Zippy Flightmax / Turnigy lipo testing

[methods]

The picture that Nicobe posted is misleading.
Please do not use that for reference when building larger packs.
Some manufactures use odd-ball wiring on their balance taps when the number of cells is less than the tap size.
Perhaps Nicobe uses one of these other types of packs and that is where he got the picture.

Here is a picture showing how to properly convert two 3S packs into a single 6S pack
Notice that the red wire is tied together with the black wire.
This is how you do it.



For the Zippy packs (and 90% of the packs out there) the red wire that is cut is actually exactly the same as the #1 black wire in the next pack.
In fact - you dont want to cut them at all - you want to *short* them together.

Please - do not use that picture for reference when working with packs that conform to the JST-XH Zippy type convention.
Also - if you are not crystal clear on how a Lipo pack is wired - please do not attempt to rig up a large pack.

-methods

 

[mwkeefer]

Okay everyone,

As part of a project my company is working on, we are about to order several hundred CC/CV chargers in the following configuration:

63v CC/CV @ 5A (Adjustable HVC of: 62.25v, 62.7v and 63v) - For 15S Lipo Pack, will charge 1P @ 1C or 2P at 1/2C (2 / 4 hour charge time): These are expected to be approx $150 retail and are supposed to be only available for our customers however... I have sweet talked my CEO (really the CFO) into helping the community (if you want help). If our companies cost remains the same we will offer them to ES members for $96.00 ea

63v CC/CV @ 10A (Adjustable HVC of: 62.25v, 62.7v and 63v) - For 15S LiPo Pack, will charge 15S2P @ 1C or 15S4P @ 1/2 C (1 / 2 hour charge time): These are more expensive but an hour recharge using a simple (though slightly larger than) computer style charging adapter. Again this is dependant upon our costs remaining the same but retail on these will be: $225.00, ES members who speak up can have them for $129.00

Finally... I have bent the bosses ear hard enough he is willing to put additional chargers on our order so if there are other "common" configurations which people would really like to have a simple carry along charger (safe) we will consider it... right now we are considering the 5 and 10A version with max CV of 50.4 for 12S LiPo packs.

Though they are not cheap and no they are not balancing chargers so they will require a BMS of some form for balancing but according to the experts here if you build your pack from cells / sub packs that are at the same state of charge and then discharge / charge them as one pack they don't tend to get badly out of balance.

I am working on a simple balance circuit similar to what I believe fetcher has already created (or maybe it was someone else, can't remember it's late). The circuit will monitor for over voltage of cell (user configurable) and shunt the inbound current for that cell. This will trick the CC/CV charger into thinking the cell is taking current still even though it's only the other remaining cells taking current. When all the current shunts are active the BMS will disconnect the charge port and the CC/CV charger will go green light as there is no longer any current draw. I will release the schematics and gerbers for this PCB shortly.

Update on the new turnigy Lipo tested it over 3 discharge cycles and man is this thing nice! Definate improvement in quality! I meansured 5833 mah under a 15A load (what it will see maximum on my eBike).

-Mike

 

[bearing]

Update on the new turnigy Lipo tested it over 3 discharge cycles and man is this thing nice! Definate improvement in quality! I meansured 5833 mah under a 15A load (what it will see maximum on my eBike).

What cut off voltage did you use?

 

[mwkeefer]

The cutout was rigged for lowest cell first at 3.2v, surprisingly (to me) they all hit within 1-2 seconds of each other (before I had a chance to react even)... If this is like the previous built turnigy 15/20C labeled packs then the cells should improve some (roughly 8-10%) over the first 10 full cycles before they reach stable performance.

Since I performed the initial charge at 1C (5A) and subsequent charges at 2C (10A) I guess my iCharger is better than I thought or these were just far closer in balance... though I took measurements when it arrived I have since lost them = (

-Mike

 

[recumpence]

I am chiming in late here. But, I figured I would post my findings.

I have a 12S 6P Flighmax pack (1.44kwh) 15C rated on my KMX Typhoon trike. I pull 300 amps off it regularly (10C) with no heat build up what-so-ever in the pack. Also, there is precious little voltage drop.

I am a big fan of these cells, and trust me, I have run MANY lipo brands in RC and E-bike applications.

Methods made a comment a few pages back that we are past the area of crap lipo.

I agree.........

