Zippy Flightmax / Turnigy lipo testing

[Metallover]

The only thing you need to worry about is a pack going below 3.0v/cell. This is why a bms that monitors every cell's voltage is great. If you have two paralleled 6s packs, making sure neither gets below 18v should be all you ned to do, if anything.

These packs are made to dischage at 20-30c continuous and with an ebike you are pulling maybe 5c up a hill (with a 10ah pack). The cells don't go out of balance very easy unless they are pushed (which an e-bike usually doesn't).

The voltage of one paralleld pack shouldn't really effect another, because they should be close already. Make sure all you packs are balanced before you start on your ride and you should be ok.

 

[Hyena]

After saying how great using DB25s are, in my latest build I kinda got lazy and just left 3 6s balance taps hanging out the back of my pack.
I solder my packs at the cell level to essentially create banks of 6S 10ah packs. This has the benefit that if one cell is a bit weak in one 5ah pack it's sister will prop it up but at the same time if it dies it'll pull the other one down with it. I havent experienced it luckily but Gary mentioned earlier in response to his LVC boards that if one cell goes in a parallel group it'll trip the LVC. As I posted earlier in this thread I found that packs paralleled at the cell level stay in balance better, even when just left sitting for a while.

So when I simply connect the charge cables (w/o charging), am I effectively balancing 8 cells (in parallel)?

If all connected at the cell level, yes. If just paralleling the discharge leads it'll still work but possibly to a less precise extent.

If out on the road, one 10Ah pack goes super low, or didn't get charged beforehand, one can could plug in paralleling charge cables and it will 'ghetto' balance itself? And may get a touch hot...?

Pay attention class, that's the exact scenario I posted a few pages back
1 10ah bank of 6S cells got to 3v/cell because I forgot to charge properly and the other 2 10ah 6S banks were around 3.9v/cell
When connected in parallel the 20ah worth of 25C cells dumped BULK current into the flat pack and quickly bought the voltage up. Needless to say the 14ga into 12ga parallel charge lead got hot very quick but 2 5 second bursts were enough to get me the remaining 1km or so to work. It's probably not good for the batteries as you're effectively probably charging at >10C for a few seconds, but i'll get you out of strife in the short term.
When I did it I did so at the pack level which is probably safer than at the cell level - I doubt the thin balance tap leads would take that current for even a few seconds.

If your pack is big enough for a return trip to work I guess you could connect this parallel lead to ghetto balance during the day, but its not needed unless your packs are prone to getting a bit out of balance. Mine 25C zippys have stayed STUPIDLY well in balance, the biggest delta v between all my packs is 0.02v after months of charging twice daily on a meanwell at around 0.7C. I check them every few days but I haven't had to balance them yet. As metallover said, we're not really stressing these high C discharge batteries in ebike use

 

[GGoodrum]

I agree with the above, but I would be extremely careful "ghetto-balancing". Hyena is right, the 22-gauge balance tap wires will never handle such high current, so just use the main discharge wires, if there's any significant imbalance between packs. Even still, I'd never try and do this with a full pack and an empty one.

-- Gary

 

[feyris]

My 2c:
I use 4 3S/3Ah 20C Turnigy battery (2S2P for discharge, 4P for charging, see my ebike setup in sign).
About 30-40 cycle for now in 2 month, no problems at all from the lipo
I check cells time to time but I never had to balance them.

I'll go to 2*6S soon.

 

[GCinDC]

Woke in the night and thought I smelled smoke! Went down and sniffed the 1010B+. Nothing but a clean electronic smell. <phew>

But it got me thinking. Say I'm ready to try out a couple meanwells.

Since I'm at 20S now, could I easily configure a couple meanwells in series to get ~83V?

Output voltages: 5 volts, 7.5 volts, 12 volts, 13.5 volts, 15 volts, 24 volts, 27 volts, 48 volts.

Or, according to this, can I only do: 48V + 27V = 75V?

Am I going to have to add another 4S 5Ah pair and use 2x48V meanwells?

Apologies if there a separate thread devoted to this.. If so, please advise...

thanks!

 

[AussieJester]

You can alter the output voltage of the meanwel psu -/+10% of their stated output so you can dial it in to the exact voltage you need looking back 2x48v as it stands would be a lil too much..when you link the two Meanwels together for example 48 and a 24v the current ouput will equal that of the lowest amp meanwe i believe.

KiM

 

[Metallover]

I would also like some charger info. Lately I have been very curious about using power supplies to charge my lipos. If someone could explain or point out a clear cut, simple way to do it I would be appreciative. I've looked at a ton of threads and it seems like you need some means of terminating the cahrge and a cc/cv algorithm. I don't know how to go about doing this.

 

[AussieJester]

it seems like you need some means of terminating the cahrge and a cc/cv algorithm. I don't know how to go about doing this.

The meanwel PSU is simple, you dial the output voltage to the maximum you want to charge your pack too..the cc/cv 'stages 'are automatic.

KiM

 

[Metallover]

I have an 18s turnigy lipo pack. 4.2v/cell is 75.6v. Would I be able to wire the outputs of two 36v chargers in series? Two 36v psu's would be just enough as each goes up to 39.6v giving me 79.2v of availible charging power.

