Anyone actually used the Boston Power 5300mAh cells?

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Buk___
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Anyone actually used the Boston Power 5300mAh cells?

Post by Buk___ » Jan 15, 2018 11:47 am

I've seen a few samples tested, but no one actually using them, despite that they seem to be very competitively priced?

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Re: Anyone actually used the Boston Power 5300mAh cells?

Post by Pajda » Jan 15, 2018 5:13 pm

Maybe because they have too good parameters for the common people?

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Re: Anyone actually used the Boston Power 5300mAh cells?

Post by Buk___ » Jan 15, 2018 5:22 pm

Pajda wrote:
Jan 15, 2018 5:13 pm
Maybe because they have too good parameters for the common people?
Sorry? Could you explain that?

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Re: Anyone actually used the Boston Power 5300mAh cells?

Post by Pajda » Jan 16, 2018 11:15 am

I apologize for this inappropriate remark. :oops:

I'm trying to get an overview of all the currently available technologies of Li-Ion batteries on the market. But this manufacturer and the type of battery has long missed my attention. I had the prejudices that it was just another Chinese variation of the useless crap battery. But after about a month of intitial testing of Swing 5300mAh battery cells It seems that I could not be more wrong. Most of parameters listed in the datasheet are achievable and in most cases are even better in real life conditions. After first 50 cycles of my already completed cycle life tests it seems that the cycle life parameters from datasheet are also correct, which can make this cell one of the most robust cell of the market of small prismatic/cylindrical cells. Even LG HG2 (which is one of the best cells based on my test procedures) is outperformed in some parameters.

The only issue of this cell is that it belongs to High Energy category of cells, so it is good only for 2C continuous loads. But on the other hand it has higher nominal charging curent 0.7C (common is 0.5C) and initial 1C charge rate tests exhibits minimal wear.

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Re: Anyone actually used the Boston Power 5300mAh cells?

Post by Buk___ » Jan 16, 2018 12:16 pm

Pajda wrote:
Jan 16, 2018 11:15 am
I apologize for this inappropriate remark. :oops:

I'm trying to get an overview of all the currently available technologies of Li-Ion batteries on the market. But this manufacturer and the type of battery has long missed my attention. I had the prejudices that it was just another Chinese variation of the useless crap battery. But after about a month of intitial testing of Swing 5300mAh battery cells It seems that I could not be more wrong. Most of parameters listed in the datasheet are achievable and in most cases are even better in real life conditions. After first 50 cycles of my already completed cycle life tests it seems that the cycle life parameters from datasheet are also correct, which can make this cell one of the most robust cell of the market of small prismatic/cylindrical cells. Even LG HG2 (which is one of the best cells based on my test procedures) is outperformed in some parameters.
Okay, thanks for that.

I was beginning to dismiss them, and take their high Ah/$ as a sign they were being dumped; but then I came across this NASA pdf that shows they are being seriously considered for spaceflight use. It doesn't say they've been selected, but it has a few graphs pertaining directly to these cells, and some positive comments regarding the form factor and thermal performance.

Pajda wrote:
Jan 16, 2018 11:15 am
The only issue of this cell is that it belongs to High Energy category of cells, so it is good only for 2C continuous loads. But on the other hand it has higher nominal charging curent 0.7C (common is 0.5C) and initial 1C charge rate tests exhibits minimal wear.
So 10.6A continuous rather than the 13A given in their specs?

If so, 3P would give approximately the same continuous draw capability as 4P 29E, but 50% more capacity for the same money.

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Re: Anyone actually used the Boston Power 5300mAh cells?

Post by Pajda » Jan 16, 2018 3:20 pm

Ah, I was looking into bad column, the continuous discharge rate is really 13A.

But I must say that I am not doing cycle life test (at least for now) with more than 1C discharge rate. When designing the HE battery for long life (more than 2 years with the goal of 10 years life) I'm using a "0.5 average" rule. That means average load(charge/discharge) up to 0.5C and 50 % depth of discharge. Almost all HE cells particularly in 18650 format are practically indestructible by cycling with 1C discharge rate up to 50% DoD but when you break this value the HE cells starts to loss their capacity very fast and so it is neccesary to use HP cells. You also need HP cells when there is demand for more than 0.5C average charge rate.

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Re: Anyone actually used the Boston Power 5300mAh cells?

Post by Hillhater » Jan 16, 2018 5:43 pm

Previously, when i have considered the Boston Power cell, i have dismissed it on cost and availability grounds...
...IE, few vendors, and high cost/Wh.
Have the prices and availability improved now ?
This forum owes its existence to Justin of ebikes.ca

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Re: Anyone actually used the Boston Power 5300mAh cells?

Post by Pajda » Jan 16, 2018 5:59 pm

I recently found price 4.28 USD with free shipping to US, EU for 100cells quote. That is 19.3Wh/4.28 USD = 220 USD/kWh. Not bad from my point of view 8)

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Re: Anyone actually used the Boston Power 5300mAh cells?

Post by Buk___ » Jan 16, 2018 6:06 pm

Hillhater wrote:
Jan 16, 2018 5:43 pm
Previously, when i have considered the Boston Power cell, i have dismissed it on cost and availability grounds...
...IE, few vendors, and high cost/Wh.
Have the prices and availability improved now ?
I've only just started looking so I have no knowledge of history; and I'm in the UK where US sources cost a fortune in shipping, so I have to avoid them.

I have an email quote (Queen Batteries) for 30 for £112 ($152) shipped to the UK which comes out at 1492mAh/£.

The next best I've found is Panasonic UR18650ZY 2600mAh @ 1247.44mAh/£ (interEu) shipping extra, but they only have a spec'd discharge rate of 1.25A.
Next comes Samsung INR18650-29E 2900mAh @ 953.35mAh/£ (interEU) shipping extra. with a 8.25A continous spec.

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Re: Anyone actually used the Boston Power 5300mAh cells?

Post by hemo » Jan 17, 2018 11:56 am

I had a 15.9ah/39a 7s 3p Boston pack made for my Swizzbee but have found the 39a not enough and it sags like hell, originally I did ask the vendor for a 5p pack but he wasn't able to fit the quantity in the space I had available.
In the end I built a HE2 battery with Korean lipo Boss spot welder and parallel it with the Boston.
The 24v Heinzman brushed mid drive hub motor can draw over 60a so at least the sag is a lot better now.

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