Wowza 20Ah Multistar 6s !

[neptronix]

I did a hard 8km ride today and did lots of wot, 60amps out of my 6.6ah packs , oh so warm. I think heat wise these packs are better rated to say 5c cont.

If you want a cool running, long lasting, high discharge efficiency, low voltage experience with any battery, the rule is always to run 1/4th the rated maximum C of the battery continuous,

That applies to pretty much every lithium battery i've seen.

So, get more amp hours in parallel..

 

[Jestronix]

Any one running these yet ?

 

[neptronix]

Any one running these yet ?

I have a pair but have been too busy to test them until next week.

 

[kiwiev]

Has anyone in Australia tried them? And if so how much?
Cheers Kiwi

 

[Jestronix]

Just to mix things up they have these 8s 12ah units now , dam things are only 2c continuous though, no that is not a typo. 24amps continuous , would that even lift a multi rotor ? However these would be a bargain for low kW ebikes. But 2c is terrible where did these come from ? Laptops ?

 

[mechhead]

I live in adelaide and I have one of these 20 ah 6s bricks on a friction drive+ vesc-x controller 1200watt setup i built myself, i just ordered another to get up to 12s i have only run it down about 5 times and i had a scare when i discharged the pack too low on on e cell 2.95v but i had the lvc in the vesc set too low as im a noob to this lipo stuff. i ave a good balancer, good multimeter and a good balancing charger. I get 18.5ah into the pack with a 150 watt rc charger set to liion 4.1v cutoff but its internal balancing device does a poor job with the charge ending with balance inconsistancy where when tested with a battery medic and my fluke meter (charger says 4.10 on all cells) = 4.10-4.11- 4.09-4.07- 4.07 4.07 on the fluke i put this down to poor quality referencing and thermal effects within the charger it is an ISDC 150 smart charger and other than this slight charging inconsistancy it works great. the lipo brick gets barely warm to the touch after a very long hill on the way to uni wher the motor is too hot to touch and the vesc-x with no extra heatsink goes in to thermal rampdown to about 2/3 power. i cant get any more than 1200 watt in to the tyre with out the motor slipping and this is with careful juggling of the tyre pressure to get good tread wrap around the motor shell (6354 200kv outrunner of cheapest aliexpress type. later i plan on a direct leftside chain drive mounted to a breakdisk mount and using a 83mm dia by18mm thick stator heavy lift 48pole drone motor pulling on a 219h chain with regen and a clutch in the sproket wheel mount if i can engineer it tobe 7mm thick and take the 2800w power or it will be direct drive and if it goes flat i will just take the chain off and tie it to the dropouts out of the way i just ordered a second 20 ah 6s brick because the 200kv motor is just too slow running out of juice at about 27kmh

 

[ScooterMan101]

Mechead,
Try cycling the Multistar's some more to see if your imbalance is temporary . ( Mine are better after 7 or more charge / partial discharge cycles )

In regards to your charger, I have two different ones, one balances much better than the other, and they read high while on the charger. A few seconds or a minute after being off the charger they read lower, like from 4.18 on charger to a real 4.14/.15 with a volt meter a minute or so later.

Even though the Multistar batteries are such a good deal, I got the Zippy's , they come in 25c and up . Zippy also makes 8 s packs now.

I would only use Multistar's on a small motor like the Q100/Q 100c CST , which likes to run at around 15 amps max.


When riding my bike I only take the battery down to about 3.8 volts per cell, on 90% or more of my rides .
Once or twice to about 3.65/3.7
one time I tried 3.6 and when I got back and put the pack on the Digital Battery Capacity Checker it displayed around 9% or so, ... so I am not doing that again. I am going to only go to a minimum of 3.65 now .

It is easy to have a back up to let you know when one of your cells drops below a certain point . I bought one of these. ... http://www.buddyrc.com/digital-voltage-checker-and-alarm.html

At such a cheap price I bought 2 of the voltage checker's with alarm , one for each series pack ( in my case 2x 6 s or 7s , with another 2 in parallel , ) Although It would be good to have one on each battery.
The Alarm does work, even with high wind noise in the ears.
The Alarm can be set , but not to a .05 , so it must be set for 3.5 or 3.6 or 3.7 volts , etc. ( not 3.65 so must be 3.6 or 3.7 , etc. )

I also like to charge to 4.15-4.18 v per cell so that I do not run the battery pack down too low. which I only did once to 3.6 v

I look forward to your write up on your Left Side Mid-Drive, Are you making it to go up the Adelaide Hills ? the ones in the Tour Down Under ? ( I need to go up 6% -to 14 % , and even steeper Grades )
What is the Altitude Gain from Adelaide to the top of the Hill . ( I forgot the name ).