Matt

 

[Hyena]

63v CC/CV @ 5A (Adjustable HVC of: 62.25v, 62.7v and 63v) - For 15S Lipo Pack, will charge 1P @ 1C or 2P at 1/2C (2 / 4 hour charge time): These are expected to be approx $150 retail and are supposed to be only available for our customers however... I have sweet talked my CEO (really the CFO) into helping the community (if you want help). If our companies cost remains the same we will offer them to ES members for $96.00 ea

Nice one. I'm currently breaking my 15S pack down into 3 banks of 5S 10ah for charging and I just bought a new 15a 24v charger (set to 20.75V) to do the job a little faster than my old one but something like you're offering is a good option for those not wanting to fiddle around or are likely to make a mistake with the series / parallel wiring. I've got a few mates that are after an ebike after riding mine but the battery charging / balancing thing as been a bit of a limitation so far. It's ok for me to ghetto charge them but if I'm going to start selling them to friends and friends of friends something more user friendly is needed.

I've got around 10 cycles on my 15S 10ah pack now and they're staying incredibly well balanced. I'm charging to 4.15v/cell so the 15S pack is coming off the charge at 62.25v. My usual 15km commute to work this morning burned 6ah pulling fairly low currents of 10-30a for most of the trip, 42a max (1-4C). Checking with the BM6 on arrival every cell was within 0.01v of each other, and the pack wasn't even balance charged prior!

I'm going to keep charging my packs without a balancer for a while and see how they hold up. I know methods has said previously he rarely balances his zippys and they stay well balanced too. Allowing a bit of headroom by only charging to 4.15v/cell unless a cell goes really badly south it's unlikely any cell with end up >4.25v. If this works out I think I'll just make a budget LVC BMS from 3 BM6's with the warning buzzer wired to activate the controller brake switch. I guess the same output could be used as a HVC for charging as well. It wouldn't balance it, but it'd stop the pack from being over charged if the cell voltages got out of range.

What's the easiest way to do this ? A relay wired to the buzzer output ? Maybe a 50a normally closed relay built into one of the battery discharge wires, that way it wouldn't need any external connection to the controller or the charger ?

 

[mwkeefer]

First off where did you source the 24v 15A CC/CV charger? That would be helpful for many here to know as you can tell most of us don't mind re-wiring our packs to charge/discharge.

My GoPed ESR750EX does this with SLA batteries; Using 4 SLAs in Series / Parallel durring discharge @ 24v but plug in the charge cord and you hear a relay or two trip off and it's reconfigured your batteries into a single 12V massive parallel for charging. - LOL

With regards to the LM6 units - They ROCK ! ~ however;
1.) Out of 6 units I ordered 5 worked correctly, one alarms no matter the voltage alarm setting or the pack voltage.
2.) The beeping sound of some is muffled (I checked nothing in the piezo transducer element), inside a pack they are a bit difficult to hear when at a stop... when moving 20-30mph they are impossible to hear and worse...
3.) The sound blends in with the noise of crickets here where I live in the states. Unless at a dead stop, I can't distinguish the BEEPING of the quieter units from the surrounding back noise (prob. 80db) of crickets!

All these issues are no-big-deals far as I am concerned, I found a thread where someone was trying to do just what you are thinking... using the BM6 for an LVC, it will work but... there are some better options with a few slight mods to the BM6 unit itself.

First, don't trigger the eBrake line... toggle the throttle to GND. Personally I use a transistor (attached to 5 BM6 units, soon to be 6) to act as a switch between the throttle return line (which varies from GND or 0v to 5v) so when the beep happens, the transistor breaks the connection and sends the input to the controller to Ground. This is much more subtle than the eBrake line being triggered which could actually be unsafe (think 20mph endo) depending on how your controller is configured (eBrake).

In addition to my collective cutout, I have added LEDs (using surface mnt LEDs) which will flash in sequence with the beeping from 1-6 BM6 units to give me a visual indicator of the LVC condition and which part / segment of which pack is it in (I run 15S2P normally and break down to 5P6S for charging / balancing, BM6 units are connected per P side as 2x6S and 1x3S for 6 total to monitor all channels.

The LED could be reduced to a single one just for a visual indicator.

I actually over discharged 1 cell to 2.8 because I didn't hear the alarm until I came to a stop sign (fracking crickets) which led to my collecting and enhancing the notification system.

I will post schematics and PCBs when I make them right now it's hacked together breadboard style and the display is made of double sided sticky tape to set the LEDs into, PC IDE ribbon cable to connect from my interface board to the LED display), clear packng tape over the LEDs for weather protection then that "strip" of LEDs is electrical taped around my handlebar (the whole display is just 3/4" wide x 1/2"" high to show 6 packs of status.

