I'd say what ever you decide to buy, the battery can be purchased with one of two mindsets:
A) Disposable, cheap, often replaced in 1 - 2 yrs with mediocre performance.
B) High entry price, high performance, last many years (even "dangerous
" LiPo can last many many years treated right!) 3 - 6 on average depending on quality of the cells, and how well treated they are, and yes, they aren't cheap! However, like most things in life, you get what you pay for.
The single best investment you will make for any E-Bike set-up is a good battery.
I have used high quality (not the what ever is cheapest) Hobby King Nano Tech LiPo batteries for 6 years now on multiple bikes, never had a single problem, not one puffed cell, only a couple days ago, one out of 8 bricks now has a weak cell (1 out of 4) and it's recovering nicely with some low amp charging.
However, LiPo is NOT half as user friendly as the average battery you buy.
#1 you MUST research and learn how to take proper care of them, because no matter the quality, if you abuse them sufficiently even once, they are very unforgiving, that said, I have used nothing more than a Cycle Analyst with a Low Voltage Cut-off, a rule of never using more than the top 80% of available capacity, and I never charge them above 85% capacity.
You will need to buy a good quality charger (don't forget to factor that into the cost of the batteries! most others have built in BMS, or are "smart" batteries that use "dumb" chargers, LiPo requires a "smart" charger), if you do not, you are playing with fire, not that it happens all the time, but I am not aware of any other battery chemistry that has resulted in more fires than LiPo.
However this is due to use of cheap low quality LiPo that is then often abused and or charged unattended (not as much a fault of the battery, but user error or dirt cheap low quality unstable LiPo, get what you pay for).
#2 Depending on how hard you run them, LiPo does not generally have as long a cycle life as other batteries, however see above and this can be an non-issue.
#3 LiPo IMHO is best suited to high powered maximum performance E-Bikes (read E-Motorcycles with out need for registration :wink: ) or for applications where light weight or extreme current draws are needed (your average hub motor will not tax the capacity of a good LiPo pack, so it's really a wasted effort IMHO unless you use it in the two above applications.)
If none of this is a challenge or barrier to you, I am someone with very limited electrical/electronic expertise, however with the help of experts here on this forum and using some common sense, I am sure you can use LiPo very safely and effectively!
I have used SLA's (GASP!
) LiFeP04, and LiPo and helped my father get into a decent Li-Ion pack (bottle battery) along with a customer or 2 using 18650 packs, and with the considerable improvements with 18650 Li-Ion, I cannot see a better choice for myself, remember, unless you're doing a pretty high powered set-up, or something requiring a very light small package with just a couple bricks of LiPo, you're not using half of the potential performance of that pack.
I really enjoy just having a good charger to plug into a decent pack with high amp charging capability and not have to monitor the charge like you do with LiPo.
That said, I was able to get nearly the same power density in a 72V 11AH 18650's as I have with my LiPo, fitting in the same amount of volume and weight with around 80% of the same capability at my current 25 amp controller, which is enough to get my 190lbs + 90lb Ebike up a 5% hill at 28 MPH (capable of 40 MPH on the flat). This is peaking at 1500W climbing that hill at speed, and cruising at closer to 250 - 300w on the flat.
I will have to test this new pack, but I expect about the same performance given my new 40A 72V controller (sold by the same company with a 6 mons warranty as a bonus!)
And just to give you an idea, with a cool running 91%+ efficient hub motor as mid-drive, (don't forget the cheap hub motors waste power making heat that would otherwise make you go faster or longer as they are closer to 80 - 87% efficient assuming they are running at speed that keeps them in their best efficiency, and that can happen while climbing hills OR on the flat, not both unless you sacrifice considerable speed for efficiency one way or the other) I am also able to get 20 - 30 miles range on that kind of battery capacity with moderate pedaling, and getting as much or little of a work out as I like.
P . S .
Don't be fooled by an apples to oranges comparison when looking at cheaper batteries, if the cells are low quality, 48v 20ah might not even equal the performance of high quality cells at 48v 10ah, go with something proven and known by other members' first hand testing. :wink:
And I would also so on average, you're going to get a lot more "bang for the buck" performance at 48v vs 36v with the batteries costing about the same, since you get more efficiency at higher voltage, meaning less current draw/waste heat = better performance all round.
Welcome to ES btw!
