Battery Medic - how to ID the REAL vs FAKE

[ryan]

So my 3 "fake" battery medics arrived. Is the general consensus after all the testing that these aren't perfect, have to be watched, and shouldn't be left connected after balancing?

Or are they so bad that they are not recommended to use at all? (as in I need to buy three more from Methods or his source)

[methods]

I dont think that anyone has shown that they are unreliable. I think the only thing that has been shown is that they are a little inaccurate - maybe 20mV
Just use them, they will be fine.

You cant leave any of them plugged in for too long - not even the good ones... since after they discharge the pack to 4.X volts the current they draw to stay one will then start to imbalance the pack.

Your best bet is to calibrate the ones you have - so you know what you are working with.

-methods

[methods]

Seems hobbyking has stock again.

I am not convinced that the Hobby King version is as accurate as this batch I have here. I suppose I need to order some and test for myself - but just because the PCB is red does not mean that it is good. I have personal experience with Hobby King taking a good product and screwing it up to save a buck.

BTW: Been getting bad batches of JST-XH-6 and JST-XH-7 extensions from hobby king. After plugging them in only 5-10 times they become completely unreliable and start presenting open circuits. They are using some kind of really bad alloy on the sockets - I just cant believe how cheap those guys can be sometimes.

I love them.... but I hate them to.

-methods

[Ypedal]

the male sides are generally " ok " but the female ends are crap..... on all the one's i've had from HK ( the jst's )

[methods]

What do you mean by male and female?

One end has a male plastic shell full of female electrical sockets
One end has a female plastic shell full of male electrical pins

See how that is ambiguous?

How about we say "Sockets" and "Pins" and refer to the electrical contact.
Plural, and referring only to the electrical contact.

Most military guys refer to the contacts when they mean sex
Most regular guys (aka customers) refer to the *housing* when they talk about sex

So which one are you using

I am talking about the electrical sockets becoming rounded out.

-methods

[methods]

That came off sounding fussy...
sorry.

Just that a lot of customers refer to the housing when they speak of sex... so it really causes confusion.

-methods

[Ypedal]

lmao.. ok mr wize guy..

[texaspyro]

It's the pins that determine the connector sex. If the pins are hermaphroditic, you can use the housing. If the pins look male, but wear feather boas or look female and wear plaid flannel then just wing it.

[FastDemise]

Well that's unsettling to hear. I just received my order of 20 of those exact connectors to just make connections out of the Male-Male connectors. I refer to Male being the part that fits inside the Female. Why should I refer to it any other way?
So if I make a daisy chain of 200cm long balance cable and hook it up so my modified balancer it'll just be a giant pile of FAIL?

[methods]

No - I still use them in a lot of applications.
They are good for the first 10 insertions.

The only reason I am having failures is because I have a testing station where I cycle the connectors over, and over, and over. Basically I will sit down with 40 boards and test them back to back - so my connectors get the shit kicked out of them. I use these extension as "sacrificial" connections so as not to wear out my test rig. For every 20 or 30 insertions the extension sees, my test rig sees only one

Move ahead - just realize that if you start getting some weird behavior it probably has to do with loose connectors.

-methods

P.S. I call a hollow pin (hermaphrodite) a socket. I know you guys are joking around - but I cant tell you how many tens of thousands of dollars I have seen wasted over connector sex miss-communication. Connectors like MDM & Micro Miniature have hollow pins and that is where most of the confusion lies... as each side of the connector has 3 different sexes... the shield over the insulator over the hollow pin over the hole inside... Like having a hollow penis inside of a vagina that is actually a panina.

[nicobie]

What do you mean by male and female?

-methods

Heshe

No matter what, they all need hot glue or gel CA between the plug and the leads if your even thinking of unpluging <> a few times.

[auraslip]

DO NOT ORDER FROM THE EBAY SELLER METHODS LINKED TOO.

I ordered two of the "better" units for $1 more each. I received the units with the yellow/green pcb. They are as much as 50mV off.

What to do now? Waste of $30 of can they be repaired?

[E-racer]

I' just received 4 cell medics from HK they are all red PCB's and look to be genuine.

[methods]

I' just received 4 cell medics from HK they are all red PCB's and look to be genuine.

It seems like I am having to say this until my face is blue.... RED PCB DOES NOT = GOOD

It has been well documented that the HK boards are hit and miss, so please folks - stop using the color of the board to determine if they are good or not. There are *at least* three different versions that are "RED" and they are totally different PCB layouts. The color of the board has nothing to do with the accuracy or genuine status of a board.

And on another note.... If you guys start asking vendors for the RED boards guess what is going to happen? They are going to change the silkscreen color to RED on all of them.

The only way to tell is to test the board with a good DMM. The Layout of the hobby king board is DIFFERENT than the layout of the boards I tested here so please do not assume that what you have is "genuine". From what I have heard, a lot of folks moved away from the Medics after accuracy issues with HK boards.

Sorry to jump on you bro - but you are like the 5th guy in a row to announce that RED = GOOD and we really need to squash that bit of misinformation.

