A4W Observer 4x4

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A4W Observer 4x4

Postby Jamest » 13 Apr 2013, 14:22

ImageI have had a free demo of this chair and thought it was great, I wouldn't go climbing stairs with it per say, but for going on the pebble beach right outside my house it was fantastic. It even did a hill which must have been at least 40 degrees and curbs were no problem, I thought it was amazing and for a fair price, has anyone else tried it? Would be great to hear some more feedback before I buy! They also have a model without the auto seat function, but that one can't climb as high.
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Re: A4W Observer 4x4

Postby Lord Chatterley » 13 Apr 2013, 18:07

It too big for my van, my home, trains, taxis, shops, toilets, paths with anti-bike barriers, lifts/elevators, school, cinema, fast food joints, etc., etc., etc..

In other words, apart from being totally unusable - it's great!

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Re: A4W Observer 4x4

Postby Burgerman » 13 Apr 2013, 18:13

My main concern is that anything that's 4x4, or / and tank steering totally murders batteries as this sucks huge amps.

To try and maintain some steering and range the only real option is slow max speeds (low geared to give better torque, range at the expense of speed) But even so - expect very limited battery power/range and battery service life.

Non of these off road skid steer things works indoors without you living in a barn, so isn't really a wheelchair as such but an outdoor buggy/car. So it beats me why so many manufacturers make them battery powered, with all the weight, speed. range, charge time and power and cost issues that this entails. There's 1001 different petrol powered outdoor only off roaders that do everything better and are nor restricted by batteries or silly costs.
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Re: A4W Observer 4x4

Postby Jamest » 14 Apr 2013, 11:02

It fits in my fiat doblo high top, I tried it, I also tried the bike barriers, it was no problem, It isn’t wider then a wide manual wheelchair, so it fits in doors and taxis easily, then when you want to go on the pebble beach or do some real tough terrain, which I don’t think any other wheelchair can do apart from this one, trust me I have tried them all, this one was the best. You should really call them up and get a free demo, they come to your home or wherever you want to test the chair. All I can say is, you should try it before knocking it!
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Re: A4W Observer 4x4

Postby Jamest » 14 Apr 2013, 11:08

They have a lithium battery aswell, lasts 24 miles between 6-8 hours apparently
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Re: A4W Observer 4x4

Postby Burgerman » 14 Apr 2013, 16:40

>>>lasts 24 miles between 6-8 hours apparently

On a flat surface. Skid steer alone will limit it to this. At best.
Lithium helps off road, with about 2 to 3x better than lead. IF its a BIG ENOUGH lithium battery. Most are not.
But off road isn't great with any type of battery power. But its also skid steer. Which truly murders batteries regardless.

If its only for outdoor use and if you don't expect too much (it only uses a weedy mobility controller so is short of amps for skid steer tested, measured and even built one so I know I am correct) then its ok.

But why bother suffering the weight or other battery power disadvantages at huge £ cost when there are a great many off road or outdoor buggies with quiet 4 stroke petrol power, twist and go electric start machines with far better performance and range, ready to go?

I am always at a loss. They call them "wheelchairs" (many off road or 4x4 "wheelchairs") and aim them at the mobility market. But a wheelchair is something that can be used in a house, bar, public loo, etc - not something that's battery powered. If it cant work indoors without a huge turning circle and ripping up carpets and rugs or wide doors then it may as well be petrol/cheaper.
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Re: A4W Observer 4x4

Postby Sully » 14 Apr 2013, 17:49

I cannot argue with that logic!
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Re: A4W Observer 4x4

Postby LROBBINS » 14 Apr 2013, 19:51

How will you drive one of the petrol vehicles if you can't use a steering bar but must have a joystick?
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Re: A4W Observer 4x4

Postby Burgerman » 14 Apr 2013, 21:09

You would need some different controls! But yes that may well be an issue depending on disability.

Girl at school had no arms. Thalidomide baby. She drove her car quite easily via a joystick (using her feet!) so I think its not a huge problem. (Servo controlled throttle and steering like a model car). Or a full sized one like this: http://www.bbc.co.uk/learningzone/clips ... /8216.html

But would need adapting if you couldn't use the bars. And maybe a rehab style seat too. My point really was that batteries and skid steer/4x4, and off road use really don't play nicely esp. with low power mobility controls and batteries. OK for slow speeds and short periods but a big shock if you are expecting powerchair style range over many hours. Unless the battery is seriously big.

