LaCrosse BC-9009 / BC-900 - The Melt-Downs Continue...

[KiwiMark]

What model charger BC-700, BC-900, or BC-9009?

BC-900 One about a year and a half old and the other about 5 years old.

 

[MarioJP]

My both AC Adapters gives out 3.05 for my two bc-9009 and I have no problems. This means that this problem is becoming clear that any AC adapter pushing above 3.05 to almost 3.1v was design for the bc-700 and mistakenly was added to the bc-9009 line, or La crosse switched suppliers that makes the ac adapters, which also explains why there has been no reports for the bc-700. Reason?? bc-700 can tolerate more voltage as the bc-700 is the crippled version of the bc-900 or 9009.

I was going to ask what happens if you used the bc-700 adapter to the bc-900 but never mind now i know the results of this.

 

[Mr Happy]

Hmm. By my calculations an increase of 0.2 V on 1.6 V dropped leads to an increase in power dissipation of

[(1.6+0.2)/1.6]^2 = 1.27

That would make it an increase of slightly over 25%. If a component was right at the edge that could be significant.

If the [average] current is constant, isn't the power increase proportional to the voltage increase?

Yes, you are quite right. I don't now remember why I thought otherwise.

 

[Bones]

Re-posted for ease of reference:

ShawnLam's high-resolution image of the power-supply which is subject to the LaCrosse replacement initiative:

.

...

And his link to the power-supply replacement initiative webpage:

LaCrosse claims to have identified the meltdown issue and is voluntarily replacing the affected AC adapters.

Link here
...

On a related note: Even with the replacement power supply, I believe this charger should still be treated with an additional degree of caution. The fact that a relatively small increase in input voltage caused such a dramatic increase in the number of melt-downs is very indicative of the marginal safety and operational tolerances documented in this thread:

http://www.candlepowerforums.com ... post1549704
.

 

[FlashPilot]

What is your adapter voltage?

Can others with the version IV adapter please post their voltage results?

Mine is 3.20 volts from the adapter, and it should be 3.0! Im in for the free replacement but I wonder if the higher voltage might have further compromised the reliability of this dangerous product.

Its amazing how crappy some of the QC is in China... lesson learned (again).:sick2:

Thanks.

 

[guggie]

My AC adapter outputs 3.194 volts. I have the recalled model. Anyone know how to modify our adapters to get teh voltage down to 3.0V while we wait for our replacements? For those of us that are technogeeks, that would seem worthwhile.

 

[Apollo Cree]

My AC adapter outputs 3.194 volts. I have the recalled model. Anyone know how to modify our adapters to get teh voltage down to 3.0V while we wait for our replacements? For those of us that are technogeeks, that would seem worthwhile.

Get the replacement. Who knows if the higher nominal voltage is the whole problem? What if the problem is that the voltage varies, sends out spikes occasionally, doesn't limit the current the way it should, etc.?

 

[MarioJP]

Does this means that the melting problem might be solved and be put back on stock like Amazon?.

 

[Bones]

jtr1962 had the answer in 2006: BC-900 power supply discovery
...

jtr1962 actually experimented with voltage levels below the 3.0V advocated by LaCrosse in an attempt to reduce the stress on the charger's MOFSETs and other components:

Hence the reason why I'm now running my two BC-900s on a 2.8V power supply. See this thread. The stock supply is around 3.0 to 3.1 volts. My modded supplies give about 2.8 volts no load and about 2.6 volts at the charger when all four charging stations are at 1000 mA. The MOSFETs get warm but not very hot like before. I agree 100% that the MOSFETs are overstressed at the stock power supply voltage. In fact, it really concerned me the first time I noticed how hot they were getting.
...

It's not posted in the originating thread, but anyone debating whether to follow jtr1962's lead should be aware of this qualifier:

jtr1962,

I believe you got the right idea. However, there is a slight problem. BC-900 uses a single output power supply. When you reduce the output voltage of the PSU, you are simultanesouly reducing the voltage to the MOSFET and the voltage to microcontroller.

The BC-900 uses a form of inexpensive mounting called Chip-On-Board (COB) to cut cost. If you've seen the guts of the charger, it is under the black epoxy. It is basically a silicon wafer without a case. These types of ICs are pretty sensitive to input voltage. Without knowing the exact specs, your supply voltage to the IC could be below the required voltage and may cause stability (latching) and reference voltage problems.

All the chargers we design almost always have a secondary voltage regulator (1% regulated output) right before the controller IC. However, I believe the BC-900 lacks this.

The best way would be to just reduce the voltage to the MOSFET but not to the main IC. I would imagine that, however, it is not an easy modification.

William

The rest of the story:

http://www.candlepowerforums.com ... post1549704
.

 

[guggie]

Get the replacement. Who knows if the higher nominal voltage is the whole problem? What if the problem is that the voltage varies, sends out spikes occasionally, doesn't limit the current the way it should, etc.?

The replacement is already ordered. I'm just looking to see if there is a way I can modify my current supplies ( I have two chargers) while I wait for the new adapters. It would be nice if someone had a simple fix like, crack open the wall wart case, find resistor xyz, change it to abc, attach another to R1345 and to R1346, etc.

 

[jhellwig]

I just don't understand why the powersupply is 3 volt. I could understand 5 but 3? I am guessing that it is 3v to eliminate components in the charger circuitry. The voltage sensitivity tells me that there isn't much regulation in the charger itself.

 

[Apollo Cree]

I just don't understand why the powersupply is 3 volt. I could understand 5 but 3? I am guessing that it is 3v to eliminate components in the charger circuitry. The voltage sensitivity tells me that there isn't much regulation in the charger itself.

