bakaneko
Well-Known Member
street on a unrelated project. I might need to use a lipo battery. can you direct me to one that you use and trust? thx m8
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- Thread starter Vic
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street on a unrelated project. I might need to use a lipo battery. can you direct me to one that you use and trust? thx m8
Street Ryderz
Well-Known Member
The packs I showed in pic above are Hyperion cells they are great but a bit more in cost than others. There are Turnigy packs from Hobby King that work very well with good cycle life and are priced better!They also have a lower line called Zippy witch I beleive is just Turnigy's B grade cells getting sold at discounted price!I have built customer packs using these cells and have had no complants!
Steve Best
Well-Known Member
The very best Li battery chargers do have individual cell monitoring built into the battery pack, as the replacement motorcycle batteries do. The unit is called a BMS (battery monitoring system) and the bettter ones limit both charging and discharge. All Li batteries are very sensitive to charge and discharge rates and levels. If you go beyond their comfort limits you reduce the life of even ruin the battery. I don't speak as an expert, I am looking at getting into Li batteries instead of SLA (sealed lead acid) in my electric bike so I have been searching for info.
I just did a long spin around hilly Halifax on my Schwinn Izip last night and loved it, lead/acid and all. The 20-30 lbs of battery is noticeable, but so is the assist. Sure would like a Li battery in there...
(not my bike, web pict to illustrate)
The electric is much more acceptable in parks and bike-only spaces. It is also great for the assist to start away on steep hills. The electric is much better in towns and cities and is hardly noticed. Without a jack-shaft shifter an ICE powered bike is not very helpful in the downtown hilly city, and seems to annoy too many people when running.
I just did a long spin around hilly Halifax on my Schwinn Izip last night and loved it, lead/acid and all. The 20-30 lbs of battery is noticeable, but so is the assist. Sure would like a Li battery in there...
(not my bike, web pict to illustrate)
The electric is much more acceptable in parks and bike-only spaces. It is also great for the assist to start away on steep hills. The electric is much better in towns and cities and is hardly noticed. Without a jack-shaft shifter an ICE powered bike is not very helpful in the downtown hilly city, and seems to annoy too many people when running.
Street Ryderz
Well-Known Member
Here is one of the biggest bms available and you can see that it does exactly what I said it monitors the first 24 cells in series then all the cells that are added on in parallel are seen as the cell they follow from the series curcit!The very best Li battery chargers do have individual cell monitoring built into the battery pack, as the replacement motorcycle batteries do. The unit is called a BMS (battery monitoring system) and the bettter ones limit both charging and discharge. All Li batteries are very sensitive to charge and discharge rates and levels. If you go beyond their comfort limits you reduce the life of even ruin the battery. I don't speak as an expert, I am looking at getting into Li batteries instead of SLA (sealed lead acid) in my electric bike so I have been searching for info.
I just did a long spin around hilly Halifax on my Schwinn Izip last night and loved it, lead/acid and all. The 20-30 lbs of battery is noticeable, but so is the assist. Sure would like a Li battery in there...
(not my bike, web pict to illustrate)
The electric is much more acceptable in parks and bike-only spaces. It is also great for the assist to start away on steep hills. The electric is much better in towns and cities and is hardly noticed. Without a jack-shaft shifter an ICE powered bike is not very helpful in the downtown hilly city, and seems to annoy too many people when running.
all the cells that are added in parallel to get a higher ah capacity are NOT individualy monitored!
- Do not use for battery packs that mix with new & half-used, or mix with different brand battery cells.
- Do not use for used and imbalance battery cells.
- Do not use for batteries with fake capacity.
- Do not touch the board by hand while it is charging / discharging.
- If you charge the battery by Lithium Balance Charger, then there's no need to use BMS.
Steve Best
Well-Known Member
Correct me if I am wrong SR, but the BMS is often built into many of the battery packs isn't it?
My Walmart Li battery booster has this on board so you just need to feed it unregulated 12-14v.
I'm using these to power a small foldable bike.
My Walmart Li battery booster has this on board so you just need to feed it unregulated 12-14v.
I'm using these to power a small foldable bike.
