Marks very flawed LITHIUM article...

[Burgerman]

Mark at "another" somewhat less informed site said THIS below (see quote), about Lithium batteries in his excuse about why they dont use them years after they became cheap enough.

They are fitted in everything from kids toys, laptops, scooters, chinese BUDGET powerchairs, motorcycles, and model aircraft and helicopters. And full sized cars... Etc. Even in full size electric planes now. TODAY, precisely because apart from being much better they are actually CHEAPER! in real terms, for better performance. They are used because its commertially more sensible and attractive financially. As I easily show below.

He obvciously spotted my new chair and doesent like it! http://www.wheelchairdriver.com/BM-MK3- ... rchair.htm

Or what it represents. It was DESIGNED to show what companies like his SHOULD be doing and wake them up. Even though it has 2.5x the speed and range of his best chairs, with a total build cost as an expensive ONE OFF build by an amateur of about HALF of a typical hi end simple pride powerchair... About 2.5k pounds. Or 4k dollars. We wont mention the off road, short, narrow, build quality, etc here...

From his new "article" explaining why powerchairs are overweight underpowered oversized, unreliable devices as produced by his company :

Another widespread example is consumer frustration that lithium-based batteries aren't standard on power wheelchairs by now. With the buzz in many technologies sectors about lithium-based batteries these days, I receive a flow of feedback from disgruntled consumers thinking that mobility manufacturers are simply lazy, merely not putting such technology in power wheelchairs. However, nothing is further from the truth. Mobility manufacturers recognize that lithium-based batteries can double the driving range, quadruple the battery life span, and charge three-times as quick as conventional batteries. Further, with battery issues like sulfation being among the top service issue with power wheelchairs, lithium-based batteries would increase reliability and increase consumer satisfaction. So, why aren't lithium-based batteries in every power wheelchair?

Again, socio-economics – that's why. The most common rehab power wheelchair battery, a 22NF, is reimbursed by Medicare and Medicaids at a national state average of $125.00. To replicate that battery with lithium-based technology would be in the $1,000 range (the battery industry estimates that it will take around 10 years for the price of lithium-based batteries to drop to 1/3 of today's price, so economies of scale are likewise difficult in today's market even if done in volume). Therefore, the question becomes, if Medicare is funding batteries at $250.00 per pair, and equivalent lithium-based batteries are $2,000 per pair, who's paying for them at approximately 10 times the cost? Insurers won't fund them, and with SSI being the largest income source of those with severe disabilities, where in April of 2011, the average SSI check was $500.80, most consumers can't afford them out-of-pocket. Again, manufacturers would love to put lithium-based batteries in products, and consumers would love to have them, but the socio-economics dictate non-existent funding. (You'll read a few power wheelchair consumers note online that they're using lithium-based batteries, as if they're boasting that they know something that others don't; however, such boasting merely points to the fact that they somehow have more money than everyone else to buy expensive, off-the-shelf technology, where they're privileged not to be living on a scant $500.80 per month, where they're the 1% who are immune from the socio-economics of having a disability in the U.S. today.)

His pricing and therefore total argument is totally incorrect.

A pair of group 24 gel batteries that typically last just 300 real world cycles is about 193 each plus delivery. So 400 UK pounds delivered for what amounts to 100lb in sheer weight, 12 month life used heavily, 300 to 500 cycles. And a 1 hour rate as we use them in bursts of power of about 45Ah or less. See http://www.tayna.co.uk/M24-SLD-G-FT-MK- ... -P721.html But gels are pretty crap under heavy loads so its even less of a difference compared to say a set of odyssey batteries at about £460 delivered!

For say 8 x 60Ah CALB lithiums, to give better energy storage, at the 1 hour rate we use chairs at, to give a MUCH GREATER RANGE as they dont suffer from the peukert affect, 10 to 20 year stand by or storage life, typical 2000 cycles (4x to 6x better cycle life!) the REAL price is around 660 DOLLARS, or 440 UK Pounds. See for proof. http://currentevtech.com/Lithium-Batter ... l-p29.html

About the SAME price!!! Not really more expensive at all!!!

