Invacare Aviva Storm RX20

[Jay_x]

I want lithium batteries and the Quantum rep recommended against them.

Hold on, Amylior offers lithium batteries? Bounder does? Quantum does? what?

I didn't know any of these manufacturers offered that.

[Burgerman]

Bounder offers a 100Ah one, way too small really but better than nothing at crazy prices. The other will be even worse drop in lead brick replacements. Agai n at stupid prices. But doing it that way offers little gain for big cost. Kind of wastes all the huge advantages of doing the lithium thing to begin with and misses the point.

Quantum rep recommended against them.

Because little to gain doing it their way, with BMS, possible reliability issues and so problems in future probably.

[BCrip71]

Amylior offers a 78AH one.

https://amylior.com/wp-content/uploads/ ... EN-R02.pdf

[Jay_x]

Amylior offers a 78AH one.

https://amylior.com/wp-content/uploads/ ... EN-R02.pdf

so they just say "Lithium batteries are much more efficient and take a fuller charge than traditional Gel batteries for better range.' But exactly how much more range do these specific batteries offer?

[Jay_x]

Bounder offers a 100Ah one, way too small really but better than nothing at crazy prices.

I don't see it on the order form


https://wheelchairs.com/resources/pdf/p ... e_form.pdf

[Burgerman]

Expresso ordered one. It wasnt really big enough in a heavy bounder and was down to under 90Ah inside a year? So he used an addon lithium to increase capacity by another 80? Ah I think from memory.

The problem with lithium unlike lead, is that it "REALLY" doesent like all the extremes.

So if you draw out a high current regularly they really suffer. So a big pack means that you are taking a much lower current per Ah of storage. Which promises long cell life.

Likewise the real lithium advantage is that it is much more energy dense. At least if its done properly. So that its possible to fit a massive battery Ah in the very same space the 80Ah of lead came out. To replace that 80Ah lead with 80Ah ithium kind of defeats the entire point! You throw away most of the supposed advantages.

Its true that a 80Ah lithium will take you further (by around 50 to 60% compared to lead) Ah per Ah. Because it allows you to discharge it much deeper as it doesent suffer from peukert like lead. So all of its 80Ah is usable. But lithium doesent like deep discharges! Or heavy currents per Ah. So by doing that you are throwing away much of the crazy good cycle life too. And with less in reserve than lead if you do that, so you might just stop dead in the street as the BMS chops off power when low, like a switch.

If they were to fit say the 230Ah (244Ah measured) cells that I have on my bench - am about to fit into my salsa, you get all the huge lithium advantages promised. SIX times the range! for a start! 20 or 30 years lifespan.

Because of that huge range its impossible on a daily basis to use half of that power. Most WEEKS you will not use half of that! So lets say you get only 5,000 average 50% cycles at a low current per Ah, (typically it would be much more) that battery then only charged twice a week will last 5000 weeks. Or a theoretical 48 years... And you could forget to charge it for a week at a time and not care. Doing it how they do, with just 80 to 100Ah it wont last much longer than lead. Maybe double. Possibly 3 to 4 years if the BMS doesent cause any problems. And the range gain is pretty minimal.

And my 230Ah cells, were cheaper than lead!

[Jay_x]

that makes sense, but then how would they make money changing out your batteries every year or two?

[Burgerman]

The problem is that they want to make a BMS equiped dumbed down system. With a easy 2 wire charger. And that takes up battery space. So smaller cells and then smaller again to fit into some casing. So they add complication, a worse charge system, and reliability issues...

They havent woke up yet. They dont really understand what they are doing and go to some battery seller who fits everything into some box/case for them that sort of works but is highly limiting. And this is 20 years late! What they really need is a system, built around 8 or 12 cells. But they still think in erms of a battery and a control system etc. Rather than a integrated setup like an EV. One day they will wake up when somone explains it to them maybe.

[Flagmax]

what about the Quantum r trak?

This sure looks like 4Front with seat turned around. https://www.youtube.com/watch?v=OpxBEMb2Srw

[Burgerman]

I watche dfew sections of that vid. Those wave washers, and the rusted thrust bearings he is "cleaning" up are dead jim. Theres no point putting those back. Replacements can be bought easily at any bearing place and even on ebay and in STAINLESS which never rusts and will outlast the chair.

