ali express LIFEPO4 packs

[curtis]

I was wondering if anyone out there are running LIFEPO4 packs around 20 Ah and ordering from ali express.

I was going to order a spot welding machine and build my own and still might but looking at Christmas or January for a winter project.

Right now I am interested in ordering one already built. I have been looking at several a couple 25 AH but the one that has the best discharge rate is a 20 Ah pack. It is also about $70 less than the 25 Ah pack so looks like it will meet all my 48V needs. I have an ebiike with a 1,500 watt hub in the rear with a 30 amp controller as well as a front 1,000 watt Unite chain drive also with a 30 amp controller.

This battery can do 60+ amps continuous and should easily do at least 15 miles on a charge. However I would like to know if anyone here has bought one like this and can tell me if it meets the specifications as advertised.

1. It is built in high quality 48v 50A BMS manfactured by IC and MOS from Japan .

2. It is built by Improtect brand 3.2v 20Ah lifepo4 Prismatic 5C high drain 100A cells with only 1 ohm internal resistance .

3.support 1000W, 1200w, 1500w ,2000W motor

Specification:

• Voltage: 48 V
• Capacity: 20 AH
• With Built-in High quality BMS ,Battery have overcharge, over discharge, over current, short circuit, charge equalization of automatic identification and protection circuit.
• Battery Size :260*200*100 mm
• Type :LiFePo4 Battery pack
• Weight: 7.6Kg
• Standard Charge Current 5A
• Max Charge Current 30A
• Max Charge Voltage 58.4V DC
• Battery Resistance ≤10mΩ
• Rated Discharge Current 50A
• Max continual Discharge Current : 62A ( can be customized)
• Pulse Discharge Current : 200A
• Discharge Cut-off Voltage :42.5V
• Charging method : CC/CV(Constant Current Constant Voltage)
• Lifecycles : More than 6000 times .

Please post if you can. Someone / anyone.


Thanks.

Curtis out.

 

[fabbrisd]

LiFePo4 (shortened to LFP often) is more "popular" for PEV's in China - especially for use for swap-out battery "rental programs there".

Here in US - "Lithion Ion" cell have been prefeered up to this point - if for no other reason than Lower Battery Weight.

Frankly Battery/Chemistry will be more of a subjectg going forward (NMC-LCO, etc).

For now if it was me - if I was building a battery for a Mobility Chair LiFePO4 - if for a eBike Li-On.

 

[m@Robertson]

LiFePO4 (Lithium Iron Phosphate) can be left in a high state of charge for long periods of time without damaging the cells the way it does for the common Li-NMC 18650's and 21700 packs we usually use on ebikes. Also, the 800 cycle lifespan bandied about so often for Li-NMC is instead 2000 to 3000 cycles for LiFePO4. Lastly, LiFePO4 doesn't go boom or burn like LI-NMC does.

Sounds perfect, right? Except LiFePO4 has lower energy density than Li-NMC. So that means to get the same battery capacity you have to use more cells. Which means the batteries are BIG and HEAVY. Which nixes them for all but specialty bikes that can use such things.

Another thing worth mentioning: I have heard of LiFePO4 packs advertised on AliExpress/Baba, that when they showed up used Li-NMC cells inside. AliAnything is the last place I would buy a battery. A 20ah battery with a continuous 62a BMS and a 200a peak? And it can take a 20a charge current? Oh and it only costs $224? Not a chance those specs are accurate.

 

[curtis]

2. It is built by Improtect brand 3.2v 20Ah lifepo4 Prismatic 5C high drain 100A cells with only 1 ohm internal resistance .

The battery is the GTK name brand. I have been researching that company. I really need a 20 Ah pack < 20 ponds.

I am not concerned as much about charge current as I am in discharge current. I really need 60 amps for dual 30 amp controllers.

Ni-Mn-Co Battery​

Ni-Mn-Co is a type of lithium-ion battery that uses nickel, manganese, and cobalt as its main materials. They are suitable for applications where high capacity is required, such as electric vehicles, power tools, and consumer electronics.

NMC batteries have a nominal voltage of 3.6v per cell and have good power performance due to their higher operating voltage compared to other chemistries. NMC batteries typically have about 500-700 cycles at 100% DOD, making them half as durable as LFP battery.

