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Battery match for QS 273 5kw

E

evglobal19

100 mW
Joined
Apr 3, 2019
Messages
35
Have a 19" hub kit ordered and being delivered. It is reportedly the QS 273 5kw matched for 72V Sabvoton 72150 controller. The supplier suggests a minimum 26.1ah battery to have a max of 100km/h (occasionally, but not likely often) and no idea of range.

There are packs all over ebay and aliexpress obviously and going on Micah's Vrzund page it looks like a 20S & 8-12P pack. Even at 20S8P kit it's $1,000 before BMS and charger (plus time and likely mistakes along the way). Just hoping for any advice about the direction to go to source the proper power.
 
I use a QS 205 and have a 20s 14p battery pack.

My controller KLS7230s can do 120a or 10,800w and will kill that pack in under 40 mins if I really push it. At just 20-25mph the same pack can last 2.5 hours. Range really depends on how fast you want to go.

You need something of similar energy density to keep from sagging if you plan to pull more than 100a for any extended amount of time.
 
so how is it that the supplier can recommend a 26.1 ah pack as a match? that's more like 20S7P not 14 in parallel?
 
It kinda depends more on the individual 18650 cell that they use in the pack.

A 5p pack of top tier HG2's can put out 100a. Some cheap off brand cells wired up to 20p can barely produce 50a.

Capacity and max current draw for every 18650 cell is vastly different.
 
Hmmm, so how would I know the difference? What information would be provided that would give me a clue?
 
Ask any seller exactly what cells are used to build their pack. Some will have the cell listed in the details.

Most of the well known and well reviewed sellers will be more than happy to tell you if they are using "A" grade genuine cells. Others who use "B" or "C" grade or re-sleeved cells won't be so forthcoming with their info. So you really need to find a good reputable seller with a good history.

There are some good Ali-Ex and ebay sellers that will build the pack using the cells you choose.

You can also post links of your battery choices here and ask the ES community if anyone has any personal experience with that particular seller or pack builder.
 
evglobal19 said:
so how is it that the supplier can recommend a 26.1 ah pack as a match? that's more like 20S7P not 14 in parallel?
Click to expand...
If they recommend what you **really** want, might scare buyers off.
 
so the hub kit is on it's way and this is what I know so far...

QS Motor says:
Continuous Battery Current 70A
Peak Battery Current 120A
Peak Phase current 280-500A

Sabvoton 71250 controller:
150A Battery
350A Phase controller

Battery will be 72V and 40ah.
Can have it made with Panasonic PF, Sanyo 18650GA, or LG MJ1 in pack but don't know how to pick or what the BMS should be.
can anyone please help me provide what the battery builder would need to know or what is a good option?
 
on voltaplex it seems:
Panasonic Sanyo GA's are 3.6V 10A 17.5A peak and a 2.9C rating
LG MJ1's 3.65V 3500 mah 10A 12.78A peak and 2.86C so both pretty similar

LG HG2's are 3000 mah 20A 35A peak at a 6.67C rate as are the Sony VTC6's
 
For those high power hub motors, I like RC Lipo cuz it really packs a punch in a small pack. I don't like carrying more than 1/1.5 kw on a bicycle.
 
never use Ga's for this. you will kill them in under a year.

use samsung 29E7 (mind the 7) or if you cant get those the older 6. PF's are also a option but are a bit more saggy under serious loads.

personally i would not get a pack that will keep under 2C for peaks and WAY under 1C for sustained loads. that way your battery will last many times longer.
 
Still reviewing choices. Found this info on 18650battery.com
Brand Type Amps MaH Cost (S)72V P40ah) cells Cost Cont Amps
LG MJ1 10 3500 $5.99 20 12.0 240 $1,437.60 120
LG M26 10 2600 $3.49 20 16.0 320 $1,116.80 160
LG HE2 20 2500 $3.99 20 16.0 320 $1,276.80 320
LG MH1 10 3200 $4.99 20 13.0 260 $1,297.40 130
LG M36 5.1 3450 $5.49 20 12.0 240 $1,317.60 61
LG M29 10 2850 $3.99 20 14.0 280 $1,120.00 140
LG HG2 20 3000 $4.99 20 14.0 280 $1,397.20 280
Pan 29PF 10 2900 $4.49 20 14.0 280 $1,257.20 140
Pan B 4.9 3400 $4.99 20 12.0 240 $1,197.60 59
Pan BD 10 3180 $4.99 20 13.0 260 $1,297.40 130
Sam 30Q 15 3000 $4.50 20 14.0 280 $1,260.00 210
Sam 25R 20 2500 $3.79 20 16.0 320 $1,212.80 320
Sam 25S 25 2500 $7.49 20 16.0 320 $2,396.80 400
Sam 35E 8 3500 $4.99 20 12.0 240 $1,197.60 96
Sam 26F 5.2 2600 $3.99 20 16.0 320 $1,276.80 83
Sam 36G 10 3600 $6.49 20 12.0 240 $1,557.60 120
Sam 26J 5.2 2600 $3.49 20 16.0 320 $1,116.80 83
Sanyo GA 10 3500 $5.49 20 12.0 240 $1,317.60 120
Sony VTC5A 25 2600 $4.99 20 16.0 320 $1,596.80 400
Sony VTC5 20 2600 $4.99 20 16.0 320 $1,596.80 320
Sony VTC6 15 3000 $5.99 20 14.0 280 $1,677.20 210
Sony VTCD 25 2800 $6.99 20 15.0 300 $2,097.00 375
 