If you don't mind waiting a few days while I check a few other things out (like if the lock bits are set on the atmels, how the display is being driven, if I can interface to the BM6 in other ways I have yet to think of)... I will finalize this design using cheap RadioShack parts (transistors, etc) and post the schematics and gerbers for the PCBs (yes I will do a perf board also) along with a faq about making "microLED displays and push button controls"). And yes this design will interface to a normal throttle line (0-5v) as is but I will provide a + and - 5v output from the collective board so others not using a standad throttle can interface to it.

-Mike

 

[mwkeefer]

**** I AM OFFICIALLY AN IDIOT *****

Found the issue with my "broken" BM6 - BM6 is fine, my damn 2x3S -> 6S wiring was FRACKED!!! I pulled a newbie stunt and clipped the "spare lead" instead of paralleling it with the next (ie: connect cell balance wires #3 GND to #4 + as they should be).

That will teach me to build packs and adapters in the middle of the night... NOT!

- Mike

 

[methods]

nOOb

I have never made a mistake in the middle of the night with any sort of electronics

-methods

 

[Hyena]

First off where did you source the 24v 15A CC/CV charger? That would be helpful for many here to know as you can tell most of us don't mind re-wiring our packs to charge/discharge.

Ebay
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=140315140944&ssPageName=STRK:MEWAX:IT

Should be arriving any day now so I'll post back anything relevant. I'm not sure what brand it is but I assume there'll be no issues with it.
The one I'm using currently is a 145w meanwell that supposedly has an output of 6a. It actually charges at 8.5a so if my new one is similarly underrated it'll probably charge at closer to 20a.

I made a similar mistake with my new lipos of accidently discharging to 2.8v / cell on one of my parallel banks. I was bench testing a charger and one of the aligator clips came off, which meant that bank didnt quite get its full charge. I was happily roaring around at 8v above LVC when I looked down a minute later and saw it sitting 2 volts under my LVC point (BM6 wasnt connected at the time). DOH! The old 'lipo holding its voltage then dropping off a cliff' trick. It recovered perfectly though.

 

[GGoodrum]

I finally finished my 12-channel Charge Balancer. Here's a few shots:

View attachment 12-Cell Charge Balancer-02.jpg

View attachment 12-Cell Charge Balancer-03.jpg

View attachment 12-Cell Charge Balancer-04.jpg

View attachment 12-Cell Charge Balancer-05.jpg

This is a modified version of the charge control portion of our v2.6 full BMS board. There are bi-color red-greenLEDs for each channel, and one for the charger control circuit. The way it works is that if the cell voltage is above 3.80V, which basically means the charger is connected, the LED for that cell will come on red. Once the voltage gets to 4.08V the green portion of the LED will start to come on, as will the shunt. As the voltage continues to rise, the shunt will come on stronger and the LED will transition to fully green. At 4.13V, the shunt will be fully on, and the LED will be solid green. At this point, the opto for this channel will come on, which sets the "ANY SHUNT ACTIVE" signal, This starts the charger control logic to start "throttling", just like the regular BMS does. Basically, when this signal goes active, it cuts off a FET which cuts the charger power. This will cause the voltage in the cell to drop back down, below 4.13V, so the opto shuts off. This oscillation keeps the voltage from any cell from going over 4.13V, regardless of what the charger voltage is set to. The LED in this part of the circuit is basically red, when the charge current is on (i.e. -- FET is on...) and green when it is off. The PWM oscillation starts out with a pretty high duty cycle, so the LED is mostly red. As the cells get full, the FET stays off, more than it is on, and the LED starts turning green. In the middle, the LED is orange-ish. Anyway, you basically just wait until all the LEDs turn green, and the pack is full.

Here is the schematic, and the layout of the board:

View attachment LiPo Charge Balancer-v3 2a.png



The board is sized so that it fits into the rails on an extruded aluminum box. The shunt resistors are mounted from the bottom, so that they make thermal contact with the bottom of the case, which turns the whole box into a heatsink. I'm using 10 ohm 3W shunt resistors, which provides about 350 mA of shunt current, for each channel. I figure this is more than enough for LiPos, as they stay pretty well balanced, unless you drain them down close to the end of capacity. It also keeps the box from getting too hot, although it still gets pretty warm, hot enough that you can't hold onto it for very long when all the shunts are active.