If Ali express is selling NMC batteries and advertising them as LIFEPO4 then that seller needs to be shut down. Not only is NMC only half as good as LFP but also prone to thermal runaway like lion and LiPo so makes it a safety risk as well.

If an NMC cell is punctured or damaged, it can easily catch fire. This poses an enormous fire risk in landfills and recycling facilities, where fires can quickly spread to other combustible materials. To make matters worse, NMC contains cobalt — a rare metal that is mined largely in Africa. Because of its high toxicity levels, environmental groups have raised concerns over the negative impact this has on miners and local communities.

I need to thoroughly investigate Ali express and the MTK battery before ordering. If the battery is a scam and advertised specifications are a big lie then it will be a big set back to me as I really need a 48V 20 Ah LIFEPO4 battery that can do 60 amps.

lion and LiPo is really not something I want to go back to. I prefer 5 to 6,000 charge cycles over 800 to 1,000 and about 5 times faster charging. The last lithium ion pack I bought a few years ago was 20 Ah and 13S 7P. It was 1,200 watts and had a 30 amp BMS. It was around $200.

It would take two of those 13S lion packs to do 60 amps which would cost almost double. Also two 13S 7P Lion packs will probably weigh more than the 20 Ah LFP pack.

The other thing is there is way too many no name brands of lithium ion. They are dangerous and not worth burning up over or losing your house. If you are lucky it will happen outside and only lose your ebike. I just can not bring myself to go backwards and order lithium ion , LiPo or SLA.

I wont be able to order anything until next week on the fourth of October. I pay my rent on the third.

Any more feedback before that will be appreciated. If there is an alternative and someone knows of a better deal besides Ali express or someone knows someone who bought one of those MTK batteries please let me know before October 4.

Thanks.

Curtis out.

 

[HumanPerson]

Here you go, https://www.ebay.com/itm/3860162345...66UmMYUBYOcfEDbGufndMMZA==|tkp:Bk9SR7rPzt_aYg

 

[m@Robertson]

Here you go, https://www.ebay.com/itm/386016234526?hash=item59e05c4c1e:g:R3UAAOSwY05kOQyi&amdata=enc:AQAIAAAA8Hxbc54OCx03AEuIZ62l1eWtzdCf8HfTARLiZwtugu/DyMiHiw9RspFCxnIijvS3JilSHyYMEdQ3A4opr5m3xePNzJX9mavMuoBSCx/EQGLCiy5qC02hSDRIuFU+lKuO7gj7CMBrfBWfYvBt7z3hmPrhCVcfIDT9D0GzzOG+R+8XeuZuw+vs+vRRcafHmDu4zHlqAGFpbEaj13szjZdDN07oCdOWSrzAgQCmh6nyWTMZ5lMQkpJH7ErRQgtauyQtLRB+JVabYZb0v26WTZAjssD3v4Vc30e0+WfpG1GxyR66UmMYUBYOcfEDbGufndMMZA==|tkp:Bk9SR7rPzt_aYg

This is a little more like it. BTRPower generally has a good rep, although I have seen one complaint of Li-NMC being what they sent when LiFePO4 was ordered. If it were me I would buy the pack from Amazon where there is an Amazon return/replacement guarantee.

Amazon.com

But that BTRPower pack - which is the same one from either EBay or Amazon - only has a 40a continuous output BMS. 80a peak, but you can't use the peak number when matching to a controller.

AliExpress has vendors who BS battery specs. They don't get shut down and thats just the way it is. Its a vending channel with absolutely zero accountability once you get past the escrow process.

@curtis all that stuff you are quoting is just advertising and none of it can be verified. On a platform infamous for shenanigans. The specs you are quoting are not believable. Also GTK Power only has a 90.1% review rating which is unimpressive even by the lower standard you have to hold AliExpress vendors.

 

[m@Robertson]

I am not concerned as much about charge current as I am in discharge current. I really need 60 amps for dual 30 amp controllers.

The point was that was an obviously false specification. 30a of current on any 20ah battery is not feasible. To get 30a you'd have to be using your dryer plug and 220v from your garage, to give you an idea how much power that is. And even then you'd be redlining that 30a plug. To think that a battery could take that is nonsense. They're playing people who don't know any better for suckers.

 

[curtis]

"The point was that was an obviously false specification. 30a of current on any 20ah battery is not feasible. To get 30a you'd have to be using your dryer plug and 220v from your garage, to give you an idea how much power that is. And even then you'd be redlining that 30a plug. To think that a battery could take that is nonsense. They're playing people who don't know any better for suckers."