That's possible to do, but my Lithium battery can do 2.5x as much as a pair of group 24s. That's not adequate for skid/4x4/off road by a long way. This showed me that very clearly: http://www.fatnfast.com/robot/page4.htm

And that lithium battery in my new chair is £1200 worth, and 3000 watt hours. I have never seen a mobility device with anything bigger than this or lithium. Double this size - If space allowed it (and it may do since it doesn't go inside anyway) - would begin to get more practical with skid/off road, and would weigh the same as a set of lead batteries. But the cost would scare everyone off!
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Re: A4W Observer 4x4

Postby Jamest » 14 Apr 2013, 22:45

How many AH is your Lithium battery? I will have to call A4W Products and ask them what theirs is.
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Re: A4W Observer 4x4

Postby Burgerman » 14 Apr 2013, 23:26

It doesn't work like that! There's more to batteries than Ah.

My battery is 45 volts. And 72Ah. That gives a total storage capacity of 3000 Watt hours. All of that is usable. Its about half what you would really want/need for skid steer/off road. See here. http://www.wheelchairdriver.com/BM-MK3- ... rchair.htm

A set of group 24s is actually 70Ah at the 20 hour rate. But only half of this is usable because of internal resistance and Peukert affect. Especially under high loads that you get with tank steer and 4x4 and off road. So from lead you get a usable 35Ah to 45Ah only. So 40 x 24 = 960 watt hours... So 3x worse!

If I take this 70Ah lead battery chair along a flat straight beach with the dog, I get about 1.5 to 2 miles slowly and the battery has had enough. Presumably that means 4.5 ish miles on heavy sand from the lithium version I am building now. But remember that this chair isn't struggling with skid steering and it turns easily. http://www.wheelchairdriver.com/ultimat ... rchair.htm

To make that thing really usable with a long wheelbase, and tank steer, and 4x4, off road on say sand, you would want about 4 to 6000 watt hours as well as a bigger output controller. Mobility controllers are limited to a max of about 100 Amps. (per motor) Here's a vid of a CLAMP AMETER over ONE motor cable on a chair that turns easily. Remember that the more you load a motor (by stopping it turning like tank/skid steer does) the more amps you would need to turn... http://www.wheelchairdriver.com/gopro/motoramps.mp4 Remember this is on casters, and on thin carpet or my flat drive. Try this on sand and it wont turn. Not enough amps. Skid steer is MUCH worse! Maybe 5 or 10 times worse when turning on grippy surfaces (or in sand?).
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Re: A4W Observer 4x4

Postby ex-Gooserider » 15 Apr 2013, 01:05

Not sure I've seen that brand before, but I know that I've seen several similar chairs mentioned on here before, with similar reports... It appears that this is some sort of China-made product that gets imported and rebranded by several different people...

In addition to the problems already mentioned about skid steering, the other chairs (which this looks like a rebranded version of) also chewed up more juice driving that chair tilting mechanism, and all the mechanical stuff needed for the wheels and tilting severely limited the size of batteries you could stuff into it - which makes the skid steering and range issues even worse...

I don't know what they are doing for the Lithium option, but I'd be willing to bet that it is NOT a smart-charger controlled setup with a pack like BM is using in his chair... I'd put my money on it being some sort of "monoblock replacement" battery with some unknown cell pack in a space wasting case, along with a BMS - Battery Massacre System...

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Re: A4W Observer 4x4

Postby Burgerman » 15 Apr 2013, 08:45

I hadn't bothered to mention that yet.
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Re: A4W Observer 4x4

Postby REPARACIÓN SILLAS » 13 Feb 2022, 21:39

Burgerman wrote:My main concern is that anything that's 4x4, or / and tank steering totally murders batteries as this sucks huge amps.

To try and maintain some steering and range the only real option is slow max speeds (low geared to give better torque, range at the expense of speed) But even so - expect very limited battery power/range and battery service life.

Non of these off road skid steer things works indoors without you living in a barn, so isn't really a wheelchair as such but an outdoor buggy/car. So it beats me why so many manufacturers make them battery powered, with all the weight, speed. range, charge time and power and cost issues that this entails. There's 1001 different petrol powered outdoor only off roaders that do everything better and are nor restricted by batteries or silly costs.



Hello...how long has it been since the last conversation in this thread, we told you that we have had a Russian OBSERVER 4x4 chair in the workshop for 2 months, the only one in Argentina as far as we know. The owner imported it from Russia and last year the R-net board broke down in its power part and we had to replace the joystick with chin command and suction for an R-net led joystick.
The chair worked immediately although we had to replace the automatic seat control board (burned) and add a potentiometer to regulate the speed of the seat movement. Yes, as BM said, it is slow, rough and consumes a lot. This chair works with 4 Yuasa 34ah batteries and it consumes tires, it really is a wheelbarrow!

https://bayfiles.com/verfP9H8x6/VID-202 ... 0021_1_mp4
Siempre aprendiendo y brindando soluciones!.
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