I'm not sure where I'm going with this just yet, but at a minimum, I'll probably offer the boards, with assembly/test instructions and a Mouser BOM, like I'm doing with the current BMS boards, but I might also offer a kit, with all the parts. I might also see if Andy Hecker wants to build these as well. Fewer parts than the current BMS, so he might.

Tomorrow I will finish of my new "matching" LVC board. It has main pack and balance plug connections for up to three packs in parallel and four in series, so 24s3p. Last night I ordered six more 6s-5000 20C Turnigy packs, so that I can use these with my other six, in an 88V/15Ah pack on my Townie, which has a 5304 and one of Methods 18-FET 100V/100A controllers.

-- Gary

 

[mwkeefer]

Methods,

That was an infineon right... worst burn up I've ever seen, WTF did u do to it, screw it into a fracking LIPO pack?? Seriously how did you burn it up that bad? I have to try it and make a you tube video (actually about to go make one in about 20 minutes when the suns up... Then I will sync the Eagle Tree telemetry and post to Youtube in HD... I got my tuning down perfect last night!

Ggoodrum - in a single word "SWEET"! Count me in for whatever... that looks very scalable (to handle 15S packs...?) and quite a nice design, can be integrated into the battery box for integrated charging... This will help to enable re-balance after regen (I have developed quite a regen addiction recently as I have learned it's the fastest way to slow down from 20-45mph into the 10mph range where real bicycle brakes are effective but I have noticed that it will vastly worsten an already out of balance pack at my speeds and with my downhill runs overcharge is always a concern (yes overcharge... i know, regen overcharge but trust me... Eagle Tree is calibrated for all sensors as nominal current draw and I see huge burst of reverse flow when I nail the ebrake at 40-45.

Would you be mad or would it be improper of me to convert your designs to a SMT equiv and post the schematics and gerbers / artwork for the PCBs... they could be made 1/4 the size (probably) - they are already tiny but when possible I prefer to use SMT as they have become cheaper than traditional sized parts and easier for me to work with (solder pot).

That's you and fechter right? Nice work, still want to do the MCU based scalable Master / Slave style BMS with all the bells and whistles but this is sweet and simple (not simple in a bad way but in a what can go wrong way).

Great work!

-Mike

 

[dontsendbubbamail]

nOOb

I have never made a mistake in the middle of the night with any sort of electronics

-methods

Methods,

Did I miss the thread where you tell us how this happened? I thought liveforphysics was the controller frying king, but yours is the best one yet. Did you get pissed and take a butane torch to it?

Bubba

 

[mwkeefer]

That thing looks more like he got mad and pissed on it, while it was hot, connected to 20S lipo and then laughed while he walked slow to get the camera to take the shots... would have made a great YouTube how not to.

Maybe we should all chip in for those of us who always KFF so we could wear helmet cams while we work, recording 24/7 and then we can all share in the humor of Mike or Methods burning the first three layers of skin off... my personal favorite "Did I just do that, really?" is when I plug the positive and negative discharge ends of a pack together, and they are the terminators for the same pack... Doh.

-Mike

 

[GGoodrum]

<methy --I "smell" a Darwin coming... >

Mike -- Yes, this is definitely scalable, but I do have some concerns about using this integrated into a closed environment with LiPos. Even with 10 ohm shunts, this will generate a fair amount of heat, so your battery box should have good ventilation, preferably with a fan. If you are going to do this, you could also integrate the LVC function back in, which would make this a full BMS. The more I think about this, the more I'm thinking trying to do regen with LiPos is not a good idea, without some sort of active limiter to keep from overcharging a cell. When that happens, you will most definitely get a fireball, and Lithium burns white-hot. In the early days of LiPo, when the chargers had a lot less smarts than they do now, a faulty charger set itself to one cell higher than the pack I was charging. The pack exploded and caught fire. The pack charging was in a Pyrex dish, and was unfortunately sitting next to 3 other packs that were still to be charged. I was able to get the dished moved off a workbench, and onto the driveway, just as the other three packs started cooking off. I spent the next 20 minutes trying to put the fire out, first with a fire extinguisher, then by dumping sand on it and then soaking it with water. Nothing worked, and I just had to let it cook until all the lithium was gone. It got so hot that the Pyrex dish exploded, and the concrete in the driveway started popping as well. It left a horrible mess. Anyway, the chargers got smarter, and the number of "incidents" went down, which has made LiPos much safer to work with, but I worry that using them in an ebike configuration without the same sort of protection the "smart" chargers and ESC's provide, is basically just asking for trouble.

