Lipo Fires Are Real!!!! - Page 2

jimsz · Jul 29, 2007, 01:44 PM

That almost looks like a Triton charger in the middle of the second shelf down in the first picture?

Dave Hederich · Jul 29, 2007, 07:01 PM

The "Plug-and-Play and Walk Away!" issue has been discussed before.

Fact is, every single person on the planet walks away from charging LiPo packs. Not a single person remains crouched frozen over their charging LiPo packs for the duration of the charge. The recommendation with LiPos is to remain nearby and vigilant so that you can respond in case something goes wrong.

So all the FMA Direct advertising copy means is that with the Cellpro 4s balancing charger, you simply plug-and-play without having to take any other steps before walking away from the charging pack as everyone walks away from any charging pack. It doesn't say go out to a movie.

The FMA Direct website is loaded with LiPo warnings. If you click on Lithium Polymer Packs on the main FMA Direct page, you are immediately taken to a list of Safety Precautions, the first two of which are:

1. Never fast-charge any battery type unattended.

2. Never charge Li-Po cells/packs at any rate unattended. Charging outdoors is preferred.

http://www.fmadirect.com/lipoTerms.htm?cat=69

RD Blakeslee · Jul 30, 2007, 06:47 AM

Indeed, the "Plug and Play and Walk Away!" issue has been discussed before, and Mr. Hederich has consistently taken it upon himself to "Explain it Away" in FMA's behalf.

What Mr. Hederich does not explain is why the blatant overstatement AT POINT OF SALE (how many don't read beyond that?) doesn't agree with the "fine print" elsewhere.

I agree with PGR.

- RD

pilotpete2 · Jul 30, 2007, 08:48 AM

Quote:

Originally Posted by RD Blakeslee

Indeed, the "Plug and Play and Walk Away!" issue has been discussed before, and Mr. Hederich has consistently taken it upon himself to "Explain it Away" in FMA's behalf.
- RD

Only one important difference here, with the Cellpro 4S you really can do it

I feel that it really irks some folks when a product actually delivers on its promise

I have used the Cellpro since its introduction and have tried to cook damaged and way out of balance packs packs to no avail, it just won't do it

Do I walk away when I have a pack on charge yes, do I leave the house no

IMHO you are more likely to have a charging incident fast charging Nimh cells with peak detection than a lipo on a Cellpro 4S, others mileage may vary

Pete

kfong · Jul 30, 2007, 10:36 AM

Cellpro 4S charges the cells individually, that's why it inherently safer. It uses the balance taps to charge them. I'm thinking of going this route. Seems to me, all lipo batteries chargers should do this. Then I bet fires would be down to only a few.

Kin
http://www.embeddedtronics.com/

hoppy · Jul 30, 2007, 10:55 AM

Quote:

Originally Posted by kfong

Cellpro 4S charges the cells individually, that's why it inherently safer. It uses the balance taps to charge them. I'm thinking of going this route. Seems to me, all lipo batteries chargers should do this. Then I bet fires would be down to only a few.

Kin
http://www.embeddedtronics.com/

You mean it has a separate charger circuit for each cell?

qban_flyer · Jul 30, 2007, 12:42 PM

Quote:

Originally Posted by PGR

From the FMA Direct website (http://www.fmadirect.com/products.htm?cat=45&nid=4):

This has to be one of the most blatant examples of irresponsible advertizing that I've seen. Although I haven't had reason to deal with them much in the past, I always thought FMA was a fairly upstanding and responsible company.

I definitely don't feel that way now.

Pete

Pete,

They have always been one of the most responsible companies in the RC field, and as far as I know (first hand experience) they still are.

Their Cellpro 4S charger is the one they refer to in that statement, not anyone else's. FMA can only vouch for the quality of their merchandise no that of others.

I can also tell by the attached photos that the charger used in this instance was a large unit. Cellpro chargers are rather compact units.

qban_flyer · Jul 30, 2007, 12:45 PM

Quote:

Originally Posted by jimsz

That almost looks like a Triton charger in the middle of the second shelf down in the first picture?

That was my first impression, though it looks a bit wide for it to be a Triton. I wonder if the thread starter could get back to his friend and ask him what the brand name is.

Dave Hederich · Jul 30, 2007, 09:50 PM

Quote:

Originally Posted by RD Blakeslee

Indeed, the "Plug and Play and Walk Away!" issue has been discussed before, and Mr. Hederich has consistently taken it upon himself to "Explain it Away" in FMA's behalf.

And others have consistently taken it upon themselves to look for any opportunity to pounce on certain individuals, products or companies.

Nothing is perfect. When examined under a microscope, the slightest flaws in anything and anyone are clearly visible. If one perpetually trains one's microscope on a single thing or person, one will forever be calling out flaws in that thing or person. But that only raises the question of why anyone would have such an unhealthy obsession.

turbine50 · Jul 31, 2007, 02:17 AM

Does anyone know if an FMA 4S has had a pack ignition incident?

Unterhausen · Jul 31, 2007, 08:03 AM

Quote:

Originally Posted by hoppy

You mean it has a separate charger circuit for each cell?

The Cellpro 4s doesn't have a charger for each cell, it is a serial charger with a built in bleeder balancer. However, it is very good at detecting the number of cells, and will not charge if there is something wrong. I hesitate to say that it's bulletproof on that score, but it is a very good design. I still felt like an idiot the other day for leaving a pack on the charger overnight.

pilotpete2 · Jul 31, 2007, 09:25 AM

I think you are off base on the mothod of balancing used in the Cellpro. If I'm not mistaken the Cellpro controls current through the balance taps by shunting, it does not a bleed off current as do external balancers, so in effect it charges each cell separately as it can control the current flowing in each cell, as I understand it this method is capable of more precise control of cell charging than a system with independent supplies.
Pete

Unterhausen · Jul 31, 2007, 10:56 AM

that's a pretty subtle difference. Granted, it does do a fairly good job of controlling the voltage across every cell. But if it had separate chargers for each cell, it wouldn't struggle so much to charge some of my cells. For the best example, I just put together two cells that were discharged to wildly different voltages (yes, I wasn't thinking too hard when I did that). I'm not sure what to do about it, the cellpro doesn't charge it. I'd rather not take the pack apart or rig something up to discharge the higher charged cell.

