Looking to replace 60V 20 AH lead acid battery

[Zambam]

I bought my Fly 7 moped new in Dec 2021 and have since put 1800 miles on its 60 V 20 AH lead acid battery. I took these measurements today: Fully charged 66.5 V. @ full throttle it sags down to 55 V with a draw of around 34 amps per my clamp ammeter. Does that sound typical for a 3 year old lead acid battery with 1800 miles?

I am thinking of replacing it with a 60V 30 AH LiFePo4 battery from Amazon for $569 (+ tax). LiFePo4 is supposedly less prone to fire risk compared to Lithium Ion chemistry. BtrPower Amazon.com

Is BtrPower reputable? It has a BMS but no mention of balancing cells. Is $569 a reasonable price for such a battery? Are there other LiFePo4's you recommend?

Will I feel more pep from the LiFePo4 battery? What kind of sag should I see @ full throttle?


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[999zip999]

My buddy got one of those about 9 months ago I'll contact him and see how it's doing. The way I see them they're on the lower end of the battery scale.

 

[neptronix]

If you want more pep, consider getting the same capacity at least.
Lifepo4 is not known for it's power, unless we're talking A123 cells.

 

[Zambam]

If you want more pep, consider getting the same capacity at least.
Lifepo4 is not known for it's power, unless we're talking A123 cells.

The Amazon link I gave had different choices of V and A. The $569 one I chose is 60V 30A.

Below is the description: (Note the "our ebike battery comes with A123 cells.polymer soft pack."). Is that any good?

About this item​

• 【60V 30AH Ebike Battery Parameter】60V 30AH LiFePO4 Battery, Max Constant Discharge Current: 50A, Size: 9.48 x 7.5 x 6.3in,Weight: 29.1LB .Charge Time: 6H.It can be recharged more than 1500 times and the life span can reach 5 years.Package Include：1 x 60V 30Ah LiFePO4 Battery,1 x 5A Fast Charger,2 x Anderson Plugs,1 x 3 Pin Charger Plug,1 x Manual Instruction.
• 【Built-in 50A BMS】▶60V 30AH Battery equipped with 50A BMS protective board prevent short circuit, over charge and over discharge ensure the above 1500 cycling long life expectancy.▶our ebike battery comes with A123 cells.polymer soft pack.Don't contain heavy metals, is non-toxic. unlike other lithium batteries will not explode or catch fire.
• 【Applicable motors】 ▶60V 30AH LiFePO4 Battery Suitable for all brands of 60V 100W-3000W motors including Bafang motors ,including Electric bicycle scooter tricycle motorcycle motors.▶all batteries have been approved by UL and CE. You can ride safely with BtrPower battery. ▶Voltage of controller: 60V.▶Rated current of controller: ≤ 50A.▶Motor wattage: 250W-3000W.▶Whether the battery size(9.48*7.5*6.3 inches) is suitable for your battery case.
• 【LiFePO4 Battery Advantages】Super Safe,It's the safest Lithium battery type currently available on the market today. safer than lithiom ion and other battery types.Unlike other lithium batteries will not explode or catch fire, Longer cycle life than other lithium-ion batteries.Can reach over 2,000 times life cycle.Higher capacity compared to similarly sized lead acid batteries.green and environmentally friendly, non-toxic, non-polluting.
• 【After-sales service】▶3Months Free Return / Replacements/ 12Month Warranty.▶If there is any problem with the product, please contact us.

---

Sponsored

 

[Zambam]

Did some googling found this:

Fisker Automotive - Wikipedia

en.wikipedia.org

"Fisker's problems started with a recall of its battery by supplier A123 systems in December 2011, followed by a second recall in March 2012, and eventually A123 Systems' bankruptcy in August 2012. In addition to production stopping for over five months, with no date announced to recommence, the planned production of the second model, the Fisker Atlantic, was postponed, together with the cessation of development of the new model."

 

[Zambam]

My buddy got one of those about 9 months ago I'll contact him and see how it's doing. The way I see them they're on the lower end of the battery scale.

Can you suggest other brands of LiFePo4 batteries that are on the higher end of the scale?

