Custom Battery Packs? INTERESTED?

[riba2233]

You are right, charging one cell at 4 A will impact cell life. I think that good compromise between fast charging and cell life would be charging pack at 1C, so at 7.5 A. That would mean that the pack would charge in little over one hour from 0% SOC.

 

[CSN]

saw this on kickstarter.

Definitely a lot of people trying to solve the same problems.

This battery design claims the user can replace individual cells.

I wonder how they are getting that kind of range with something that weighs a lot more than an eboard. Gearing?

https://www.kickstarter.com/projects/hongquan/the-kben-a-modern-electric-bike-for-the-human-race/

 

[thepronghorn]

What in the world are you talking about lipos not being regen compatible? Hobby lipo's are capable of much higher charge rates than your he2 cells, which means they are capable of much stronger regen than the 4A charge rate your he2 packs are rated for.

Stop spreading misinformation with your "Not Regen Compatible" claims.

I am talking about a specific configuration of components that is required to build a pack, using lipo, that offers the same features of the EnertionUltra Cell.... one of the key features of the ultracell is an "on/off" switch. If you use one of the high amp on/off switches sold by alien power systems, DIY electric skateboards and myself you cannot send power back into the pack due to the switch design.

Remove the high amp on/off switch and you can recharge lipo using regen....

But now you can't easily turn your eboard on/off.. .. see the problem. UltraCell solves this problem.

So please stop accusing me of spreading false info.

Sorry I didn't know that your $60 switch only allows current to flow one way. My point stands about the the relatively low charge rate of the HE2 cells either limiting your regen rate or punishing the cells as they struggle to absorb the 20A of regen current you are trying to shove into them.

 

[Hummina Shadeeba]

why is a switch so complicated that it cant support regen, or I guess current, going in the different direction.

why a simple switch for high current such a big deal I cant find out. I was going to bust open a high current switch but it was too strong. what the hell is in a high current switch? And yours onloop is more complex than it...or maybe not as it doesn't support regen. I do like the button.

 

[bandaro]

Cant answer as to why, but the solid state relays won't support a 'backwards" current. Easiest way to do this is to get a massive switch capable of 100 amp, but these are stupid so don't actually do this. Will a mechanical relay work both ways can anyone confirm?

 

[riba2233]

It will.

 

[onloop]

I'm sure someone could design a seperate switch that works for regen..... but nothing comes cheap when you want something to be designed from scratch ...everything has a cost. SO unless you happen to be an electronics engineer.. I'm sure you could design it easily... otherwise you have expensive development costs....

Also it doesn't really make any sense to have a seperate device, that adds weight and cost and complexity.

This is why i made the Enertion ULTRACELL with everything built in...the switch is using the BMS to switch the power off. Additional PCB and mosfets just for a switch would be redundant.

Enertion UltraCell not only solves this problem, it also solves all the other problems, such as charging, balancing, soldering connectors, routing wires, mounting charge ports, mounting voltage meters.... etc.

UltraCell has more features, is more economical, is safer, has better longevity and easier to install and use... its just a better option for DIY builders..

 

[onloop]

Also. I can supply a 4A charger instead of the 2A standard charger. But this cost $30 more.

Also it may reduce lifespan of batteries.

But it will charge twice as fast.

 

[DodgyBob]

HI Onloop,

Is it also possible to make one of these but in 6S ? My Esc is only rated max 6S and I want to avoid having to replace it + I dont really need the additional speed.

 

[BShady]

At least for the first test run im not really willing to pay $330.

My budget only allows me to pay a measly $200. That's all I got

 

[Vanarian]

Onloop it's pretty simple, your UltraCell has been thought for easy use, so even with all the advantages you put into this you will inevitably face the "DIY dilemna".

For electronic builders who are equipped with machines tools and 3d printers etc, the first reaction they will have is "Is it legit?" once solved this becomes "ok this thing is clean but why so expensive ? I can make a simpler pack for less money plus C specs etc"

Here you go! DIYers hardcores are already equipped with chargers and stuff etc, know how to balance cells etc that's why.

Now for many of us here you have the average guy who isn't a pro electronics and wants to build his cool e-bike or e-board to go chillin. He is not on ES because he likes PCB, he's here to learn either where to buy his cool EV or better, build EVs for his pleasure. He wants to enjoy them quicky and spend the less possible time to build. This is your target, right? And that's what kits are made for, gaining time and being user-friendly.

Yes it costs a certain amount but I salute the work and hope you'll get quick sales.

Also. I can supply a 4A charger instead of the 2A standard charger. But this cost $30 more.

Also it may reduce lifespan of batteries.

But it will charge twice as fast.

Do you plan to sell chargers separately? Or would you mind linking the model? I might be interested by two!

 

[Freshair]

Hey onloop, when you say

"NOTE: This battery is also actually serviceable, you can remove any faulty cell and replace it, the individual cells are really cheap and readily available for $10-$15"

Do you mean to say this pack has no permanent connections like solder or spot welds?

 

[torqueboards]

I think it's a decent deal for most people. Price is high but that's typically the price of these type of batteries already pre-built.

