Search found 2125 matches

by flippy
May 17 2021 8:14am
Forum: Battery Technology
Topic: New battery cells for robot vacuum cleaner Rowenta
Replies: 3
Views: 48

Re: New battery cells for robot vacuum cleaner Rowenta

it has 60min runtime in low mode. so at least 4.5A of current. on high its at best double that so lets go with 8A. its a 4S2P battery so you can just get something like the LG INR18650-MJ1. that should give you a 35% capacity bump.
by flippy
May 17 2021 4:23am
Forum: Battery Technology
Topic: Building a large capacity battery for bicycle trailer
Replies: 5
Views: 66

Re: Building a large capacity battery for bicycle trailer

that would be 400 cells clocking in at a solid 45lbs just for the cells alone.

even doing high speed at 25mph without pedaling yourself that would give you 160+ miles of range.

yousure you got your numbers right?

and forget lifepo4, the bike would break in half just from the weight and size.
by flippy
May 16 2021 3:05pm
Forum: Battery Technology
Topic: Compression of pouch cells, info/data
Replies: 33
Views: 202

Re: Compression of pouch cells, info/data

the cheap cells are "folded" as its cheaper and faster to produce, the more expensive cells are layerd.

there is a guy that tore open a winston: https://www.wanhunglo.com/2019/citysax- ... own-whl-51
by flippy
May 16 2021 12:36pm
Forum: Battery Technology
Topic: 18650/21700 Case Material?
Replies: 34
Views: 419

Re: 18650/21700 Case Material?

Perhaps but I feel a thing is easier to imagine once you have seen it already, as you have Sir. Thanks anyway I do appreciate your experience shared. just read carefully and use common sense. it will get you pretty far. if you make a mistake you learn from it. you don learn to ride a bike by lookin...
by flippy
May 16 2021 11:40am
Forum: Battery Technology
Topic: Compression of pouch cells, info/data
Replies: 33
Views: 202

Re: Spot Welding Copper Strips to 18650 Battery Cells

You need the resin in a potting to be soft enough to expand a bit as the cylindrical cells slightly expand with heat. Otherwise potting seems the safest way to deal with a battery in my mind. I can throw my potted battery down the street potting is like a crumple zone in a car. great for hitting a ...
by flippy
May 16 2021 11:37am
Forum: Battery Technology
Topic: 18650/21700 Case Material?
Replies: 34
Views: 419

Re: 18650/21700 Case Material?

its not that hard to imagine the tape i linked to, the foil i mentioned and a tactical and liberal application of closed cell foam. :wink:
by flippy
May 16 2021 9:43am
Forum: Battery Technology
Topic: 18650/21700 Case Material?
Replies: 34
Views: 419

Re: 18650/21700 Case Material?

Ham wrote:
May 16 2021 9:28am
Do you have any build threads showing how?
no, i dont. i do commision jobs for single commision requests. and i dont share how i build my larger industrial batteries for obvious reasons.

i am here to help people along in their DIY stuff and teach people the basics and does-donts.
by flippy
May 16 2021 9:04am
Forum: Battery Technology
Topic: 18650/21700 Case Material?
Replies: 34
Views: 419

Re: 18650/21700 Case Material?

How does it not add structural strength, that seems counter intuitive? you make a large, flat surface (aka: a piece of paper) of resin and expect it to be structural. that is not how it works. thin sheets of resin are very flexible in all the wrong directions. you are aksing the resin to absorb for...
by flippy
May 16 2021 6:38am
Forum: Battery Technology
Topic: 18650/21700 Case Material?
Replies: 34
Views: 419

Re: 18650/21700 Case Material?

The resin, so I am advised, will turn softer and much more pliable in a thermal run away event and thus not be an issue for venting. your normal 2 part resin you buy at your local store will not do that. please dont forget that the resin does not give you structural strength and adds a considerable...
by flippy
May 16 2021 5:59am
Forum: Battery Technology
Topic: 18650/21700 Case Material?
Replies: 34
Views: 419

Re: 18650/21700 Case Material?

Nothing wrong with potting a cylindrical cell pack. In fact I'd argue it's the safest thing to do. The PTC plate will function just fine in most cases. only for specific use cases (i.e. diving gear) and with extremely careful selection of materials. and even then its safer, lighter and cheaper to j...
by flippy
May 16 2021 4:00am
Forum: Battery Technology
Topic: 18650/21700 Case Material?
Replies: 34
Views: 419

Re: 18650/21700 Case Material?

Thanks for the reply, appreciated. How would you create a pack that is fully waterproof and shock resistant? simple, you create layers. first a enviroment case that protect against direct elements (aka: metal case) but that does allow for small ventilation and drainage. then a shock absorbing layer...
by flippy
May 16 2021 3:33am
Forum: Battery Technology
Topic: Compression of pouch cells, info/data
Replies: 33
Views: 202

Re: Spot Welding Copper Strips to 18650 Battery Cells

Something else to consider: cells will produce small amounts of gas in normal operation, and if they are held in an extremely rigid enclosure, the pouch may over-pressurise and burst. Properly designed packs include a compression preload, but with a slightly elastic packing (usually a specialised P...
by flippy
May 15 2021 6:37pm
Forum: Battery Technology
Topic: Compression of pouch cells, info/data
Replies: 33
Views: 202

Re: Spot Welding Copper Strips to 18650 Battery Cells

pressure depends on the expected application. the pack of a volt has strech bolts to get the proper pressiure. for context: its the same style of bolt used to keep the cylinder head on the engine. offically they are a 1 shot use but nobody actually replaces them. fun fact: even with several tons of ...
by flippy
May 15 2021 6:30pm
Forum: Battery Technology
Topic: 18650/21700 Case Material?
Replies: 34
Views: 419

Re: 18650/21700 Case Material?