Did you mean 60 amps ?

I bought that same battery about 4 years ago but only had a 30 amp BMS. I stopped running lion due to the safety factor and way less charge cycles than LIFEPO4.

Since LIFEPO4 is known for greater discharge than lion / LiCo then a 20 Ah LIFEPO4 pack pushing 60 amps does not seem impossible. I know for a fact A123 - 26650 cells can do 50 amps and that is at 1P. I built 8P packs I am currently running.

The GTK cells in the pack are advertised as prismatic cells not 26650 cells so the big question is are they genuine LIFEPO4 or those dangerous Li-NMC cells.

The BTRPower pack wont work as I need 60 amps. What about these.

I bought piss poor used 8 Ah cells from Battery Hookup awhile ago for $5 each. They were advertised for 80% capacity and less than half were around 40% the rest around 60%.

I never bought brand new Headway though. It will still cost me > $300 for 20 Ah though as will need 16S - 2P. I will also need a 60 amp BMS and could throw in a 5 amp active balancer. The problem is it is way out of my budget.

That is why I was hoping someone has ordered a GTK battery. I really am getting disgusted. I have about 6 e bikes and only a couple of batteries which I built from used A123 cells from Battery Hookup.

I have two 5S - 8P and a 7S - 8P. Also a 3S - 3P pack from piss poor 8 Ah used and abused Headway cells. Why I went 3P.

I can run 43V or 56V but too heavy for my 700c Giant and 27.5" full suspension. Also I want a single pack for 50V instead of having to hook up three packs in series. I have a 20" ebike with an 1,800 watt motor and 38 amp controller which handles the weight of 17S LFP as lower center of gravity vs a 700c or 27.5" bike. It is why I want the factory made battery.

Also I do not run a BMS on those I built. I externally balance but only good for short trips as if I go too far without BMS protection the cells run too low and have even had a fire with Headway cells reversing polarity and caught a 12S active balancer on fire. The case was plastic. I simply placed a pail over it and put out the fire as LFP wont burn with no oxygen. LiPo Lion and Li-NMC will burn under water as does not need external oxygen.

I got lucky on a batch of 168 cells awhile back as they had nickel tabs to solder to. The last batch did not and solder wont stick. I was thinking about ordering a spot welder but have heard that they are very unreliable and break. That goes for the cheap portable units as well as the AC spot welding machines.

Thanks.

Curtis out.

 

[m@Robertson]

Did you mean 60 amps ?

No I meant 30. The charge current they claim on your battery in Post #1 is impossible. It says it is capable of taking a 30a charge current, which is ridiculous. Its what a 13S6P pack? 7P? 8P tops. Claiming you can charge anywhere near 30a is laughable. If the seller lying is easy to spot there, what else are they lying about that isn't so obvious? Probably a lot so run in the other direction.

All of my packs that can take big power are custom builds. You can't expect top level performance from a crap bottom-of-the-barrel Far East supplier. My daily driver is a 35ah 14S 21700 pack with a 100a continuous BMS, I have another on a different bike that is 14S, 32ah 21700 with a 70a continuous BMS. These are 2wd bikes with dual motors running together so my amp draw is strong. Because of the quality issue and the danger of using BS suppliers, I only use a USA seller with a stellar reputation in the community, who makes them to order in the States - even the off the shelf ones from his catalog.

The two above were from Bicycle Motorworks. Before that it was Hi-C Battery. In between I have had some off the shelf packs from BMW that do 50a each, and I parallel them directly which boosts the effective amp capacity well beyond my needs, which are in the 50-55a continuous range, so no matter what I am operating with a fudge factor that will not let a BMS pop and send me walking.

You pay more, but you get f**ked in the ass less, and you burn your garage never.

Based on your posts above it sounds like you've been around enough to know these risks exist. So... caveat emptor and good luck I guess

 

[curtis]

What is your opinion on those 10 Ah Headway cells listed as brand new ?

That is my alternative. I could order 16 in October and run them and if they perform good and have decent capacity then I could order 16 more in November.

I have two 8S 1.2 amp active balancers to hook up but no BMS. I was thinking of two 8S packs one on each side of the bike triangle. I built a bracket that goes over the bottom bar for lower center of gravity.