 

[999zip999]

Yes the best lifepo4 cell. At the time. Invented by MIT sold to A123 . They had machines running making these cells one of the machine was spitting out crooked tabs and shuffled into these packs 28s 3p. And pretty closely took down Carmen fisker as a car company Plus they added everything in the kitchen sink kind of like Alfa Romeo did in the '80s or they had it so complicated they couldn't get it right.

A lot of us here we're able to buy that cell in group buys a love is here we're able to buy good sales without the crooked tab I bought 26 to make a 24s battery I made it 12s 12s no BMS. I still have it it's pretty close to 10 years old 1, 480 charge cycles 40,000 Miles. I was playing with it and I over discharged it and lost a couple cells. It's now living as a 18s 1p no BMS and works well.
Big heavy sells that can be abused as long as you don't hit lvc. It caused the death of four cells

 

[999zip999]

Even though lifepo4 is big and heavy did I say in a battery pack it makes for a very big and heavy pack lasts a long time. And a lot safer than other chemistries it's still stored lightning in the box and can make fire.
Nowadays most people are going with the 18650 or the 21700 sell because it's smaller and lighter.

 

[999zip999]

To get the proper battery we need to know the demands of the controller on the motor.
How many voltage can your controller take how many amps does it deliver this will tell us how strong the battery you need.

 

[999zip999]

Okay I talked to my buddy he bought a 60 volt 24 amp hour battery for scooter or the mid drive after you already sold it and the person who sold it to while it was still under warranty had a lot of problems he doesn't know what happened exactly. Well I guess his battery lasted about a year. Are the new guy wasn't sure how he's supposed to use it maybe. Or maybe it was a poor construction and was going to break given time one year.
So from what I hear BTR batteries aren't that good.

 

[999zip999]

You can always make a battery why don't you tell us the size of your battery compartment and there might be a good bolt together solution of course we'd have to know what type of controller you have how many volts it can take and how many amps it demands from the battery because the word controller is true in this instant.
Okay I looked up your $1,300 scooter it probably has a 40 amp or a 60 amp controller at the most. Plus I'm only guessing. Now how big is your battery compartment ? Important

 

[Zambam]

This is the exact controller from my Fly 7 moped. I messed it up by poking around with a DVM behind the instrument panel, shorted something and lost the Km/hr speed function (I was trying to find battery voltage to wire up a volt/% meter). I brought it to the dealer and they replaced the controller for $40 and I kept the bad one. I will take a measurement of the battery compartment later.

 

[Zambam]

Here are the dimensions of the odd shaped lead acid battery that weighs 68 lbs. It fits snugly into the same odd shaped compartment below the floor board. The BtrPower 60V 30AH LiFePO4 Battery Size: 9.48 x 7.5 x 6.3in will fit into the compartment with bracing and is much lighter @ 29.1LB.

 

[Zambam]

Is this true?
"After opening a factory before sales materialized, A123 went bankrupt. Chinese parts maker Wanxiang Group scooped up its remains in 2013."

Remembering A123: what America learned from the demise of its EV battery pioneer

The demise of America's EV battery pioneer, A123, serves as an elegy for America’s innovation machine. Read more here.

financialpost.com

 

[999zip999]

A123- 20ah cell is a very good battery cell it is big it is heavy it lasts a long time mine never seem to go out of balance. Can be used at a high amp demand.
They are big and heavy for a bicycle maybe a big cargo bike or a four-wheel Siri.
One tab is aluminum and one tab is copper they cannot be soldered they must be laser welded together or I bolted . Mine I bolted together through an aluminum block there's a couple hundred page article on building A123 20 ah pouch batteries..
All the A123 pouch sells I see for resale have been ripped out of a pack and a laser weld at the very bottom with a new tab I do not trust these cells for a battery project.
I told you what I know about BTR batteries. It seems to have a USA Warehouse ? So maybe the new person who bought his electric scooter didn't know how to charge and discharge it properly. To own and use the battery you have to be educated and how to use the battery properly or else you'll have one dead expensive battery.
I have a battery with Bluetooth and it shows the voltage of each independent cell I like that very much.
But it's something you would have to pay for.
You have a big enough battery tray. That you can bolt together a 60 volt battery.