 

[docnjoj]

I unfortunately destroyed 2 6S multistars running in series by forgetting to recharge before a second 20 mile ride a day after the first one. I believe they were down to0volts, but I slowly recharged them ad go t couple of months more out of them. They were great before this but never the same after and I finally ditched them when the voltages were a few tents of a volt off every time the Thunder charger stopped.
I now know I should have use the alarm.
otherDoc

 

[MadRhino]

...
I now know I should have use the alarm.
otherDoc

Fit a voltmeter right in your face on the handlebar. 3$

With the power I feed, letting them fall lower than 3.7 start to smell, and fire is only a minute later.

 

[mechhead]

yes scooterman101 I live in adelaide where the tour downunder races, the biggest hill is the old freeway to near the top of mt lofty (peak 727m city centre is about 45m) but this is not where I commute to. I dont expect I would get to the top on two of these multistars although I may try one day to see how far I get although I worry about smoking the motor, I guess I would have to have a few cool down stops . I ride from walkervill near the city centre about 22km and altitude change of about 120m to flinders university, this battery gets me all the way there and 9/10 of the way home before my controller quits from LVC. I had that set to 3.5v per cell but now realise that charging to 4.1 and going no lower than 3.6 will get me a lot longer life. I ordered a second one of these lipo bricks. The lazy cell seems to have stabilised and the pack now holds balance well and after the last long commute it took a whole 20.8ah from 3.5 to 4.2 but I have changed the LVC to 3.6 and only charge now to 4.1 and after several more trips to the city for shopping with my daughter 3Yo and her trailer full of shopping a 10 k round trip this typically uses about 11to 12 ah from the pack . the battery seems to be growing larger as it wears in and now soaks 18.5 ah between 3.6 and 4.1 mind you some is charge efficiency loss and charger wastage

with my current settings of 40 amps battery max (2C) battery is rated at 10C it gets barely warm in its winecooler/battery warmer bag after draining half its capacity over about 45 minutes, come warmer months ill finish the proper battery box on the down tube using the bottle mount and fanforced cooling through corflute board packing around and between the batteries, this will allow a good mix of insulation for cold weather and active cooling for when its hot , i found a cool cpu cooler fan driver board that has adjustable fan speed temperature sensing that i can modify down to manage for 35 degrees

my home made motor bracket is a kepler copy of my own construction made with a heavy steel door hinge and some 50x50x5mm alloy angle section and a lot of work with hacksaw ,hand file and a drill press. The design could be better the fulcrum is too high and the motor requires an elastic strap to assist it to climb up the tyre, with only the gravity spring (coat hanger wire) it would only engauge properly at full power and slip on the tyre with any less but with the elastic it works perfect from minimum throttle to about 800w, any more and it slips against the tire. with better enguagement angles it would probably work better at higher tire pressure but i doubt it would be able to take any more power. I think im doing well as many other friction drivers say they struggle to get more than 500 w into the tyre .

I love the simplicity of only charging one or two large lipos and wiring compared to massively Series and Parallel packs of small lipos . They had the best price per watt I could find here in aus as well. I cant wait to get the second pack in with my new solid state switch to prevent arcing, my xt90 plugs are beginning to show some splatter marks and the extra volts should be good for about 60kmh, better efficiency in the controller and lots more range but my leaden thumb may kill the extra range unless I set the controller limits lower. I love the vesc on foc sine mode it makes the motor so quiet most people I have passed dont even notice the motor trapezoidal controllers squawk loud in comparison, most people dont believe such a tiny motor could pull the skin off a banana, let alone me and a kid trailer full of small girl and shopping, i have the ebike grin, im now a confirmed addict

 

[ScooterMan101]

mechhead,

The Old RC Pilots out at the Flying Field say that you can charge to 4.2 volts or 4.18 , However , you only do that just before you use them.
Example :
When you get home charge them to 4.0 - 4.1 volts, it is Ok to let them sit at that voltage over night, 4.0 if you are concerned , then just before going out for your ride charge them to 4.18 or 4.2 .

You can also take them down to 3.65, However the little Battery Checker and Alarm does not let you do that , they only work to tenths , like 3.6/3.7/3.8/3.9 etc.

If you charge to 4.18-4.19 just before your ride perhaps you can make it all the way back home before getting to 3.6 v per cell.