I could order two 80 amp 8S LFP BMSs in November and still run the active balancers.

Please let me know.

Curtis out.

 

[curtis]

"Claiming you can charge anywhere near 30a is laughable. If the seller lying is easy to spot there, what else are they lying about that isn't so obvious? Probably a lot so run in the other direction."

Yea. I agree. Anything from China is SUSPECT. Could be SHADY or an outright scam. I get it.

COULD BE.!!!!

I respect your opinion , but looking for further information / investigation. I was hoping someone somewhere already ordered and run them so we can all

( anyone interested )

Know you are correct for a fact. That way nobody gets ripped off.

Or on the other hand they are half way decent,

Maybe not exactly as the specs advertised but close. Maybe a good deal.

Been looking on Youtube as a lot of videos there on ebike batteries , ebikes , even spot welders , ect. The main thing I would like to know is are those batteries in question genuine LIFEPO4 or that FAKE inferior Li-NMC chemistry that could be a fire hazard like lion or LiPo. That kind of s**t NEEDS TO STOP! Those sellers need to disappear.

I bought a 15 amp 54.6V dedicated 15S LIFEPO4 charger about 3 years ago after ordering 24 LTOs for $640
54.6 / 20 = 2.73V. < the 2.8V maximum charging for LTO. The best chemistry available so far today.

50V - 20S LTO. Lishen 18 Ah. 900 grams each cell so about 45 pounds for 50V and over 50 pounds for 60V.

Smoke any 2700 or any battery including Telsa cells. Looking at 400 continuous amps for each 2.5V cell.

Looking at the Currie 24V 900W motor. Two in the back and one up front. Single Kelly controller. They make a 100 amp for less than $100. 10 LTOs are 25V and < 20 pounds.

Thing is I don't have the $$$$$$ to fund such a project. I already own a 1,500W 48V hub kit currently installed on a 27.5" full suspension.

Also a 60V 3,000 watt brushless chain drive with 70 amp 3 kilowatt controller all still in the box. Bought it back when stimulus checks were sent. LOL

Then the 1,800W brushless motor on a 20" ebike. I run that with 56V - 17S LIFEPO4. 8P A123 cells. Used from Battery Hookup.
They were used and already put 500 to 1,000 cycles on them and still running strong.

My biggest regret to this day is not installing a 1,000W brush Unite up in the front of that and gearing the bike for around 40 mph. LOL. It is currently geared for about 35 mph.

I am researching my options for new batteries.

could order a spot welder and start building with the cells I got and order more.
or
those 24V packs from Battery Hookup.
or
Those brand new 10 Ah Headway
Or
the pack built in the far east. LOL.

I have 5 days to make a decision.

Thanks.

Curtis out.

 

[HumanPerson]

Curtis,
Please just be careful, ok mate..

Stay Safe man!!

 

[ElHegpah]

Curtis, you tend to rush into things. That is why you make a LOT of poor purchasing decisions. I remember you started this whole adventure buying the WRONG replacement motor for your original Currie drive. But, you made it work, not as well and needing extra parts and time and effort and money, but it DID work.

Take your time, consider your options, do it Better AND Easier.

Those Headways are easy to assemble, though I thought they went belly-up several years ago. Lifepo4 is VERY forgiving and much safer, I agree.
Important not to over-tighten the connector bolts. Can ruin the cell.

I would not trust anything off Alibaba or Aliexpress, total crapshoot.

 

[m@Robertson]

What is your opinion on those 10 Ah Headway cells listed as brand new ?

Please let me know.

This isn't something I have any direct experience with, so my opinion comes as another self-appointed internet expert who doesn't actually *know* what he's talking about.

With that said, the seller has a 100% rating and is in the USA, so thats a good start in terms of the seller (only). I'd trust nothing that comes from any of the Ali's on general principles. Ebay is a close second in terms of trust, but its not a hard always-no.

 

[curtis]

I was at a friends house last night. I put a 350 or 500 watt rear Bafang hub on the back of his beach cruiser a couple weeks ago and he needs batteries. Like me he is on disability so on a budget. He can not afford $200 + for a battery. Also he is not at all computer smart and not capable of ordering anything himself.

Next week on the third I will order four of those 24V LIFEPO4 batteries from Battery Hookup rated at 9.6 Ah. I will use two and hook the other two up for him. I could order a 48V charger but not knowing if they are equal as used cells I am thinking I should order 4 small 24V - 2 amp chargers.