My original version of this was for my a123 packs, and with those I didn't care about whether a high cell overshot the cutoff a bit, so it did not have the "throttling" logic. For LiPos, however, it is critical that you don't let any cell get to about 4.3V, or higher, as that is when the fireworks start ( ), so I added the throttling logic from the BMS circuit. If you are starting out with a full pack, and then go down a hill, to use Richard's favorite example, you can easily overwhelm a 350mA shunt circuit, without the FET to cutoff the current, and overcharge a cell. What you really need is some sort of active circuit that will dump the excess current into the motor windings. This could be triggered by the "ANY SHUNT ACTIVE" opto signal.

-- Gary

 

[methods]

I am at work so I only have a minute:

RE- BMS -> I broke into Gary's garage when he was drunk the other night and stole 3 of his 12S balance boards and 4 of his 24S LVC boards. I finished a 24 cell LVC and that is what is currently running on my 24S 15Ah lipo pack.

I am in the process of building the balancer part - only mine is 500mA and 24S. 8)
Anyone thinking about doing 1A shunt current - forget it. I already did it and it gets too hot. I was the first to convert a V2.2 BMS over to Lipo and 1A balance (AFAIK)

RE- Toast -> That is an old picture. That was my first 12 fet V2 xlyte that I had modded for 100V 100A. Was running 24S 9Ah lipo - turned it on one day - spontaneous combustion (after 500 miles with no problems). My wife said that it sounded like I was cooking popcorn in the front yard. Smoke and flames were shooting out of the wire holes. Since I was not running a fuse I actually had to reach into that fireball do detach the lipo. Could have severed my fingers if the wires had been red hot.

Lipo survived and runs my wifes bike to this day

When I opened the controller I literally pored the solder balls out. I have more pictures around here somewhere.
I already earned a fried guinea pig.

-methods

 

[methods]

Oh yea - I almost forgot:

Looking good Gary!

I will post my pictures - maybe after this weekend.

-methods

 

[will_newton]

noticed something after my last ride on the 10s2P (2x5s 5000mah) pack the other night. It was pretty warm feeling! So, the next time I went out I measured the pack temperature when I got home. It was 149 degrees, which is very warm, also it had also not been used for about 5 minutes, so was probably much hotter than that in use. This temp was measured on the cells between the two battery packs which are stacked on each other. The exterior cells were about 122. I pulled around 25-30A for the majority of the ride.

For the next ride I went 10s4P (4X5s 5000mah). In between packs internal temperature of 120ish and external temp of 110. This is a good temp.

110-120 felt warm, like coffee at a drinkable temperature. 149+ felt hot, like coffee that would burn the hell out of your tongue.

Ambient temp was mid eighties, packs were in a closed bag.

Watch your temps related to your amp draw guys!

 

[will_newton]

I've also noted something that I didn't notice before. There are questions about paralleling batteries and whether it's evil or not and requires a BMS, because a paralleled cell may fail and cause the partner cells get overdrained or overcharged.

So correct me if I am wrong (I know you will), but if I am looking at the BMS diagrams correctly cells are charged individually, but can be parallelled on the BMS contact pads once you exceed the 24s limit.

So for example, using 4 x 6s 5000mah packs will fill the first set of pads and the BMS has pads to parallel 3 of these sets so you are looking at 72 cells total providing 15aH at 48V, but not individual balancing.

Did I get it right? pics of Gary's BMS. http://endless-sphere.com/forums/viewtopic.php?f=14&t=9170&start=75

So for ultimate balancing for the above mentioned pack, I'd need three BMS's, but could just use one and get by. By the same token, if I am willing to just "get by" by paralleling the balance taps on the BMS, then why not just skip the BMS and parallel solder all the balance taps? I am not referring to the handy charging and LVC cutoff benefits of the BMS. I am only referring to paralleling the packs.

 

[Arlo1]

Posting to find this thread easier. I found these turnigy batteries from hobbiy city last night and couldn't belive the price so I will be building a 27s 5ah 20c 30c burst pack. And I might just oder 10 3s packs to make sure if one is a dud I have what I want. It is funny that they are so cheep compared to the others that if you order a few extra its still cheeper!

 

[methods]

Posting to find this thread easier. I found these turnigy batteries from hobbiy city last night and couldn't belive the price so I will be building a 27s 5ah 20c 30c burst pack. And I might just oder 10 3s packs to make sure if one is a dud I have what I want. It is funny that they are so cheep compared to the others that if you order a few extra its still cheeper!