 

[999zip999]

I read through BTR they have hvc, llvc and cell level balancing. For extra money you can build a custom pack of what cells you desire what BMS ect. Or So as it is printed. A 60v 20ah battery with charger 389.00usd.
I'm going to go have to read this sales promotion again.
I wish someone would chime in who has bought batteries from this company.

 

[Zambam]

I am glad I didn't buy one! I've been emailing BtrPower Official back and forth to get details on their A123 pouch battery w/o much luck. I wanted p/n, test data on the cells, photos of internal construction etc. All I get is how great their batteries are and that there is only 1 left in the US warehouse in the size I need.

I just came across this post Denzel 72v 4-spd Gearbox Build 125cc Dual Sport from forum member skeetab5780 where he had a very bad experience with BtrPower. Check out photos of the opened up battery.

 

[Zambam]

After 5 months of not riding my Fly 7 moped and forgetting to turn off the circuit breaker, the 60 V 20 Ah SLA battery ran down and will not take a charge using the factory charger. It was down to 27 volts. Each of the five 12 V battery was down to 5.5 V. I tried charging each with a car charger but could not bring them up to full. Brought them to Autozone to recycle in exchange for $50 store credit.

Now I need a replacement battery. SLA from the dealer is $300 but I really don't want another 70 lb boat anchor SLA! The dealer has a 60 V 45 Ah Lithium for $900 but I don't want to spend that much!

What about this 60V 25Ah Lithium https://www.amazon.com/CSTAL-Electric-Bicycles-Scooters-Protection/dp/B0CBX96RZ8/ref ?
Do the specs look legit? It should fit in the space vacated by the SLA with room to spare for padding so it can be shock mounted & well protected with padding. Lithium should sag much less than SLA resulting in better performance right?

 

[Gruesome]

I do not believe (believing means not knowing, so take it for what it's worth) that this is a 25Ah battery. It looks like a 4p battery, so I'd guess 12 - 15 Ah at most. The quoted weight of 3.6kg also points at about that capacity: 3.6kg times 200 to 250 Wh/kg divided by 60 V gives 12 - 15 Ah.

 

[Zambam]

I do not believe (believing means not knowing, so take it for what it's worth) that this is a 25Ah battery. It looks like a 4p battery, so I'd guess 12 - 15 Ah at most. The quoted weight of 3.6kg also points at about that capacity: 3.6kg times 200 to 250 Wh/kg divided by 60 V gives 12 - 15 Ah.

Thanks! Yes, appears to be false advertising. 25 Ah/ 64 cells = 0.3906 Ah per cell, which is available on the best (expensive)18650 cells, not in a cheap battery. Let's say it's only 15 Ah, how will it compare to a new 20 Ah SLA in performance? Maybe still worth a try to get it back on the road?

 

[Gruesome]

Thanks! Yes, appears to be false advertising. 25 Ah/ 64 cells = 0.3906 Ah per cell, which is available on the best (expensive)18650 cells, not in a cheap battery. Let's say it's only 15 Ah, how will it compare to a new 20 Ah SLA in performance? Maybe still worth a try to get it back on the road?

Zambam, the same charge has to 'travel' (current flow) through cells that are in series, so you can't add the charge capacity (Ah) for the 16 cells in series. The whole string of cells only delivers as much charge as the smallest cell in the string can store.
You add the voltages for those cells in a series string.
You do add the charge capacity in Ah for cells in parallel, so in this case (4p battery) you multiply the single cell capacity by four.
For the energy storage capacity (Wh) your math is exactly right: you do add all the cells, so for a 16s4p battery that's 64 cells.

From what I have read, 18650 Li-Ion cells exist with up to 3,600 mAh = 3.6 Ah charge capacity. That would be an energy storage capacity of up to 13Wh (3.7V * 3.6Ah).

I don't know whether that battery is still a good deal or will show good or acceptable performance. I just don't have enough experience with batteries built with different quality cells. That battery has zero reviews though on Amazon. I think personally I would steer clear of that.

Regarding performance, for motorcycle batteries, Li-Ion are advertised as being able to deliver much larger instantaneous currents at the same capacity, compared to lead-acid. But I don't know whether that is generally true. Especially for Li-Ion batteries marketed as lead acid replacement, there seems to be lots of misleading or false advertising regarding the charge capacity.

