30Q - 6p build... bike range disappointing - IDEAS?

Batteries, Chargers, and Battery Management Systems.
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30Q - 6p build... bike range disappointing - IDEAS?

Post by djbrandonr » Feb 21 2018 3:55pm

So I built my first 10s6p build using a vruzend kit and had a thread about that here about a month ago.

At any rate the actual range I get out of the pack is way less than what I was expecting... out of 3 batteries I use on my ebike, which is also a delivery bike in NYC, my 30Q has the worst range for Ah.

So heres some specs for reference... im running a 500w front hub and Im about 135lbs... Beside variables I think what is most important from it all is that my driving/riding habits are pretty consistent regardless of which battery is plugged in and NYC is pretty flat for the most part with minimal hills and climbing needs.

Since my bike is a work bike I usually swap the battery before its dead...more like when the juice is low and i need to start pedaling a bit more than normal, or the battery is starting to slow me down then its time for a swap... probably around 20% at rest.



Battery 1 - is a 10s5p 10Ah from diyeboard.com about 16mi before the bike starts getting slow

Battery 2 - is a 10s8p comprised of 4 - 10s2p packs all connected in paralell. These are the ebay packs from alarmhookup if youre familiar and although advertised as 4.4Ah per pack, online tests show closer to 4Ah... so 16Ah and this will yield me 25mi about before its slow

Battery 3 - DIY 10s6p 30Qs (from NKON) and supposed to be my highest capacity pack at 18Ah.... sadly i get about 16mi from this pack and not sure why.

If you have any ideas...thoughts...trouble shooting.. im all ears.
Last edited by djbrandonr on Feb 25 2018 8:32pm, edited 1 time in total.

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by Marin » Feb 21 2018 5:03pm

Is it still a Vruzend pack now
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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by djbrandonr » Feb 22 2018 8:38am

yes...its been maybe a few weeks of running this new pack

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by Honk » Feb 22 2018 1:53pm

Perhaps fake or old cells with low capacity.
Have you timed the pack at controlled discharge rate to see actual capacity?
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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by amberwolf » Feb 22 2018 2:08pm

The first thing I'd recommend is running all the packs in parallel, becuase the load will be less on every one of them, and have less voltage sag and less power lost as heat. So you'll get more total range with them all connected at the same time in parallel than you will with them separate.


The second thing is to check that all the cells in the Vruzend pack are actually getting good connections, with equal connection resistance. If some of the paralleled cells in each group (or any one group) are not connected well, those cells will contribute less to the current provided, and sag more, and the whole group will perform poorly.

If the series connections between groups have high resistance, then teh entire pack will perform poorly, with a lot of voltage sag, and as it gets closer to empty that sag means cutouts due to LVC (either of the controller or the BMS, if any), even though there's potentially plenty of capacity left.


The third thing to check is whether or not those cells are actually all good, (or what they say they are). Bad cells cause low capacity or poor performance or both. One cell group that's not fully charging, or is self-discharging, will reduce the whole pack's performance by that amount.

If it's just an unbalanced group, if you have a BMS, leaving it on the charger overnight will fix a small imbalance, but a large one may take days or weeks to fix. If you have a single-cell charger you can manually fix it a lot quicker. If you have no BMS then the SC charger is the only way to fix an imbalance, or an RC charger that has a balance mode.

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by brumbrum » Feb 22 2018 3:36pm

I'd be extremely surprised if the cells from Nkon are fake. I actually have just built a pack 20s 9p with 30Q's from Nkon. I too have been a little underwhelmed by their performance. But this is mainly due to changing from an equivalent lipo pack that had much steadier voltage discharge, which meant much steadier speed, less voltage drop and more usable capacity. Just out of curiosity, what do you set your low voltage cutoff to? I would suggest that it could be voltage sag, but a 6p pack should be good for 60 to 90amp pulls from the motor which i doubt very much you are doing from a 500w rated motor.