I will have to teach him how to hook up and charge each battery separately so they are always equal and discharge equal. He will pay me the money for his two batteries and then I might order a spot welder. I need a good one. I got at least 50 - 26650 cells from Battery Hookup and still have a box full of lithium ion 18650 cells also used from either Battery Hookup or Battery Clearinghouse.

I do not want the 18650 cells but could build them and sell them cheap to somebody. I will install them in an Ammo box. Hell I might just run them myself as I have a full basement with a cement floor. I could put a metal garbage pail over them or keep them in a charcoal smoker grille. LOL. I could even order LiPo but the price on them went way up.

"I remember you started this whole adventure buying the WRONG replacement motor for your original Currie drive. But, you made it work, not as well and needing extra parts and time and effort and money, but it DID work."

It ran perfect for close to two years but when I moved to a second floor apartment it was too heavy for the stairs so took the motor off to install it on a 20" bike and broke the magnets hitting it with a hammer. I have had several motors on it since then and am looking at sanding / stripping the frame this winter and ordering brand new stickers and paying someone better at painting than me to do the job.

Then I might put two 900 watt Currie motors in the back and one up front with a 100 amp Kelly controller and 10S - 25V - LTO. I will build two so I have a back up. 18 Ah @ 25V should work for 8 to 10 mile trips. I will need to build more LFP - 8P packs from A123 cells for longer distance as the ones I am currently running have a lot of cycles on them and were used to start. I hit 32.5 mph with the 1,800 watt brushless motor and 33.5 mph with my brand new 1,500 watt hub kit on my dual suspension. With newer batteries both e bikes should hit 35 mph easily. I could run 22S - 55V LTO but way too heavy.

I am glad we go back that far. I consider you a friend as you have followed my adventures and mis adventures a lot of years now. My original post got shut down by bully's over on ES. I have many new posts on several forums and they do not know me on ES any more. I have a totally different profile there but still post regularly.

I got my phone stolen and need a card to make my camera work. I have six e bikes I am working on. Three need new tires and am getting brakes hooked up on one I plan on running soon. It has a 750 watt gear reduction motor chain driven in the rear and 350 watt Bafang up front. It works off a single throttle and can run at 36 or 48V.

I hope you guys keep posting. I will be building e bikes and batteries as long as I am above ground. I am hooked for life.

Thanks.

Curtis out.

 

[ElHegpah]

First post I read there was your #1. Read pretty much the whole saga.

They finally shut you down, eh? Had my own issues with management there. Can't say I miss it.

On your friend's battery, get the 48V charger and a decent BMS. Much safer.

 

[curtis]

"On your friend's battery, get the 48V charger and a decent BMS. Much safer."

Thing is when dealing with Battery Hookup you probably have the same cells but some battery packs might have a longer shelf life or different batch of cells with maybe more charge cycles than the other battery pack. They even say sometimes that it is a mixed bag.

Parallel charging could work using a 5 or 10 amp charger but the BMS is typically 1.2 amp for balancing.

Unless a 5 amp active balancer is deployed with a BMS then a 1,2 to 2 amp charger is better so the pack is balanced.

Each 24V pack comes with a BMS already installed. Probably 1.2 amps. I am not installing a active balancer. That is a fact.

If one pack is greater in capacity than the other , series charging will eventually , after a few cycles leave one battery at 10 to 20% and the other 70 to 80%. It could even get worse than that. Parallel charging both 24V batteries can help but with seperate BMSs take time to equalize.

The bottom line is separate charging with identical chargers make sure you get the greatest capacity possible from each pack.

I know this as when running 43V I have two identical 5S - 8P A123 - 26650 packs. They charge IN SERIES with 3S 3P used < 1/2 capacity 8Ah Headway cells. 13S - 43V. 3.3V * 13 = 42.9V. I get 4 or 5 charges with my 43.6V dedicated LIFEPO4 charger.

43.6 / 13 = 3,35V

I have to separately charge after 3 or 4 cycles with my 6S LiPo chargers. I can do the two 5S - 8P in parallel with my 400 watt Mega charger. The 3S - 3P Headway with my 200 watt Sky charger. Amps can start at 3 but only 75 to 80% capacity. changing setting to 1.5 amps yields close to 90% capacity.

