Minimo autofold

[GusGf]

My partner has got a 2yr old TGA Minimo autofold which she got locally and I believe the battery has just died on us. I don't want to bring it back to the shop as they will have to send it back to TGA and I know it's going to cost a packet and it'll be away for weeks. Problem is the scooter is in the folded position so we can't get the damn battery out and it's not taking a charge from the outboard charger whether we connect to the battery directly or the charge point on the chassis. The controller is from Dynamic Controls DR50-A01. Main fuse is good and the charger output is c28V. Putting a multimeter across the battery terminal leads going to the controller (disconnected from controller) I'm getting about 10v and I believe it should be 24v which leads me to believe the lithium battery pack has had it's day. When I press the power button on the tiller I'm getting zilch not even the LED power / battery lights are coming on. I've bypassed the battery and connected crocodile clips from the charger's XLR 3 pin plug to the controller's power inputs +/- directly to see if it would even power the tiller LEDs but nothing.

Would anyone have any suggestions. I don't believe the controller (just a hunch, but I could be wrong) is the problem, I'm convinced it's the battery. I'm just surprised bypassing the battery and connecting up the controller directly did nothing!

Is there anyway of testing the controller? I know the Wizard software can be downloaded but the cost of the programming hardware looks extortionate

[rover220]

The folding part probably doesn't get its power from the module so connecting direct to the module won't help. Can you connect 24v to the xlr port?

[foghornleghorn]

Is it indoors in the warm or somewhere cold?

All TGA lithium battery packs contain a temperature sensor. When this sensor records a temperature of 10°C, the internal circuit board will stop the battery charger from working in order to protect the battery cells. Once the battery pack reaches a temperature of approximately 20°C it will then allow the charger to start working again. This is only relevant if the pack drops below 10°C, so long as the battery pack is stored and remains above 10°C then the charger should work as normal, standard room temperature is sufficient.

[Burgerman]

It contains a dumb BMS too. And if any cell is allowed to discharge below safe voltage of whatever the programmer decided, through self discharge, or from powering the BMS itself, then it also cuts off power or charging completely.

[GusGf]

First of all thanks for the replies

The folding part probably doesn't get its power from the module so connecting direct to the module won't help. Can you connect 24v to the xlr port?

Well all I'm trying to do is confirm that the battery really is the culprit. So I thought by disconnecting the battery power leads from the controller and connecting the off board charger directly to those power inputs on the controller I'd be able to get enough power to see some life i.e. see some lights come on at least. I would not have attempted to unfold the scooter using power from the charger, god knows what damage that might do?

Is it indoors in the warm or somewhere cold?

It was in our conservatory and was aware of the 10°C limit for charging. We only put it on to charge during the day.

It contains a dumb BMS too. And if any cell is allowed to discharge below safe voltage of whatever the programmer decided, through self discharge, or from powering the BMS itself, then it also cuts off power or charging completely.

So how do you rescue it? I have isolated the battery and trying to apply external power via the control board but getting nowhere. Not sure if anyone on here is familiar with these controllers.

or from powering the BMS itself

Wasn't sure what you meant by this


Why on earth they designed this scooter whereby you can't get the battery pack out when it's folded is

[rickystyx]

there should be a foot paddle that will allow you to unfold it even when the battery is flat

[rickystyx]

or have a look here https://www.johnpreston.co.uk/unifile/f ... t_id/2386/

[Burgerman]

It contains a dumb BMS too. And if any cell is allowed to discharge below safe voltage of whatever the programmer decided, through self discharge, or from powering the BMS itself, then it also cuts off power or charging completely.

So how do you rescue it?

Dissasemble battery case. Add 4.200v TO EACH CELL INDIVIDUALLY one at a time to both fully charge and balance in one go. Do so until current falls to a couple of mA for each individually. But if any cell has dropped lower than say 2.5V its probably toast. Also do this oustide as these are really fireworks disguised as battery cells.Thats why the BMS wont allow you to charge it in the first place.

As I say, the BMS takes power 24/7 from the battery causing this problem to occur faster. A self fullfilling prophesy. And many take their power from just 1 or 2 of the cells. Instead of all 7. So unbalancing the pack in the process. This is one of the reason when converting to lithium we dont use any BMS. Theres others!

