Buggy convertion project

Saul Gonzalez

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Joined
Jun 11, 2017
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8
hi guys, merry Christmas and happy new year !

I want to go EV on a buggy and want to use a 3000w 72v motor, listed here 72v 3000w motor

now I have a few choices for the battery and I need your help for the best suit.
option 1: build a 18650 pack with 20S 60P so that i could get near the 100AH witch will have a huge weight on the buggy.
option 2: 6 deep cycle 12v batteries in series, these are expensive...
option 3: build a pack with headway 38120HP, 23 in series. this could be a lot lighter but not sure about the life cycle.
option 4: WHATS YOUR CHOICE ?

please help, is this the correct motor ?, should i use a different voltage ?, what battery to choose !!?


thanks !, I'll keep updating this post until the project is complete, might take a while...
 

floydR

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Aug 23, 2017
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800
option 1: 20s40p 2600mAh 10A cells would give you 104Ah battery capable of 400A continuous output.
There are cells with both higher mAh and higher discharge rates. weight probably ~90 lbs or less (based on weight of a 7s10p 26AH 18650 battery I had on hand). ~85 lbs 38.5kg if made without holders (based on wieght of10s2p hoverboard packs). even 60p would be light compared to deep cycle Lead acid You would have the capacity to drive for a while and the amp for acceleration.
Option 3: for safety. Would need12p for 96Ah. Expensive But less stress on the cells?

What will the buggy be used for? paved surfaces, sand, around the homestead, racing etc?
Later floyd
 

OffGridInTheCity

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Korishan

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The next question is where have you gotten the 18650 cells? Are they new or are they reclaimed? If reclaimed are they from new-old stock (aka barely used like if from medical packs) or are they from salvaged used packs (such as from laptop packs and the like)

If the cells are new-old or new, then as Floyd and OffGridInTheCity states use Option 1. If they are the latter, then I would probably not use them for this particular application. Just because of the instantaneous repeating high loads a "buggy/go-cart" would have on them.
With that said, if this is a test for your own experimentation and knowledge, and you make sure the battery pack can be discarded quickly in the event of a failure (which, honestly, this should be the case either way), then go for it. Ohh, and it's only "you" or another adult who's working with you use it. If children will be using it, no go, imho. Use new, new-old stock grade cells.
 

floydR

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Aug 23, 2017
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800
The LGGBM261865 cells i am using test 2550-2750 Supposedly "The battery packs come from a commercial product where one model was replaced with a newer model" not sure if they are NOS or if they were removed from service and replaced.
later floyd
 

Saul Gonzalez

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Jun 11, 2017
Messages
8
Hey guys, Happy new year !, thanks for the replies. thanks all of you, I'll be making the pack with 18650, i haven't order any of them, i have around 600 but all used for about 3 years on a power wall that i made. Option 1 is the go go.

I'll keep posting the project details.
 

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Ebikeforlife

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Jan 6, 2021
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Hey guys, Happy new year !, thanks for the replies. thanks all of you, I'll be making the pack with 18650, i haven't order any of them, i have around 600 but all used for about 3 years on a power wall that i made. Option 1 is the go go.

I'll keep posting the project details.
If I were quoting and building the pack, I would be asking the following questions

1: what is the space that you have available to fill with cells for a pack?
2: what is the rating of the controller... 3000W at 72v is around 42A, is that Peak or continuous?

I have designed batteries for ebikes that peak at 20kw with a lot less cells.

depending on the budget for the cells, i would look at something with the higher capacity because of the amount of cells you are putting in the pack, you can get away with having lower individual discharge.

The LG MJ1 has a capacity of between 3400mAh and 3500mAh and can output 10A(Datasheet) but i recommend 5A max continuous, so that you avoid too much heat generation. so you would only need a 20s30p to give you 105Ah and a discharge of 150A cont and 300A peak
Pair this with an ANT-8s-24s Bluetooth BMS and LCD and you have ability to monitor cell voltages, Cell health, Balancing, charge levels(3.1v to 4.1v for longevity of cells)

Hope this helps... Any further info by all means ask
 
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