Not saying I am an expert on charging but I learned a thing or two by building custom DIY packs for years. Looking at 2 chargers and two of those 24V LIFEPO4 batteries next week for my friend.

I will get his bike running great as 24 amp battery and 18 amp controller. He will pay me and then I will order a decent AC spot welding machine. I will then build packs with much greater capacity as still have the 3 kilowatt brushless motor and 70 amp BOMA controller brand new in the boxes to deal with.


.Thanks.

Curtis out.

 

[curtis]

"No I meant 30. The charge current they claim on your battery in Post #1 is impossible. It says it is capable of taking a 30a charge current, which is ridiculous. Its what a 13S6P pack? 7P? 8P tops. Claiming you can charge anywhere near 30a is laughable. If the seller lying is easy to spot there, what else are they lying about that isn't so obvious? Probably a lot so run in the other direction."

2. It is built by Improtect brand 3.2v 20Ah lifepo4 Prismatic 5C high drain 100A cells with only 1 ohm internal resistance .

Doing an Ai search I came up with this.

Generative AI is experimental. Info quality may vary.

The Improtect brand makes 3.2v 20Ah LiFePO4 prismatic cells with the following specifications:

• 5C high drain
• 100A cells
• 1 ohm internal resistance
• CCCV charging method
• Constant current of 0.3C
• Constant voltage of 3.65

As far as 26650 cells in a 6 , 7 or 8P pack here is the specifications for the single cell.

Nanophosphate® High Power LithiumIon Cell ANR26650M1-B

Recommended Standard Charge Method 2.5A to 3.6V CCCV, 60 min

Recommended Fast Charge Method to 80% SOC 10A to 3.6V CC, 12 min

I built and am currently running A123 packs. I have two 5S 8P and a 7S 8P. I charge them separate with a 6S LiPo charger.

For the 7S pack I charge at 6S LiPo setting which is 4.2 * 6 = 25.2V. 25.2 / 7= 3.6V. I usually charge at about 6 amps to take it easy on the chargers. 5S LIFE @ 6 amps for both 5S packs in parallel with my 400 watt Mega charger and 3 amps with my 200 watt Sky charger for the 7S pack. I have also charged 43V LIFEPO4 10S 8P A123 in series with old used 8Ah HEADWAY 3S - 3P with a 10 amp 43.6V charger and the 15 amp charger when I ran 15S LIFEPO4 about a year and a half ago.

Unfortunately my 15 amp 54.6V charger wont charge a 16S pack to 80% as 54.6 / 16 = 3.412V. I still can charge from 20% to about 70% at 15 amps and then plug in the 58.8V charger that comes with the pack to get up to 80 or 90% when out on the road.

I have been looking at 20 Ah cells from other companies besides GTK and see similar charging specifications.

Here is the specs. on Topband cells made in the USA.

This specification defines the performance of rechargeable LiFePO4 battery pack TB12200F-SC-S110A manufactured by SHENZHEN TOPBAND LITHIUM BATTERY CO.,LTD describes the type, performance, technical characteristics, warning and caution of the battery pack. 2. Battery Specification（@ 25±5℃） NO Items Characteristics 2.1 Normal capacity 200Ah 2.2 Nominal energy 2.56KWh 2.3 Nominal voltage 12.8V (LFP-4S) 2.4 Internal resistance ≤20mΩ @1kHz AC 2.5 Normal charge voltage 14.6±0.2V 2.6 Float charge voltage(for Standby use) 13.8±0.2V 2.7 Allowed MAX charge current 200A 2.8 Recommended charge current ≤40A 2.9 Allowed MAX discharge current 200A 2.10 End of discharge voltage 10.0V 2.11 Dimension Length 485±2 mm Width 170±2 mm Height 241±2 mm 2.12 Weight (No accessories) About: 24.5Kg 2.13 Operation temperature Charge 0～45 ℃ Discharge -20～60℃ 2.14 Self-discharge rate Residual capacity ≤3%/Month ; ≤15%/ year Recover capacity ≤1.5%/Month ; ≤8%/ year 2.15 Storage environment ≤1month ：-20～+60℃、5～75%RH ≥3month ：-10～+45℃、5～75%RH Recommend environment 15～35℃、5～75%RH 2.16 Series connection spplication Support series connection Version：V00 Page 4 of 7 3. Electrical Characteris

Recommended charge current ≤40A

LIFEPO4 can charge at a much greater rate than lithium ion or LiPo. Only LTO can charge at a higher current than LIFEPO4. It is one of the main reasons I like to run LIFEPO4 vs Lion/LiPo.