I'm also looking into 8S3P and 12S3P options for more power and a cheaper option. But in the end --- I"m thinking you might as well go 12S3P. 66A cont and 105a peak using Samsung 25R cells. Same size as onloop. 23mm H, 140mm W, 380mm L.

Everyone will soon be moving away from 6S and moving to higher voltage. You can run with more torque and higher voltage and still get the same speed. Also higher voltage and same setup will result in more range/distance because of a bigger Wh pack if the riding style is the same.

 

[onloop]

@torqueboards I doubt you can make a 12s3p pack 380mm long. Without BMS and without cell holders the length is 324mm... but making it without cell holders is not recommended. The length of the cells alone with cell holders is 18 cells x 23mm is 414mm. With very small BMS it will still be about 450mm Long.

Also 12S might be an issue for the emerging hub motor builds.... you need really low KV if you have 12S. I think 10S is about the limit.

 

[onloop]

Hey onloop, when you say

"NOTE: This battery is also actually serviceable, you can remove any faulty cell and replace it, the individual cells are really cheap and readily available for $10-$15"

Do you mean to say this pack has no permanent connections like solder or spot welds?

The cells are spot welded. But you can open the pack Locate any problem cells. Cut the nickel plate off and remove the cell. These cells tend never to get out of balance though.

Unlike LIPO the pouches are normally stuck together with strong adhesive. Seperating them without tearing the foil wrapper is really difficult. Also you can't buy single LIPO pouches easily.

You can buy single 18650 cells very easily.

With BMS and quality cells like LG HE2 you would probably never have a problem. The chemistry is very stable and highly reliable. Hence the reason Tesla use these cells And not Lipo.

 

[emepror]

What kind of BMS units does everyone plan on using? My research into readily available ones hasn't turned up any decent one that won't fry/damage cells through just normal use. i.e. ~4.3V overvoltage cut off and ~2.4V under voltage cut off as an example. I have a plan to develop my own 6-10S BMS using TI chips but thats a side project for the summer.

 

[onloop]

Here is some video of one of my testing days.

The battery works flawlessly!

I am running with dual vesc. 10s Enertion UltraCell battery. 250kv motors (this is not optimal..Way too high KV should be about 190kv... but it's what I had.) 90mm wheels.

[youtube]59d9JLXF2TI[/youtube]

 

[longhairedboy]

Cant answer as to why, but the solid state relays won't support a 'backwards" current. Easiest way to do this is to get a massive switch capable of 100 amp, but these are stupid so don't actually do this. Will a mechanical relay work both ways can anyone confirm?

I tried using a massive switch on the battery lead. I can in fact confirm it is stupid. :wink:

What i didn't realize is that the electronic switches didn't allow regen. This explains my subtle drop in range when i moved from the original enertion ESC that had some sort of onboard power switching to an older on-sale enertion ESC that needed a separate switch. I'm no longer filling my batteries with goodness when i'm coasting down hills. Lame.

If anyone else pre-orders the ultracell, i want to see reports of people using a 4amp charger and not killing the batteries. Currently it takes me about 1.5 to 2 hours to take my lipos from 20 to 25 volts. 4 hours won't be a total deal breaker, because charging will no longer be a monitored affair. I can walk away from it and go do something else.

Also, does anyone here only charge and ride once a week? I'm out there every damned day, son. Beating the crap out of my rig in the name of science. Every afternoon i take my board out into my neighborhood on some of the most terrible roads in existence for extensive vibration testing. I lose screws on occasion, but every screw lost is a lesson learned. But on the weekends, bike trails in the woods for a 9 mile sprint. Hell yeah. Heads turn, dogs bark, kids yell "where did you get that i want one."

 

[torqueboards]

Regen at most will bring back 10% if not 4% on average. 4% out of 100 is only 4. 10 miles is .4 miles. Just need a bigger pack... but... might as well have it if you can have it.

 

[riba2233]

It's good for braking itself, especially on skateboard. On my moped I get 10% regen or 15% if I ride more aggressive, but I live in hilly area.

@longhairedboy: charging at 4A wont do anything to cells, don't worry. It's three times below maximum.

 

[thepronghorn]

Almost all RC controllers do not actually do regen braking. They instead short the motor phases together and use the resistance in the motor phases/esc to dissipate the energy from slowing down as heat. The Vedder esc does do regen as do most ebike controllers (by ebike controller I mean the big ones in the extruded aluminum cases often called infineon: available from lyen, em3ev.com, ebay, and other places).

 

[torqueboards]

Almost all RC controllers do not actually do regen braking. They instead short the motor phases together and use the resistance in the motor phases/esc to dissipate the energy from slowing down as heat. The Vedder esc does do regen as do most ebike controllers (by ebike controller I mean the big ones in the extruded aluminum cases often called infineon: available from lyen, em3ev.com, ebay, and other places).

Really? I read a while back even on RC forums that most of all RC controllers all have regen braking.

 

[simpes]

Actually if a diode (say one capable of 60A as specified) is to be connected in reverse parallel configuration together with the anti-spark switch, shouldn't the switch support regen braking as well? Since it would allow current to flow in the opposite direction.