I miss Adelaide, I lived in Unley , in a an old Blue Stone House, quiet street, with a very short and easy bike ride to down town. I often think I would like to spend a few months each Winter ( our Winter ) down there,
The Airline Ticket Cost, and Where to Stay are the only things presently in the way , of me getting back there. ( I am not going to tie a bunch of balloons to a Deckchair )

What is the name of the road up to Mt. Lofty ? where the Roadies ride ? I forgot where it is, I never did go up there.
Also
Is there now a off road/trail up there that you can bike up ? or is that no motors allowed ?

If you have any youtube videos of your rides around Adelaide / up the hill , I would certainly watch them.

 

[docnjoj]

...
I now know I should have use the alarm.
otherDoc

Fit a voltmeter right in your face on the handlebar. 3$

With the power I feed, letting them fall lower than 3.7 start to smell, and fire is only a minute later.

Yes Mr I thought of the voltmeter as we were coming back on the second 20 mile ride. I got towed but those cells were quite dead. No fire no smoke and they did recharge at about 0.1 amps. I finally put them in a bucket of salt water outdoors and let them die completely.
otherDoc

 

[John Bozi]

I'm proabably going to do 4 x these 6s 20ah packs for my new qulbix 76 frame. 100v 20ah

A few points mentioned.

smaller packs are better to weed out the dud cell. My counter argument to this is I will be more likely to balance charge more often 4 batteries instead of 8, 12 or 24 for that matter.

price per watt is higher for sure but again, I would be happy to pay extra to have less connections to deal with in the balancing scenario. In this case NO parallel harness too.... I would probably cut off the xt90s and crimp in some gold bullets for daisy chain too.

why not 7s? there are tons of cheapish 6s balance chargers, a lot of those odd packs last time I checked a year or so ago were all double complexity to charge something like a 3s + 4s...

mentioned on another thread

This frame was designed for 18650s which many say end up lighter and tougher I think designing a couple of thin boxes for the packs shouldn't be too hard and the weight shouldn't be too noticable....

The complexity of battery making is yet another field of tools and time.... I have had cylindrical cells before and found it impossible to fix with my limited knowledge....

This

vs

I just hope this will deliver 5kw continuous a few burst a bit over.

 

[ScooterMan101]

There are 7s chargers ( up to 8s ) available now, one for around 50 US $ , at H.K. I have one and it works great. And I use the Balance mode every time I charge , I most often just charge 4.16-4.18 volts or even less, per cell.
it seems to keep them within a
.03-.04 difference for all packs. ( mostly .02 difference max between all the cells in the pack. )

and

Contact iSDT in China, they make great little and powerful 6s DC chargers now, However they said that latter this year they are are going to be offering/selling their newest model which will go up to 8 cells.
I say contact them because the more people who contact them and ask them when they are going to make a DC charger that charges up to 8 cells ( 8s ) the faster I think they will make it available.

Not sure what final voltage you want to go with, Zippy makes higher C rate 7 s batteries . ( I have 4 of them ) they are all lower amp hours, so there would be more of them/ more connections.
However with 5.5 mm bullets I find connections simple enough. ( I have a different color heat shrink , a small band that I put on the Red + wire of one pack and Black - wire of another pack and then I connect those two packs into series.
that makes the connections simple and makes for a quick double check of connections )( to further make it simple I label the packs 1 & 2 , and 3 & 4 , always connecting packs 1 & 2 together and packs 3 & 4 together )

Making your own Parallel Harness is very easy.

Less connections to to deal with in the balancing scenario ? ? Each Lipo pack has balancing wires / plug that plugs into the charger . and if using a Parallel Charging Board, they have the correct number of connections/plugs .



So if the 7 s packs or even 8s packs will fit into the frame better , you could get them. As far as having allot of batteries, I just make it simple by using 4 together in a Series/Parallel set up, then when going for further distance , just un plug them and plug in another 2 packs during the ride, there is always a reason to stop, weather riding the Road or Off Road.

Remember, very important if you are going to make a high power e-bike, the Multistar's are only 2 c rated, meaning in reality you should only pull ... 0.5c that means one half of 1 , continuously.

