Batteries recelled with higher capacity newer lithium cells

[Staps]

Hello All!

I have an old Freego Raptor ( no new batteries now that are out of business) and am looking to Recell at home my samsug 26F batteries (on the cheap ish as the bike has constant punctures) I can see that other batteries have different specifications in regards to discharge rate, discharged time, max voltage, low voltage etc especially different brands

Many times it been mentioned that batteries can recelled with higher capacity newer lithium cells but little detail is given.

I am essentially thinking of Samsung 26F batteries for 30Q or another cheap battery and if anyone has first hand buying experience or a cheap legit source that would be awesome!

Thanks
Staps

 

[Nealh]

Your 26F cells are manufactured Korea dated 2014 Jan 4th so a few years old now.
Your battery I'm guessing is 10.4ah a re-cell with 30q would be 12ah and a 3500mah cell would be 13.8 - 14ah dependant on the cell. There are better cells to be had then 30q for low power bikes, LG MJ1 & M36 will out cycle life the 30q. Sanyo GA I would also give a miss regards to cycle life.

Unless you already have a spot welder then get a price from Jimmy at ebikebatteries .co.uk.

 

[Staps]

Hey thanks for the reply! Its just a 5.5AH battery but thats a massive jump.. it holds 9 cells. My previous quotes were for £250+ and seemingly these are a £5 each.

I have seen all the stuff about spot welding, but gonna try and solder them. Maybe not as stable but why not at this price and the youtube videos look ok with a tight fitting case

 

[Nealh]

The Raptor I realise is 24v not 36v now so must have more then 9 cells, surely 14 cells for a 2p7s battery. 26F is 2600mah so will give 5.2ah.
The most you can hope for with new better 18650 cells is between 5.8 - 7ah, so I can see why you are looking at 15a/30q rated cells. If you can get genuine cells then LG HG2 20a/3000mah rated cells might be an option, HG2 are the most commonly cloned cells around so needs a reliable source.

Soldering cells is a bad idea as to much heat is applied to the cell for to long and adds ageing to them instantly, the Negative end of the cell is crucial to keep as cool as possible.
The best option for soldering cells ( if you call it an option) is to buy cells with nickel Z tabs pre welded and then solder to the tabs and not directly to the cell end.
Nkon.nl will add a Z tab for you, check the box on the cell product page, then all you need to do is pre solder the tabs where they meet without touching the middle of the cell.
You will need to buy insulator rings for the positive end to prevent cell shorting, a cell insulator needs to go on the positive cell end so it sit's under the Z tab.

 

[Staps]

Oh wow thats great advice, i will look into LG HG2 cells with Z tabs! I better get some really good shrink insulation. Not sure where the insulator ring is going though, did you really mean below the tab? Is this to get away from the sides (which are negative)Does that mean button top cells are required? I will definitely get some to go between the batteries never seen them before.

Thanks very much!

 

[Nealh]

You don't need button top cells just regular flatter top cells.
95% of the cell is negative ( the whole casing )only the top middle contact on the Pos end is positive, when the tab is soldered on it has link/connect to the next cell either in parallel or series. Shorting can occur as the tab when flat will cross the negative cell body.
If cells have no tab you just place a card insulator ring on the Pos end of every cell, with tabbed cells you bend the tab up 90 degs to slide a ring over and on to the cell top then push the tab flat again before soldering to the next tab. The neg end of a cell doesn't need an insulator.
The insulator simply protects any shorting of cells when paralleled on the Pos end or when placed in series, it is just another layer of safety to prevent buggering your diy pack up. The cell wraps are thin and heat can shrink or melt thru, usually under the wrap the cell had a plastic ring on top as well this can melt leaving no protection to shorting.

 

[Staps]

Thanks for that, I got it now. But I am only now realising that that you recommend a LG HG2 20a/3000mah over Mj1 10a/3500mah.

These are essentially the same price at the moment. The original battery was 26F 5.2a/2600mah could l ask your reasoning for the HG2? Is it that the BMS does not control amps so it wold be better for the low power motor?

 

[Nealh]

Which cells to use depends on the max controller rating, do you know what the controller rating is ?
You need to select cells that will have more amp head room then the max that the controller can take out of them. The reason I mentioned the hg2 is that you battery is 7s 2p so two cells in parallel, 2p part is important as this is the current which will give the head room and stress the cells less.
The 10a cells will only give 20a current with 2 in parallel and may not be much head room above your controllers max amps. Cells with a higher ( A ) current rating will suffer less voltage sag and ageing, IR causes ageing which is related to cell heat as well. In my view a 10a cell in a 2p configuration is to close a call to make with ( A ) current headroom.
Another cell to consider is the excellent Sony/Murata VTC6 and would consider it above the much cloned HG2.

 

[Staps]

Got it, thanks for your advice