newbie

First of all hi to all in this community!

Im relatively new to all this, but im in RC so i have some experience lets say in batteries, so that leads me to my first question

why do people avoid Lipo batteries, i have been using them for more than 6 years with 0 issues, ok you need to be aware of risk and you cant leave them overnight to charge
on positive side they are relatively cheap, if you find them on sale, for instance you can make a pack 12s 10000mah for under 150$, and its plug and play, and of course you have hgh performance battery, so why they are avoided?

I have my mtb that i want to convert to electric, of course rear hub, i can see that there are different setups/types, im not talking about front middle or rear, rear hub, i can see that there are with pas and without pas? or im wrong?
with pas, how does it work, you need to pedal always or no, or just to start rolling
can i lets say sometime use pas and sometimes drive only on batteries with throttle?

those ebay kits, are they any good or no, for first project?

thanks,
im sorry for long post but i have million questions and i have difficulties to find answers

The big danger of lipo is people in general, are not able to handle them sensibly. Particularly, the lack of a bms leads them to overdischarge them, sometimes to the point of flames. Or after such abuse, they do leave them on chargers overnight, and burn the garage down. Easy to damage those pouch cells too, then they can flame. Lipo duct taped to bikes makes me cringe.

On the other hand, " safe" cells with bms burned my garage down. My big mistake was NOT treating just like my lipo.

The quality of the ebay kits is a bit random. Some go 10,000 miles no problem, but a few never run right out of the box. So definitely buy from a vendor in your country, or spend a lot on a more quality controlled kit from reputable in country vendors.

Lipos are a bit more fragile than other battery types. Using and abusing them in an RC car or plane is one thing. Riding a bike with them strapped to it is another entirely.

Kits come is a variety of flavours. They can be PAS only, throttle only or both. If a bike is PAS only you need to keep your pedals moving to keep the motor turning. If it has a throttle and PAS, the throttle generally overrides the PAS feature so you can use either.

I think most generic controllers will accept inputs from both, so you can often add a throttle to a kit that does not include it originally. Check the specs of the controller to be sure.

Keep asking questions, but the more we know about your needs the better we can answer.

Big difference between a 300 pound guy and a 150 pound guy, and wanting to climb hills off road, or wanting to ride the path along the beach.

There is no doubt you are ready to run lipo on your bike.

marmil said:

why do people avoid Lipo batteries, i have been using them for more than 6 years with 0 issues, ok you need to be aware of risk and you cant leave them overnight to charge

on positive side they are relatively cheap, if you find them on sale, for instance you can make a pack 12s 10000mah for under 150$, and its plug and play, and of course you have hgh performance battery, so why they are avoided?

Click to expand...

The reason I avoided lipo is fear of fire and lack of knowledge. After all, you experienced guys reinforce that by telling us about the risks.

As for cost, doesn't your $150 lipo need a $100 charging system? Anyway, I don't mind paying $300 to $500 for a ebike battery with charger. I get some peace of mine, but I still charge these suckers outside.

By the way, for cheapness, I will use two $35 36V4AH hoverboard batteries and a $10 charger. These have no balance circuits and the LVC is set at 25V. No wonder they had a rep for fires, but I am comfortable with them.

I did have some lipo car starter batteries I bought on closeout. While charging them outside, it rained. Water inside and ruined the BMS boards. I took the loss and dropped them at the recycler.

sorry for my delayed answer,
ok to give some more details, im normal weight 165lbs, i live in a hilly city,so is mixed, lets say it this way, if i go from one city to another, that is 20km, i have 18km of flat more or less and 2km of uphill/downhill, moderate inclination

lipos
charger i have from rc, i would like to use 48v, that is 12 cells, my charger charges maximum 6 cells, so i can have 2x 6s batteries and i can charge them...but charger costs +-100$ and power supply from pc 10$ , and of course never leave them alone on charger
they are dangerues but if you are aware of danger always you wont have any problems

and they are cheap, you can change them once in a year and they are still cheaper and of course lighter than other batteries

my plan is to have 1000w 48v, and batteries 10000mah or 15
i want to achive +- 40-50km, and max speed is for now enough 40km/h

I have a bunch of lipos for rc stuff. They are fine to use just be a bit cautious with them as you said.

If you are after speed, you need to maximise voltage. If you are. Running a 48v controller you really want to run 14s for maximum speed for that system.

You can run 6s+4s+4s in series for 14s lipo.

Just make sure they are the same brand, capacity and discharge rating. And always make sure they are fully charged before hooking them up to the bike.

Under voting a pack will make it puff or worse. Given they wont have a BMS, you need to be careful not to run them too low. If the controller has a configurable low voltage cut off, set it conservatively.

Actually, the set LVC of most 48 V controllers is either 41 Volts or 42 Volts, which, when used w/ a 12S LiPoly string results in the cells stopping around 3.65 Volts. My experience is, this the level where the cells start to stray, usually downward. 48 Volt controllers and 12S are a perfect match and if one intends to use LiPoly in that general range, use a motor speed that gets the top speed desired on 12S(46.5 V Nom.). That usually means a geared motor, which are more optimised for lower Voltages than a direct drive motor.