PINNED - Lithium battery conversion/info

[Burgerman]

How long does it take to decide what pizza toppings to get?

[expresso]

not long - plain - margarita style --

so would the Auto reset work ? 100A -

https://www.waytekwire.com/item/46935/B ... t-Breaker/

https://www.waytekwire.com/item/46935/B ... t-Breaker/

https://www.waytekwire.com/item/48925/1 ... 1-4-Studs/


https://www.waytekwire.com/item/48935/1 ... 1-4-Studs/

looking at these models -

also does it have to handle more than 24V -- since lithium is higher volts - ?

[Burgerman]

I am using one at 47.6V fully charged! They dont care about volts much. worst case, it may arc a bit if it opens under a short circuit. So the least of my worries if its already stopped a fire! Auto reset? Probably... Never saw one so cant say. If theres a short, do you want it to keep resetting? Probably best to get a non resetting one.

No anchovies?

[expresso]

this is one of them
Auto https://www.waytekwire.com/item/48935/1 ... 1-4-Studs/


i mean the breaker - some say it handles 12 to 24V - some go to 30V and more

would at least 24V breaker work fine or need higher on the breaker ?

[Burgerman]

Around and around! Its a switch. Volts not critical.

[Burgerman]

No anchovy? How can you not!

[expresso]

i just want to make sure i get the correct one -

i figure Auto to make it easy on me - maybe just a fluke and trips - with auto it resets and i keep; going - unless theres a real ongoing issue

how it would handle that - i dont know

[expresso]

that looks good - i would have some of that -

[Burgerman]

Me either. Likely keep resetting and melt! wouldnt like thousands of amps much.

[expresso]

https://www.waytekwire.com/item/48977/1 ... 1-4-Studs/

Ok done deal - i just ordered this model - and a few MIDI fuses at 125A time delay - since it was cheap cost -

i just checked my chair - and i cant mount it outside the chair except in the front divider area - right in the middle under my seat on top of the divider would fit - but the i have to redo the main wiring and make it alot longer cable so i can slide the pack out the back of the chair if needed - i still have to disconnect it if i have to remove the pack - but i have to make the wires long enough slack if i need to slide it out without removing it

would use the NEG wire to connect to the breaker since its closer to the breaker - i though i had room near the rear of my chair under me - i dont -

trying to get the wire to the breaker is a pain for me from battery to outside breaker -

one way or another i have to do something - worst case - i connect it and leave it inside on top of the battery pack in front of the top Row - i may have just enough room to lay it there - - that would solve the cable wiring - easier for me that way - but if needed to be reset - have to open the rear cover slide it back - reset - and back inside - close cover -

i think those are my only two options with this breaker - and last is just a fuse inline - and cross my fingers it never blows - i guess at this point - that would be the same as before i realized its not fused - only this time i be fused at least the breaker was to make it easier if ever tripped -


chair front where i would mount it -

[expresso]

No anchovy? How can you not!

you making me want pizza Again now - that does look very good

[expresso]

https://www.waytekwire.com/item/48977/1 ... 1-4-Studs/

i should be receiving this in a few days - how can i safely test this unit to make it trip to make sure it works ? with out using my Pack

[Burgerman]

You cant.

[expresso]

Oh - Ok - didnt expect that answer from you - i was waiting for you tell me to hook it up to something and short it out just to see if it worked


i though maybe with the Volt meter - show how - someway it can show me if its working or make it trip - its brand new - military spec - triple heavy duty - dust proof - water proof
under water for hours - according to there data sheet -

i have to just believe its working when i get it and connect it - once i get the wires made -

[Burgerman]

Not seen its data sheet. But a short will trip it but about 350A will flow first for an instant. Or run it at 170A for an hour to test that should trip it eventually. So not practical.

[expresso]

https://www.waytekwire.com/datasheet/mpseries17cb.pdf


https://www.waytekwire.com/item/48977/1 ... 1-4-Studs/

[Burgerman]

Read it yourself carefully. Will take 135% of rated current for about 1000 seconds. So so about 195 A for 10 or 15 mins or so should trip it. By then your cables will be on fire. And if you short it it will trip in about 1 second at 1000 amps... Dont test.

A 100 would be safer.

[expresso]

Oh - i read it but dont have the experince as you and others here to know for sure

you dont think 8 AWG can handle that ?

[Burgerman]

Approx 195A Continuous? No. Not for long. At 40A it gets quite warm to the touch.