If it uses a linear series pass element in the voltage/current regulator in the power supply, the lower input supply voltage will generate less heat inside the unit. The ideal thermal design would be to have the input voltage at the minimum voltage that would still allow the device to work. Any extra voltage on the input would have to be "thrown away" in the charging process.

It's possible that the relevant regulation circuitry inside the charger is a switching circuit instead of linear, which could be less sensitive to a slightly higher input voltage.

 

[MarioJP]

so is this charger really is discontinued for good??

 

[Apollo Cree]

so is this charger really is discontinued for good??

It seems the most likely outcome is that the manufacturer will change the power supply (wall wart) and continue selling them.

 

[jtr1962]

It's possible that the relevant regulation circuitry inside the charger is a switching circuit instead of linear, which could be less sensitive to a slightly higher input voltage.

Unless LaCrosse changed something on their newer BC-900s, there is no switching circuit. The PCBs on the ones I modded had absolutely no inductors. It's a pure linear circuit, which is why my power supply mod reduced the operating temperatures. I'll also add that my modded BC-900s are still working fine, although I used them a lot less once I purchased a pair of MH-C9000s.

 

[Bones]

The latest review of the BC-9009 at Amazon:

LaCrosse warranty service is fake, February 16, 2010, by Alexander Shakhnazarov "MV"

I sent my BC-90009 for warranty repair.

I've been told that unit is backorder and I'll get replacement after 6 (six!) months or they can send me MUCH CHEAPER BC700.

With no other option I agreed to get BC-700.

More...

I can't help but wonder why LaCrosse is, in effect, refusing to replace his unit with another BC-9009.

Their excuse that it's on back-order for over six months just doesn't sound bona-fide (sorry, Oh brother, where art thou? re-runs are showing on a few of the super-stations).

 

[FlashPilot]

The latest review of the BC-9009 at Amazon:

I can't help but wonder why LaCrosse is, in effect, refusing to replace his unit with another BC-9009.

Their excuse that it's on back-order for over six months just doesn't sound bona-fide (sorry, Oh brother, where art thou? re-runs are showing on a few of the super-stations).

The most likely reasons are:

1) They are being sued and cant stand the publicity. :thumbsup:

2) They are reengineering their monstrosity before more of these trashy devices become firebombs. :thumbsup:

3) They are no longer allowed to distribute their trashy products within the US. :thumbsup:

I still cant believe I bought one of these things! Thanks to all those that contribute in this forum, I'll never leave this thing plugged in while I'm not close by to monitor it.

It'll be interesting to measure the current and voltage output of their new wall wart... for all the good it'll do me.

LaCrosse would rather let houses burn to the ground rather than admit to a gross engineering deficiency and recall their chargers. I'll be leaving my own warnings around the net informing others not to purchase ANYTHING from this irresponsible company. I hope you will all be diligent in doing the same.

For now, Ill charge AAA's @ 200 mA and AA's @ 500 mA... and hang out to babysit this trashy thing to completion. On one occasion, it failed to terminate the charge of a AAA. After an hour past when the other 3 batteries completed charging, the battery became hot so I pulled it off the charger. I wonder what might have happened if I wasn't around to stop its self-destruction.

SUCH JUNK!

 

[Turbo DV8]

For now, Ill charge AAA's @ 200 mA and AA's @ 500 mA. On one occasion, it failed to terminate the charge of a AAA. After an hour past when the other 3 batteries completed charging, the battery became hot so I pulled it off the charger. I wonder what might have happened if I wasn't around to stop its self-destruction.

SUCH JUNK!

Don't blame the BC-9009 for a AAA cell failing to terminate at 200mA charge rate! Blame cells that are beginning to become junk, and won't terminate at 0.25C. Keep in mind, the cell that didn't terminate was being monitored by the BC-9009 in identical fashion to the other three that terminated fine, so don't be so fast to blame the La Crosse. That points to a cell getting finicky, not the charger.

 

[FlashPilot]

Don't blame the BC-9009 for a AAA cell failing to terminate at 200mA charge rate! Blame cells that are beginning to become junk, and won't terminate at 0.25C. Keep in mind, the cell that didn't terminate was being monitored by the BC-9009 in identical fashion to the other three that terminated fine, so don't be so fast to blame the La Crosse. That points to a cell getting finicky, not the charger.

Point taken, thank you. Still, I can find no information from the manufacturer specifically instructing the user that their AAA's cant be charged on their own equipment at 200 mA, so in fact the manufacturer should be liable. This happened with the brand new batteries that came with the charger after only 3 or 4 full cycles. It hasn't done it again since, but the heat of the battery at the time was such that the plastic coating had greatly softened. and it burned my finger when removing it from the charging bay. Im sorry but I tend to strongly disagree with you. The failure to terminate the charge in a timely manner is well documented in the forum and other places. I do accept partial blame, as I wasn't to diligent in doing my investigations BEFORE I bought this cheapo charger. Now looking at the Maha and dumping this POS in ebay.

The replies of denial that La Crosse continues to tell its concerned customers is nothing short of an outrage and borderline criminal. May they find their way to the gods of "chapter 11" in an extremely expeditious manner.

 

[Turbo DV8]

This happened with the brand new batteries that came with the charger after only 3 or 4 full cycles. It hasn't done it again since...

That is also not uncommon for new, non-LSD cells to fail to terminate the first few cycles when using too-low a charge rate. From everything in your description of your incident, what you experienced had nothing to do with the charger melt-downs, and was quite normal when chagring new, non-LSD cells at too-low a current.