Which of these two batteries for pack build?

Bikes4two

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Feb 21, 2020
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  • I am looking to build a 10s2p 36v battery pack for my 250w TSDZ2.
  • The TSDZ2 controller is set to a max current draw of 15A
  • I nearly always ride in ECO mode with an average current draw of around 4A with the ocassional peak of 8A-10A in the next higher assist level.
  • With generous help from @Nealh I have narrowed my choice of battery down to either the Molicell P42a (nominal 4,200mAh, 30A) or the LG M50LT (nominal 5,000mAh 14.4A)
  • The battery price at Fogstar (wholesale) are £3.75 and £2.99 respectively giving a 20-cell pack price of £75/£60 respectively
  • For comparison I have used the data published by Mooch on the e-cigarette forum - for the P42a see here and for the M50LT see here, but for convenience I have posted the constant current discharge curves below.
  • Price-wise the M50LT is better than the P42a but the difference isn't a factor.
  • The P42a has a higher current rating than the M50LT but at 10A running each deliver around 3,100mAh at the 3.3v point
  • I know that many (including @Nealh ) are fans of the Molicell, but putting that to one side, which of the two would you pick for a battery pack build like the one I'm doing and more importantly why?
Thanks in anticipation (and hopefully this post won't be sidelined as my first post on this subject was).

50229

50230
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
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Hard to see anything negative about the LG at the modest current the TSDZ2 requires, and it has greater capacity and lower price.

For a direct drive hub motor the extra current rating of the Molicell would become important.

It might boil down to what is in stock!
 
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guerney

Esteemed Pedelecer
Sep 7, 2021
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I found myself planning another build earlier today, and if I did assemble a smaller faster lighter and more powerful bike, I could use the same battery for both - perhaps making a battery pack which is capable of delivering 20A+ continuously would be a good idea, in case (like many here) you end up with several ebikes? Or for if your health deteriorates over the next couple of years, due to excessive cake and tea consumption? (Prefer biscuits myself...)
 
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harrys

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Dec 1, 2016
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Both cells can provide the 14A you might occasionally pull from a TSDZ2, I would chose the M50LT's because they might give me 4AH while the P42's are probably like 3.2AH. I figure we get 80-90% of the rated AH when a cell is used to run an ebike,

I power my TSDZ2 on a 13S-2P using Sanyo GA's. Those are 3.5AH cells, and in real life, the battery is good for 6 AH on the bike. That's like 300 watt-hours, and if it were summer, I bet I could approach 50 miles, but I've only ridden it in Fall/winter and 40 miles is tops.
 
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Nealh

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Aug 7, 2014
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M50 will give longer run time so a good option for lowish current of 5a.
The 14.4a rating is a it of a red herring as one would have to keep them at 25c or less , a near impossiility one might think. At best they are a proper 10a cell.
 
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Bikes4two

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Feb 21, 2020
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I've just 'stressed tested' the LG M50LT battery pack I've built (10s 2p) over three long-ish rides with good results as I've mentioned in another post HERE.