Success with first electric go kart project (pics)


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The-J-Man

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May 2, 2017
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DarkRaven said:
You can't do that endlessly though, at some point more cells in parallel won't give you more power and just increase the runtime :)
By the way, you were a bit generous on the main positive connection (and I guess on the main negative one as well). You can do it like that and go all the way down the length of the battery, but you don't need to. It has no beneficial effect. The cells are already connected, you are just providing a bigger connection between the terminals of the cells and it doesn't effect the way current flows through the main wire.
But with nickel strip of that size being good for about 10A continuous and 15A where it starts to get hot all ready, having the connection just at the end would cause the nickel strip just before the connection to the wire to be over its rating right? at 27A with 9p config you are looking at the nickel carrying 3A more per cell adding upgoing towards the wire connection. So ideally you shouldn't have more then 3 cells without a connection that can handle higher loads (in his scenario).
garolittle said:
So I gave into the temptation for more power. :) I will soon replace thecomponents on the electric go cart referenced above with the following set up:

  • 48V 1000 Watt BrushedMotor with rated current of 26.7 amps
  • 48V charge controller
  • 14S9P batteriesusing Samsung INR18650-25R 2500 mAh 18650 cells (connected with spot welder using pure nickel strips)
I added a 35 amp fuse (rated for up to 58 volts) and I hope to hook everything up to the go kart this weekend. Thanks to those on this forum who have provided advice to me. I really appreciate it. Here are a few photos of the newbattery pack I createdand the motor/charge controller that I will soon install.
Looks amazing!!
That 48v system will be a lot of fun.

Since you probably want more fun in that gocart then range im guessing you arepushing it pretty hard. That 1000W motor which is as you stated 26.7A all readywill most likelyhave peaks of 2000W, so maybe increase the size of the fuse and the wiring respectively, if you don't want it to pop ( I dont know what you used in terms of wiring)
Of course maybe test it first and see if it does pop, but from my experience with 36V 250webike motors, where technically the current is at 7A, I can tell you they pull 18-24A under heavy load (peaking at 800W). So if you are constantly pulling max power you will likely be above the Amprating of the motoryou mentioned.
 

DarkRaven

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Well, this was before the change to the new motor. We weren't talking about 27A back then. Makes sense to re-evaluate the situation now. 27A from the 14s9p battery means 3A per cell, that's ok. But sure, you have 27A running through each pack of parallel cells so the main battery connection along the battery would make sense now, but as I said just because it provides a bigger connection. But you don't only need that on the main positive and negative then, maybe it would make sense to weld another layer of nickel over the parallel connections.
 

garolittle

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UThanks to both of you for the response. I may add another layer of nickel strips as suggested (very easy to do with the spot welder). The question concerning the wiring set up is the one that has concerned me the most. The motor and charge controller came from the vendor with 12 gauge wires so I have been worried about the amperage. I disassembled both the motor and the charge controller to see if there was an easy way to add larger wires such as eight gauge or 10 gauge. However it was beyond my capability so I left the 12 gauge wiring as is. I did manage to add the 35 amp fuse by splicing togetherthe 12 gauge wire with the eight gauge wire that came with the fuse. This is why you see a bulge near the front and back of the fuse. Any more suggestions are greatly appreciated. I really enjoy this forum. :D
 

The-J-Man

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May 2, 2017
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DarkRaven said:
Well, this was before the change to the new motor. We weren't talking about 27A back then. Makes sense to re-evaluate the situation now. 27A from the 14s9p battery means 3A per cell, that's ok. But sure, you have 27A running through each pack of parallel cells so the main battery connection along the battery would make sense now, but as I said just because it provides a bigger connection. But you don't only need that on the main positive and negative then, maybe it would make sense to weld another layer of nickel over the parallel connections.