I was thinking about ordering 25 Ah TOPBAND cells and building my own pack but will cost > $320 just for the cells.
The GTK pack comes with a charger and a BMS installed and is $100 less.

I am still thinking about ordering it from Aliexpress. 16 of the 25 Ah TOPBAND cells weigh 25 pounds + hardware and wiring. The GTK pack weighs < 17 pounds.

7.6 Kg = 16.7551 lbs.

I am still researching the GTK company.

Any feedback is appreciated. I have been weighing my options. I have searched extensively for many hours / days.
I have a power meter that measures amps , watts and volts. I also have two 30 amp controllers on my full suspension.

I am wanting to place my order tomorrow but still have my doubts.

m@Robertson is saying 30 amps charge is impossible but LIFEPO4 specifications for both prismatic and 26650 cells in 4 to 8P configuration says 30 amps will work.

TOPBAND 40 amps

A single A123 26650 cell 10 amps

Here is 8Ah HEADWAY specs.

I think m@Robertson might have thought it was Lion or LiPo. Not sure as he runs lithium ion I think.2700 cells. I know Lion and LiPo as well as SLA have a 1C charge rate I think so for 30 amps a 30 Ah pack is required and 1/2C is recommended for longer pack life. LIFEPO4 has much higher C charge and discharge rates up to 5 to 10C on some cells. I wont ever go that high. 1C for a 20 Ah battery is 20 amps right ?

I am not trying to piss anyone off here. I am just interested in the facts. I also want a pack that will push 60 amps discharge and 20 Ah capacity for the cheapest possible price. I cold run 45 pounds of LTO for 55V and 22S. I would rather not have a bike that heavy. I could also run lithium ion 18650 cells but rather not deal with 1,000 or less charge cycles and possible thermal runaway / fire / total disaster. I could order LiPo and get an ammo box.

I could but rather have a 20 Ah LIFEPO4 pack that will last for years and years and discharge at 60 amps and can use my 15 amp 54,6V 900 watt charger to get it to 70% then switch to the 5 amp 58.8V charger.

If I do get it and get ripped off I will post a youtube video and post a really bad review. I will not accept 1/2 my money back or a return. I will rub the sellers name in the mud. I just hope it will not come to that.

I have looked and looked and do not see any cheaper deal for an assembled 20 Ah LIFEPO4 pack with a 60 amp BMS and even a 5 amp charger.

Feedback is important to me and if anyone has more information on these GTK batteries or knows anyone who bought any

Please let me know.

Thanks.

Curtis out.

 

[m@Robertson]

You are over-analyzing this and trading Google AI (!) searches for experience.

As I originally said, it is impossible to have a pack that charges at a rate of 30 amps, and a smart shopper who realizes this should also realize they are being bulls**tted in other ways. Forget all that battery spec word salad. Just think about this: The only 30a current that is even possible to deliver is through a 220v dryer plug in your garage. Its THAT much current. And if you pull a full 30a from that plug its likely to blow a breaker. Even the home charge for an electric CAR is typically less than 30a.

Even if a home was able to deliver the current, all the spec sheets in the world will not change the fact that 30a is WAY too much to try and feed a bicycle-sized pack. And its not even a big one. A mere 20ah.

I'm not unaware of LiFePO4 in the least. My home solar system uses over 9kwh of it, and my portable (barely) SoGen has another 2kwh. Yeah you can feed it a lot. My 9kwh system eats about 15a. But that is Nine Kilowatt Hours worth of battery. EDIT: I just checked the system specs, it maxes at 24 amps.

If you are smart, you will STAY AWAY from AliExpress batteries. You are focusing on the wrong thing with respect to a battery, which is price. Those of us who have been around for awhile have seen countless people prioritize cost over quality and accountability .. and watched people pay the price for it. Don't be Yet Another One.

This is worth a read. Not for any details about battery chemistry, which frankly don't matter when you start looking at a bigger picture.

What to look for in a battery?

What should i look for when purchasing a new battery? I’m looking for 48v 24.5amps. Prices on Alibaba seem to range from $500-$700. What is a mark of quality when looking at batteries?

ebikesforum.com

 

[curtis]

I probably wont order anything this month. The TOPBAND cells made in the USA are probably the best deal. The HEADWAY packs might be ok too.

