Reliability of the FMA Cellpro 4S size chargers - RC Groups
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Nov 22, 2014, 08:56 AM
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Prof100's Avatar
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Reliability of the FMA Cellpro 4S size chargers


I, as one of the early adopters of electric powered planes, am asked which charger should someone buy for charging up to a 4S pack. I would always recommend the Cellpro 4S (one in the series). But I don't recommend the chargers any more for a few reasons.
  1. One reason is I have had two of them just given to me because they experience faults when attempting to charge a pack, I was asked what was wrong and said clean the contacts because they can oxidize. Second, I said contact FMA for service because they really good. The charger was sent in and declared as No Trouble Found by FMA service.
  2. The other reason I won't recommend the FMA Cellpro 4S size chargers is people get frustrated when they experience faults they can't fix. They simply buy another brand charger. The frustration is so bad that I have been given a Cellpro 4S and a Multi-4. The Cellpro 4S was fixed by using contact cleaner and switching out the charge leads. The Multi-4 I have not yet been tested by me.

Bottom line, the other flyers in my Club don't want to use a charger that has system faults when trying to charge. Nor do they bother with a company (i.e., FMA) that checks the unit out and declares it as no trouble found. Consider this a posting that might require FMADirect to consider they have a product line that deteriorates with use or simple exposure to the elements. I would say that FMADirect probably is aware of the issue to a certain degree and I would suggest either a PM plan be defined (i.e., clean contacts) or simply state the customer should replace the charge leads and / or clean the contacts.

I, for one, will not be recommending the Cellpro 4S line of chargers to others since they have a short useful life. I would recommend the PL8 but that's overkill for 2-4S packs.

Bill
Last edited by Prof100; Nov 22, 2014 at 09:30 AM.
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Nov 22, 2014, 01:14 PM
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Bill,

Thanks for posting, rather than just silently going away. My own experience with the Cellpro 4s is that I still have the unit I purchased in 2007 and it still works today. As a matter of good practice, I have cleaned the contacts as well as replaced the balance/charge boards. I have also observed heating on the connector and balance wires when operated above 3 amps. For this reason I have kept my unit at 3 amps or below. That is perfectly suitable for my small packs. For anything larger, I put them on the Powerlab.

That being said, I understand a soft limit of 3 amps and regular service might be more than most users are to accept. However, I would contend that all chargers and packs should have their contacts regularly serviced. There are two big differences with the Cellpro4s / Mult4. The Cellpro4s performs many checks before starting the charge cycle and will not let an cycle start until they are passed. Many other chargers don't perform as extensive checks and may just go ahead and charge the pack even with a bad contact. While the user is never alerted until they the voltages of their packs and find one cell was over charged.

The second issue is the high current going through the small connector. My preference would be to have a couple 4mm plugs on the charger so the main leads could be used to charge at higher rates (above 3 amps). This would put less stress on the connector. The flip side of this is that many people really like the option of charging only through the balance leads. With this added convenience comes the burden of additionally maintenance. Perhaps the user manual should go into more detail on this point. But, I'm not so sure that would help as the user manuals are already greatly under utilized.
Nov 22, 2014, 07:27 PM
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Prof100's Avatar
Quote:
Originally Posted by Gregor99
Bill,

Thanks for posting, rather than just silently going away. My own experience with the Cellpro 4s is that I still have the unit I purchased in 2007 and it still works today. As a matter of good practice, I have cleaned the contacts as well as replaced the balance/charge boards. I have also observed heating on the connector and balance wires when operated above 3 amps. For this reason I have kept my unit at 3 amps or below. That is perfectly suitable for my small packs. For anything larger, I put them on the Powerlab.

That being said, I understand a soft limit of 3 amps and regular service might be more than most users are to accept. However, I would contend that all chargers and packs should have their contacts regularly serviced. There are two big differences with the Cellpro4s / Mult4. The Cellpro4s performs many checks before starting the charge cycle and will not let an cycle start until they are passed. Many other chargers don't perform as extensive checks and may just go ahead and charge the pack even with a bad contact. While the user is never alerted until they the voltages of their packs and find one cell was over charged.

