HI i have a quickie 6000z and i have no battry for them. I just build a lip 13s4p 48volt battery3,7 nominal (54.6v once charged)

• Model of the cell it contains: US18650VTC4
• Manufacturer: Sony
• Country of Origin: Japan or China
• Chemistry: NMC
• Max. continuous discharge current: 30A
• Nominal capacity: 2000 mAh
• nominal 3.7 v

i would like to use this lipo battery to power my wheel chair so someone told me to buy a dc dc buck converter.

i need help cause i did contact a chinese guy on aliexpress and he said he can build one for me and asked me to send him info.

I talked to a wheelchair expert and he told me that this wheel chair works at 25 26 volt . minimum working volt being23 and max 26. it told me the amp is between 10 -20 range.

1 now do i need other information?
2 in a regular battery, the more energy is spent the more the voltage drops for esxample gel batt maybe 26v full and after 3 hours of rodad usage they have dropped to 24 v maybe. With a buck converter, 48 to 24 volt for example is the out put current always 24 v or it will also drop as energy is spent ?
tx

 

Why dont you use 7 cells this will give you the correct voltage, but the cells are rated at 2Amps..

 

Yes, use 7 in series and as many in parallel as needed to get the capacity. This would be 29.4 at full charge, and they would provide 23V downs to 3.3V. Sounds almost perfect for this range. Don't worry about the 29.4, it will drop below 29 almost immediately when running.

Bob

 

Hi my interrogation is around if it will fonction without burning since 29,4 is kind of far from the 24 volts intended. the wheelchair probably have some inferior and supperior voltage limit wich it cannot fonction or fonction without burning if out of its range.
What to do

 

Just remember, swapping to LiPo batteries will entail a new charger and battery discharge monitor. You cannot just drop one in safely. If you do, without the appropriate battery state control, I would be quite worried about a battery fire or explosion.

There is another similar thread going...
https://forum.allaboutcircuits.com/...lithium-mobility-scooter.160531/#post-1401687

 

is battery state control what you mean by battery discharge monitor? how is that important ?

 

The battery state control may be the same. But, if you change the battery type, so must the control be changed to suit.
Most batteries can be damaged by overcharging and also be being discharged below a certain point. And many will not recover. So, if you were to drive the motors until there was nothing left in the battery, you would most likely kill the battery.
Overcharging can cause fires and explosions in some chemistries.
For instance, my Prius (old model), according to what I have read, only allows the battery to charge to 80% capacity, and discharge to 40%. So less that half of the battery capacity is utilized, but the like is greatly extended.

 

HI english being my second language, could you explain what you mean by battery state control

also if i have a bms on my battery does it solve the problem you are pointing at?

 

If the BMS is correctly designed, it should be ok. But, if it is for Lead/acid type, it will not work for LiPo.
You must get the correct one. And see if the BMS has both overcharge and battery discharge protection. Some are only overcharge.
Getting the BMS right is very important!

 

If the BMS is correctly designed, it should be ok. But, if it is for Lead/acid type, it will not work for LiPo.
You must get the correct one. And see if the BMS has both overcharge and battery discharge protection. Some are only overcharge.
Getting the BMS right is very important!

HI english being my second language, could you explain what you mean by battery state control

also if i have a bms on my battery does it solve the problem you are pointing at?

I built a 13s 8p pack for my e bike. Rather than a bms I used 2 Lipo Battery Low Voltage Tester 1S-8S Buzzer Alarm indicators and monitor my pack manually. I don't know how you connected your cells spot weld or solder? I soldered 8 cells in parallel with thin wire then connected those to a buss. The thin wire acts as a 5 amp fuse. Either way 7s is the way to go, you can get a bms or use the testers. I like the testers because I can see the state of each group of cells.

 

would these Low Voltage Tester 1S-8S Buzzer Alarm fonction on lithium li ion battery?

 

would these Low Voltage Tester 1S-8S Buzzer Alarm fonction on lithium li ion battery?

That's what they're made for. you can set the alarm so if one cell gets to low it will activate. That's really the only concern with lipos, if they get to far out of balance. If you go that way connect however many cells in parallel first then connect those groups in series.

 

what would be the use of them in the case where i install a bms?