[GusGf]

there should be a foot paddle that will allow you to unfold it even when the battery is flat

There is indeed a foot paddle and yes I totally agree it should but pressing it does not allow me to unfold the scooter manually. I could use more force than I currently am but it doesn't feel right and am worried about breaking something!

I also have the users manual you linked to but it makes no mention of unfolding by hand.

[GusGf]

It contains a dumb BMS too. And if any cell is allowed to discharge below safe voltage of whatever the programmer decided, through self discharge, or from powering the BMS itself, then it also cuts off power or charging completely.

So how do you rescue it?

Dissasemble battery case. Add 4.200v TO EACH CELL INDIVIDUALLY one at a time to both fully charge and balance in one go. Do so until current falls to a couple of mA for each individually. But if any cell has dropped lower than say 2.5V its probably toast. Also do this oustide as these are really fireworks disguised as battery cells.Thats why the BMS wont allow you to charge it in the first place.

As I say, the BMS takes power 24/7 from the battery causing this problem to occur faster. A self fullfilling prophesy. And many take their power from just 1 or 2 of the cells. Instead of all 7. So unbalancing the pack in the process. This is one of the reason when converting to lithium we dont use any BMS. Theres others!

So if you don't use BMSs how do you maintain the health of the batteries. I'm assuming with your setup you arrange the charging so that each Lithium cell is charged individually/separately and the BMS is built into your charger rather than the batteries. I take it when delivering power they are in series. Be interested to know more about your charging setup.

[shirley_hkg]

First of all thanks for the replies

The folding part probably doesn't get its power from the module so connecting direct to the module won't help. Can you connect 24v to the xlr port?

Well all I'm trying to do is confirm that the battery really is the culprit. So I thought by disconnecting the battery power leads from the controller and connecting the off board charger directly to those power inputs on the controller I'd be able to get enough power to see some life i.e. see some lights come on at least. I would not have attempted to unfold the scooter using power from the charger, god knows what damage that might do?

That's a correct move . However , charger won't start if it cannot see a battery connected （even with a out of range battery ）. You need a 24v power bank or supply .

[rickystyx]

I also have the users manual you linked to but it makes no mention of unfolding by hand.

It seems to indicate the need for a separate battery or at least your battery having been charged and then a lead from that to the chair - it appears from that to need a seperate 24v supply of some sort that is substantial enough to operate the unfolding motors - sounds about as daft as the design of my Skoda
Where abouts are you - one of us may be able to help with a 24v hook up if you are somewhere near but you haven't said in your profile

[Burgerman]

Do you live in a house? Take upstairs. Open a window. Throw it out. Battery not visible? Chair not unfolded? Rinse and repeat. No luck? Find higher building. Try again. This would eventually work. Probable last resort though. Its what it makes you WANT to do.

[GusGf]

I also have the users manual you linked to but it makes no mention of unfolding by hand.

It seems to indicate the need for a separate battery or at least your battery having been charged and then a lead from that to the chair - it appears from that to need a seperate 24v supply of some sort that is substantial enough to operate the unfolding motors - sounds about as daft as the design of my Skoda
Where abouts are you - one of us may be able to help with a 24v hook up if you are somewhere near but you haven't said in your profile

No worries I'm getting my hands on a power supply tomorrow and will update if I've had any success. Incidentally with the XLR barrel connector from the charger there are leads soldered to each of the 3 pins and the on-board XLR socket also has 3 leads. I won't bother wiring up an XLR plug to the cable from the power supply as I can just plug into the power inputs on the controller.

Incidentally looking at the TGA charger's XLR plug and how is wired (see attached pic) I'm seeing red, yellow and black. Am I correct in assuming
power(+) red
power(-) black
ground(⏚) yellow

XLR wiring v2.png (220.87 KiB) Viewed 2927 times

The onboard charging socket has red, black and blue leads going to the scooter's controller. The manual says the pin where the blue lead is connected to the controller is a Multi-function Input/Program pin, not sure if it's being used. The blue cable also immediately goes to the battery pack. The large sheathed cable in the pic contain the leads from the battery pack and I measured the voltage across these as 10V should be 28V! Tomorrow the plan is to connect up a power supply to the power terminals on the controller and get this damn thing unfolded.

