Fatal Flaw in Chinese LiFePO4 chargers

[Ypedal]

Got any pictures of the pack ?

When i received my Life pack i had a horrible time reasuring the cell voltages consistently, turns out the tabs were coated with glue/flux/other crap.... i cleaned all the tabs with alcohol and Q-tips.. and then could get consistent readings..

Don't use the pack if in doubt, better to prevent a problem than to cure one.

 

[fechter]

OK, here's where we need the Yesa-Battery guy to chime in.

 

[cerewa]

Got any pictures of the pack ?

When i received my Life pack i had a horrible time reasuring the cell voltages consistently, turns out the tabs were coated with glue/flux/other crap.... i cleaned all the tabs with alcohol and Q-tips.. and then could get consistent readings..

The pack is still in its shrink wrap so I can't access the cells directly; I can only access the BMS which is mostly open and in plain view.

Pic is here, with voltmeter (multimeter) leads placed where I measured cell voltage on hte BMS. (I'm not 100% confident I'm measuring correctly, but i suspect I am)

http://farm3.static.flickr.com/2296/2067737750_7ae2ec1ca3.jpg

 

[Ypedal]

Can you disconect the black pigtail with all the blue wires ? if the pins are too small to reach with your volt-meter prongs ( AND BE VERY CAREFUL NOT TO SHORT ANYTHING IF YOU ATTEMPT IT ) .... You can twist a thin wire around your voltmeter leads to fit in the holes to get readings.

Maybe Mr Yesa could chime in here with the pinouts for you !

 

[Doctorbass]

balancing charger

Where did you got this charger? what is the price?

 

[solarbbq2003]

charger is from my iron phosphte supplier in china ( will keep supplier name under wraps for a while),
they have a range of balancing chargers, depends what voltage/amps you want on price and if they have in stock.
As there are so many different volts/amps combinations they dont always have all types in stock,
not very cheap, from memory price was between $150 to $200usd,
they've only been making rectangular type cells but are just starting to make cylinder types now, they have been around for about same time frame as a123 and valence, but is chinese ownded company. Went to visit them about 4 weeks ago, factory seems pretty well run, machinery to make the batteries isn't chinese made, i forget which country came from, but was interesting to see the process, final part of process packing of copper/aluminium sheets etc into packs is done by hand, but testing facilities is their strong point, quality seems quite good on the batts, but cylinder cells will be better option as rectangular cells bends the copper/aluminium and I think might effect longevity.
Haven't been using the batteries or chargers for a long time, probably a 4 or 5 months or so, looking promising. Certainly a cheaper option than a123 and valence but how they last in the very long term is unknown, apart from test data from manufacturer

 

[Ypedal]

How do these chargers mate to their intended battery packs ? In order to offer ballancing they require connection to each cell somehow.. so it has to be a multi-pin type setup of some sorts.. any info to share please ? 8)

 

[PJD]

I thought these packs could be charged by ordinary bulk charging. Isn't the balancing part what the BMS is for? A number of the more reputable LiFePO4 battery makers like Valence, say bulk-charging is fine - they even recommend an ordinary lead acid charger as long as charging voltage is kept to no more than 3.7 volts per cell.

 

[Deepkimchi]

I got the flintstone charger running again and made modifications.

Took the case bottom half of the charger Andy sent and mated it to the other case for more room, cut a hole out for an extra fan. Now I have 3 fans hooked to an external 12V supply, instead of tapping off the 4th DC output.

The spacing is much greater between the upper & lower boards.

Was sick yesterday, so this is not the final hookup (with loose wires).

Check your flintstone chargers - if the terminals to the FET on the heatsink read as follows, it's open.
Reads low resistance, then the meter creeps up to about 1,500 ohms (like a capacitor) - does this both ways when switching polarity on the multimeter leads, then it's open.

If okay, it should read a steady low resistance one way, and do the above the other way.

If this FET is open it will cause the FET near the black box (in the white goop) to short out!

 

[Deepkimchi]

Ypedal - here are my cell voltages after 6 hrs setting. 2nd time charging - first time they varied more.

3.615, 3.602, 3.540, 3.576, 3.596, 3.617, 3.590, 3.634, 3.590, 3.607, 3.628, 3.608

4 of my charger outputs on the top board - unloaded. I've put so much time in repairs, was scared to stick a pair of leads down into it.

3.737, 3.741, 3.719, 3.739 VDC

I've got 3 fans, 2 leds and auto-shutoff when complete. Light is green, trap is clean. (Ghost busters )

 

[Deepkimchi]

:wink: Yeh bud - why get the dinky little toy charger, when you can get the big, tough American modified charger ?

I know you guys out there, driving those big macho SUVs and Jeeps.

You need a charger the size of 2 lunch boxes and a six pack of suds.

This thing is pure ego, the base station mutha of all chargers :wink:

(I couldn't help myself - and have not been drinking).