BYD has reportedly received 10 GWh of orders from Tesla for LFP batteries • Hacker News Board

Re: BYD has reportedly received 10 GWh of orders from Tesla for LFP batteries

#121

Post by sudosysgen » Fri, Oct 22, 2021, 2:31 AM UTC

jacquesm wrote: post #116

dylan604 wrote: post #115

Earlier quoted context omitted.

Couldn't tell you. The website doesn't list that level of detail. It's a 750W motor. It took me 6 weeks after ordering before it shipped due to "global supply chain" blah blah excuses. It is serving me quite nicely without those kinds of mods. I'm not looking to set any speed records. Just needed something to help me get up the damn hills when I have a load of stuff. It does that better than hoped, so I'm happy.

Neat :) Bafang is one of the larger suppliers. Keep an eye out on the temperature of the FETs in your motor controller, that tends to be the weak point for more powerful motors, 750W is a lot of power for an e-bike, mine only has 350 but it is 'street legal' and insured, if I would hack that it would become a liability. Since I have an e-bike my car has hardly moved. Do you have a link for your bike? Mine is a Riese…

Hey, I've done something similar with a Lenovo battery. If you're willing to scrap a battery pack, it's definitely doable by reusing the electronics. You should add your own BMS though. It's fine to run them in parallel for the balance wires, but connect the phase wires to your own BMS. It should work :) I recommend Daly BMS's, they're not too expensive and they kept my 1.5kWh pack in balance and protected it from a few accidents.

Re: BYD has reportedly received 10 GWh of orders from Tesla for LFP batteries

#122

Post by jacquesm » Fri, Oct 22, 2021, 2:31 AM UTC

sudosysgen wrote: post #119

jacquesm wrote: post #107

Earlier quoted context omitted.

What drivetrain does your bike have? I have a ton of documentation on the Bosch system. And I'm working on an extended range pack (2000 Wh, the bike is a speed pedelec doing 30 mph).

I have KunTeng controller and disply, with a GS Motor hub drive, pushing 2.5kW peak right now with a 1.5kWh battery pack. The motor itself is capable of 6kW+peak power with a bit of statorade, but my battery and controller aren't up to snuff I'm personally pushing 60kph :) But it's pretty scary at those speeds even with the best tires I could find and pretty good disc brakes, so I'm generally at 20mph or under. I'm p…

That's one very mean bike. I think I have enough steel in one leg to keep me off rides like that but consider me impressed that you are taking that into traffic. Is this street legal where you live? You'll be doing wheelies if you are not careful :)

How much does the whole thing weigh? Mine is at 29 Kg, and that's with only a 500Wh pack, I figure about 6 Kg/KWh so by the time I'm done building the new pack it will be around 40 Kg in total or so.

Re: BYD has reportedly received 10 GWh of orders from Tesla for LFP batteries

#123

Post by dylan604 » Fri, Oct 22, 2021, 2:31 AM UTC

sudosysgen wrote: post #118

dylan604 wrote: post #111

Earlier quoted context omitted.

I don't care what is on the inside of the battery itself if the shape of the battery doesn't fit what I want to use it. I'm pretty sure this is everyone's definition of unique battery per vendor.

Well you should - the fact they're pretty much electrically identical means that you can confidently buy off-brand batteries if they have good cells and that adapters can be possible.

I think you're missing the point focused on your point. We all understand the internals are probably coming from the same factory line. The problem is that they don't connect universally. As someone up the chain elsewhere stated, if the markets can be forced to use the same USB charging port, there should be a similar regulation for these kinds of things as well. Whether that's a universal battery shape/connector for tools, eBikes, whatever. We've unified things like 110v mains plugs, 220v mains, etc.

The fact that they do all use the same internals makes this even more egregious.

Re: BYD has reportedly received 10 GWh of orders from Tesla for LFP batteries

#124

Post by sudosysgen » Fri, Oct 22, 2021, 2:31 AM UTC

jacquesm wrote: post #106

sudosysgen wrote: post #7

Earlier quoted context omitted.