They should have been stainless, from new, greased from new, and they would be as good as new 20 years later.
I keep telling everyone to throw away all the steel bearings on a chair as they die from corrosion not wear!

As for recalibrating, that magnetic sensor, if that is needed then yet again this is why I keep on telling people NOT to buy any chair that they cannot buy or get hold of, borrow, beg or use an OEM level programmer for... And right now that leaves just R-Net and the door is gradually closing. Then you dont get these issues and could reprogram or reset the sensor as required.

I replace bearings and spacers, many bolts, and anything else that looks likely to die from corrosion as soon as I get a new chair or within the first few months BEFORE they end up corroded from a damp day and turn red and disintegrate that way... Again as I keep on advising. Repairing is a lot harder than prevention.

[Burgerman]

eBay wave or wavy washers used to spring load components.
https://www.ebay.co.uk/b/bn_7023626119 every size under the sun.

Here are STAINLESS versions that stay shiney! No rust.
https://www.ebay.co.uk/sch/i.html?_nkw= ... m570.l1313

Thrust bearings that are steel.
https://www.ebay.co.uk/sch/i.html?_nkw= ... m570.l1313

Again every size type and material known to man. Nylon, ceramic, or stainless DO NOT CORRODE to death...

Theses are STAINLESS STEEL which doesent corrode even in sea water...
https://www.ebay.co.uk/sch/i.html?_nkw= ... &_osacat=0

Do the same with all shims, bearings in wheels and chassis and suspension parts and with spacers etc. GREASE everything that moves and every bolt. Or loctite it as that prevents corrosion too.

[Flagmax]

BM, this got me thinking, maybe I could install a Thrust bearings instead of bronze spacer washer on the Aviva.

Another good video to watch on the 4Front https://www.youtube.com/watch?v=hoxEr4k2h34 which I assume very similar to R Trak.

[Burgerman]

If it has 2 flat surfaces.

But the real solution since that only removes the friction from the vertical loading, is to replace the whole isolastic/polyurethane/rubber bush thing completely. Since a caster is off centre due to its trail angle it loads that thing up sideways too. And since its got WAY too much human sat on the front it wont ever steer properly due to all the added friction.

Then way better, remove that bush thing, just use normal bearings, a pair, instead. You will lose the marketing suspension but then you will have proper bearings. If you make sure that the one that takes the vertical load, is an angular contact one, or a taper roller bearing then all the better. Use stainless ones, gob everything with that red sticky grease and it will work as good as new in 2 decades.

[Burgerman]

If I used a quantum chair it would first need to get a full rebuild properly. Then its control system ebayed while I fitted R-Net so I could program it properly. Then it might be OK.

Much the same with the invacare chair on this thread...

What is it with these people.

I cant believe everything has so many problems, bad assembly, bad design, bad choices, with impossible to program control systems. It shouldnt be this way.

[Jay_x]

what about the Quantum r trak?

This sure looks like 4Front with seat turned around. https://www.youtube.com/watch?v=OpxBEMb2Srw

could very well be but I don't think thats necessarily bad.

[Flagmax]

After cleaning the parts, this is what we see. The bottom of the bronze spacer/washer developed grooves and lost about 1 thou.

[Flagmax]

Outer rubber, middle metal sleeve, inner plastic sleeve.

[Burgerman]

Theres nothing wrong with any of that. It looks exactly the same as every caster fork I ever saw. The same as all the normal ones that sit in 2 bearings.

Its the other half on the chair we need to see. I still cant understand what is there.

Does any of that turn. Is there a bearing of any kind or is it meant to turn in that inner plastic sleeve?

If theres no bearings then its designed by an idiot. It should still turn however, ONLY IF it was lubricated properly, and wasnt overloaded by being too front heavy.

Or it will obviously just jam. And it will do it again if they replaced it exactly the same.


