For those who are just now entering the field of diy electric skateboards or just looking to upgrade I figured it was time to talk about the pros and cons of 18650s vs lipos and which in general makes more sense. So from my research a li ion is going to be safer than a lipo however both chemistry’s are dangerous. li ion cells do however allow for packs to be made in different shapes and sizes and a bms to be added as an extra safety feature. The main question I would like your opinion on is for an average or entry level diy electric skateboard builder what makes the most sense?
18650 cells generally have a lower continuous discharge rate (unless you have a couple high discharge cells in parallel), but they last much longer than lipos. They are more expensive though.
Hobbyking’s new Graphene series packs also look interesting; people have charged and discharged them over a thousand times, and they still had a low internal resistance and resting temperature. They are pricy though.
A123 cells also look interesting (high dischage rate)
in your opinion do you think the graphene has a safer chemistry than an ordinary lipo?
I haven’t caught up on the rcgroups thread on them yet, but last time I checked, HobbyKing was being very vague about what differentiated Graphene packs from their other lipos. Here’s the thread: http://www.rcgroups.com/forums/showthread.php?t=2592234
thanks ill give it a looksie
Okay so it depends on a lot of factors in my opinion…
Ive done both types and im usually more satisfied with lipos just because my bank account agrees with them. I mean they are sometimes 2 or even 3 times cheaper for a comparable pack. So when you think about it that way, is a 18650 pack going to last 3 times longer than a lipo pack? the answer is that it might, but you can still buy 2 more of the exact same Lipo packs if they die out.
People will tell you to go 18650 route because they are more stable and you get the BMS advantage and they last longer, but once you run the numbers… until Elon Musk builds his battery plant, 18650 batteries are too expensive. 18650 packs are more professional, and i only use them on builds where lipos aren’t the best option.
Remember you can make a Lipo battery with a BMS and you can seal them in a hard case.
Dont get me wrong, i like them both. Im just fighting for the underdog. If you have the budget, go 18650, if not then Lipo will do the job pretty well at a discounted price.
here’s what i have found:
Lithium Polymer prismatic pouches (lipo):
- far fewer charge cycles, like 200 to 300
- more explosive power discharge for acceleration
- mass produced as an entire pack so less expensive and easier to work with
- commercial packs from hobbey king etc are a great source of pouches if you want to repack the packs into either a different layout or a different voltage (like taking a 6S2P and makeing a 12S1P or just flat packing it to fit in the box better)
- more puncture prone and therefore more dangerous to use in general, so a tough box is critical
- allegedly start more fires than li-ion 18650 cells
18650/26650 li-ion cells:
- way more charge/discharge cycles (alledgedly measured in the thousands, not hundreds)
- lower discharge rates, so less total power output at one time which means you need to stack them up more in parrallel to get the burst you want, luckily they’re shaped for just such an occasion
- you have to order individual cells and make your own pack or have somebody make a pack for you or buy a Space Cell or other such pack which is less common and more expensive than LiPo pouches
- Less puncture prone as they are in a metal cylinder, so they are safer under the board
- will start a fire without hesitation if the electronics paired with them are shit and they are allowed to over charge/over discharge, so don’t be fooled. This is still fucking lithium people.
- the fire may be a little different do to the fact that the cylinder is guiding the reaction in a particular direction instead of just letting all hell break loose like a pouch would
Like you said later in your post, you can use a BMS with lipos just as easily. In fact more easily because they come off the shelf with balance leads that BMSs often have plugs for already. if you go with cells and making your own packs, you’ll need to solder in your own balance leads.
Exactly it’s just plug and play, almost
Don’t 18650 explode when shorted lol they literally explode because of the pressure. (When they’re not internally fused)
Where as pouches will just vent usually
Almost all 18650s have vents to relive pressure
Those cheap hover board cells don’t have fuses or vents.
But good to know for the legit cells thanks
i know for a fact sammys do ima look in to sony, pana, and lg right now look for an edit when i get back.
yeah pretty much if it has a flat top and not a button it has a vent.
also with sammy 25r cells if you short them they dont explode. how do i know? i shorted one.
Oh okay this is all good information. Thanks for that
my sammys have what look like vents. I have 94 cells sitting on my bench right now. The ones from the 10S group by and the ones from the 12S build i’m doing just arrived, so i’m probably going to dump them all out and roll around in them to make sure they’re safe for everyone else.
@willpark16 everyone has done a good job summarizing pros\cons. My opinion is that if you are an entry-level DIY builder, use lipo or buy an 18650 battery pack that someone else makes for you. Figure out the other stuff first (your riding style, actual speed and range requirements, component preferences) and get into making a battery pack later with some experience under your belt.
After a year of riding lipos I’m finally building my own 18650 pack and although it’s not incredibly complicated, it’s hard enough (and dangerous enough) that I wouldn’t recommend it for an entry-level builder.
oh ive done a few builds for friends, i wouldnt say im a pro but i understand the average things and a tiny bit more in some areas. I just made this thread for my friends and anyone else that needed some help. Btw are u soldering that pack?
do lipos are cheaper? I calculated by wh and it seems that they both preety much costs the same.
depending on where you get them they can be and once you throw in a bms onto the li ion they can easily be 50 to 100 dollars more than before