But with better range, faster charging, and FOUR to SIX TIMES the cycle life. Meaning no replacement needed during the typical 5 year life span of a powerchair, and greater reliability. So in reality lighter, more reliable, better range, and 4 to 6 times CHEAPER!!! Which is why they are now used in everything...

My pack huge cylindrical pack was 1200 UK Pounds only because I have choosen to have THREE TIMES THE USABLE WATT HOURS (or stored power) compared to a typical set of group 24 batteries. So it's 3x the cost too. And I use 45v for efficiency reasons and higher speeds. And still its only a fraction over HALF the weight of a pair of lead boat anchor gels!

His argument is absolutely and totally flawed. He doesent understand batteries. Plus economics mean that a wheelchair company can buy scarce not very well marketed or easy to get lithium battries WAY cheaper than I can... But we will ignore that for now.

So realisticaly they are even better than they seem. At about 5 times CHEAPER than a set of gel lead weights, I mean "batteries"... With better performance.

So that article is plain wrong!

[Burgerman]

Someone should post a link to this thread on his board since I am not "allowed" to comment there. Although he is welcome to post here.

Here is a link to his ill-informed "article" in which he claims it will be ten years before prices are the same! But prices are ALREADY the same, and about 5 times cheaper in service. Thats why the rest of the world ARE using them.

http://www.wheelchairjunkie.com/mobilit ... omics.html

[JoeC]

Alternatively, they could pack this cell into an enclosure with a BMS so that it's a totally drop-in brain-dead replacement of the group 22 gels:

http://currentevtech.com/Lithium-Batter ... 4-p40.html

I think four series, four parallel, and for $288 in cells, maybe $50 to $100 for the rest, and you'd have a ~15 pound box that would be the same as a group 22 for all intents and purposes, but would last 2,000 cycles. The first pair of batteries (if we stay with the convention of a pair of boxes) might cost in the neighborhood of $800, far short of the $2,000 figure mentioned. Yes $800 is a lot for people to pay out of pocket, but if the insurance companies looked at the cost of replacing batteries it wouldn't take a lot of math to figure out how long before this pays for itself: about three years of use.

The reason why I give a range of $50 to $100 is because I recognize that there will be some labor, some raw materials, design work, and safety testing to show that they haven't created a bomb.

[Burgerman]

Quite... But there are better and cheaper ways of doing it. His 2000 dollar lithium replacement figure is about as far off the mark as its possible to be! Even if it were true it would STILL be better and economic long term!!!

The guy is plainly clueless about batteries and powerchairs.

But its not even true. I already gave some competitive retail prices and links of equivelents that show its the SAME outlay, with 5x the service life!!! Thats a reaI life 500 percent saving, possible today!

Like for Like.Ah per Ah. But its possiible to go bigger and have 3x the usable watt hours and half the weight at 3x this cost. Thats a REAL improvement in power, 3x range, half weight, 2.5 to 3x the speed, around 5x the battery longcaellvity, 3x faster charging, and for an additional 650 uk pounds over a starock "hi end" powerchair... Well worth it ecoy if onnoly becamuse its good for a real 2000 cycles rather than the usual year...

[JoeC]

Unfortunately the chairs aren't just designed by committee, they're designed by legislation. Chairs in the US used to go 7.0 mph as a fairly standard thing. Now nobody (no insurance) will pay for a chair that goes more than 6.0 mph. It's just a few turns of wire, and they'll charge you an arm and a leg for it. For a lot of lightweight people in flat areas, a 7 mph has plenty of torque and range (on group 24s), and the extra 1mph makes a noticeable difference and is very annoying not to have!

The real problem is that a lot of the users don't pay for their chairs or their batteries, and if there's not a line in the formula for a lithium battery then the insurance won't pay for it, and nobody else will either. Some bean counter will need to add up the cost and see that they can save money, then they'll need to change the policies, then they'll start paying for lithium in a strictly defined way.

[Burgerman]

Even in the US there are people that actually buy powerchairs.

