Replacement 36V 16AH LiFePO4 batteries?

[bazwaldo]

Hi,

I have found the following product on Alibaba.com:-

36v 16Ah LiFePO4 battery pack,electric bike battery for electric scooter products, buy 36v 16Ah LiFePO4 battery pack,electric bike battery for electric scooter products from alibaba.com

Would it be a drop in replacement for my current 36V 16Amp Lithium Ion (Li-On) battery in my Bearprint New City 505 Ebike?

It looks as though they do a minimum of "2 units" if that means just 2 individual batteries I would be tempted if the price was good and they were compatible with my bike.
I would look to use the batteries alternately each day.

What do you think?

Thanks,
Barry.

 

[amigafan2003]

No reason why it couldn't replace it, bearing in mind it will be 1.5x the size and weight of your existing battery though.

This would be nearer the size/weight of you existing battery:-

36V15Ah Li-Ion Alloy Shell EBike Battery Pack - BMSBATTERY

 

[bazwaldo]

Hi amigafan2003,
I thought it would be the same size and weight, there are confusing references to 48V 20Ah but the one I am after is the 36V 16Ah which is what I aleady have.
The battery in your link looks good but is designed to fit a rear rack, my battery is the slide behind the seat post variety.
As long as the battery was 36V would it matter if the Ah was higher say at 20Ah instead of 16Ah?
Thanks,
Barry.

 

[Scottyf]

The 20amp hour one will larger in size. Due to having more cells.
However it would give you an increased range.
It would also mean the cells are under less stress.

Eg more cells doing the same job means each one is under less stree when pulling power or current.

 

[bazwaldo]

So as long as the voltage is the same 36V type the ampage can vary say between 10, 16 0r 20Ah?
I was wondering if my controller and other electrics could cope with a higher ampage?
Do you think the LiFePO4 type of 36V 15/16Ah battery will be the same size as my current Lithium Ion (Li-On) battery?
I do not know what the difference is, the seller seems to suggest the LiFePO4 chemistry gives advantages in staying power, number of charges and stability.
Time will tell I suppose if this is correct.
Thanks,
Barry.

 

[Scottyf]

Lifepo4 usually has a slightly lower nominal voltage at 3.3v vs 3.6 (or 3.7).
So generally even at the same voltage and amperage the are slightly bigger.

Your best bet is to ask for diemensions in all cases.

You can change the amperage for higher if you like, it will extend your range. Think of the battery as the following :-

36v 10ah = 360watts (Total Energy) Cells = 3.6v 2.5ah, 10s4p = 40cells
36v 15ah = 540watts Cells = 3.6v 2.5ah, 10s6p = 60cells
36v 20ah = 720watts Cells = 3.6v 2.5ah, 10s8p = 80cells

More watts = more range. Its like the total fuel capacity of a battery. However a 20ah battery will be twice the size of a 10ah battery.

So please check the size before purchasing. You can usually rehash the cells into an avaliable container but is not advised. It would also void warrenty.



Lifepo4 cells are rather at longer life cycles than there Lithium-ion counterparts generally getting anything from 1000 to 2000 cycles. There are some people on endless sphere forum with batteries from Ping that used lifepo4 cells and so far have worked out very well without much deteriation of cell life and avaliable range.

For what you pay and the use currently it worked out to be worth paying the extra.
Really depends on the end use of how much you use a bike.


Like all batteries they are usually used for an application and specified for that only.


Currently the same cost Lithium Ion batteries have higher discharge rates (C ratings) than the Lifepo4 cells for the same cost. However you never really pull more than 2c out of an ebike (20amp peak) so the lifepo4 cells seem ok for this application.

 

[bazwaldo]

Scottf thanks for your reply.
I am communicating with the seller at the moment to see if the 15/16Ah LiFePO4 battery will suit my bike.
If anything promising happens I will give another update.

Barry.

 

[steve.c]

Battery?

That battery looks exactly like the one on my Freego Eagle even down to the runner slide on the back and mines a 36v 19amp just the same,and i regulary get 50+ miles from one charge.

 

[bazwaldo]

Hello steve.c,
My Bearprint is built in the same factory as the Freego bikes and as I noted in my review the connector case on the front of the bike even has "Freego" stamped on it!
My battery is advertised as 36v 16ah by Bearprint and my commute is about 26 miles a day 5 days a week to work. Currently I have done nearly 4600 miles in just over 10 months of ownership.
I am expecting the battery performance to degrade at some point but so far I am able to do my regular commute on 1 daily charge.
Barry.

