3.1kWh Chevy Volt Battery Upgrade

[EpsilonZero]

Today I finally got my Chevy Volt 3.1kWh (16s2p) battery installed and took my kart out for an hour long abuse test ride. My battery subframe contraption held up, though I am getting wheel hop instead of spinning when accelerating hard while cornering now. I ran the pack down from 65v to 58.26v over the hour, so it has more in it. My plan is to switch between my RELiON 51.2v 30Ah and this Volt pack, using the RELiON as a reserve; I am just waiting on my new 3 position switch to arrive. The RELiON is just running all accessories (lights, phone charging, horn).

I must say that this battery added noticeable power. It doesn't have the same sag under heavy load and isn't running out of voltage at high RPM, being stopped only by my 5500RPM setting in the controller. The extra weight makes cornering at higher speed without spinning out a given instead of something to be wary of, but it is some work to stay in the kart when going that hard.

Also, I made some mud flaps for the front wheels to keep little rocks and whatnot from hitting me and getting all over the kart. They work reasonably well, but hitting water at speed still gets some spray on me.

 

[Kartorbust]

So what's the weight of the battery pack and motor combo?

 

[EpsilonZero]

The ME1717 motor is 20.5lbs, Volt battery is 49lbs and RELiON battery (up front) is 34.4lbs. I guess the whole back weighs maybe 20lbs more than having a predator 212 with a gallon fuel.

So, the kart went from basically no weight in the back to almost 70lbs not counting my battery subframe. Come to think of it, the tires I had on hand were too wide for the split rims I bought and the deformation is probably contributing to the wheel hopping. I ordered some wider rims so we'll see how it goes.

 

[Kartorbust]

It's not bad weight wise. Hour of run time isn't too shabby either.

 

[EpsilonZero]

Yeah, it was an hour of beating on that Volt battery and I gave up (coffee + bumpy ride = go home). On top of that, I have gotten an hour of more conservative driving out of the RELiON. After I get the rest of my parts, I may have to pack a lunch and go on a couple hours or so road trip!

 

[Budget GoKart]

now i wanna see an electric racing mower lol

 

[EpsilonZero]

now i wanna see an electric racing mower lol

I was thinking about converting my riding mower to electric once the engine dies.

 

[KMEFA]

That's very innovative .

With the bit higher center of gravity in back now ,, have you had any thoughts on widening the rear wheel base ?

Looks like you could space the wheels out an inch or so on ea. side yet.

 

[EpsilonZero]

That's very innovative .

With the bit higher center of gravity in back now ,, have you had any thoughts on widening the rear wheel base ?

Looks like you could space the wheels out an inch or so on ea. side yet.

My new wider split rims will bring the wheel base back out over an inch and a half on each side, but I haven't felt in any danger of tipping over yet.

 

[Functional Artist]

Very Kool!

Um, your maxing out what that frame was designed to handle (weight, speed & dynamics)

So, I'd regularly inspect/keep an eye on the frame tubes (fatigue) & the welds (cracking)

 

[EpsilonZero]

Very Kool!

Um, your maxing out what that frame was designed to handle (weight, speed & dynamics)

So, I'd regularly inspect/keep an eye on the frame tubes (fatigue) & the welds (cracking)

It seems like my total weight is still reasonable; the frame manufacturer says the weight limit is 400lbs and the frame itself is very heavy duty (not like a racing frame). With me on it, the weight load is under 300lbs including around 110-120lbs of components. I guess what I need to do is weld a platform to the top of the seat and add a couple more batteries so I don't waste that extra 100+lbs.

My welds would probably be the first to go, so I have been beating on the kart and inspecting them repeatedly, though I have an automatic weld crack detector so that may be overkill. If the welds break, my battery will automatically fly off the back of the kart to alert me.

I did notice that my brand new chain stretched a little bit, so I will adjust it and replace the rear rims with the new wider rims tomorrow. I had to use my whole body weight to pinch those tires between the too-small split rims. I wouldn't suggest doing that. Hopefully, the hopping problem will be resolved shortly. In the meantime, cornering is insane and I was able to make myself dizzy going hard around a small loop in my neighborhood that I would have just spun out going around before.

 

[Kartorbust]

What chain pitch are you using? If its #35 or #40/41/420 you can get pre-stretched racing chain that'll last longer and not stretch out too fast.

 

[EpsilonZero]

What chain pitch are you using? If its #35 or #40/41/420 you can get pre-stretched racing chain that'll last longer and not stretch out too fast.

It's #420. I usually just run the chain a bit and readjust once later on. If there is a good price for the pre-stretched chain, I'd certainly consider it though to save some time.

 

[Kartorbust]

$39.95 for #420 pre-stretched chain https://www.gopowersports.com/did-420d-motorcycle-chain/

 

[EpsilonZero]

$39.95 for #420 pre-stretched chain https://www.gopowersports.com/did-420d-motorcycle-chain/

I actually started with that chain from gopowersports. I improperly installed the masterlink one time and popped it off into the ether, never to be found again. I had a little bit of an issue with some links kinking, so I had replaced it by then (was just testing another gearing combo).

 

[EpsilonZero]

My parts came in and I swapped out the narrow rims for wider ones and tightened the chain. I went ahead and threw my 14t/54t sprockets to see how it felt with the new battery. The wheel hop is still there, but is controllable by just not putting too much power when turning. I noticed that a bit of a wobbly wheel I had going on seems to be a misaligned wheel hub (factory defect?). I put on one of my other rims that is true in the meantime.

So, the end result is wheel hop is here to stay for now and the kart goes past 55mph frighteningly fast. The kart seems to accelerate faster and faster as it increases speed until it flies past the 5500rpm suggestion I set in the controller. It seems to be a little better at jumping rises in the road (e.g., manholes) since the front doesn't dip and land first like before, but I wouldn't really recommend it at all.

Maybe I just need a stronger motor to fix the hopping.

 

[EpsilonZero]

I finally took the battery out for a more rigorous test. I was able to run it at high speeds (mostly 45+) for about 24 miles and had over 57 volts left when I got back. I also tried out mounting my camera to the top of my head, which I think turned out pretty well compared to kart mounting.

 

[EpsilonZero]

Since I have voltage to spare, I decided to do some testing. Raising max RPM to 6200 (from 5500) with the 14t/54t sprockets broke 60MPH. I tried to film at 1080p instead of 5.7k and found that the ultrawide angle was narrower. That ruined my video, basically.

 

[EpsilonZero]

I read somewhere that increasing tire pressure could fix wheel hop, but that didn't work for me. So, I decided to try the opposite and I basically eliminated the hopping by lowering the rear tire pressure to 20psi. I usually run max rated psi of the tires with the tires varying between 40 and 50psi. Now the tires have better contact and spin instead of bouncing like basketballs.

Here's a video of the kart in a construction area avoiding raised manhole covers. I messed around with editing a bit this time...

 

[KMEFA]

I think where you read of increased tire press. could fix wheel hop,, that they were smok'n someth'n… lol

What bounces better & easier ,, a basketball full of air, or one that's half inflated ??

Got to remember also,, that for every 10+ degree increase in ambient air & tire temps,, increases tire psi by 1lb.

I never run ''max rated'' tire press. ''cold'', on anything.

Am running 10lbs. ''cold'' on the rears of mine, & am also liking 6 lbs. in the fronts,, but they are totally different tires than yours.

My elder Guru / ''vintage racing Kart Dude'', that races over 80mph, with a 36+ hp 2 stroke ect. , run's between 6 - 8 lbs., with racing slicks.
Think max press. typically on those tires, is around 20 lbs.