-methods

[methods]

DO NOT ORDER FROM THE EBAY SELLER METHODS LINKED TOO.
I ordered two of the "better" units for $1 more each. I received the units with the yellow/green pcb. They are as much as 50mV off.
What to do now? Waste of $30 of can they be repaired?

What did you use to measure the error?

FWIW I never said that was the unit I ordered (the more expensive of the two he sells). What I said is that I was trying to order a large lot of the cheaper ones and the seller steered me toward a higher quality unit for a dollar more each. BUT - that was a dollar more when I was buying 30pcs with the intent to buy 100 more. That was also with $60 of express shipping, so really I paid $17 each for these units shipped. This was an off ebay deal.... that just happens to be his ebay account.

I will sell these units that I have for $20 each if anyone wants them. I am sorta busy so I had to put the mods on hold.

As far as your bad luck - that sucks... but that is the name of the game when you are trying to save a buck and order from China. I rolled the dice and purchased 30 totally blind.

No they can not be "repaired" - unless you want to put about $50 worth of labor into them

I doubt they are 50mV off... you using a cell log 8 to make that judgement?

-methods

[E-racer]

Ahhh thanks methods. Sorry I'm guilty of not reading this whole thread. Checked all my medics against one of my 6s 40c batts with the Fluke 77. These things are pretty much dead nutz +/- 0.01v the cells resting voltage was at 3.85 per cell. I'm impressed.

[auraslip]

Sorry if I came off as being harsh towards you methods. It's in no way your fault I mis-read your posts to mean what I wanted it to mean.

And yes, this is a shining example of why ordering from a quality seller like you is cheaper in the long run.


Yes - compared with a cell-log. Two cell-logs from different batches actually. Both battery medics had a cell listed at 4.1v-3.9v when the cell logs showed it at 4.14v.

Ack - waste of $30. When will I learn? I'm too broke to buy cheap tools.

[methods]

Ahhh thanks methods. Sorry I'm guilty of not reading this whole thread. Checked all my medics against one of my 6s 40c batts with the Fluke 77. These things are pretty much dead nutz +/- 0.01v the cells resting voltage was at 3.85 per cell. I'm impressed.

Ok - thanks for the good report. So 1 vote for hobby king.... though +/- 10mV might not be considered "dead nuts" everywhere. Fluke 77 does 1mV resolution so I am guessing that you just rounded out?

If you could throw up a set of measurements accurate to 1mV that would be super. Thanks!

DMM MEDIC
X.XXX X.XXX
X.XXX X.XXX
X.XXX X.XXX
X.XXX X.XXX
X.XXX X.XXX
X.XXX X.XXX

-methods

[methods]

Yes - compared with a cell-log. Two cell-logs from different batches actually. Both battery medics had a cell listed at 4.1v-3.9v when the cell logs showed it at 4.14v.

It is dangerous to measure accuracy with an inaccurate device - or even two inaccurate devices Those things only have resolution to 10mV so right off you worse than +/10mV. If you look at one of the other Medic threads going right now another guy was surprised when he actually tested his Medic with a DMM instead of his Cell Log - he found both to be quite inaccurate.

-methods

[Hyena]

You guys wanna bitch about inaccuracy ? I had one arrive totally dead - it does nothing when you connect up a battery.
Having to buy another and hoping that it works +/- being accurate makes the cost of that one working unit essentially $35. Take methods up on the bargain price he's offered you guys for a known, good working unit!

[methods]

Actually... please dont

It is not worth my time to open, test, pack, communicate with the customer, Pay PayPal, print labels, ship, then assume the risk for shipping losses, offer customer support, etc for $6 bucks. I would actually prefer that you guys just buy more of the junk units

Thanks for the plug though

-methods

[Alan B]

I bought two of them earlier (before these recent threads), and they seem to be good ones though I didn't compare them with a precision DMM. Then I lost one. Probably wasted a couple hundred dollars worth of time just looking for it. Found it tonite, right where I put it. It had become obscured so even though I looked there it wasn't easy to find.

Just how much accuracy do we really need here? Really NEED?

[methods]

Just how much accuracy do we really need here? Really NEED?

+/- 20mV is fine for what we are doing.

For Me?
I like +/-5mV
I would use +/-20mV if that is all I had

Keep your packs less than 100mV out of wack and you should be ok.... but just remember to add some margin on your pack level LVC.

These poor quality units are fine for poor-mans balancing.... better than sitting there burning your fingers with a 5W resistor

-methods

[auraslip]

These poor quality units are fine for poor-mans balancing.... better than sitting there burning your fingers with a 5W resistor

That's been my method lately..... 3x 10ohm 10watt resistors in parallel. God I have too much free time.

[nicobie]

As usual, methods is right. I got one with a red board and all it would do is unbalance my pack. It went from .02V unbalance to .07V. When I checked it with both my Fluke 87 and Ideal DMM the readings were surprisingly only .03V off. Something else must have been wonky with it. Like everything else lipo, don't just walk away when trying out new kit!