The second issue is the high current going through the small connector. My preference would be to have a couple 4mm plugs on the charger so the main leads could be used to charge at higher rates (above 3 amps). This would put less stress on the connector. The flip side of this is that many people really like the option of charging only through the balance leads. With this added convenience comes the burden of additionally maintenance. Perhaps the user manual should go into more detail on this point. But, I'm not so sure that would help as the user manuals are already greatly under utilized.
I still use my 3 original Cellpro 4S chargers which I bought back 2008. One did have a fault which would not got away with cleaning so I returned to FMADIRECT and they replaced it. The FMADirect charger line is the best and safest if used in auto mode.

Now I have 5 of them.
Last edited by Prof100; Nov 22, 2014 at 07:43 PM.
Nov 23, 2014, 08:06 AM
Registered User
ggcrandall1's Avatar
Quote:
Originally Posted by Prof100
I, as one of the early adopters of electric powered planes, am asked which charger should someone buy for charging up to a 4S pack. I would always recommend the Cellpro 4S (one in the series). But I don't recommend the chargers any more for a few reasons.
  1. One reason is I have had two of them just given to me because they experience faults when attempting to charge a pack, I was asked what was wrong and said clean the contacts because they can oxidize. Second, I said contact FMA for service because they really good. The charger was sent in and declared as No Trouble Found by FMA service.
  2. The other reason I won't recommend the FMA Cellpro 4S size chargers is people get frustrated when they experience faults they can't fix. They simply buy another brand charger. The frustration is so bad that I have been given a Cellpro 4S and a Multi-4. The Cellpro 4S was fixed by using contact cleaner and switching out the charge leads. The Multi-4 I have not yet been tested by me.

Bottom line, the other flyers in my Club don't want to use a charger that has system faults when trying to charge. Nor do they bother with a company (i.e., FMA) that checks the unit out and declares it as no trouble found. Consider this a posting that might require FMADirect to consider they have a product line that deteriorates with use or simple exposure to the elements. I would say that FMADirect probably is aware of the issue to a certain degree and I would suggest either a PM plan be defined (i.e., clean contacts) or simply state the customer should replace the charge leads and / or clean the contacts.

I, for one, will not be recommending the Cellpro 4S line of chargers to others since they have a short useful life. I would recommend the PL8 but that's overkill for 2-4S packs.

Bill
Quote:
Originally Posted by Prof100
I still use my 3 original Cellpro 4S chargers which I bought back 2008. One did have a fault which would not got away with cleaning so I returned to FMADIRECT and they replaced it. The FMADirect charger line is the best and safest if used in auto mode.

Now I have 5 of them.
I may be dense, but did I understand you to say in your first post that you would not recommend the FMA 4S chargers? And then in your second post you sing their praises? I am confused.

Glen
Nov 23, 2014, 08:58 AM
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Prof100's Avatar
Quote:
Originally Posted by ggcrandall1
I may be dense, but did I understand you to say in your first post that you would not recommend the FMA 4S chargers? And then in your second post you sing their praises? I am confused.

Glen
Glen,


Let me clarify. Key customer wants such a "Safe to use," "Fast charging, and "Easy to use" the FMA Cellpro 4S does well when I conduct a customer satisfaction survey in my head. For my purposes they score great. But, there is one more customer want I must consider -- "Long Life or Durable." I am tolerant that one of the three Cellpro 4S chargers I own had to be sent in and replaced because of a system fault. FMADirect replaced it a no cost to me. 1 of 3 failing is nothing to brag about. For the other people who took my recommendation and bought a Cellpro 4S would not be so kind because they could not get the faults repaired or the charger replaced so they have moved on and bought different brand chargers. Remember, I do routinely use contact cleaner to clean the connectors. That said, two people have given their Cellpro 4s charger to me because they would not work for them. Their rating of these chargers is they fail to work after a year with various system faults.


I like the FMA Direct line of chargers but I know to keep the contacts clean. I give FMADirect a pass on the one Cellpro 4S charger that had to be sent in and replaced. Others who have asked me to advise them on which charger they should buy and I told them the Cellpro 4S is the best because of it auto detect features that prevents overcharging. However, with 3 separate people having problems they could not resolved I will no longer recommend the Cellpro 4S line of chargers. I have told those with problems to clean the contacts but advice doesn't appear to be working.


Bottom line is I will continue to use the FMADirect line of chargers (including a PL8) but I won't recommend to others at my flying club because of the high failure rate they have experienced.