 

[bazwaldo]

Another update.
My first day back to work after my nice long holiday break and a minor misfortune struck again.
The front light bracket snapped off at the 90 degree angle where it attaches to the mud guard bracket.
I suppose the constant bumping on uneven road surfaces has caused it to weaken to breaking point. The light attaches to the end of the bracket and this acts like a lever bouncing up and down with all the stress on the angle bend.
I have contacted Bearprint and they will look at getting out a replacement.
This is fair enough I believe as the lamp is certainly not fit for purpose at the moment and it is within the various warranty periods which might apply:-

1 year
2 year for electrics
6 years for frame

Last night coming home in the dark after 10pm I was glad I added twin battery front lights on the handlebar.
Even though I can cope without the original front light I really want to get it back as this was a selling point for me the fact there are front and rear lights which run from the bike battery and can be conveniently turned on from a switch on the handlebar.

Barry.

 

[bazwaldo]

Well as per my other post about Bearprint battery woes I am resurrecting this thread as I have been emailing various Alibaba vendors about replacement batteries.
I have found out that my battery case is referred to as a "Silver Fish" style and that I can possibly get a 36v 15ah li-mn type including charger and delivery for about £250.
Providing the quality was ok that seems a very competitive price.

Barry.

 

[Scottyf]

It does seem quite competative for the 15ah battery. Well I hope you get a replacement and you get it all working!

 

[Kudoscycles]

I promised I would ask again from my battery supplier about 36v x 16 Ah LifePo4..I was hoping it would be a straight swop for the 10Ah unit ,just longer. But my manufacturer has advised it would overhang the back of the bike too much and also would need a new controller. We could change the shape to a fatter battery but that would require a new rack. It would be possible on an OEM bike but 90% of my customers are very happy with the 10 Ah battery. So I think it is not economic.
LifePo4 is definitely the economic route to go to get a good battery at an inexpensive price with long cycle life-if you want long range carry 2 x 10 Ah LifePo4
Dave
KudosCycles

 

[Kudoscycles]

Be careful with Alibaba,despite Alibaba's claims not all vendors on that site are honest...be especially careful with vendors in the Yongshan region. Look for those who have a 5 year gold standard and avoid the traders who try to sell everything from batteries to wedding dresses-China is the great intertrade nation-a chinese vendor will never say no-first take money then look for product,it is not usually dishonesty more about making promises that ultimately they cannot keep.
Dave
KudosCycles

 

[Eaglerider]

Hi Bazwaldo

Does this mean your battery warranty is void?

 

[JuicyBike]

Hi Barry
You have found an excellent price for a new 16AH LiFePO4, we can't match that, even though ours (in stock) should fit your bike.
You need to check that the battery is able to cope with the demand your bike places on it. Look at the rating of your controller (I suspect 15Amps) and the rating of the battery (hopefully more than 15amps and nearer to 20).
If you go ahead and buy from the source you have found you may then need a new controller matched to your new battery and existing motor. But that's not the end of the day and quite doable.

Flecc is the person to ask you know and I would hope he and the other more experienced members would confirm the above.

 

[Scottyf]

I don't understand why you would need a new controller if all your doing is buying another battery?

So long as the C rating matches or exceeds the controllers capabilities from an amp point of view it should be all good to go.

 

[bazwaldo]

Thank you all for your replies.
I do not know about C ratings.
I sent some photos of my battery and charger label to several vendors and was told that the Li-mn battery has a 42v charger as is mine from Bearprint. The LiFePO4 batteries I was told required a 43.8v charger.
The most promising vendor has said that the largest LifePO4 battery comparable to my battery case size would be 12ah.
Apart from the power density all the advantages appear to be with the LifePO4 type which is what Dave at KUDOS has been saying.
Whatever transpires I do know that it is a risk buying direct and it all could go horribly wrong.

Eaglerider I am still waiting to see what happens about my 2 year battery warranty, in the longterm though I will need to make other arrangements and source my own batteries at hopefully a cheaper price.
Other concerns are that the locking button matches to the slide rail on my bike - it could be that the vendor will need to supply a slide rail to go with any new battery.
The 12ah LiFePO4 battery is a few dollars more expensive than the 15ah Li-mn type from the same seller.

Barry.

 

[bazwaldo]

Latest update from the vendor for a LiFePO4 36v 12ah battery with almost the same dimensions as my original battery:-

Concerning the “metal back bracket”, I think I have misunderstood your meaning before. We always call it “slide rail”, just as you called in your last email. We will offer all the accessories together with battery, including slide rail, keys, bottom case, and lead wires.
Price is USD272 (for battery together with accessories). Cost of charger (DC: 43.8V 3A with UK three pins) is USD 23 per unit.
About the quality, all our batteries are produced according to European safety and production standards, and approved with CE certification. We have many customers from Europe, European market and America market is our main markets, please don’t worry about it.

Together with delivery the cost is quoted as 373 USD or about £240.
This is quite tempting as long as it is all as described.
I suppose there is a chance I might have to pay import duty and VAT.

Barry.

 

[bazwaldo]

I have been asked to pay by Western Union for the battery.
After signing up for an account Western Union will charge £25 for the £242 money transfer.
This seems rather expensive, is there another cheaper way to pay for the battery?
I asked if they do PayPal but I guess not as they did not mention this at all just stating Western Union was what they preferred.

Barry.