fuse size r-net 120a controller

[timmmay71]

is the r-net 120amp controller really capable of drawing 120 amp from a 4 pole motor? what would be a safe fuse size for this controller?

[timmmay71]

what fuse size does it usually come with? i wonder if 100a is enough, or go with 120a?

[Burgerman]

Sunrise use 150A fuses in both battery loom halves on modern stuff. With 120A chairs.

Seems overkill to me as a 125A one has never blown on any of my chairs. But it must be more reliable and still safe of the correct sized looms.

Yes the 120A rnet controller can draw a max of 120A per motor.

See here as I do a turn in place on a heavy carpet on a rehab chair, note MOTOR CURRENT is well over 100A on M1 and M2 at the same time. In this case 102, and 114A respectively. That is NOT the same as battery Amps. At slow, stall speeds the battery Amps is much lower than motor amps. As you speed up, they eventually match. So at one speed only, at max load, the battery Amps can reach a peak of 240A for a short period. Say accelerating up a steep hill. But a 125A fuse can cope with that for short periods reasonably easily. A 150A fuse can cope with it very easily.

Right turn in place at zero speed:

[timmmay71]

thanks bm

[expresso]

i never seen a sunrise chair here in the US with a 150A fuse - i never seen any chair with that size fuse - what you will find is normally 80ah fuse on the batteries from a new chair - sunrise quickie chairs - which makes me think - if they put an 80A fuse - with Rnet 120A and 8.5 motors -

and the 80A fuse never blows - why add a larger fuse - ? i have a 100A breaker on one of my chairs - another pack i made for someone - i added a 125A fuse - used thicker wiring for the battery - but if they all use a 80A fuse - even my bounder is i think 80A - breaker - i have to check it one day but i was told its that -

seems strange to use 80A fuse on 120A controller - but it works and never blows - so makes you wonder - whats the deal -

[timmmay71]

thanks expresso! i believe the bounders that are fitted with linx electronics and lithium batteries come with 120a breaker. maybe it's the same for their 120a r-net version?

[Burgerman]

and the 80A fuse never blows - why add a larger fuse - ?

The original F55 used an 80A fuse. With an 80A pilot plus controller. I blew the fuse. Replaced it with 100A. I blew the 100A when I fitted a 100A Pilot plus power module 3 years later... So I suspect I would blow a 120A fuse with the 120A R-net...

Your mileage may vary. Why? Because my chairs and my angry drive it like you stole it use, easily maxes out what the power module is capable of. It CAN draw up to 240 Amps! Infrequently. If you have it programmed like a grandma though (99% of everyone?) or drive like one then you will never blow a 30A fuse.

This is what does it:
http://www.wheelchairdriver.com/gopro/control.mp4

And yes I checked a recent R-Net/VR2 loom from a sunrise chair recently and was surprised to find a 150A fuse. They used to be 125A here. Remember that the fuse is there to protect the CABLES. So maybe they started using better quality cables. I can make those get hot enough to smell of burning just by driving like the vid above for a few mins.

[expresso]

must be a UK thing then - my bounder uses there own electronics - the big black box - and i have lithium - who knows

my friends chair sunrise a few years old - she has 80A fuse on the batteries - its not replaced with lithium and i added a 125A fuse -

when in get my new chair i can check when i swap them out - what did they do was change the connector going from the main wire to batteries - before they were black SB50 - not they are RED - most likely for changing batteries so the tech cant make a mistake - i will check mines

[Burgerman]

You need a sharp scalpel, and its under the heat shrink on most chairs. You will not know its there unless you cut a square window in the heat shrink on the loom to see the 150A on the fuse... Whichever side you do first will be the wrong side.

[expresso]

it was actually printed on the head shrink - either there near it - i recall - was no need to cut it off to check - i was surprised to see it -

[expresso]

this is off my 646se 8.5 mph motors - most of them are 70a or 80A fuses - wiring seems decent on this one -

so if they never blow at that amp - do we really need 150A fuse - ? when i get my new chair - will check it - this one was from 5 years ago

[Burgerman]

do we really need 150A fuse

70A? I could reprogram your chair so it actually responds. And then blow that fuse without leaving your apartment in a matter of minutes just by driving like I do! Wheelies and stuff. Hard accelerating turns in place.