I there isnt anything in there that is a bearing, then what you are looking at is a pathetic attempt to claim its got suspension by expecting it to turn properly by sliding in that plasticc sleeve and wobbling a bit in the WRONG DIRECTION when it hits a bump. Suspension needs to move vertically not bt twisting backwards! That was done by the marketing department to sell chairs. OBVIOUSLY that wont work properly iven if it seems like it does at the moment. Too much load, too much friction. Are you SURE that steel bit doesent turn in a bearing? Makes zero sense otherwise.

[Flagmax]

Nothing turns inside the headtube. It only flexes. The fork shaft rotates in the red hard plastic sleeve. There were no grease.

[Burgerman]

Then it will never work properly.

Remove circlip. Use circlip pliers. Then use a hammer and a spacer and knock the whole thing out from the opposite side. You will then see that it was really designed for normal bearings. And so go to eBay, buy stainless sealed bearings that fit the caster stem, and the barrel. You may need a spacer in between these or not depending on depth of barrel. Reassemble and its back to a normal seatup. Without the marketing wobble...

Because that setup is rediculous. You can even see that the steel bit has a gap where the off centre overloaded caster has bent it out of shape...

[Burgerman]

You want

Either 2 of these... Top and bottom

like most chairs have.

Or ONE of those at the top, to take side loads, and a TAPER ROLLER (or an angular contact one) at the bottom to take the crazy weight that a nose heavy chair causes.

With spacer in between.

Or an ANGULAR contact bearing at the bottom to take the load. These are narrower.

[shirley_hkg]

You forgot AVIVA wants their casters act like suspension forks too.

[Burgerman]

No I didnt forget. I already said its a marketing department suspension... It doesent work, just wobbles back and forwards! Suspension needed to go up/down... Its marketing bullshit.

[Flagmax]

Here are some measurements I took. Looks like 0.75 ID x 1.5 OD bearings would fit but are they available? Maybe need a sleeve?

Forks shaft OD is 0.748in / 18.99mm
Forks shaft Length is 2.165in / 54.99mm
Headtube bottom ID is 1.502in / 38.15mm

[Burgerman]

They should be.

Forks shaft OD is 0.748in / 18.99mm likely thats all metric. 19mm.
Forks shaft Length is 2.165in / 54.99mm. And 55mm.
If your 38.15 is correct then its either worn, or very odd... Even if true then bearing loctite would work. I suspect that removing the circlip and that sleeve will see a real 38mm.

The barrel diameter will probably be imperial or metric, and SHOULD be the same standard sizes as bearings are as the found a bush that fits. Probably a repurposed motor industry one.

IF it isnt, you just need a man with a lathe (I have one in my bedroom) that can make a sleeve. But I would expect it is a standard size.

38mm??

1.5 inch?

These are cheap and nasty but stainless is available sealed in standard sizes too.
19 x 38 x ?
These are also thrust bearings so only in the bottom half.
You want normal sealed ones on the top half.
https://www.tradebearings.com/128802-au ... 43764.html

Seal will keep dirt out and grease in...
https://www.bearingrevolution.co.uk/19-38-7-tc-44443

Standard sized for top. Or use 2 of these sizes. No seal required, greased for life.
https://size.name/en/products/dg-1938-ac3

[Burgerman]

Whilst this will undoubtedly fix it, I suspect it shouldnt be your job!
I also suspect that once you remove the red plastic sleeve you will see that the rubber bush is actually 2 seperate ones used instead of the 38x 19x 10mm bearings it was originally designed for... And they just added the rubber things and a red sleeve to make it fit. So they can market it as having (non functional) "suspension" that doesent rotate properly or take out any of the bumps...

[Jay_x]

b y the way the suspension on this chair is not good at all. You feel every little bump. The suspension on that Quantum I linked looks light years better.

[Burgerman]

That 50 and 78Ah lithium on the link above for ami systems looks suspisiously like those on aliexpress.

https://www.aliexpress.com/item/1005008 ... %221%22%7D

I bet they dont charge the same (joke, battery/charge geddit?)

[BCrip71]

They are all too big too fit.

[Burgerman]

They are all kinds of capacities voltages and sizes. I mean it looks like one of those many chinesium companies made them. Cheaply. I bet they are not charging £250 a go...