Street Ryderz
Well-Known Member
I love that folding rig! Yes many if not all should come with a bms!The problem is that the bms is really just to make it consumer freindly not to actually get the best life from the cells.The bms looks at the voltage of the first cell in the parallel bank so if one of the cells in the row start to go bad the other remaining cells in the row have to make up the difference of the bad cell witch in turn starts to kill off the whole row until combined they all show as bad to the bms so instead of having to replace one bad cell at 4 or 5 bucks you have to replace the whole bank more like 30 bucks or more depending on the capacity being used!I dont know about using an unregulated power supply as these cells dont like to see any ac ripple and will kill them quick!With a 12v pack thats only 3 cells for the voltage when using the most comen 18650 cells and then however many added in parallel to get the capacity so the bms can be very small since really it's only monitoring 3 cells the discharged voltage will be 11.1v and fully charged at 12.6v thats a very small window of 1.5v and going below the cut off or above the peak v also kills the cells very quickly that's why they need a bms to make it consumer freindly or every one would be returning their li powered products saying they dont work!
KCvale
In memory of KCvale 1959 - 2019
So you pull out each cell and charge them individually?
It all comes down to what LI batteries you are using to make your pack.
~3.6V 18650 LI batteries make for a great pack.
Each cell has it's own regulator inside on the - end, you can put them in series and they self balance, I discovered this when trying to solder a lead to one and the bottom came off revealing the tiny circuit board.
The Battery Management System (BMS) inside the pack keeps all the parallel sets of serial cells balanced during use and during charging.
https://lunacycle.com/triangle-52v-panasonic-pf-18650-20ah-pack/
This ~1KW shifting build from '14 is still on still on the road and no hassle to charge..
In short, street is wrong.
Good 18650 cells and a BMS make for great battery pack.
Street Ryderz
Well-Known Member
KC you don't know your self what I'm refering to so how can you say I'm wrong? If you understood what was going on in that board you wouldn't be saying anything!I posted the schematic it's pretty simple the voltage is read across the series cells nothing else!The pack you put a link to is a 14s 7p arangement that's 98 cells total and the pack has a 14cell 52v bms so how is it reading the other 84 cells? Is there wires leading to all those other cells NO!And the cells with the pcb ends are not meant for high output uses like ev's!I was talking about li-po cells not having a bms built in and had showed my 52v li-po pack set up that with wires was only 5 lbs big weight advantage with higher cycle life because each cell get's individually monitored!So you pull out each cell and charge them individually?
It all comes down to what LI batteries you are using to make your pack.
~3.6V 18650 LI batteries make for a great pack.
Each cell has it's own regulator inside on the - end, you can put them in series and they self balance, I discovered this when trying to solder a lead to one and the bottom came off revealing the tiny circuit board.
The Battery Management System (BMS) inside the pack keeps all the parallel sets of serial cells balanced during use and during charging.
https://lunacycle.com/triangle-52v-panasonic-pf-18650-20ah-pack/
This ~1KW shifting build from '14 is still on still on the road and no hassle to charge..
In short, street is wrong.
Good 18650 cells and a BMS make for great battery pack.
KCvale
In memory of KCvale 1959 - 2019
Apparently not.
I just can't my head around how you can individually charge 70+ batteries from a single 2 lead charger input.
[ quote]
If you understood what was going on in that board you wouldn't be saying anything!
I posted the schematic it's pretty simple the voltage is read across the series cells nothing else![/quote]
I have not seen the schematic, but I am a degreed Electronic Engineer so I can certainly understand it ;-}
Ohh for heavens sake...
I'll leave it at that ;-}
Cool, best of luck with it.
This is where I got a few big packs from.
https://em3ev.com/shop/50v-14s9p-large-triangle-pack/
The BMS is not just for charging, it is for discharging power to the motor.
From their site...
"BMS Protection Current >100A.
This is a very robust BMS, that can deliver around 40A continuous, but much more for extended bursts."
In short, I won't buy or build a battery pack without a BMS in it.
Street Ryderz
Well-Known Member
I have not seen the schematic, but I am a degreed Electronic Engineer so I can certainly understand it ;-}
Ohh for heavens sake...
I'll leave it at that ;-}
Cool, best of luck with it.
This is where I got a few big packs from.
https://em3ev.com/shop/50v-14s9p-large-triangle-pack/
The BMS is not just for charging, it is for discharging power to the motor.
From their site...
"BMS Protection Current >100A.
This is a very robust BMS, that can deliver around 40A continuous, but much more for extended bursts."
In short, I won't buy or build a battery pack without a BMS in it.[/QUOTE]
Li-po packs have balence leads to each and every cell individualy monitored and need a balencing charger to do it!If you read the posts that was covered!As I said my packs can deliver over 200 amps continuous and 325 amp burst and actually get 800 + cycles!The current and peak limits of the pack dont mean s**t if the controller only pulls 25-30 amps like most do, I have customers using 100+amp controllers and this is where cell quality shows up quick the packs you are using are not even close to capable of such a high discharge rate and be able to get more than a few full capacity cycles from!