[GusGf]

Do you live in a house? Take upstairs. Open a window. Throw it out. Battery not visible? Chair not unfolded? Rinse and repeat. No luck? Find higher building. Try again. This would eventually work. Probable last resort though. Its what it makes you WANT to do.

[Burgerman]

Its a scooter so who knows. But o a powerchair and all mobility devices theres no ground. That yellow wire is the 3rd pin, usually used as an inhibit so you dont drive away with charger connected or for programming.

If you add 12v to that white and pink connector it actuates that ram. Does that open the chair? If so it will save you taking it upstairs.

[woodygb]

Tomorrow the plan is to connect up a power supply to the power terminals on the controller and get this damn thing unfolded.

...Ummm , I suspect that the controller has NOTHING to do with the unfolding bit ...it will just controls the drive motors.

You didn't specify the EXACT model ...but here is a YouTube vid of a plus 4 and a different model.

youtu.be/pe1I73z5tdM

youtu.be/xNIzDuFMAHw

[rickystyx]

You need to be very careful with TGA wiring as on all the tGA's I have dealt with their wiring of the plug was the opposite of everybody elses. Check with a voltmeter for which is positive and which is negative - the third connection is an inhibit to stop anything from moving whilst the charger is connected.
There must be some residual voltage left to give you a positive and negative reading

[rover220]

You need to be very careful with TGA wiring as on all the tGA's I have dealt with their wiring of the plug was the opposite of everybody elses. Check with a voltmeter for which is positive and which is negative - the third connection is an inhibit to stop anything from moving whilst the charger is connected.
There must be some residual voltage left to give you a positive and negative reading

Yes good point, for some reason tga choose to wire their xlr sockets back to front.

[woodygb]

The instructions for unfolding the Minimo with the battery removed actually involve using the removed battery as the power source.

Connect the ‘Remote battery connection lead’ that was supplied with your scooter to the
charging socket on the top of the battery, and to the charging socket on the side of your
scooter, ensuring that they are firmly located.

[GusGf]

Its a scooter so who knows. But o a powerchair and all mobility devices theres no ground. That yellow wire is the 3rd pin, usually used as an inhibit so you dont drive away with charger connected or for programming.

If you add 12v to that white and pink connector it actuates that ram. Does that open the chair? If so it will save you taking it upstairs.

Hmmm now that's a good idea. Worth a shot but how do you control which direction the ram goes once you apply power

[GusGf]

You need to be very careful with TGA wiring as on all the tGA's I have dealt with their wiring of the plug was the opposite of everybody elses. Check with a voltmeter for which is positive and which is negative - the third connection is an inhibit to stop anything from moving whilst the charger is connected.
There must be some residual voltage left to give you a positive and negative reading

I suspected as much

[GusGf]

Its a scooter so who knows. But o a powerchair and all mobility devices theres no ground. That yellow wire is the 3rd pin, usually used as an inhibit so you dont drive away with charger connected or for programming.

If you add 12v to that white and pink connector it actuates that ram. Does that open the chair? If so it will save you taking it upstairs.

Hmmm now that's a good idea. Worth a shot but how do you control which direction the ram goes once you apply power, is it some kind of toggle operation

[Burgerman]

Hmmm now that's a good idea. Worth a shot but how do you control which direction the ram goes once you apply power

Reverse it to go the other way.

[woodygb]

Hmmm now that's a good idea. Worth a shot but how do you control which direction the ram goes once you apply power

IF the wiring is equipped with limit switches ... it should be ..., then it will only operate in the correct direction and unfold.

[GusGf]

The instructions for unfolding the Minimo with the battery removed actually involve using the removed battery as the power source.

Connect the ‘Remote battery connection lead’ that was supplied with your scooter to the
charging socket on the top of the battery, and to the charging socket on the side of your
scooter, ensuring that they are firmly located.

Her's looks exactly like the ones in your videos it's just called the Minimo Autofold not sure which version.

