60ah ADD ON build with Pictures

[shirley_hkg]

700W 12A
CC / CV step-down module .

[Burgerman]

Yes those or similar.

[shirley_hkg]

I thought of it too. A power bank for wheelchair ,
like the one used to charge cellphone.

[expresso]

that would be cool if you can come up with a small carry fast charge solution - just plug it in the xlr and leave it alone - for those times its needed - if its not big and heavy etc, can carry it on my seat cushion on the side and use it if needed - would have to be something a person can use when alone -

then charge it when you get home - with the PL 8 - i carry a Cell phone battery bank all the time - for the Camera - and if needed my phone

[Burgerman]

It can only charge via XLR so it would attempt to float charge at 12A as and when needed, as you drive the chair ALL DAY. It would otherwise mean you sit down, plug it in, and wait for hours.

It doesent allow the lead to discharge, unless the lithium is used up. UNLESS you are driving uphil all day!

[expresso]

i see - so you would just plug it in when you go out and leave it there the whole time as you ride and use the chair ?

if this worked - then no need for a diode - ? or would it be even better with diode and this unit - ? if it works as intended

to be honest - even with no diode in place etc, this 60ah pack goes a great job - 30 miles is very good with a lead chair - i dont feel limited

some places i do need that extra 5 miles at least or 8 -- but for others its fine - i can make up those 5 miles if i take the city bus - a block away - to its last stop is 5.1 miles - battery saved -

that can work if i really wanted to go where i would have gone with my other chair - i dont go that far often but i actually made some friends there since i first went - they work for boat basin - in NJ - every so often i go and hang out a hour chatting - before i head back - i only been there once this year before my chair stopped - i may wait till its repaired before going -

222 chair is very light front end - and with the 60ah in the back - i cant do big hills with it - i would lift up and get stuck tipped all the way back and cant move - i happened before with the smaller pack - its just a tipsy chair - i love it but has some limits because of it -

[biscuit]

What would happen with the inhibit on the xlr with that?

[Burgerman]

You wouldnt connect it.

The charge inhibit thing, only works if the negative wire inside the XLR is also linked to the 3rd programming/inhibit pin.

You can take up to 12A max to run anything, or feed it up to 12A max as you drive as long as the 3rd pin is not connected.

12A isnt adequate to keep up at max speed. But most people stop to talk, cross a road, or buy a paper, eat a burger or just look at something now and again. And it will be merily charging at these times too. So while it takes about 15 to 20A to go full speed on the flat, you dont do it all of the time. So the 12A you are adding will almost keep up. And then will catch up if you behave normally and slow or stop periodically. And so total range will be extended by the amount you have in the lithium pack.

Remember you are adding 12Ah per hour to the lead as you drive. So in 3 hours you add as much back to the chairs battery as you can use at full speed in 2 hours. So in reality you will have used about 1/3rd the amount you normally would from the lead battery. And the moment you stop or slow, or go downhill, or wait to cross a junction, it will be charging faster than you are using it...

[biscuit]

An XLR pin that leads nowhere? Or does the pin itself do the inhibiting? IDK how that works - I didn't understand woodygb's explanation the other day, tbh.

My inhibitor on my own wheelchairs is as from factory.

So would this system work if the inhibit connection on the chair/scooter side is disconnected? I could easily do that. But if that's the case, my mom would have to be careful not to drive off while plugged into the charger at home. And I know (from experience, believe it or not) how challenging that is.

Hope that makes sense as I've just spent a happy hour syphoning my apple wine from its fermenter into bottles.

[Burgerman]

You dont need to do a thing on the chair or scooter.

Undo your chargers XLR plug. It just unscrews. Look inside. You will see the charger has TWO wires. Those charge your chair. The negative one will have an extra link inside the plug, to connect it to the third pin.

Snip this link with scissors, and your inhibit will not work. You can then drive your chair away while charging and drag the charger onto the floor... Ask me how I know.

In the charger plug theres a small wire joining pins 2 and 3. Pin 3 is the charger inhibit, and the programming pin. Not ground as it calls it below.

[biscuit]

You have also had the experience of knowing for a fact that the chair is not on charge... and being wrong!

[Burgerman]

Thats why they connect that extra link, to stop you doing that. But thats not needed on tha extra battery pack because it goes with you.

[expresso]

OK i got the Diode - pretty fast considering -

I need to know which way to attach it - in the picture - the XT 90 is coming the battery pack ADD ON - would this be correct if i soldered the wire on the Diode with the 3 prong end to the XT 90 end - ?

or is the other way around ?

would it be OK to solder the wire on each end ? or do i need to screw it down instead - the hole is very small on the diode end - and my ring terminal is larger so will be hard to find a screw to fit both - reason for thinking of soldering the wire on the diode instead - and will heat shrink it just up to the diode body -

leaving it exposed the Body and the rest metal part of it heatshrinked with the wire

so which way is the correct way to attach it - i will give it a try -

thanks

[Burgerman]

The spiky end with 3 spikes gets the positive from your addon pack. The other end gets the wire that feeds the chair. And thats from memory which is 90% good!

