar will come with his diy electric smart!

Glad to see you here !

Doc

 

[Hillhater]

You may want to consider a front wheel brake upgrade kit for that kart.
The weight of motor, batteries, combined with the speed potential will put a lot of stress on one disc and 2 tyres.
....especially if you intend to run on a circuit track at all .

 

[mistercrash]

+1
It's fun to go fast but we gotta think of stopping fast also. That motor doesn't look bad at all, the commutator looks good from the pics. No pitting or traces of over heating. I don't know what new brushes look like for that motor but those ones look like they are not even done being broken in. A bit of cleaning, maybe new bearings and that's it. If you can't save enough A123 cells, that thing screams Leaf modules to me. Really cool project

 

[liveforphysics]

I was looking to clean the armature and maybe change the brushes on the motor if they are not in good shape,
I will open that motor soon.

Hi Queb,

Photos show the commutator (comm) which is part of the armature. I suggest you read up on commutators before cleaning it. Commutators need a film or patina to function correctly. The photos appear to show a decent film. If you remove it or clean it or otherwise contaminate it, you can experience damage under load unless you go through a lengthy break-in period. Likely the best advice is not to touch it, literally. You can take a look at the brushes, but to me, they look good. That is an old, but good heavy duty motor which can tolerate a 1000 Amps.

Regards,

major

+1.

It's a short list of folks in the world who would be better to take advice from on brushed motors than Major.

The coating on the copper that makes it look dark colored is a complex oxide and hydride coating that is in kinda a special relationship with the brushes to let it survive in the wild. Fastest way to cook a nice series DC is to touch it to sand paper.

 

[QuebecoisSti]

Since the DC motor is working and looks not too bad, I decided to do nothing with it, I will keep it like that for the moment.

I (finally) receive my powerful soldering station and desolder all the older cells! I don't plan to use those cells with the kart but for other projects.



I made a small 5s1p pack to charge it up using a RC charger, it looks good. I now need something to test the power


it made quite few plastic racks


and all the copper wiring!

 

[Hillhater]

][i
I made a small 5s1p pack to charge it up using a RC charger, it looks good. I now need something to test the power

i hope i am not seeing those red and black wires soldered together ??

 

[QuebecoisSti]

No. Thats the perspective of the picture. the connector is on the side so that's why

 

[mistercrash]

okashira, a member of ES selling used Tesla Model S cells and Chevy Volt modules has figured out a way to re-arrange a Tesla Model S module in a 12S37P configuration. They are originally 6S74P, so just two Tesla modules would be a lot more powerful than the A123 cells the kart had before. The modules are 3.25'' thick X 27'' long X 11.5'' wide and would weigh just a little over 100 pounds for the two.

 

[Doctorbass]

guys never forget what is the fundamental use of the E-kart here: DRAG RACING..

Usually drag racing require NOT ENEGY cells but POWER CELLS

POWER CELL HAVE HIGH C RATE AND MEDIUM ENERGY DENSITY

It all depend on what is the purpose!!

What he need is cells that can get enough energy for one run of drag racing witch usually require under one kWh for that perspective of vehicule weight.

Tesla cells are no more than 10C... The best drag racingc ells actually have about 100C/200C!!

So you need 10 time less energy = way more light!!

I have built a pack capable of 70kW burst for 15 sec that weight under 13 pounds.. It is made from the Lonestars Racing cells and supplied from from our epic John Metric itself

I have made a post of it here on E-S

The TOP quality Lonestars cells cost the same as the "best" Lipo from Hobbyking but they have been truely tested and confirmed for 100C and even 200C on the 1/8 mile, come with 8AWG cable and 8mm ultra low resistance bullet connectors.

There is an excellent discussion i started about DRAG RACING BATTERY here :

https://endless-sphere.com/forums/viewtopic.php?f=14&t=67135&p=1151088&hilit=lonestars#p1151088

Doc

 

[Doctorbass]

Here is my last battery build:

 

[fechter]

The 20Ahr A123 pouch cells would be good in this application. Lipo is about 2x the energy density so would be better from a performance standpoint, but too dangerous for me.

I bet that thing has really snappy acceleration

 

[mistercrash]

guys never forget what is the fundamental use of the E-kart here: DRAG RACING..

Doc

Au Kabak on appele ça des ''Vertical Racers'' sti!

You're right, I totally forgot that drag racing is the reason that the OP wants to do this project.

 

[Doctorbass]

The 20Ahr A123 pouch cells would be good in this application. Lipo is about 2x the energy density so would be better from a performance standpoint, but too dangerous for me.

I bet that thing has really snappy acceleration

In the last document i have foundabout the 20Ah A123 cells they mention they can discharge at 30C and even charge at 10C!!.. not the 26650.. but the 20Ah pouch!.

But the problem is that these are 20Ah cells and these offer too much energy to get the desired voltage.. the kart will need far less than 20Ah...

Top fuel are extremely dangerous, lipo are dangerous.. but for drag racing and not daily racing these are perfect.

Doc

 

[sketchism]

id like to follow this project

 

[QuebecoisSti]

Hello guys,

Some time pass... few updates about the project.

We found another chassis with front brake system. It was too expensive to add front brake system to the chassis we had (too old, not so much used part on the market, new parts too expensive).







I am waiting a quote of John Metric from LoneStar EV racing battery system with BMS. I receive greatful help from DoctorBass, a pioneer here, who help us choose correctly.

The motor is currently at a shop being balanced, cleaned, commutator on lathe and "soaked".

I've talked with a brush manufacturer. I told them my needs and they are making a special brushes for us. The spring system will also be upgraded.

Actually we are supposed to have a ready motor on May 13th. For the battery system, I can't tell since I don't have the quote and shipping date yet.

 

[Hillhater]

Nice new chassis..
Just so you are aware,...karts have 2 main issues when drag racing..
Traction:- the small tires limit the traction available, when you get to the power levels needed for fast times.
The 5 & 6 inch race tires have limited compounds and widths available. Maybe look for some of the special . size and compound tires the "speedway" karters use ?
Poor aero: again , faster times mean higher speeds. The aero of a kart is very bad and really slows things down above . , , 50mph. Make sure your seat is reclined as much as possible and the steering column is lowered. Use a fairing if it is allowed.

 

[QuebecoisSti]

Some update for you folks.

Still working with Lonestar EV for the battery pack. We change our mind a bit with the greatful help of DoctorBass. We found the correct battery pack configuration. Waiting for the quote right now.

Motor was ready last monday. We now have a clean, balance, commutator cut, new improved custom made brushes and "soaked" intern DC motor.






Since I have the motor in hand, I started by doing a box shaped one to figure out the best way to hold this heavy beast. I made few cardboard brackets and try to make one without using welding. My plan is to have all plates that can be cut by a Laser or plasma table. It will be held together with screws and bolts.

 

[fechter]

Since I have the motor in hand, I started by doing a box shaped one to figure out the best way to hold this heavy beast. I made few cardboard brackets and try to make one without using welding. My plan is to have all plates that can be cut by a Laser or plasma table. It will be held together with screws and bolts.

CAD (cardboard aided design). One of my favorite techniques.

The motor looks like a beast for sure. I'll be interested to see how fast it goes.

 

[c_a]

What pot box are you using for the throttle?

I just started my e-kart project with a 35kW BLDC motor (16kg!) and a 5,15kWh lipo battery.