Excl sanyo...$$$
Excl any cell under 10a Max discharge
Excl any cell under 3000mah
Include any combo that gives : cell cont amps x #P groups = >120amps

Then choose 30q :lol:
 
You could consider the Boston Power Swing 5300s maybe. 13A continuous discharge per cell, half the batteries in parallel to have to weld or solder ....and you will not be spending anywhere near the $$. You could also increase capacity/discharge with those savings. If interested I have a good quantity of them. They are a very good under rated battery.

Here is a link to the spec:

http://liionbms.com/pdf/bostonpower/swing5300.pdf

And a link to a review of them by Thunderheart on this forum:

https://endless-sphere.com/forums/viewtopic.php?t=90938

If interested PM me and I can put a package together for you.
 
Headrc said:
You could consider the Boston Power Swing 5300s maybe. 13A continuous discharge per cell, half the batteries in parallel to have to weld or solder ....and you will not be spending anywhere near the $$. You could also increase capacity/discharge with those savings. If interested I have a good quantity of them. They are a very good under rated battery.
Here is a link to the spec:
http://liionbms.com/pdf/bostonpower/swing5300.pdf
And a link to a review of them by Thunderheart on this forum:
https://endless-sphere.com/forums/viewtopic.php?t=90938
If interested PM me and I can put a package together for you.
Click to expand...
is there data about how they respond to dead shorts and other fun stuff? oval means they can puff a bit and how violent do they vent/explode under thermal situations?
the weird form factor makes it a pita to mount properly.
 
I have had several customers that have told me that they they feel the Boston Power's take a lot of abuse. One in particular found that because of some bad solder joints he had several cells that were over-discharged but he still was able to use the pack for several days before discovering it ...and then the rest of the cells were still rock solid. I personally have committed the error of having some dead shorts when building some of my own personal packs. But did not experience any damage to the batteries and all was well after that happened. Dealing with these batteries for the last couple of years, I nor anyone that I have sent these batteries to have experienced any puffing. The aluminum casing on them also helps with heat dissipation. Yes the oblong design could possibly provide a design challenge, but it really is like two 18650's in one package so you also have the advantage of a little less plastic holder dimension as well as 1/2 the parallel connections. There are all kinds of good batteries out there, but the Boston Power's are an under rated and good choice for many applications ...and that is not just because I have a good quantity of them and sell them. I would choose them for my projects many times over for all of the stated reasons. Not to mention good discharge rate and long cycle life. Hope that helps.
 
flippy said:
never use Ga's for this. you will kill them in under a year.

use samsung 29E7 (mind the 7) or if you cant get those the older 6. PF's are also a option but are a bit more saggy under serious loads.

personally i would not get a pack that will keep under 2C for peaks and WAY under 1C for sustained loads. that way your battery will last many times longer.
Click to expand...

Hey flippy

How are Samsung 29E7 better than the Ga cells? They both can deliver max 8 Amp continious. Only difference I can see is the Mah. Hope u can make it clear for me.
 
the GA are higher capacity and sag considerably more and have much shorter lifespan by comparision. and they are much cheaper then the 29E's.

fun fact: i discharged a couple 29E7's to 0.5V and left them 6 months and recharged them and still have 90% of their capacity.

old jedi proverb: higher capacity does not a better cell make.
 
flippy said:
the GA are higher capacity and sag considerably more and have much shorter lifespan by comparision. and they are much cheaper then the GA's
Click to expand...
You just stated GAs are cheaper than GAs.

 
john61ct said:
flippy said:
the GA are higher capacity and sag considerably more and have much shorter lifespan by comparision. and they are much cheaper then the GA's
Click to expand...
You just stated GAs are cheaper than GAs.
Click to expand...

sorry, the 29E7 is cheaper, the 29E6 is even less.

also: the nickel plating on the GA is shit. once they meet humid air they tend to start rusting pretty fast.
 
Thanks for the info flippy. I though the Sanoy GA is reliable enough to use. Lucky I havent bought any cells yet. If we compare the E29 vs E35, how is the life span between these 2 cells?
 
anything higher capacity will by defenition have lower lifespan.
for the price per Wh you can build a bigger battery with the E29 then any other cell increasing the lifespan even more.
 
My understanding is, the energy **density** is in opposition to longevity.

Not Ah capacity in itself, if your use case doesn't care about weight.

 
john61ct said:
My understanding is, the energy **density** is in opposition to longevity.
Not Ah capacity in itself, if your use case doesn't care about weight.
Click to expand...

density is equal as all 18650 cells are...18650 in size. so the equalizer is capacity in whatever format you prefer. and GA has more so they have shorter lifespan.
the only reason to choose a higher capacity cell like the GA is because of size constraints as you need to sacrifice cost and lifespan for a higher energy density battery.
 
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