Probedude · Jul 31, 2007, 11:08 AM

You're both saying the same thing but from a different angle.

External balancers have a transistor across each cell and a resistor too to dump off the excess voltage, the Cellpro only has the transistor but is used to shunt current around a cell. Turn the transistor on hard enough on the Cellpro and you can reduce the voltage of a given cell too. Problem is with no resistor to help dissipate the power, this single transistor would rapidly overheat and blow.

Unterhausen,
What are the individual cell voltages? From what I've read the cellpro should have no problems bringing your pack up to fully charged state unless a given cell is < 0.5V.

What FW are you running?

hurleybt · Jul 31, 2007, 11:10 AM

Yeah, I love that charger... but they should take that off their site... or they're risking a lawsuit, in today's litigious society.

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Jul 29, 2007, 01:44 PM	#16
jimsz Registered User Join Date: Apr 2007 Location: Crescent Beach BC Posts: 109	That almost looks like a Triton charger in the middle of the second shelf down in the first picture?

Jul 29, 2007, 07:01 PM	#17
Dave Hederich Registered User Join Date: Feb 2000 Location: Walled Lake, MI, USA Posts: 11,182	The "Plug-and-Play and Walk Away!" issue has been discussed before. Fact is, every single person on the planet walks away from charging LiPo packs. Not a single person remains crouched frozen over their charging LiPo packs for the duration of the charge. The recommendation with LiPos is to remain nearby and vigilant so that you can respond in case something goes wrong. So all the FMA Direct advertising copy means is that with the Cellpro 4s balancing charger, you simply plug-and-play without having to take any other steps before walking away from the charging pack as everyone walks away from any charging pack. It doesn't say go out to a movie. The FMA Direct website is loaded with LiPo warnings. If you click on Lithium Polymer Packs on the main FMA Direct page, you are immediately taken to a list of Safety Precautions, the first two of which are: 1. Never fast-charge any battery type unattended. 2. Never charge Li-Po cells/packs at any rate unattended. Charging outdoors is preferred. http://www.fmadirect.com/lipoTerms.htm?cat=69

Jul 30, 2007, 06:47 AM	#18
RD Blakeslee Registered User Join Date: Jan 2002 Posts: 6,548	Indeed, the "Plug and Play and Walk Away!" issue has been discussed before, and Mr. Hederich has consistently taken it upon himself to "Explain it Away" in FMA's behalf. What Mr. Hederich does not explain is why the blatant overstatement AT POINT OF SALE (how many don't read beyond that?) doesn't agree with the "fine print" elsewhere. I agree with PGR. - RD

Jul 30, 2007, 10:36 AM	#20
kfong Registered User Join Date: Nov 2003 Location: Sterling Heights, Michigan, United States Posts: 493	Cellpro 4S charges the cells individually, that's why it inherently safer. It uses the balance taps to charge them. I'm thinking of going this route. Seems to me, all lipo batteries chargers should do this. Then I bet fires would be down to only a few. Kin http://www.embeddedtronics.com/

Jul 31, 2007, 02:17 AM	#25
turbine50 AMA#577223 Join Date: Dec 2006 Location: Houston Posts: 239	Does anyone know if an FMA 4S has had a pack ignition incident?

Jul 31, 2007, 09:25 AM	#27
pilotpete2 Registered User Join Date: Jun 2004 Location: The Northeast Kingdom, Vermont Posts: 2,536	I think you are off base on the mothod of balancing used in the Cellpro. If I'm not mistaken the Cellpro controls current through the balance taps by shunting, it does not a bleed off current as do external balancers, so in effect it charges each cell separately as it can control the current flowing in each cell, as I understand it this method is capable of more precise control of cell charging than a system with independent supplies. Pete

Jul 31, 2007, 10:56 AM	#28
Unterhausen Registered User Join Date: Aug 2005 Location: 5 miles from the geographical center of Pennsylvania Posts: 2,140	that's a pretty subtle difference. Granted, it does do a fairly good job of controlling the voltage across every cell. But if it had separate chargers for each cell, it wouldn't struggle so much to charge some of my cells. For the best example, I just put together two cells that were discharged to wildly different voltages (yes, I wasn't thinking too hard when I did that). I'm not sure what to do about it, the cellpro doesn't charge it. I'd rather not take the pack apart or rig something up to discharge the higher charged cell.

Jul 31, 2007, 11:08 AM	#29
Probedude Registered User Join Date: Jul 2006 Location: Ventura, CA Posts: 1,847	You're both saying the same thing but from a different angle. External balancers have a transistor across each cell and a resistor too to dump off the excess voltage, the Cellpro only has the transistor but is used to shunt current around a cell. Turn the transistor on hard enough on the Cellpro and you can reduce the voltage of a given cell too. Problem is with no resistor to help dissipate the power, this single transistor would rapidly overheat and blow. Unterhausen, What are the individual cell voltages? From what I've read the cellpro should have no problems bringing your pack up to fully charged state unless a given cell is < 0.5V. What FW are you running?

Jul 31, 2007, 11:10 AM	#30
hurleybt Registered User Join Date: Mar 2007 Location: Athens, GA Posts: 1,201	Yeah, I love that charger... but they should take that off their site... or they're risking a lawsuit, in today's litigious society.