When you say... You swap the battery when the bike slows down, is this your only way to determine the state of charge? 18650 cells have a very linear discharge track that will steadily give less and less top speed as they discharge.
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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by djbrandonr » Feb 22 2018 4:44pm

brumbrum wrote:
Feb 22 2018 3:36pm

When you say... You swap the battery when the bike slows down, is this your only way to determine the state of charge? 18650 cells have a very linear discharge track that will steadily give less and less top speed as they discharge.
i have a cheap voltmeter wired in... displays battery voltage or a percentage... usually around 20%

https://www.ebay.com/itm/LCD-12V-24V-36 ... 2749.l2649
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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by djbrandonr » Feb 22 2018 4:49pm

amberwolf wrote:
Feb 22 2018 2:08pm
The first thing I'd recommend is running all the packs in parallel, becuase the load will be less on every one of them, and have less voltage sag and less power lost as heat. So you'll get more total range with them all connected at the same time in parallel than you will with them separate.
not enough storage space on the bike to have all batteries in parallel and the bikes getting heavy enough as is =P
The second thing is to check that all the cells in the Vruzend pack are actually getting good connections, with equal connection resistance. If some of the paralleled cells in each group (or any one group) are not connected well, those cells will contribute less to the current provided, and sag more, and the whole group will perform poorly.

If the series connections between groups have high resistance, then teh entire pack will perform poorly, with a lot of voltage sag, and as it gets closer to empty that sag means cutouts due to LVC (either of the controller or the BMS, if any), even though there's potentially plenty of capacity left.
what value would i be looking for when testing resistance?
The third thing to check is whether or not those cells are actually all good, (or what they say they are). Bad cells cause low capacity or poor performance or both. One cell group that's not fully charging, or is self-discharging, will reduce the whole pack's performance by that amount.
If it's just an unbalanced group, if you have a BMS, leaving it on the charger overnight will fix a small imbalance, but a large one may take days or weeks to fix. If you have a single-cell charger you can manually fix it a lot quicker. If you have no BMS then the SC charger is the only way to fix an imbalance, or an RC charger that has a balance mode.
I got the bms from vruzend as well.. overall the pack charges up to 41.6 roughly and seems to be balancing well so far

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by Voltron » Feb 22 2018 10:40pm

How's the temperatures been? Abnormally cold or anything?

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by TheBeastie » Feb 22 2018 10:56pm

Yeah I was wondering if they do not like the cold, maybe the 30Q don't do well in the cold, I have noticed I get a fair bit more range during the summer on my Samsung 29E's vs winter.

It's something I been wondering how and that is how much energy can be lost from low quality contacts that the battery kit you used cause, I have my dodgy built neodymium battery pack solderless battery but I don't on average draw more than 400W from it and its 12S7P.
Obviously, low power draw is crucial at least to some degree with solderless battery setups but the real question is by how much.

Also how are you charging the battery? As you charging at a high rate? I charge my pack at no more than 1Amp per cell ever, I charge probably at an average of .3amps/300ma per cell via a CB86 pure parallel balance charger. From my experience charging at a low amp rate gives more range.
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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by Hillhater » Feb 23 2018 1:10am

Cold sure can hit range (capacity) hard.
Even Tesla, with their pack heaters suffer badly in severe cold.
There is a guy on this video with a Model 3 who says this cold weather has cut the range by more than 50%
https://youtu.be/D2gmphV8IZQ
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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by dogman dan » Feb 23 2018 7:49am

All any of us can do with the above information is guess. But my guess would be resistance is higher at the contacts in the no weld pack. But just one defective cell in the pack would also do the trick nicely.

What I mean by guessing, is that nobody knows the actual real world capacity of any of these packs. If I was you, I'd buy at least a cheapie watt meter. Then measure the actual real world capacity of the packs. Your current device is calibrated for lead, and you aint running lead. So you might have more left than you think in all your packs when you stop.