I would set the chargers each to 37.7 or 37.8v and attach my watt meter to measure what the charger is doing. The psu's would simply charge my 18s pack with no problems? It sounds too good to be true.

Do I have all my ducks in a row?

 

[nomad85]

Woke in the night and thought I smelled smoke! Went down and sniffed the 1010B+. Nothing but a clean electronic smell. <phew>

But it got me thinking. Say I'm ready to try out a couple meanwells.

Since I'm at 20S now, could I easily configure a couple meanwells in series to get ~83V?

Output voltages: 5 volts, 7.5 volts, 12 volts, 13.5 volts, 15 volts, 24 volts, 27 volts, 48 volts.

Or, according to this, can I only do: 48V + 27V = 75V?

Am I going to have to add another 4S 5Ah pair and use 2x48V meanwells?

Apologies if there a separate thread devoted to this.. If so, please advise...

thanks!

I just got 2 meanwell 320-48v units. I am planning a 20s pack with a 83v charger voltage, the 48v units adjust down to 41v, so they can be used in series to get the 83 volts. I got mine off ebay, I think you have to mod the shunts to keep them from putting out more current than they can handle, from what I have read there should be 3 shunts inside and snipping one makes it output around the rated continuous amps. There is an entire thread on that though, so I would read it before taking any advice from me

 

[Hyena]

Yep, check out THIS THREAD
I've posted alot about modifying them for lipo charger use and also about extending their rated voltage range.

metallover yes 2 36v units will do what you want, or if you want a faster charger 3x24v units.
That's essentially what I use for my 18s pack, only I use a single 24v supply and charge my 18s pack in banks of parallel (fully charges in 2 hrs which is good enough for me). My packs always stay spot on in balance charging like this but I've found that in another pack of mine and one I built for a friend they get more out of balance if you discharge and charge them as a single pack.
Just this afternoon I checked the balance of a 10S pack I built for a friend after about 15-20 shallow discharges. With the charger set to 41.5v (4.15v/cell) I checked each 5S 10ah sub group (I solder them like that) and found half the pack was reading 4.05v/cell and the other half was reading 4.25 v/cell. Each 5S 10ah half of the pack was very well balanced with itself but out of balance with the other half of the pack(and very nearly lead to overcharging). Obviously this wouldn't happen with a BMS but if you're not using one its something to be aware of.

 

[Metallover]

Thanks for the help guys! I assume the packs will stop charging with a 36v meanwell when it gets to the specified voltage and there is no need of a charge stopping device. The only thing I need to worry about is current. I want to charge at about 1c, 10a, but the packs can do 2c, 20a.

This is the ps I am looking at - http://www.meanwelldirect.co.uk/product/SP-320-36/SP-320-36/default.htm

The rated output is 8.8a. That is pretty good for what I want. If I wire two in a series then the chargers will only output a total of 8.8a, and not 17.6a, am I right?

Also, if anyone can point me out to a good deal, I cant seem to find any. :|

 

[AussieJester]

This is the ps I am looking at - http://www.meanwelldirect.co.uk/product/SP-320-36/SP-320-36/default.htm

I use the sp35-48v myself has been flawless providing more than enough power unfortunately

The rated output is 8.8a. That is pretty good for what I want. If I wire two in a series then the chargers will only output a total of 8.8a, and not 17.6a, am I right?

Right

And yes when they reach the set voltage they stop...they actually start tappering off before that i have found, mine
reduces the current steadily the closer it gets to the set voltage.

KiM

 

[methods]

Set the supply to X * 4.16 or X * 4.17 for margin.
The set point on supplies will drift around a little with temperature and time and there is no point in charging cells over 4.20

-methods

 

[GCinDC]

I've been riding w/o my BM6s because they've been beeping randomly. (They actually started beeping in the lobby of a DHS building yesterday.)

I haven't worried since I parallel charge and only discharge 1/2 the pack, and I recently inquired about whether one cell dropping...

Anyway, I just charged the pack up 5s in parallel, and my iCharger shows each cell spot on at 4.15 (though I didn't include it in the vid).

The BM6's seem to vary though. Is this a connection issue? The JST-XH's are not glued, btw.
[youtube]stjwKiXgDcw[/youtube]

 

[recumpence]

Those BM6s are unreliable, from what I have read on-line. However, it looks like you have a bad connector, or something because you have switch from one BM6 to another with the same result.

Matt

 

[GCinDC]

I think you're right. I just plugged in the iCharger and jiggled the JST-XH and got the same result...

Is it potentially dangerous if while wiggling, one cell measure's 2.8V and another reads 5.5? Or does it read a low V on the poor connection and subtract the total V to calculate the next cell's V?

Think glueing it will fix it, or should i get a new JST-XH?

 

[Hyena]

I had a couple do the same thing. Are they v3s or v2s ? I have an older v2 that I've had for ages now and I've really not treated it well: bashed it around in mud, swinging on its leads hitting against the frame, had it FULL of water etc and it still reads fine. I bought 2 of the newer v3s for a friends pack I built and they worked ok for a few weeks then started showing random voltages with one cell usually 0.5-1v higher than all the rest so they'd always beep while anywhere near a full charge which is a useless.

