a cost benefit comparison of lifepo4 and lipo for newbs

[Hillhater]

Like this?

60 psi cells? Heavy? Hell yeah. Fast and with lots of range? Yeah! A maintenance free car replacement? Definitely!
This is my ideal bike.... ...

Unless you have limited the travel , or locked out that front fork...you can expect a very nasty accident first time you hit a large bump !

 

[auraslip]

Unless you have limited the travel , or locked out that front fork...you can expect a very nasty accident first time you hit a large bump !

I'm not sure how that turned out for this bike. For the record though, this happened on one of my builds where I miscalculated the clearance of a hanging box. I hit a big bump. The wheel didn't lock up, but it almost ripped the suspended box off. I felt stupid that day!

 

[dogman dan]

Heh heh, watch those unexpected wheel lockups. I'll never forget mine when I fumbled the water bottle into the front forks.

Some of those bikes have a lot more clearance there than you think, and yeah, he may have locked the forks. Or just set them so stiff they barely move.
Nevertheless, that bike looks to me like eventually he's going to have the wheel hit that top part of the box. mounting stuff lower, near the pedals is fine. But that one has taken up space too close to the head tube for me to want to ride it.

Re the noobs comment. Probobally 90% of new guys to ebikes just want 1000 watts. But there are guys with good mechanical skills that go straight to welding a custom frame for a velomobile, or whatever, and want 3000 watts right away. It's our duty to put out info, what worked for me, what didn't work for me, etc so they can make their own decisions.

It's not our job to decide, "this is too dangerous for you". It is our job though, to let em know what is dangerous, like charging lipo unattended while we sleep or are in class or at work. Not saying you can't charge unattended at all, just saying do it in a smart place, preferably off the bike if you don't want your bike on fire.

 

[wojtek]

A123 AMP20 Prismatic Pouch Cell

http://www.a123systems.com/products-cells-prismatic-pouch-cell.htm

30C discharge rate

 

[liveforphysics]

But there are guys with good mechanical skills that go straight to welding a custom frame for a velomobile, or whatever, and want 3000 watts right away. It's our duty to put out info, what worked for me, what didn't work for me, etc so they can make their own decisions.

My first ebike build was a pair of the big HXT motors on a downhill bike with 2kw-hr LiPo pack. It's turned about 20 controllers into plasma, but the giant LiPo battery is one of the few things that never has given me any trouble, and still works like new.

And NOBODY was recomending or talking about LiPo when I built my bike. Recompence and Method's were the only guys running it (AFAIK), and EVERYONE was telling us on a daily basis that we were definitely going to burn our houses down and/or explode into flames while riding etc etc... Bunch of arm-chair ass-clowns writing about sh*t they don't know about.... Now many of them run LiPo themselves....

 

[SamTexas]

..., and EVERYONE was telling us on a daily basis that we were definitely going to burn our houses down and/or explode into flames while riding etc etc... Bunch of arm-chair ass-clowns writing about sh*t they don't know about.... Now many of them run LiPo themselves....

And you are basically doing the same thing today: Telling everyone that Lead Acid is the most dangerous battery, followed by Nickel based battery. And Lithium is safest. When was the last time you actually had a disastrous problem with lead acid or nickel based batteries?

 

[TylerDurden]

And NOBODY was recomending or talking about LiPo when I built my bike. Recompence and Method's were the only guys running it (AFAIK), and EVERYONE was telling us on a daily basis that we were definitely going to burn our houses down and/or explode into flames while riding etc etc... Bunch of arm-chair ass-clowns writing about sh*t they don't know about.... Now many of them run LiPo themselves....

Guilty as charged.

Lowell was the first guy to speculate on RC motors (but he was running an X5, IIRC) ~2007. There were large lipo packs coming over, but they were pretty sketchy and sealed in mystery boxes or blue shrink. Only a few members were hardcore RC or large EV guys (Patrick Mahoney, "Patrick", Gary, AJ and a few others.) BMS quality was very poor and bulk charging was undeveloped.

Xyster had a couple of close calls with his 18650 ghetto setup. Guys were having meltdowns with nickle too, ask Ypedal or Justin.

Flooded PbA is nasty... the quantity required for usefulness means having a barrel-full of sulfuric acid tied to a lead anchor and a hydrogen igniter.

The better options back then were tool-packs and then came Ping. Noobs could have problems without total thermal runaway; the downside was energy density and power density (respectively). Then came PSI, Headway and Thundersky... all were mysteries until ES members spent their own money to test and report.