Regarding LiFePO4 (Lithium iron phosphate) vs Li-Ion: googling '18650 lifepo4 specific energy', and the equivalent for Li-Ion, I see that LiFePO4 cells have about half the energy storage capacity per weight (specific energy) as Li-Ion, about 125 Wh/kg vs 250 Wh/kg. You are (or were) looking to replace a 60V 20Ah lead acid battery, so that's 1.2kWh and would weigh about 10kg (22lbs) for LiFePO4, and about 5 kg (11lbs) for Li-Ion, probably a bit more in both cases, since the densities were just for the cells.

Regarding cell quality: As I've learned here, a) cells fall into different classes, some optimized for instantaneous current, others for total stored charge, and b) batteries (cell arrays) differ in the current carrying ability of the interconnects they are built with.
So you could have a battery built with cells of high intrinsic current capability, and weak interconnects could still ruin the performance.

Hopefully other people will chime in with actual battery recommendations.

 

[Zambam]

Hey Gruesome, didn't you buy a used Lithium battery pack from a robot that was not very expensive? Is it suitable, does it have enough cells for reconfiguring to 60 V 20 Ah pack? I do have good skills in soldering and working with electronics in general. Have not worked on a Lithium battery pack yet but there's always a first time.

 

[Gruesome]

I bought two 48V 13s6p packs, one from Amazon, $220 or so for 15 Ah (advertised as 20Ah), the other here in this forum from AESolutions, $129 for 20 Ah. I haven't opened either of them, so I don't know how easy it would be to reconfigure to 60V. I suggest contacting @AmericanElectricSolutions and ask him about a 60V pack. Maybe he has some, or can reconfigure one. He is not the fastest to reply, but he does reply.

 

[Chalo]

Rather than getting hung up on chemistry, I think you should distinguish between packs that are safe enough for automakers to use them, and packs that aren't certified by any regulatory body or industry group.

16S:

Chrysler Pacifica NMC 60V 45Ah 2.6kWh 16S Battery Module

PLEASE READ THE DESCRIPTION CAREFULLY. Shipping to Lower 48 USA states only via Ground Shipping. No shipping to PO Boxes. No international shipping including Hawaii, Guam, Puerto Rico. High power Battery modules suitable for many DIY applications like EV conversions and golf carts that can...

jag35.com

15S:

UR18650ZK V52A Sanyo 54V 38Ah 2kWh 18650 module | Greentec Auto

A compact 15S battery module with plenty of space to install your own BMS. Great for small projects or modular systems! These modules contain Sanyo 2.5Ah cells in a 15s17P configuration. Price per kWh: $50/kWh $25/kWh and $20/kWh Years: 2019 Shipping: Free Ground or Freight Warranty: 3 Months...

www.greentecauto.com

Either one would make your pretend motorbike go nicely. The latter one is stoopid cheep, like pay you to take it away cheap.

 

[Zambam]

Rather than getting hung up on chemistry, I think you should distinguish between packs that are safe enough for automakers to use them, and packs that aren't certified by any regulatory body or industry group.

16S:

Chrysler Pacifica NMC 60V 45Ah 2.6kWh 16S Battery Module

PLEASE READ THE DESCRIPTION CAREFULLY. Shipping to Lower 48 USA states only via Ground Shipping. No shipping to PO Boxes. No international shipping including Hawaii, Guam, Puerto Rico. High power Battery modules suitable for many DIY applications like EV conversions and golf carts that can...

jag35.com

15S:

UR18650ZK V52A Sanyo 54V 38Ah 2kWh 18650 module | Greentec Auto

A compact 15S battery module with plenty of space to install your own BMS. Great for small projects or modular systems! These modules contain Sanyo 2.5Ah cells in a 15s17P configuration. Price per kWh: $50/kWh $25/kWh and $20/kWh Years: 2019 Shipping: Free Ground or Freight Warranty: 3 Months...

www.greentecauto.com

Either one would make your pretend motorbike go nicely. The latter one is stoopid cheep, like pay you to take it away cheap.

The Greentec Auto battery is too long and appears to be not be easy to shorten it to fit https://endless-sphere.com/sphere/attachments/img_3197-jpeg.347179/ . The Chrysler battery almost fits!
Maybe I can "shoehorn" it in? Does it have a BMS?