That leads to a question of measure to where? With a better device, you can with some experience, find out where the cliff in the discharge curve is at the bottom of the discharge. Measure capacity in watt hours or amp hours by discharging to that cliff. That cliff may not be the same voltage for each pack. It certainly wont, if any of these are different chemistries. At 20% left, you are not measuring the full capacity. You can actually find the cliff in the discharge with just a voltmeter. Riding slowly near the end of the discharge, you will suddenly see a very quick drop in voltage even under very light load. This is the cliff, and the time you absolutely must stop. By then, be riding in circles near home. But your device will not measure capacity, so you need the blue wattmeter on ebay.

I think you have discovered though, that sag under load is worst on the new pack, again, this could be extra sag caused by the connections. You might be stopping with more than you think left is what I mean. So it rides like 20% left, but might be more left than you think.

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by djbrandonr » Feb 23 2018 9:48pm

dogman dan wrote:
Feb 23 2018 7:49am
Your current device is calibrated for lead, and you aint running lead. So you might have more left than you think in all your packs when you stop.
no, it works for lith ion...you just set it up for what ever battery type u got... today i payed a hair more attention to voltage and would say around 34-35v is about when the batteries start to get sluggish...

I cant say the weather has been too cold..it is nyc but the main cold snapped has gone and passed already... if it were cold weather diminishing range Id expect to see it across the board (of batteries) not one particular pack

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by TheBeastie » Feb 23 2018 9:52pm

Hillhater wrote:
Feb 23 2018 1:10am
Cold sure can hit range (capacity) hard.
Even Tesla, with their pack heaters suffer badly in severe cold.
There is a guy on this video with a Model 3 who says this cold weather has cut the range by more than 50%
https://youtu.be/D2gmphV8IZQ
Yeah wow, that is crap, 50% loss of range due to cold, its things like this you never see on mainstream media or even all the silly big-fan Tesla 3 youtube reviews, found the spot where they mention that specifically https://youtu.be/D2gmphV8IZQ?t=5m47s
Speed Kills Range, 10mph = 46 miles range, 20mph = 20 miles, 30mph = 8 miles range https://goo.gl/1JNL53
Over Charging Kills ur battery bit.ly/1hzWKl4
Consider PAS as your only throttle https://goo.gl/Kg1F8F
Fuel-Cell is the ultimate battery coupled with 4th-gen Nuclear https://goo.gl/ZhFFot
https://goo.gl/gfa215
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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by 999zip999 » Feb 23 2018 10:16pm

? Where do you live what's the temp as it is freezing cold here in Southern Cal

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by brumbrum » Feb 24 2018 5:01am

You have in total a voltage range of 42 to 25. That is a big range which will hugely effect top speed during the discharge. Once you get past nominal voltage of 36 you will notice an ever growing lack of speed. You will be able to still pull the amps you need with of course more sag but speed due to voltage will be lower. I guess in percentage that will be between 25-30% . So 30mph could possibly go to 20mph by end of capacity. These are rough estimations, no math.

otherwise, something else is causing sag,
Weak cell
Weak insufficient cell connections
Loose battery connection
Insufficient wiring
Cold weather

If you are just road riding with a 500w motor i would expect to see at least 1.5 mile per ah.

I thought the vruzend connections wer only good for 3-5 amps? Giving you a total of 30amp. How many amps is the motor using?
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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by 999zip999 » Feb 24 2018 9:02am

Si what is the amperage demands of the controller you are using

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by djbrandonr » Feb 24 2018 11:35am

999zip999 wrote:
Feb 24 2018 9:02am
Si what is the amperage demands of the controller you are using
no clue, but heres the link to the hub i bought... id assume a range of something like 30-40amp? but the BMS is a 35amp max so that would cap it even if the controller wanted more...

https://www.amazon.com/Pinty-Conversion ... +ehub+500w
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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by djbrandonr » Feb 24 2018 11:39am

brumbrum wrote:
Feb 24 2018 5:01am

I thought the vruzend connections wer only good for 3-5 amps? Giving you a total of 30amp. How many amps is the motor using?
heres what the site says which i may have overlooked but an interesting thought..