In the spinal injuries unit that I was in, in the UK, my ward alone had 9 people at that time out of 13 that were claiming well over a million £ each for damages. Some were 3 to 6 million... I wasnt even one of them. But like some of the others I had several businesses, a paid for house, and some money put away. Fortunately.

These other people like myself, and many disabled still work too remember, or have money from family, previous businesses, investments, property, that also value their mobility /comfort, and functional capability over a few dollars for a powerchair dont give a monkeys who pays, what a decent chair costs or much else. One way or another they WILL get the best possible solution available.

People often spend 30k to 200k on a fancy car, or race car for track days, or 20k on a bike. I spent 6k on a camera and a few lenses! People often pay more for hobby stuff like boats, jet skis, collectables, fishing gear, etc

So how much is your mobility actually worth? Seems to me that my powerchair that I sit in all day, every day is rather more important than my camera, or my motorcycles were in the past. Its a style thing, a 24/7 thing, a capability, beach, pub, house, office, workshop thing. They are THE thing that brings me as close as equal to able biodied people as possible. They enable me.

Not every powerchair user is destitute like Mark seems to think. There are a lot of people like this. I see them daily, I personally know about half a dozen within a couple of miles from my front door that buy their own gear since the system will not provide anything suitable.

I wouldnt give a rats behind how much it costs to get hold of what I need to make disabled life more bearable, and allow me to be more involved. There are a great many people that think the same.

Now in the US pride make powerchairs to suite the US system. But lithium is actually about 5 times cheaper!!! And in any case the US system is one country from 100s that do not have this strange insurance system/politics. In fact its 250 million out of 6 billion people.

[Burgerman]

A reply to Gac3rd ON THE JUNKIE FORUM proves he really hasnt got the remotest clue about batteries!

Gac3rd, when you're looking at lithium-based technology in powerchairs, the two biggest benefits to consumers are increased range and lifespan (there are other such benefits like less weight, and a more compact size -- but, it's really extended range and lifespan that most benefit from). In this way, when you suggest somehow creating a lithium-based battery that's "equivalent" to a traditional deep-cycle, you're discounting the foremost benefit for most users -- increased range.

So he doesent "get" that the lack of Peukert, and the C rating at 1C as well as the fact that you can use 100 percent of the charge in a lithium phosphate battery and STILL get 1500 cycles, combined with a weight reduction to 1/5th of the battery original weight means around 50 percent better range at least??? With an equivelent Ah pack...

You also seem to be basing your numbers on "piecing together" lithium-based technology via an online web site, and while individual cells can be constructed into rudimentary batteries, it's not the approach manufacturers can ethically take.

ALL lithium batteries used in EV and cars are seperate cells! He want group 24 lead acid look alikes!!! He plain doesent get it. That wastes space, removes flexibility. And doesent seem to worry car manufacturers! And a lead acid battery is just 6 cells lumped together. And you need 2 of those. He really is on another wavelength. Theres nothing wrong with my "rudimentary" "pieced together" (as the manufacturers intended) 3000 watt hour battery! Its THREE TIMES better than a set of lead ones...

Lithium-based batteries for powerchairs -- again, that would offer double the range and faster charging -- require highly-refined battery "packages," based on aspects like internal circuitry and lithium iron magnesium phosphate technology, all of which remains costly.

You mean the lithium ion phosphate CALB cells that are as cheap as lead batteries??? And the plug and play BMS systems that are sold along side these? OK well I am pleased you know what you are talking about! I suspect hes been on the web "researching" and getting a bit mixed up!

Therefore, I don't think your do-it-yourself online example reflects the level or cost of commercially-viable lithium-based batteries.

They ARE commertially viable, used by many people and manufacturers. As are A123 systems, Headway etc. The guy hasnt a clue.

Interestingly, even the Toyota Prius has used a MiMH battery technology because a commercially-acceptable lithium-based version has simply been cost-prohibitive.

Its an old design. Lithium was expensive and in its infancy then. Almost EVERY new hybrid or electric car and scooter, laptop and camera, motorcycle and my powerchair uses lithium ion or lithium ion phosphate batteries. What is he on!