We've all come a long way and so has lithium tech; much of the progress is due to ES members taking calculated risks and testing the limits.

 

[auraslip]

Bunch of arm-chair ass-clowns writing about sh*t they don't know about.... Now many of them run LiPo themselves....

I represent that statement.

Then came PSI, Headway and Thundersky... all were mysteries until ES members spent their own money to test and report.
We've all come a long way and so has lithium tech; much of the progress is due to ES members taking calculated risks and testing the limits.

Totally. We owe a lot to those people. It kinda sucks now though...cause no one wants to risk their money on anything else, when they know exactly how lipo will work for them. It's a bit of a shame because there are tons of different chemistries and ways to care for them. Instead we're using cell-logs, r/c chargers, and modded power supplies. Maybe there is a better way..... maybe not..... the problem with relying on the DIY approach is that we'll never find out what products meant for ebikes are actually quality products and work well. Smartec quoted me $50 for a 70a continuous BMS and they're gonna set it up for lipo. Then I contacted the people that make the chargers bmsbattery and ping sale, and I got a quote for 12 of their 600w charges for like $40 each. If everything works, it blows cell-logs and r/c chargers out of the water on price and performance. Although I admit that I don't know what I'm doing, so it may not work.

 

[liveforphysics]

It kinda sucks now though...cause no one wants to risk their money on anything else, when they know exactly how lipo will work for them. It's a bit of a shame because there are tons of different chemistries and ways to care for them. Instead we're using cell-logs, r/c chargers, and modded power supplies. Maybe there is a better way..... maybe not..... the problem with relying on the DIY approach is that we'll never find out what products meant for ebikes are actually quality products and work well.

Are you really so bonkers you think we've collectively given up on the pursuit of new battery technologies????

I actually purchase every new battery offering I find, and part of my job is to find new battery offerings.

Just as my personal effort, I spends thousands of dollars every year on buying garbage batteries in the event I may find something useful to the community, or something might even come close to what the spec-sheet data-sheet claims (which almost NEVER happens).

I even buy every new 18650 cell, even the pathetically low c-rate cells, every brand of LiFePO4 cell (even though they are generally all the same cell with a different colored plastic case or shrink-wrap), and have a sampler platter of the Alibaba lying scamming sh*t battery packs that perform at 50% of what they claimed in all aspects, and BMS boards that explode when you connect power to them, or just destroy packs by leaving shunts on or drawing power from only the first 2 cells in the string (which almost EVERY SINGLE Chinese BMS does).

As far as RC chargers go... I've only ever used them for RC or cell testing in the last year. Nothing can beat a power supply for quality, reliability, and extremely high power in a tiny footprint. They simply piss on everything else, which honestly only makes sense due to the budget just for developing better server supplies being larger than the entire LEV industry combined.

 

[auraslip]

and have a sampler platter of the Alibaba lying scamming sh*t battery packs that perform at 50% of what they claimed in all aspects, and BMS boards that explode when you connect power to them, or just destroy packs by leaving shunts on or drawing power from only the first 2 cells in the string (which almost EVERY SINGLE Chinese BMS does).

Have you tried the15c DLGcells? They sold by peak energy in las vegas. They've been compared to a123 and come out a head. I got a quote for a pack 48v10ah pack including shipping, charger, and bms for $350 direct from DLG. (they gave me a qoute of $250 for the same pack made with 1c cells) The 15c packs seems like a very viable competitor to building a lipo pack. It just takes some one who doesn't mind taking the risk test it out. As far as the quality of the BMS, this is sorta of my point in a nutshell. You aren't interested in BMS at all because of negative experiences in the past and because you don't actually need them for your bikes. I refuse to believe that an industry that produces millions of boards a year there are no quality contenders.

. Nothing can beat a power supply for quality, reliability, and extremely high power in a tiny footprint. They simply piss on everything else, which honestly only makes sense due to the budget just for developing better server supplies being larger than the entire LEV industry combined.

I really can't disagree with you on that. Although for the price of the pair of $30 48v12ah PSUs that you use for around town charging, you could get a 1200w "toy" charger from KP for the same price or less. Provided you ordered 12 of them at a time..and they'd probably be a lot bigger....and less efficient...and so on.

As I said though...I'm an armchair battery enthusiast. You actually do it for a living... so you know what you're talking about.