I've just been reading and watching about grins potted packs... they seem to be holding up well and still for sale. The failure testing was also very interesting. Have you seen it? i have seen it and i have one of their batteries and tested it. they are not made to handle dutch cobblestone roads no...
by flippy
May 15 2021 3:32pm
Forum: Battery Technology
Topic: Compression of pouch cells, info/data
Replies: 33
Views: 202

Re: Spot Welding Copper Strips to 18650 Battery Cells

I've never heard of anyone cranking up pressure like that on pouch cells. My drag race (Lonestar) cells are lightly compressed in a polycarbonate enclosure. It's stiff enough to inhibit swelling but nowhere near that kind of pressure. I wonder if Zero actually does that? it depends on the size of t...
by flippy
May 15 2021 1:08pm
Forum: Battery Technology
Topic: Compression of pouch cells, info/data
Replies: 33
Views: 202

Re: Spot Welding Copper Strips to 18650 Battery Cells

Frank wrote:
May 15 2021 12:56pm
That sounds insane! It implies that a pack with cells measuring 4" X 5" requires compression of 2,000 lbs. I doubt anyone builds packs anywhere near that. What do the automotive OEM's use I wonder?
3/8 allthread does 600lbs, so 4 of them will handle that with plenty of room to spare.
by flippy
May 15 2021 12:42pm
Forum: Battery Technology
Topic: Compression of pouch cells, info/data
Replies: 33
Views: 202

Re: Spot Welding Copper Strips to 18650 Battery Cells

Interesting. I’ve always wondered about that. I want to research this too. It seems like the cylindrical cells would naturally have more energy density but I guess it depends on the cells. the energy denisty comes from the chemistry used. prismatics as used in phones and laptops are made for capaci...
by flippy
May 15 2021 4:14am
Forum: Battery Technology
Topic: 18650/21700 Case Material?
Replies: 34
Views: 419

Re: 18650/21700 Case Material?

put a wall between the controller and the battery. it needs support on that side as well. and make sure you use thermal pads for the controller to dissipate heat. that thing will get hot if you mount it there. and a "floor" for the battery to sit on. it needs to be "naturally" su...
by flippy
May 15 2021 3:51am
Forum: Battery Technology
Topic: LiFePo4 15s Charger?
Replies: 33
Views: 525

Re: LiFePo4 15s Charger?

If your BMS requires holding CV for more than a few minutes in order to "finish" balancing, then you're doing it wrong, either replace the BMS or stop using it for balancing.. do you even understand how cheap bms actually balance? comments like this seem to indicate that you dont. if it t...
by flippy
May 14 2021 2:48pm
Forum: Battery Technology
Topic: LiFePo4 15s Charger?
Replies: 33
Views: 525

Re: LiFePo4 15s Charger?

no, your charger does not shut off. the light on your ping cahrger only indicates that the current has dropped below the set level. thats all. it does not mean anything. think of it as a light on your dashboard of a car that turns red if you go above 10mph and back to green if you slow down. you can...
by flippy
May 14 2021 2:36pm
Forum: EScooters/EMotorcycles
Topic: More low end torque for up hill climbing power
Replies: 26
Views: 535

Re: More low end torque for up hill climbing power

Akore wrote:
May 14 2021 2:07pm
So with no temp sensor it must have been the Controller itself that slowed the motorcycle down and then shut off the entire system?
flippy wrote:
May 12 2021 3:50pm
does the motor even have a temp sensor? i am willing to bet it was the controller that shit the bed.
called it :mrgreen:
by flippy
May 14 2021 1:43pm
Forum: Battery Technology
Topic: 18650/21700 Case Material?
Replies: 34
Views: 419

Re: 18650/21700 Case Material?

the PTC is the plastic disk that is underneath the positive terminal. its the fail safe of the cell. it pops under high heat or pressiure and breaks the connection and vents the cell. its what keeps the cells from becoming a bomb in case of a fire for example. i have done loads of testing with potte...
by flippy
May 14 2021 12:56pm
Forum: Battery Technology
Topic: 18650/21700 Case Material?
Replies: 34
Views: 419

Re: 18650/21700 Case Material?

I thought the same about potting until I spent some time chatting with an experienced builder in the workshop and after seeing their previous builds and current three year old 40ah pack that has taken years of delivery abuse with deliveroo riders powering mxus 3k hubs I have decided to give it a go...
by flippy
May 14 2021 12:13pm
Forum: EScooters/EMotorcycles
Topic: De-restrict for off-road use?
Replies: 4
Views: 127

Re: De-restrict for off-road use?

none of those wires i can tell you that. :lol:

turn signal are usually self contained, so you need to replace the unit or just fill the beeper with hot glue.