Best to use te terminals as they will take more heat away. But not sure if that will be a problem or not.

[expresso]

ok so i had it right in the picture then -

now why does it have to be on the Pos. line vs the Neg. line - ?

i actually found a little screw i can use - amazing first ever the hardware store i found something correct

i will use heatshrink over the it - just enough to cover the metal and leave the main black body without -

[Burgerman]

It doesent have to be in the pos line. It can be in either. But in the neg line it would be confusing to me... And need to be fitted the opposite way around.

[shirley_hkg]

Turn it around , if you were gonna put it on the negative path to avoid sparks .

[expresso]

Ok so in the Neg. line to be safer

in that case - the 3 spikes end goes facing away from the xt90 - i will do that then - and then heatshrink the exposed areas only -

when i get a chance - weekend maybe i try it

thanks -

[expresso]

It doesent have to be in the pos line. It can be in either. But in the neg line it would be confusing to me... And need to be fitted the opposite way around.

why would that be confusing ? just turn it around and the 3 spikes end is away from the XT90 - instead of facing it -

i will try the Neg. line - anything thats safer is good - if it does the same thing - dosnt matter to me -

[Burgerman]

How does that stop sparks? A different battery voltage causes current to happen wherever it goes. There is nothin like a chassis ground on a chair. So its irrelivant where it goes as far as I can think. But its good practice to keep all the negative/ground cables at the same potential. So tradition says pos cable.

[expresso]

Turn it around , if you were gonna put it on the negative path to avoid sparks .

thanks

[expresso]

SO it dosnt matter which line i ADD it then ?

just the order if going Neg. or Pos. - I will do which is best - to be safer - let me know which is best - Neg. or Pos ?

i wont be doing it till sunday - so hopefully we can figure it out by then

i be curious how much more range i can get out of it - if any at all -

[Burgerman]

As far as function goes, it doesent make a difference. But it makes my head hurt thinking how it works in the negative wire, as your 0 volts will be .65 or something. It will not make less sparks in the neg. Not sure why shirley thinks it will?

[shirley_hkg]

I'd felt exceptionally uncomfortable with exposed metal parts that carries 26V
. If both ways work , I choose exposing the -0V .

[Burgerman]

Its all fully floating. The chairs chassis in not 26V or 0V its not anything. So it makes no difference which is exposed. Both are equally safe. You could look at it and call the pos 0V and the negative -26V if you understand what I mean. Its floating.

[expresso]

Ok so either way works fine and one way over the other makes no difference in sparks or safely ?


3 prong end facing the XT 90 if using the POS - wire

3 Prong end facing away from the XT90 if using the Neg. wire


so the verdict is ? Pos or Neg. ?

[steves1977uk]

You're over thinking things again expresso! I'd put it in the positive wire, but it shouldn't matter as long as you get it the correct way!

Steve

[expresso]

i want to be sure its done the correct way and safe way - two different answers to same questions makes me think a bit

i welcome all input - i dont like guessing when it comes to this stuff - i dont have a problem either wire - but if one is safer then the other - which it seems to make no difference from what i understand - then its no big deal either way -

thinking is a good thing sometimes

[LROBBINS]

In a car, the chassis is the ground connection for all of the things like lights, horn etc. and for decades that's always been the negative side of the battery. A short from B+ to chassis WILL then make sparks, and can even start a fire - but this is considered safe (and certainly cheaper than running a separate ground wire to each electrical device), but that's because they figure that people can get out if there is a fire.

Wheelchairs are not wired that way - if you could run from a fire you probably wouldn't be using a wheelchair. Thus, certification rules require that the chassis not be connected to the battery in any way. (Well, not quite - the rules say you can't have any low impedance connection. It is permitted to use the chassis for noise shielding, but it must be isolated from the battery by, for example, a capacitor at every connection. Noise - alternating current - can get through the capacitor, but DC can not.) That's why there are both positive and negative wires connecting everything on a chair, while cars have wires for positive and chassis for negative.

So, on a wheelchair, you can safely put your diode in either the positive or negative wire. On a car, you can but shouldn't.

[expresso]

Today i wanted to Push this 60ah Pack to its limits - i got very close at 33.2 Miles - lowest Cell 2.9V - which is Cell 3 the weak/Bad cell of the bunch

the Cells are rated to go down to 2.5V safely as i was told by the seller - at this point i dont care if i hit 2.5v on Cell 3 - and no lower - i think i may have been able to get a few more miles - i may replace Cell 3 in the winter - i am trying to get a replacement - will test it and then see if its worth it or may be even worse for all i know -

NOW even if nothing changes and i leave it as is - its still an AMAZING ADD ON considering - 30 miles safely - and maybe up to 34 - 35 Miles if i push it down to 2.5V - the rest of the pack would be safely at 2.9V if anything so not too worried -

i did this just to see what it can do - more or less - before i add the Diode in line - if that works once in line - i can easily get 35 miles as is - and maybe more if i replace the weak Cell 3 -

i was a bit worried going over 30 miles - but i was close to home to test it at this stage - and surprised it was fine with the Weak Cell 3 at 2.975V -