My full suspension with the 1,500 watt hub in the rear and 1,000 watt chain up front is currently set up to run heavy 45 pounds to 50 pounds of LTO batteries. I really want 22S - 55 working volts but only have a 54.6V charger. That will do 20S for

54.6 / 20 = 2.73V. 2.8V is maximum.

I was looking for a lighter pack for my Giant Roam. There is a 700c - 1,500 watt hub kit for that about $220. I wanted to go with a lighter LIFEPO4 battery < 20 pounds. The bit power packs sold on ebay and Amazon are like 18 pounds and have a 40 amp BMS. The 700c 1,500 watt motor has a 45 amp controller in the specs but probably will only push 35 to 40 amps tops.

52V * 40 = 2,080 watts so the bitpower pack should be a perfect match. I might order that but not enough $$$ this month. I need to pay off my electric and gas bills so I am caught up. $220 is about my maximum budget for this month. The bitpower battery is about $280. Why price matters to me. I am on disability and my $$$$ must last all month.

The 1,500 watt motor on the full suspension is only 30 amps. It says 48V and 1,500 watt on it but everything else is Chinese. The fuse inline is 35 amps. The advertisement states 30 amps. I wanted all wheel drive for off road so installed a 1,000 watt Unite 48V chain up front with a separate throttle as the rear hub kit came with a twist throttle.

I ran the full suspension one time with my old 17S lifepo4 pack which is maybe 50 to 60% capacity so a lot of voltage SAG. I hit 54 kilometers per hour which is 33.5 mph. That is with just the rear motor. I have not tested it with the front but is geared for about 30 mph so wont increase top speed. The main purpose for the front chain is up steep hills and for steady 30 mph cruising for long distance as two controllers / motors will share the load and heat making the ebike more reliable.

The 700C hub kit sports a 12 mosfet controller and rated at 45 amps. The cheaper 30 amp controller on the full suspension is probably 9 mosfets so will benefit by the front chain motor.

As far as not being able to charge at 30 amps you forgot the fact that the AC outlet will NOT see 30 amps. It would be around 15 maybe 17 amps as my 900 watt 15 amp charger would draw.

900W / 110V = 8.18 amps. It might be 9 or 10 amps though when factoring in heat from converting from AC to DC. A 30 amp 1,800 watt charger should draw < 20 amps and that is at 110. At 220

1,800W / 220V = 8.18 amps so maybe 10 amps. I am a college undergraduate for electrical technology. I was big into home and car audio in the 90s and 2,000s. I started with e bikes back in 2013 / 2014. I also know a little about computers mainly hardware. Not so much software.

I want to order two 24V 900 watt Currie chain drive motors and a 60 amp Kelly controller. I would need high temperature silicone wire rated at least 100 amps as the lower the voltage the greater amps required for a given wattage. That is why increasing voltage does not require upgrading the wiring. 10S or 12S LTO weigh 20 to 24 pounds NOT 45 or 50.

That would work for my old heavy duty steel Currie ezip frame but not for my $800 Giant Roam 700c. That needs the sleek and powerful 1,500 watt rear hub kit and a battery pack < 20 pounds.

I have a lot of other ebikes to work on. My 20" 1,800 watt chain already built with a flat tire is set up for 22S 55V LTO.
With 48V controllers they might have 60V CAPS so looking at 55V 22S LTO and a 58.8V charger so

58.8 / 22 = 2.672 charging voltage. Close enough to 2.7V II guess. 2.8V being maximum charging voltage. I defiantly would not want to go any lower than that.

I also have a brand new in the box 60V 4,800 rpm 3,000 watt brushless chain drive with a 48 to 72V 70 amp 3,000 watt controller. For that build I plan on 53 mph gearing and a 1,000 watt 48V brush Unite up in the front geared as close as possible to the rear motor. That is because 53 mph might be over gearing with just a 3 kilowatt motor as

3,000W / 60V = 50 * 55V = 2,750 - suitable for 43 to 45 mph gearing tops. However.

1,000W / 48V = 20.8 * 55V = 1,145 watts. 2,750 + 1,145 = 3,895 watts. 3,500 watts is about right for 50 mph. I would not want to go any less than that.

Thanks for posting.

Curtis out.