"We recommend that for best results, you limit the current draw of the battery pack you build with Vruzend battery caps to approximately 3.5 A continuous per cell. Current bursts of up to 7 A are acceptable, but for periods not exceeding 10-15 seconds. Higher current results in more waste heat being generated which can rob your pack of performance. That means that if you build a battery with six cells in parallel, you should try not to exceed about 20 A continuously with that pack, though bursts of higher current are ok. We’ve had some people do tests with higher current, but it usually isn’t worth the extra waste heat. Extremely high current can even be dangerous. Please be safe and don’t try to pull too much current from your battery cells – this is true with any battery building project, not just with Vruzend kits."

so does this mean 30Q s are too strong a cell for this kit, especially in 6p meaning all the range is lost in heat? i would say I run half throttle most time maybe a hair more, trying to balance out range instead of just speed.

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by brumbrum » Feb 24 2018 12:08pm

you can never have too strong a cell, only too strong a draw from the motor and controller which the battery cannot feed enough juice to. Its not your batteries themselves, its going to be something else stopping the current from flowing that would cause resistance , equalling a heat issue.

I have a 500w rated motor on my commuting bike and it only tends to pull about 22amps on a steep hill, other than that it only uses half that when up to speed.. Though it is a slow motor 201rpm top speed 18mph.

But, we do not know if this is the issue. Perhaps you now need a way to see how many amps your motor is pulling from the battery, and have an idea what the amp limit of the controller is. You need a watt meter
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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by brumbrum » Feb 25 2018 6:39am

https://m.ebay.com/itm/Digital-1602-STN ... SwEzxYShI9

You will be able to get one closer to home if needed quickly
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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by docw009 » Feb 25 2018 6:31pm

djbrandonr wrote:
Feb 21 2018 3:55pm
Battery 1 - is a 10s5p 10Ah from diteboard.com about 16mi before the bike starts getting slow

Battery 2 - is a 10s8p comprised of 4 - 10s2p packs all connected in paralell. These are the ebay packs from alarmhookup if youre familiar and although advertised as 4.4Ah per pack, online tests show closer to 4Ah... so 16Ah and this will yield me 25mi about before its slow

Battery 3 - DIY 10s6p 30Qs (from NKON) and supposed to be my highest capacity pack at 18Ah.... sadly i get about 16mi from this pack and not sure why.
I bought the earlier Samsung/LG batteries from Alarmhookup. I've run them down and filled them up, and my wattmeter always says they're 4AH. So using them as a calibration, your new battery is 16AH x 16/25, or 10 AH? That is way off. However, it's very consistent with your first battery.

I would think that there's a bad connection in the new battery, and one or more of your parallel cell groups has bad contacts to 2 or 3 cells. Off the top of my head, I cannot tell how to check for that, unless those cell group come down faster in voltage. They probably should if you are pushing higher currents. Have you walked your voltmeter up the BMS balance points to check for consistency in voltage?

As for your Vruzend response, sure it's good to hold down the current on a battery, but with 6P, I think you're in the safe operating range. Are they saying between the lines that 4A per cell overheats their metal parts and increases contact resistance? That would negate the usefulness of their system.

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by djbrandonr » Feb 25 2018 9:03pm

brumbrum wrote:
Feb 24 2018 12:08pm
You need a watt meter
ordered a cheap watt meter off amazon the other day..so will see in a few days once it arrives..

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by djbrandonr » Feb 25 2018 9:05pm

[/quote]

I bought the earlier Samsung/LG batteries from Alarmhookup. I've run them down and filled them up, and my wattmeter always says they're 4AH. So using them as a calibration, your new battery is 16AH x 16/25, or 10 AH? That is way off. However, it's very consistent with your first battery.


[/quote]

no.. ebay packs equal 16ah and about 25mi range

diyeboard pack is 10ah getting about 16mi....

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Re: 30Q - 6p build... bike range disappointing - IDEAS?

Post by 999zip999 » Feb 25 2018 9:16pm

Those kits usually have a 22 amp a 26 amp and a 36 amp controller. So ?

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