[nandol]

They are fitted in everything from kids toys, laptops, scooters, chinese BUDGET powerchairs, motorcycles, and model aircraft and helicopters. And full sized cars... Etc. Even in full size electric planes now

John,if lithium fits all above means they have chargers and BMS too,logical!!
so,does chargers and BMS can´t be used in powerchairs?
obrigado

[Burgerman]

Yes. EG go to any lithium battery supplier and look at the menu. They all supply chargers, bms systems etc. Some better than others, non simple, many different voltages, balance capabilities etc. So you need to understand what you are doing and why.

For eg there are many companies like this http://currentevtech.com check out "battery management".

With the hyperion I dont need any of this. Cameras, laptops, toys etc use custom systems built in. EV cars do the same. Battery management can be simple or complex with lithium. BMS are from cheap and simple to complex and expensive...

[nandol]

Cameras, laptops, toys etc use custom systems built in

finally i figure out why u said that lithium still not easy for powerchairs...because theres no controllers like does above,of course that makes it hard (unnecessary!!)
always the f......money,damn

when i get the mk2,maybe i´ll go a fine technical college nearby and challenge teachers & studants to help me "transforming" my 11yrs old Meyra into a Lithium XXI chair,i pay the items and kids do the rest...now,is just an idea,let´s see.
obrigado

fellas,how can i put my picture in my profile?

[Burgerman]

Dont understand. There are batteries, chargers, and BMS systems for dummies... Its all there ready to buy?

[woodygb]

avatar.jpg (25.94 KiB) Viewed 5753 times

[nandol]

obrigado woodygb,i´ve tried that..didn´t work,i´ll try again

John,i meant if powerchairs controllers have BMS,etc..than it will be much easyer to migrate from leadead to lithium,at least for the common user like me. (reason for me to maybe contact school kids+teachers)
~with you is different...u´re PRO

[Burgerman]

No its easy. You fit a BMS on the battery. Then forget about everything. And then just use a simple dumb charger...

Even Mark from Wheelchair Junkie might be able to understand it!

[nandol]

John said...So you would also need some kind of battery management system. Something that prevents overcharge, cuts power before undercharge, and something that accurately balances the cells as they charge. Lithiums are not so simple... And what voltage will it charge too? Headway cells 3.65v per cell. Most LiFePO4 are 3.600, some like the yellow prismatic ones are 4.00v per cell, 4.2v initial charge

[Burgerman]

Yes. You need to get the figures correct, use a suitable BMS, and then its plug and play. The complicated bit is finding a suitable BMS, that is reliable, affordable, works at the correct voltages, has enough amp capability as well as enough balance ma capability etc. It takes study, and a bit of knowledge. I can probably figure that all out. But can you?

I also prefer the control, graphing, and accuraccy of the hyperion. It does all that the BMS systems do other than stop you at a specific voltage. But the Roboteq can also do that! So its a "system" that works together. Batteries are never simple.

When I say simple (so Mark can get it!) I mean after someone that does understand this stuff has already fitted a suitable system...

[nandol]

I can probably figure that all out. But can you?

olá John,after so many questions about lithium,now i can figure out..at least i have a better image of what it involves
my main issue is the lack of "hands"to do that for me,reason why i´m thinking to contact the technical college and challenge does kids+teachers to do for me..might be fun!!
but,that is only after summer,more by end october...~
now,it´s time to get totally discharged by BBB (brazilian burnette barbara)

p.s-noticed in the picture i have the tshirt in my lap,always do that,is a good way to prevent sun to beat directly in the sitting area,which means skin not so hot...just a tip for all "ass skin sufferers"in the forum,me included

obrigado fellas,cheers

[Burgerman]

olá John,after so many questions about lithium,now i can figure out..at least i have a better image of what it involves
my main issue is the lack of "hands"to do that for me,reason why i´m thinking to contact the technical college and challenge does kids+teachers to do for me..might be fun!!
but,that is only after summer,more by end october...~

Thats ok but you dont want to be experimenting on your only powerchair! Getting stuck, or screwing up an expensive lithium battery are both bad.

You need a second chair to experiment on.