[expresso]

what i dont understand - is - if the Rnet is 120 A - even 100A - and 120A short burst -

i believed that it should be at 120A or more to be on the safe side of not having it trip during those times - the factory use 70A - so somehow 70A seems to be just fine - how i dont know -

[Burgerman]

120 Amps means MOTOR Amps. Not Battery Amps. Those are different. Your R-net can do 120A on each motor! 240A total!

So if your 26v lithium battery and controller feeds say 10V to your stalled motor, as you try to turn, or climb a curb, that motor can for a few seconds pull up to 120A max - limited by the r-net...

So when your motor is at 120A x the controller actively limits it to this level via its pulse-width control. It does this by lowering average motor VOLTAGE. Or in fact controlling the pulse-width. At say 10V ? (a guess) that means 120 x 10 = 1200 motor watts.

The amp draw on the BATTERY will be 1200 watts, div by 26v = 46 Amps. You have 2 motors. So it could be: 46A x 2 motors = 92 BATTERY Amps.

Has your head exploded yet? The actual figure depends on motor impedance.

[expresso]

NO i am still here - so the number is close to 100A for the battery end -

i may just try a 100A then and see if that ever trips on me - up to now i had no protection - i didnt know - i though i was fine - worse case if the 100A trips - i can swap it out for the 150A model ? i figure a little head room would be ok also

[Burgerman]

I doubt you will trip a 100.

[LROBBINS]

Remember, the 100 A breaker will hold for about 16 minutes at 135 A (135% for 1000 sec). You'll be OK with that.

[Gnomatic]

120 Amps means MOTOR Amps. Not Battery Amps. Those are different. Your R-net can do 120A on each motor! 240A total!

So if your 26v lithium battery and controller feeds say 10V to your stalled motor, as you try to turn, or climb a curb, that motor can for a few seconds pull up to 120A max - limited by the r-net...

So when your motor is at 120A x the controller actively limits it to this level via its pulse-width control. It does this by lowering average motor VOLTAGE. Or in fact controlling the pulse-width. At say 10V ? (a guess) that means 120 x 10 = 1200 motor watts.

The amp draw on the BATTERY will be 1200 watts, div by 26v = 46 Amps. You have 2 motors. So it could be: 46A x 2 motors = 92 BATTERY Amps.

Has your head exploded yet? The actual figure depends on motor impedance.

Wow BM this is good stuff!

[Burgerman]

Once you understand that the controller and battery voltage behave as a gearbox, it helps you to understand why my lithium BM3 at double the voltage goes twice as fast (obviously),yet has the same torque and MOTOR current draw as its 8.5mph motors ever did. Since we changed nothing here.

At 0 up to 8.5mph they still need the very same Amps, and 0 to 24V as before. And at a 120A current limit the max torque level also remains the same. But battery Amps are halved due to the voltage being doubled. (same total watts, and watts is Volts x Amps.)

So instead of making a 4mph chair into an 8mph chair for eg. By using taller gearing as the entire mobility industry does. Which doubles the Amps at every speed, and so reduces range, and halves available torque. I doubled the voltage instead. Meaning I get a doubling of speed with zero cost to torque, or range. Now has your head exploded?

[expresso]

Remember, the 100 A breaker will hold for about 16 minutes at 135 A (135% for 1000 sec). You'll be OK with that.

thanks Lenny -

[Burgerman]

Battery Amps. V Motor Amps. Simplified!
Remember that TORQUE = AMPS directly.

BATTERY_________50A_24v______CONTROLLER_______100A_12V_____MOTOR!

50A X 24V
100A X 12V both equals same amount of power (watts)
The red bit is the wires...

This 12v figure is because the motor has a resistance, or impedance. That allows 100A to flow when you feed it just 12V.
If that impedance was halved (lower resistance) again, by heavier winding, that motor now draws 100A at just 6V. Now the battery amps are:

BATTERY_____25A_24V_____CONTROLLER_____6V_100A________MOTOR!

In both cases the same torque is produced. And half the battery amps, so double the battery range. So for range, speed, efficiency a low impedance motor is best!

[expresso]

Just got my breaker in - and a few lugs - i can compare now the difference between the copper ones i used on my pack - - the other two i got a few of to compare - looks like i found a heavy duty lug which i like - and will use those on the wires i need to make now -

if they work good - dont see why they wouldnt - i would use those from now on for the next pack i do -

[expresso]

more