A RC Helicopter Pilot I know , Only ... uses 45c or higher c rated batteries !

smaller packs are better to weed out the dud cell. My counter argument to this is I will be more likely to balance charge more often 4 batteries instead of 8, 12 or 24 for that matter.

price per watt is higher for sure but again, I would be happy to pay extra to have less connections to deal with in the balancing scenario. In this case NO parallel harness too.... I would probably cut off the xt90s and crimp in some gold bullets for daisy chain too.

why not 7s? there are tons of cheapish 6s balance chargers, a lot of those odd packs last time I checked a year or so ago were all double complexity to charge something like a 3s + 4s...

mentioned on another thread

 

[John Bozi]

.5c rated? obviously not on their packaging then by who? I don't have any helicopter hobby friends but I do have some riding buddies who have won electric bike races running multistars. Here is one of his posts. https://endless-sphere.com/forums/viewtopic.php?f=14&t=61672&start=425#p1261007


I thought they are 10c advertised so go by quarter of that for a truer 2.5c x20ah = 50a x 100v should pull 5kw or realistic end of pack voltage 4kw should be enough cruising.

less balancing connections than some say running 4s and 2s packs should be obvious. I own enough 6s balancers to buy higher counts.

My last bike was 22s "10ah" like that to "save money" 10x4s 2x2s hardcase packs.

Each to their own, I prefer not making and carrying a harness. Less wiring the better. I still consider the max I can fit around is with the 12ah packs but the 2p wiring hassle for an extra 4ah is mmmmm spaghetti.

My final voltage should be clear 4 x 6s will do more than I need.

 

[ScooterMan101]

John,

I was stating the 0.5 because I read on this thread that they are 2c rated, for longer life it advisable to use 1/4 of their rating, or up to 1/3 .
I will go and look at HK and see what they list .

There are people who run Lipo's at their full C rating or near to full C Rating , but from all I have read, and from RC Pilots that I have talked to , that shortens the life of the batteries quite a bit.

If you do get big packs like 10 amp hour packs you can run more powerful motors, especially if you are paralleling, but I am also looking at your drawing and it is showing that the 4 multistar's are
not fitting into the frame.

And for off road don't you want plenty of padding in there , since Lipo's are so volatile ? or are you making a pavement track racer ?

Edit: I just went to H.K. website, and they list the battery you are looking at buying, at 10c constant. so someone in a post above in this thread was mistaken, And me reading that lead me to the 0,5 I listed above. he said they were 2c but he probably meant the you should only run them at 2c,
So I stand corrected, I would think that running them up to 3c would be fine . ( for longer life and less possibility of problems )

 

[John Bozi]

I've asked for the lip of the frame dimensions and fastener dimensions on ES already a few times with no answer. So whether or not I can buy this battery will have to wait till I get the frame in my hands.

Padding a battery with sponge is a joke. 10+ kg and some sponge is going to do nothing but leave space for hits. What it needs is a solid hard shell to stop the corners weakest points hitting ( a bit of hard rubber if fits), and lots of suspension between the bumps and the battery, if you can't get that to happen at your forks and rear suspension you will be in trouble.

This is my 4th bike I am about to build for off road running lipo after cylindrical cells. I just keep seeing the same thing recently.

I think the last 4 fires were 18650s so robust.

https://www.thesun.co.uk/news/3777723/cyclist-runs-for-his-life-after-electric-bike-explodes-in-a-fireball-under-his-bum/

 

[ScooterMan101]

https://www.thesun.co.uk/news/3777723/c ... r-his-bum/

" Experts said the bike had been fitted with an electric conversion kit available online for around £140 that can reach speeds of 28mph. "

One of those cheap E-Bay kits ?

>

I agree on not using soft sponge , H.K. does have some more dense foam/padding , it is thin so a few layers would be good.

https://hobbyking.com/en_us/peel-n-stick-foam-double-sided-tape-10x5inch-4mm-white-c.html

 

[ddk]

I've been running 4x 2S 2P of the 16Ah 6S multistars for over a year now and so far they've provided satisfactory service.
With 32Ah available I don't really worry about c-rates, but I did test one up to 2C where it showed no signs of significant heating. (the scientific notion of significant is actually just a measurable change, so it might be my methods used that indicated no heating where there might actually be some)
Also it's nice 4 of these 6S 16Ah packages neatly fit into one of my pre-determined battery cases.

Since my controllers are less than or equal to 30A I don't see any issues. The part I like is that I have so much capacity in *just* the multistars I only need to recharge my batteries about once every four weeks.
~OK~ I overdid this battery thingy *0_o* but to be fair, I use the trikes for ALL my transportation/recreation needs I use these meters installed in each battery case so I can keep tract of how much power I've used. And I usually recharge when the cells resting voltage is about 3.85V.

I over-discharged one pack to 1V point something, but unlike docnjoj, I was able to recover the cells probably because I didn't discharge them to 0V and they were discharged at a relatively low rate (left that controller turned on for a couple of weeks)

hope any of this is helpful.