Absolutely, it's a big part of why they're cheaper. I just wish I could actually get them for reasonable prices in smaller quantities. I have to pay a 3-5x premium for LiFePO4 batteries. I'd love some at a reasonable premium for my ebike :)

Some pretty good deals here: https://www.nkon.nl/rechargeable/li-ion/chemie/lifepo4.html

Hmm, it's better than others, but I can still find Li-ion for a better price. Besides, I'm outside of the EU, I can't imagine the shipping costs haha

Re: BYD has reportedly received 10 GWh of orders from Tesla for LFP batteries

#125

Post by sudosysgen » Fri, Oct 22, 2021, 2:33 AM UTC

dylan604 wrote: post #123

sudosysgen wrote: post #118

Earlier quoted context omitted.

Well you should - the fact they're pretty much electrically identical means that you can confidently buy off-brand batteries if they have good cells and that adapters can be possible.

I think you're missing the point focused on your point. We all understand the internals are probably coming from the same factory line. The problem is that they don't connect universally. As someone up the chain elsewhere stated, if the markets can be forced to use the same USB charging port, there should be a similar regulation for these kinds of things as well. Whether that's a universal battery shape/connector for…

The internals are completely interchangeable. You'll even find the same model with different internals.

I agree with you 100% about the need for regulation.

Re: BYD has reportedly received 10 GWh of orders from Tesla for LFP batteries

#126

Post by jacquesm » Fri, Oct 22, 2021, 2:34 AM UTC

sudosysgen wrote: post #121

jacquesm wrote: post #116

Earlier quoted context omitted.

Neat :) Bafang is one of the larger suppliers. Keep an eye out on the temperature of the FETs in your motor controller, that tends to be the weak point for more powerful motors, 750W is a lot of power for an e-bike, mine only has 350 but it is 'street legal' and insured, if I would hack that it would become a liability. Since I have an e-bike my car has hardly moved. Do you have a link for your bike? Mine is a Riese…

Hey, I've done something similar with a Lenovo battery. If you're willing to scrap a battery pack, it's definitely doable by reusing the electronics. You should add your own BMS though. It's fine to run them in parallel for the balance wires, but connect the phase wires to your own BMS. It should work :) I recommend Daly BMS's, they're not too expensive and they kept my 1.5kWh pack in balance and protected it from a…

That's exactly the plan, with one very small modification, I'll be adding a 1A balancer that gets triggered on the 'charge' signal, and I'll replace the balance wires to the original BMS with a laddernetwork of resistors to fool the old BMS into thinking it is still seeing a nicely balanced pack.

This is the balancer (not a BMS, just an active balancer):

https://www.aliexpress.com/item/32945565819.html

What's neat about this one is that it uses two supercaps as a chargepump so it can rebalance quite effectively without producing a lot of waste heat or wasting power (of course you waste some but a small fraction of a resistance based balancer, which just burns off the power in the cells that are highest voltage).

I'm building a small test pack (20 cells) right now, and if that works properly I'll scale it up eight fold for full range. It will still plug into the standard charger and I'll have a switch that will allow the pack to be charged to 100% capacity in case it is needed for an even longer trip.

Re: BYD has reportedly received 10 GWh of orders from Tesla for LFP batteries

#127

Post by danans » Fri, Oct 22, 2021, 2:37 AM UTC

AYBABTME wrote: post #102

danans wrote: post #8

Earlier quoted context omitted.

Adding to this info - LiFePO4 batteries are far more chemically stable and therefore need no cooling system. I have LiFePO4 home backup batteries and they are completely passively cooled.

Advice on legitimately adding this to your house in a DIY manner? Or is it the kind of stuff you 100% need to hire licensed folks for legal reasons? I built offgrid systems for boats but now I'm considering doing my house.

Enphase has a self installer certification program that I used to DIY the design. I still hired a licensed electrician for the physical installation, though.