Oh I see, didnt notice that.
Regarding the parallel connections, When I built my 10s6p pack for my electric longboard I was researching about if I need to double up on the parallel connection and came up with No because I have a piece of nickel strip going from each cell to the next cell so the current is split between 6 pieces of nickel. On the serial connection though (since the pack is built with the cells flat and not like the pack we are talking about here) I tripled up on the nickel.
Was that the right thinking? or might the parallel connections heat up?
The pack in this thread has 9 pieces of nickel, one for each cell to the next, even on the serial connection.
Is there a flaw in my thinking of how the current is transferred between cells? From what I know the electricity will always travels the path of least resistance right, and flowing directly over to the serial cell instead of through the parallel connection makes more sense to me (so at no point would be parallel connection between the cells be carrying 27A as its flowing over to the next bank of cells directly. Might be a noob question :D
 

DarkRaven

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You are right. It's needed at the main positive and main negative terminal. Between the cells it is probably just nice to have with identical cells but it might come in handy when the cells start to get older and the current flow isn't that even anymore. Another strip of nickel will make sure you don't get any probleme there and as this battery is already spotwelded it is also very easy to add. So there is no harm in adding it now and it ensures that you will always have a nice connection between the cells and groups of cells.

If it would be a massive PITA I would say don't do it and try it like it is now first.
 

garolittle

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Oct 27, 2017
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So I finally finished an upgrade. I swapped out the old 24v motor and lithium ion pack for the following:

48V 1000 Watt Brushed Motor with rated current of 26.7 amps

48V charge controller

14S9P batteries using Samsung INR18650-25R 2500 mAh 18650 cells (connected with spot welder using pure nickel strips)

I added a 35 amp fuse (rated for up to 58 volts).

Finally, I added a voltage/amp meter and shunt so I can constantly monitor the power.

The results were awesome. I briefly hit 16 mph on a slight uphill road and the low center of gravity from the forward mounted battery pack allows for some fun drifting. I weigh 145 pounds (66kilograms) so it looks a little odd for a grown man to be riding a kids Razor Drifter Go Kart but it is really fun.Previously, the 24 volt motor struggled to gain speed on the same road. The increase in power and speed is really noticeable. I will post some videos and pictures soon but I wanted to thank everyone again for all of the great advice.
 

Korishan

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We need video proof of big man in little cart drifting ;)
 

garolittle

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Lol. I will post a video tonight. Here are a few photos of the project. My son name the project Phoenix. The battery is housed within the homemade wooden box that sits in front of the seat. I cant wait to get home from work to write it again. :D

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garolittle

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Oct 27, 2017
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Korishan said:
We need video proof of big man in little cart drifting ;)

Ok LOL I will post a video soon. Here are some pictures of the upgrade (yes that is electrical tape holding the battery box together :). My son named the project "Phoenix".


A few more pictures. The 52 volt battery pack and BMSarewrapped in 1/8 inch sheets of foam rubber and were shrink wrapped. Everything fits nicely in the home made battery box.

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Korishan

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Duct tape and electrical tape is what the pros use! :D
 

garolittle

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Ok I have tried several video formats but I have been unable to upload a video from my iPhone to this discussion forum. Which format (wmv, avi ...) will work? Thanks for any suggestions
 

Geek

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garolittle said:
Ok I have tried several video formats but I have been unable to upload a video from my iPhone to this discussion forum. Which format (wmv, avi ...) will work? Thanks for any suggestions

You will have to upload to YouTube then embed it into your post. Can't wait to see how well that thing goes!
 

garolittle

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Thanks for the YouTube suggestion. I dont know why the easy solutions always escape me. :). Heres a quick video of my son in action.



One more video. This time a burn out from standstill.

 

garolittle

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Oct 27, 2017
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I added an LED headlight on the frontand some white LED strip lighting underneath each side of the go kart tonight. This adds a degree of safety since it is much easier to see the go kart from a distance now. :)

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Korishan

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AWESOME! :D

You could put some RGB lighting on there and have it pulse to music ;)
 
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