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Oset Batteries Lithium (LiPo) Conversion Directions

474 posts in this topic

13 minutes ago, lennie said:

I don't know a lot about these batteries, read about them on ebike forums they prefer them over the hobby king batteries. I am going to get a decent battery before summer for my lads 36v oset hobby king have been out of stock for my ideal batteries fir ages so ive been looking for alternatives.

these are called 18650 and are found in laptop batteries and TESLA cars

These cells are great but also there are not so great Chinese versions that advertise as 9000 mah but have like 500mah

 

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just looked up the spec for these cells:   ( as long as they are genuine cells then )  10A max discharge for a single cell (3-4C)   found some discharge graphs   discharge @ 2C capacity drops to around 2000mah per cell so that then becomes a 8000mah pack is discharging @ 2C and from what i can tell in do not include a bms with that listing ... it should be ok for a small 36v bike that dont get taxed to hard ( much better with 2 packs) as long as a suitable bms is also installed, then the cost dont look so good . you would need a CC-CV charger to charge these batterys so the standard sla  charger will not do the job.

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Why is this all so difficult??? :)

 

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thanks for that gwhy.

 

greg , its a pain in the ass, I am still hoping the ideal hobby king batteries come in stock soon, not sure what the compromise will be if they don't.

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I was excited about possibility of using cells from Fiat 500 electric car battery but they are way too big :(

 

PS. Anyone wanna make Home Powerwall?

17021825_1349374228458991_4888899041961271552_n.jpg

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this is one of the main problems with electric bikes... there is not a lot of room on a bike to put batterys. ebike batterys ( legal ebikes ) are only rated for a max of around (average) 500w ( these depends where in the world you are ) and all legal ebikes should do no more than a average of 15mph ( again depend where you are in the world ) now those batterys in the link will be fine for this sort of spec but once you start getting into higher power or higher speeds the choices are few... higher voltage  runs a motor faster and the plus side to this that less discharge current ( from the batterys ) is needed for the same power .. . the big down side to this is that small motors ( the ones on bikes ) run way to fast to gear it down to a sensible speed if a high voltage is used so there is always a compromise between voltage and current.  i.e the telsa indeed do run on laptop batterys ( well the very yealy models ) but they ran on about 350v so to get the power needed the discharge current will not have to be so much.. if you run a small bike (oset 16 ) on 350v (dont try it as the motor is not designed for that sort of voltage :-) ) then the speed will just be way to high and if the discharge current was adjusted down to i.e 10A max ( thats still a wopping 3.5kw) but the motor will not have enough torque to get you moving as it will be geared for around 200mph @350V ..

 

i think the ktm runs around 350V but this is a motor designed for that bike ... personally 350v on a bike is way to high ( especially a off road bike )  and a bit dangerous .

 

normally the bigger the motor the slower it will run per volt ( kv of the motor )  .. thats why cars can get away with it as they have much more room for the motor and batterys.. but bikes you are always struggling for space.   

 

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On 2/10/2017 at 7:51 PM, gwhy said:

or if it will fit just get one of these

https://hobbyking.com/en_us/multistar-high-capacity-6s-20000mah-multi-rotor-lipo-pack.html

the less interconnections you have the less room for error.. you may want to source a 6s bms for charging and basic battery protection.. you can bypass the current limit on most bms's for the discharge so you dont need to source a very expensive one..i think hobbyking sale a 6s bms but not to sure what the max charge current spec is.. 

 

4A max charge bms  https://hobbyking.com/en_us/6s-li-ion-pcm-charge-4a-discharge-10a.html

10A max charge bms https://hobbyking.com/en_us/6s-li-ion-10a-pcm.html

Would two of these in series be enough to power a Oset 20.0 Race?  I'm fairly versed in RC cars that use LiPO and have a quad charger with balance boards, but I'm guessing the BMS is to balance all 12 cells at the same time while each battery is charging indepently of eachother?

 

thank you for your time!

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yes 2x 6s 20000mah lipo's will be enough to run a oset 20.0 . 

a bms normally is fitted permently to the battery and protects ( prevents cells from overcharging 4.2v ) and balances the battery when charging AND it also  prevents any cells from dropping below the safe level when discharging ( when in use ) a bms will also prevent the battery from charging if any cells are below the safe level (3v).

if you have 12cell battery then you would need a 12cell BMS  and you would treat and charge this 12cell battery as 1 battery ( 1x 50.4v li-ion charger ).

so if the battery is fitted with a bms and wired correctly and using the correct charger there is no need for low voltage alarms or a balance charger as it becomes a Plug 'n' Play system that is 100% protected 100% of the time.  

when selecting a bms you need to make sure it covers the max charge current that you will be charging your battery with and that its for the correct chemistry of your batterys ... lipo is 3v - 4.2v the bms also needs to be correct for the amount of cells that make up your battery.  12s lipo bms's are quite hard to get hold of ( expensive a 12s bms's bms start @ around $50) 13s are more common ( cheaper ) .. normally the higher the discharge rating of a bms then the more expensive it is , it is possible to bypass the max discharge current limit of a bms.. i.e a cheap 13s bms @ $10.00 - $15.00 will do the job but it will only be rated for a max discharge of around 30A so the the max discharge will have to be bypassed .. but you can still have the bms protecting the cells within the battery by using the bms to turn off the bike should any cell drop below the safe level.

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Posted (edited)

Hi,

Super thread this!

I am new to the forum here and new in the Trial sport.
From Norway by the way :)

I have bought an Oset Spider 16 for my son who is 4 years old on Thursday.

Thinking about upgrading with LiPo.

Will this package (battery and charger) be sufficient with regard to spec on the battery?
There should be no shortage of ah anyway :)

http://www.ebay.com/itm/36V-30AH-LifePo4-Battery-Electric-Bicycle-High-Power-Rechargeable-Batteries-Pack-/262969455281?hash=item3d3a3372b1:g:uv8AAOSwxGRZhVWf

Anyone who has experience using 36v on a 24v bike?

Best regards tommy

Skjermbilde 2017-08-15 kl. 22.35.04.png

Edited by tommykh
Pic add

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