Re: BYD has reportedly received 10 GWh of orders from Tesla for LFP batteries

#128

Post by jacquesm » Fri, Oct 22, 2021, 2:39 AM UTC

sudosysgen wrote: post #124

jacquesm wrote: post #106

Earlier quoted context omitted.

Some pretty good deals here: https://www.nkon.nl/rechargeable/li-ion/chemie/lifepo4.html

Hmm, it's better than others, but I can still find Li-ion for a better price. Besides, I'm outside of the EU, I can't imagine the shipping costs haha

Ah yes, that complicates matters considerably. And true, Li-Ion is still a better price (and higher density to boot). But it's worth monitoring this because at some point there will be a crossover.

Re: BYD has reportedly received 10 GWh of orders from Tesla for LFP batteries

#129

Post by jacquesm » Fri, Oct 22, 2021, 2:42 AM UTC

dylan604 wrote: post #120

jacquesm wrote: post #116

Earlier quoted context omitted.

Neat :) Bafang is one of the larger suppliers. Keep an eye out on the temperature of the FETs in your motor controller, that tends to be the weak point for more powerful motors, 750W is a lot of power for an e-bike, mine only has 350 but it is 'street legal' and insured, if I would hack that it would become a liability. Since I have an e-bike my car has hardly moved. Do you have a link for your bike? Mine is a Riese…

Sorry, totally forgot to provide a link to it [0]. I bought a cargo version specifically to use as a total car replacement. It has a 300lb capacity, so that's the why of the big motor. I wish I had done it sooner. I've only had it a couple of weeks, but I've already used it for trips to the hardware store, grocery trips, firewood (i'm sure some people laughed at that), and all sorts of stuff I'd have never attempted…

Ah! Now I get why you have those power requirements, ok. Indeed, you'll need a good sized battery to keep that moving for any duration. We have a 'regular' pedal bike, a Christiania older model cargo bike, it did duty for the last six years as child transportation, every day, rain or shine and still runs great (and we are not even the first owner), just basic maintenance. They're very useful. I've been toying with the idea of electrifying that one too, but the arrangement is going to be quit tricky (likely: two front hub motors, it's a trike).

Re: BYD has reportedly received 10 GWh of orders from Tesla for LFP batteries

#130

Post by sudosysgen » Fri, Oct 22, 2021, 2:42 AM UTC

jacquesm wrote: post #122

sudosysgen wrote: post #119

Earlier quoted context omitted.

I have KunTeng controller and disply, with a GS Motor hub drive, pushing 2.5kW peak right now with a 1.5kWh battery pack. The motor itself is capable of 6kW+peak power with a bit of statorade, but my battery and controller aren't up to snuff I'm personally pushing 60kph :) But it's pretty scary at those speeds even with the best tires I could find and pretty good disc brakes, so I'm generally at 20mph or under. I'm p…

That's one very mean bike. I think I have enough steel in one leg to keep me off rides like that but consider me impressed that you are taking that into traffic. Is this street legal where you live? You'll be doing wheelies if you are not careful :) How much does the whole thing weigh? Mine is at 29 Kg, and that's with only a 500Wh pack, I figure about 6 Kg/KWh so by the time I'm done building the new pack it will be…

Well, any bike will do wheelies if you have the knack for it :) But if you're wondering, no it doesn't do power wheelies - I can definitely feel the weight shifting back though.

I haven't weighed it yet, but:

The bike itself is 15kg. The battery weights 48g per cell, so at 140 cells (14s10p) that would be 6.7kg, but I'll round up to 7.5kg for the wiring, mounting, etc...

The motor and controller and screen are around 11kg or so. The hub motor is very very heavy!

Summing it all up it's around 35kg. Sounds about right from hauling it around.

It's not technically street legal, no. But I'm far from the worst offender - a lot of people ride what's basically a 125cc with a hub motor on the end, and they're sold everywhere, so I'm never going to get in trouble for it.