It all depends on HOW you use your chair. What power module, which motors, HOW its programmed. And the big 4 pole motors take LESS motor amps much of the time than 2 pole cheap motors do. Heavy 190kg rehab chair, 120A controller, programmed to respond, heavy and you can accidentally pop a 100A fuse as you try to climb a steep ramp.

They obviously came across a few users that were extracting and using every bit of the power and so over the years had problems with certain setups. And certain people. If 150A is safe, and its possible to blow smaller fuses in some configurations/users/power modules (120A ones take twice as many Amps than 60A PM's) then why now. The last thing you want is it to pop while you are in some forest, garage, etc where theres nobody and only hen find you have no phone. Because you would die.

Remember that not all fuses are equal either. Some 70A fuses can take 150A for a second or so no problem. Some cant ... And you never know till it failS. And that an old woman in a nursing home likely never exceeds 30A. But I exceed 150A every time I use the chair. I know this as I can use the clamp meter to read amps. And because with r-net I can read it on my laptop as I drive around in real time.

And low impedance high power 4 pole motors take LESS battery amps at the 120A motor limit than cheap 2 poles do. The 2 pole motors are higher impedance. So less torque, and more battery amps! Its absolutely the inverse of what you would expect. I can explain why but you wouldnt read it!

[expresso]

646se chair - 4 pole 8.5 mph - i reprogrammed also years ago - i wheelie up curbs and hills without trying - with the larger rear tires - its effortless to wheelie

my programming is not as extreme as yours for sure - i am only 160lbs - - my previous chairs P222se 8.4mph - pilot - reprogrammed also after finding this site etc, - that one i believe is 80a breaker -

in 20 years i never blew a fuse - only the last 5 or 6 years since i started to get involved and reprogram - but still - uphills - some very steep that it wheelies without me wanting to - actually i got stuck on a hill with my front end up only on my anti tippers

now if i visit that same area dosnt feel the same - i avoid it or go a different route to get to the same location - i must be getting Old -

other than You - how many other users blew fuses on there chairs over the years ? i bet not many at all - so what does it all mean -

the bounder heavy as shit - 12 mph easy - suffers on hills - and yet - still so far never tripped the fuse - i was told its an 80A in there - i have yet to check it - one day when i am in the battery box - i may check the breaker - in an extra box in the box -

i believe you blew your fuses - as you say - just showing that stock fuses - must mean the motors and chairs just dont pull that much in the first place beside some short bursts - but not enough to blow them -

i for sure dont want to blow one when i am out - i wont be close to home - i am going to use a 125A on my new pack as i did on one before for someone else - on my 646 chair - i added a 100A breaker - so for so good - - i like breakers - but no room in the chair and dont want to run wires again - then if i remove the pack - have to remove the breaker wires etc, so i will use a fuse also 125A -

the wiring i use can handle it - not sure if the chair wiring could ? something really has to short it out i would think to blow that fuse - it be fine if all the chair wiring is good from factory

[Burgerman]

Obviously the chair wiring can as they fit 150A fuses to many chairs.

[expresso]

thats in your case - your chair - why not use them here - unless they use better wiring over there ?

i have to check when i get my chair - and also check the Connector make sure what color it is before i add mines to my pack - chair from a few years back - they changed it to red - i had to remove the black one on the battery pack to replace with a red to make it connect -

i didnt have a Red - but removed it from the battery end - and ordered a few extra to put back - and in case mines is red - i have it already -

i bet the fuse here is going to be the same 70A or 80A -

if i use a 125A on my battery pack i make - my wiring is good enough to handle it - But what if the chair wiring isnt as good - thick as mines -

would that be a problem ? if something goes wrong or shorts - i would think it makes sense to add at the very least 100A or 125A because of the Rnet 120 PM -