A autofold scooter which locks the battery in when folded and cannot be unfolded manually

Ever notice how all the people demoing these mobility scooters are all able bodied. They may even have a lady lifting a folded mobility scooter out of the boot all by herself all 30Kg. Good luck with that if you have any back problems at all.

You'll also notice that many don't have a fob to operate remotely (with the key fob she's got you actually have to brush the fob up against the tiller to drive it, otherwise the fob does not initiate the fold/unfold sequence) so the user will still have to bend down to press those buttons. Is anyone in these design depts actually disabled or in possession of a fully functioning brain?

[GusGf]

Hmmm now that's a good idea. Worth a shot but how do you control which direction the ram goes once you apply power

Reverse it to go the other way.

Okay so you'd reverse the connection from the power source, got ya

[GusGf]

Hmmm now that's a good idea. Worth a shot but how do you control which direction the ram goes once you apply power

IF the wiring is equipped with limit switches ... it should be ..., then it will only operate in the correct direction and unfold.

That makes sense. Was wondering if there was a power toggle (this is where toggle switches would come in) which operated the ram in the opposite direction it was previously every time a fold/unfold operation was signalled. But Burgerman suggested a reverse polarity operation.

[ex-Gooserider]

Essentially the way the typical actuator / ram works is that you have a DC motor that spins either a nut or a threaded rod internally moving the outer piston that is attached to the non-spinning part, so that you are screwing / unscrewing a nut and bolt.... DC motors spin in either direction depending on which way the power wires are connected...

In many cases an actuator is wired with limit switches and diodes that will turn the motor off at the 'end of travel' in each direction, while still allowing it to be run in the opposite direction, but not always. For instance, sometimes they might have a sensor that is connected to the controller and plan on having the controller shut off the motor, or there are other ways of doing it....

Running an actuator momentarily in the 'wrong' direction is unlikely to do any damage, but you don't want to for long. So, it is important to connect in a way that you can do a quick making and breaking contact.

If you can get at the wiring for the unfolding actuator, you should find two wires. Connect one side of the power supply to either one of them and make a momentary connection with the other side of the supply to the other. If nothing happens, or the actuator 'tries' to move in the wrong direction (it might hum as the motor strains against the mechanical stop) reverse the connections and repeat. If the actuator moves to unfold, keep the connection until it is unfolded but be ready to break it as soon as it is unfolded....

If you find multiple wires, it is likely that two will be for the motors, and the rest are sensors - typically the motor will be heavier wires and the sensors lighter ones. It is possible to damage some sensors (and not others - but we don't know what is in there) by putting the wrong voltage / polarity to them, so be sure you have identified the motor wires.

ex-Gooserider

[GusGf]

In the end I invested in a power supply and connected it up to the controller and the scooter came to life . So have now managed to unfold the scooter and extricate the battery pack. Now that the battery pack is out of the picture I noticed some odd behaviour. According to the label on the battery casing and the manual the scooter is rated as 11.5Ah 24v. BUT when I connect up the power supply in place of the battery (capable of 30v 10A) and switch on the scooter and leave it idle the power meter on the tiller is reporting the following:

NOTE. The power meter from right to left has 4 green leds, 3 amber leds, 3 red leds. There are a further 2 reds which flash when there is a problem accompanied by an audible alarm.

@28v I'm getting 4 green leds, no surprise there.
@27v Goes down to 2 green leds, huh?
@26v Only 1 green led remains lit!
@25v All green leds now extinguished and I'm left with the amber and red leds all illuminated
@24v From 3 down to 1 amber led remain lit in the space of a few minutes. All red leds illuminated and the 2 leds off to the far left flash and an alarm goes off from the moment 24v is applied.

I have measured the voltage from the power supply using a separate meter and it verifies the power supply voltage. Remember the PS is putting out a constant voltage and the scooter is in acquiescent mode. So I'm wondering if the controller has been programmed to be ultra conservative when it comes to what the battery is capable of. I can't think of any other reason. I know some of you have built your own Lithium packs and my knowledge in this area is limited. I'm having an engineer at my place of work who builds lithium packs take a look at battery pack cells but would appreciate your input.