Endless Sphere

I think I did see a video of his single cell holders - fine if you never ask more than half an amp from the cells. Flexible printed circuit strips are only good for sensing - milliamps at best. Even thick PCB traces would require lots of copper area to carry more than a few amps without heating up. ...

The flexible PCB is definitely only used for the BMS.
The Model 3 battery uses proper busbars with cell terminals wire-bonded to them. The encapsulant ensures uniform temperature and vibration protection.

Depends what happens to the cell. An internal short will cause the cell's voltage to drop through self-discharge. Depending on the impedance of the short, the cell's voltage will drop quickly or slowly. In the case of a high impedance short, current will flow from the adjacent cells in parallel into...

Hillhater wrote: ↑

Jul 15, 2018 11:51 pm

Here are a few..
* EVs are economical to own and run
* EVs are cheap to service.
* EVs do not need a transmission.
* EVs will outnumber ICEs within 10 years

Myths or truths? Can't quite tell with you HH

You guys speak of pouch cells as if expansion is normal - it's not! If a pouch cell is puffing it's because something has gone wrong - either an internal short, physical trauma, over charge or over discharge, or the cells were allowed to get too hot for too long. And yes, any lithium chemistry which...

An annual payment reminder for $100 would work for me.

I never use the wiki.

But then again, I also know how to use the search function properly

Yes and no. Rated capacity is a useless figure compaired to the actual capacity you can draw from it in the test use case. The first cycle sets the benchmark capacity. I mark the cell as worn when i lost 30% of that initial capacity. Doing a 0.2C discharge test is fun and all but it does not mean a...

In order of most capacity remaining: 4.05>3 at 2A discharge and .7A charge 4.05>3 at 3A discharge and .7A charge 4.1>3 at 2A discharge and .7A charge 4.2>3 at 2A discharge and .7A charge However you need to calculate 'equivalent full cycle life' The number of equivalent full cycles is obtained by di...

I'm not so pessimistic about grid scale storage. I doubt that grid scale battery storage will be used in quantities to replicate pumped hydro, but I can see all new RE generators being required to have some amount of battery storage for stability. I think home energy storage is going to take up abou...

No doubt Hillhater will be along shortly to try and claim it was somehow caused by unreliable wind generators. That's for Hillhater to comment on, but the observation is that while almost 5 GW of coal fired generation went offline, the shortfall was being met by generators elsewhere in the grid - p...

Interesting to note that four of the five big coal fired power stations in NSW tripped out this weekend. You can see they've been using hydro to fill the gap. NEM1713_10052018.JPG Also it looks like Tassie has got the Basslink interconnector re-established. I think Snowy 2.0 and Tasmania's pumped hy...

Batteries are actually getting a bit more expensive now. The old supply and demand thing

Great to see if able to taxi on it's own steam - the e-aero equivalent of spinning the back wheel of a bike

How far off a maiden voyage do you think you are?

I ordered cells from FEP - same place I get the pouches from. They were about AUD$6.30 each landed.

If you have a multimeter, set it to test conductivity and check that the pin for B1 is connected to B- (it shouldn't be). That will answer your query.

If your motor and controller is set up to run more efficiently at a higher voltage, then build the 20s pack.

It depends on what your motor/controller combination works best at. If it's got a pole count and turns count such that it spins up to a useful top speed while delivering good torque throughout, then pick the voltage to deliver accordingly. The key benefit to a lower voltage pack is less cells in ser...

Thanks Mike, I figured I would only need one of them.

Of all the weird redundancy measures... Surely a couple of 200 ohm resistors on either end of the pot would create a safe buffer and protect against accidental WOT or chopped?

Seems as good a place as any to post... I'm looking for an electronic throttle for a car conversion I'm working on. Looks like many late model vehicles (and all electric vehicles :wink: ) use a dual potentiometer system. That is, instead of the usual 3-wire pot (5 V, analog wiper and ground) you see...

This crazy contraption: https://www.facebook.com/TodayTonight/videos/1173124852726969/ Only flew because of the massive pile of LiPo I built for it. It was about 6 kWh of 40 C peak cells. The system was powered by six separate motors and controllers, each running on a 100 volt bus. In hindsight high...

Yeah when you look at the major loads in an EV, they probably stack up like so: Driveline (inverter, motor): 100 kW+ Aircon: ~6 kW Heater: 2-5 kW Pumps_fans: <1 kW Headlights: ~100 W So anything that draws more than 2 kW is best run from the traction pack. At 12 volts, 2 kW is 167 amps - far too muc...

Not sure if this is the best place to put it, but in any case, I recently got a quote to send batteries from Australia to the east coast of the USA. I had an enquiry about a 5 kWh battery build, which I'm happy to do, but shipping it to Baltimore was going to cost AUD$1766. This was for a 1 cubic me...

I have some data on the specific heat capacity of a Li-ion cell in my literature collection. I'll dig up the relevant papers, but from memory it was a range between 1100 and 1700 J/kg.

My shipment of 7000 mAh pouch cells is due to arrive in a few weeks time. Unfortunately all of 1100 of them are spoken for, but if you want more let me know - minimum order is 1000 unfortunately, and at $20 AUD landed they aren't cheap (but no worse per Wh than the other FEP cells). Stand by for som...