I've been running without them for months now because my I never take my packs too low and they're so well behaved I just check em once a week for balance. I supposed I shouldn't be so blase, Aussiejesters recent misfortune with his 8 turnigys is a bit concerning.

 

[mwkeefer]

GCinDC,

The bad news - it is likely that the iCharger and the BM6 are off the mark and I agree with the above comments that it looks like a bad connection issue too.

From the factory the BM6 were all over the place - but within their advertised range mostly of +- 10mv (but at the cell not pack level) the iCharger had a linear ramp from cell 1 to 5 where the lower cells were accurate but as I went up in my testing, they were reading lower and lower than the actual voltage of each cell.

There is some stuff on one of the rc forums about calibrating the iCharger 1010B+, you will need to discharge a set of 5s packs down within 3.90-3.99 range per cell and then you simply connect them as a 10S and perform the manual calibration...

I have 4 of the HK Balancers/Conditioners (cheap ones) for 1-6s with the LCD screens... only 3 of them are useful, the 4th always leaves a pack > 25mv out of balance because it's out of calibration (and no way to recalibrate)... I use these when charging with the bulk charger mode to keep each 5s subsection of cells within the right range... balance actually only works durring last stages of CC/CV taper but I am consistently getting < 8mv difference the pack (15s) over.

Hope it helps!

-Mike

PS: I have all my balance leads soldered into parallel and then I have balancer and celllog8 connected to each 5s sub section via dedicated soldered lines - before doing this, I would frequently have issues with the balance connectors and have to fuss with them alot due to LVC and HVC errors... since soldering up, I have no more errors or intermittent connection issues.

 

[AussieJester]

I supposed I shouldn't be so blase, Aussiejesters recent misfortune with his 8 turnigys is a bit concerning.

It's just a part of my cunning plan to get platinum status with Hobby City

KiM

 

[methods]

The original BM6's were awesome. Then they started distributing thu hobby city and they cut every corner you can cut. I have some that look like they are 100 years old but they perform perfectly.

That is not the problem though here. You clearly have a poor connection. IIRC at one point in the video the BM6 thought your max cell delta was >400mV

Replace the JST - or at least pull all the sockets (one at a time unless you like smoke) and inspect / repair them.

-methods

 

[methods]

I take back everything nice I have said about the iCharger 208B
(and I also apologize to those I ignored when they claimed it was unreliable)
Damn thing self destructed on me while discharging a 6S 30Ah pack
I was using an external 1.2ohm load to draw 20A @ 20V - well within the specification.
There was a sizzle, a snap, then bad smells.

View attachment iCharger.jpg

I went in and replaced the discharge fet (it was an 8mOhm model) with an IRFB4110 4mOhm - no help

After that things just went down hill. I beat it to death with a hammer to make sure it was dead.

I ordered another to hold me off (my 4th going back to the 1010 and 106). I also ordered that fancy new charger that is due out in March. I really like the idea of regenerative discharge - makes a heck of a lot of sense for a guy that has 26kwh to test I can charge the "next" battery why I discharge the first.

On a positive note - look what I have hooked up in my car for testing
Of course you can ask - but I wont tell.

This will never be for sale - but who knows.... Maybe something like this will be. I would certainly want to buy it! The ultimate toy for the man who has everything. A CA on Crack!

View attachment 1

That GUI is a nice testing platform for all the toys I am working on. It interfaces both with my LTC board and it picks up the data stream from the CA. I am working on a different version that has datalogging, graphing, running calculations (wh, wh/mile etc), etc.

-methods

 

[Arlo1]

I love you man!

 

[GCinDC]

Very, Very Cool! Gonna be hard to keep your eyes on the road, isn't it?? :lol:

re the iCharger: now I'm freaked! Time to hire a babysitter if charging unattended... or resell?

What's the Achilles heel on these things? Discharge? mwkeefer, you were doing a Lipo Cycle when it blew, weren't you?

 

[methods]

Many have stories - I am sure they will sound off.
My failure modes have been as follows - most recent to longest ago


208B: Smoked out during a discharge+ phase. Thinking back - bad smells came 1 cycle before the thermal runaway

208B: Hooked it up to 32V (highest rated voltage) and it popped. Read out "over voltage" then died. Returned it for the one I have now.

1010B: Accidentally plugged in a 24S pack Clearly my fault

106B: Cant remember

To be fair - none of my failures resulted in fire or battery damage. This one might have - but I stopped it before it did. The case of the 208B got so hot that I could not touch it if that is an indicator.

I have noticed flaky behavior with these things - especially revolving around the discharge+ mode. Often times I would have to "trick" the unit into going into high-current mode by first presenting a 2 ohm load, waiting until it ramped up, then presenting a 0.4 ohm load.

No need for anyone to panic - just realize that the iCharger is perhaps a little less reliable than it should be.

I bought one of THESE 1000W Charger / Discharger

-methods