27S will be 113.4V fully charged.
You should just stick with 24S. This works out to (4) 6S packs.
If you want to run 27S you are SOL with your controller and CA:

* too high for the 4110 mosfets
* too high for the 100V capacitors
* too high for the regulator circuit
* too high for the Cycle Analyst

24S lipo is a multiple of 6 (good), charges to 100.8V (in range), perfectly matches the Fechter/Goodrum BMS (good), etc.

If you must run 27S then you need to go back to the drawing board with the controller.
I am sure you can do it - but why?

-methods

 

[Arlo1]

27S will be 113.4V fully charged.
You should just stick with 24S. This works out to (4) 6S packs.
If you want to run 27S you are SOL with your controller and CA:

* too high for the 4110 mosfets
* too high for the 100V capacitors
* too high for the regulator circuit
* too high for the Cycle Analyst

24S lipo is a multiple of 6 (good), charges to 100.8V (in range), perfectly matches the Fechter/Goodrum BMS (good), etc.

If you must run 27S then you need to go back to the drawing board with the controller.
I am sure you can do it - but why?


-methods

I was just looking at nominal voltages and wanted to keep them as hi as possible to keep the amps down a bit in the motor to keep things cooler! But you are the man 24s it is! You just pointed out enough reasons to keep it simple for me. I did know I could replace the caps to 160 v but didn't know it was to hi for the rest I will keep designing as for I am still in the stator design stage as well and have to save up for the battery anyway! But yeh 24s will be alot eiser to buy as well. Well time to go to the shop and work on some carbon fiber and my stator reserch!

 

[will_newton]

4 more 6S 5000mah lipos making their way to the battery bag via hobbyking! http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10095&aff=146283 mmmmmm, batteries good. I am going to be trying a few different configurations of 5s and 6s to make some 11s packs. I would've bought 6s batteries to start, but I have a BD36 and didn't want to get into overvolting it, now I do. I have heard of folks running them on 48V with no issues, but I just got this controller and didn't to risk it. Now that I have the Cycle Analyst and digital temp. measuring gadget (another hobbycity find, nice!) I can keep track of how things are going under the hood. I also snagged a couple of the Chargery low voltage meter/alarms.

I also also sent the following e-mail to HC about why the very low priced (relatively) USPS priority mail was available but not during actual checkout. It looks like a bug in their shopping cart system. It would be great if it worked. I mostly just wanted to point out that I got a response from HC in THREE hours-how cool is that?

Hello, I am trying to place another order with you and I am having some trouble with the shipping. I have placed the items in my cart and I am offered the choice of shipping from the US by Priority Mail, however the shopping cart will not let me choose this option when it is time to check out. On the checkout page I can only choose EMS or Air Parcel shipping. Can you please help me so I can place my order?

Thank you,
Will Newton

Hi,
Thanks for your email.
The option USPS Priority Mail 2-3days 0-450g (Within USA)$4.99 is only available when all items in your order are available in USA warehouse, other wise we will ship internationally from Hong Kong main warehouse.
Besides there is a limit on weight 450g for this option. If you only have Air Parcel or EMS options, your order weight must be over 1kg. So you are not able to choose option USPS Priority Mail 2-3days 0-450g
Meanwhile, should you have further queries, please feel free to contact us.

Regards,
Yuky
Customer Support
HobbyKing.com

 

[recumpence]

I have ordered alot from HC. They are great to deal with.

One thing I MUST point out, though, is they freakin RIP YOU OFF in shipping! I am sorry, there is no reason why 10 of these packs should cost me $121.00 shipping. No reason what-so-ever. They know how to make money for sure. I would just rather see that cost show up in the pack cost, not in the shipping cost after the cart is all setup.

Matt

 

[will_newton]

to me it's the 450 gram limit that is bogus. :?
Would've cost $37.00 to ship my package US priority mail.
I actually think hobbycity may be one of the few companies that make money shipping.
OR
I guess I could've paid over $300 for one 6S 5000mah lipo at my LHS. Sure it would've been a ThunderPower, but at the amps I pull it would have been major overkill.

Somehow $65.00 shipping from hong kong in three days for a rock bottom price battery seems OK. I got 4 for the price of one and it's delivered to my house with no sales tax.

I almost felt guilty about buying from HC vs. visiting my very friendly LHS I've been going to for 20+ years. I even spoke to my local owner about HC. He said he is going to start carrying a line products (plane engines) direct from China and can understand why I shop there for some very specific items.