Bill
Last edited by Prof100; Nov 23, 2014 at 09:16 AM.
Nov 23, 2014, 10:34 AM
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ggcrandall1's Avatar
Bill,

I apologize if I am beating a dead horse but here goes.

Your failure rate of one in four is not a realistic number. You are using your four as a total number. But that is not accurate for statistical use. You would have to know how many chargers FMA produced and sold to be able to get an accurate failure rate.

For instance I have four CellPro4S chargers and none have ever failed. Therefore the failure rate is zero. Additionally there are at least four more in use at my field and no failures reported to me (and they would be because I am a known FMA bigot ).

So as I see it you have been the unfortunate recipient of one of probably a very few failed CellPro 4S chargers. Hey it had to go to someone.

As far as the need to clean contacts. That is a fact of life with any and every charger. FMA does not have a corner on that market.

Glen
Nov 23, 2014, 10:57 AM
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Prof100's Avatar
Quote:
Originally Posted by ggcrandall1
Bill,

I apologize if I am beating a dead horse but here goes.

Your failure rate of one in four is not a realistic number. You are using your four as a total number. But that is not accurate for statistical use. You would have to know how many chargers FMA produced and sold to be able to get an accurate failure rate.

For instance I have four CellPro4S chargers and none have ever failed. Therefore the failure rate is zero. Additionally there are at least four more in use at my field and no failures reported to me (and they would be because I am a known FMA bigot ).

So as I see it you have been the unfortunate recipient of one of probably a very few failed CellPro 4S chargers. Hey it had to go to someone.

As far as the need to clean contacts. That is a fact of life with any and every charger. FMA does not have a corner on that market.

Glen
Four of six had faults...1 was replaced free of charge. Two were given to me because they did not work. I resurrected one of them by cleaning contacts. third was thrown away because FMA tested fine and reported as "no trouble found.".then the customer threw it out. The one multi charger with a fact was just given to me has not been checked and tested by me.
Last edited by Prof100; Nov 23, 2014 at 11:48 AM.
Nov 24, 2014, 10:26 AM
Registered User
The return rate for the Cellpro 4S charger has been less than 2% since we introduced that product back in 2003. The newer Cellpro chargers including the PowerLab series have experienced lower than a .5% return rate since their introduction in 2008. These statistics include all chargers returned to FMA/REVO for any reason including user error such as over voltage. We consistently receive feedback from customers who are using their 8 to 10 year old CP4S chargers that are still going strong. I would challenge any other designer and manufacturing of charging products in the R/C industry to exceed that level of reliability.

Jamie Marks
VP and General Manager
FMA Direct
Nov 25, 2014, 10:27 PM
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Prof100's Avatar
Quote:
Originally Posted by Jamie Marks
The return rate for the Cellpro 4S charger has been less than 2% since we introduced that product back in 2003. The newer Cellpro chargers including the PowerLab series have experienced lower than a .5% return rate since their introduction in 2008. These statistics include all chargers returned to FMA/REVO for any reason including user error such as over voltage. We consistently receive feedback from customers who are using their 8 to 10 year old CP4S chargers that are still going strong. I would challenge any other designer and manufacturing of charging products in the R/C industry to exceed that level of reliability.

Jamie Marks
VP and General Manager
FMA Direct

Jamie,

I commend you for being candid with the return rate for the Cellpro 4S and PL series chargers. I like them both and have them for charging and managing my batteries. I bought three 4S, one had a fault and was sent in for repair or replacement. Your firm returned it and it worked. My PL8 has behaved flawlessly.

That said, I, when asked which charger do I recommend will no longer recommend the Cellpro 4S, simply because the people who have bought them have had system faults that rendered them useless. By the way a 2% return rate (read failure) for electronics is very, very high. It is a 20000 ppm failure rate which is astronomical in contemporary mfg standards and capabilities. .5 % for PL series is better but still 5000 ppm. The real field failure rate is much higher because you are using return rate as the quality metric. How many were not returned but simply tossed in the trash or given away to someone else to tinker with them?

Here is automotive industry benchmark targets for auto commodities:

PPM Expectations - Automotive Mfg Purchasing/ Supplier Quality high-low range

Stampings : 66, 47 ppm
Mechanical Control Systems: 113, 80 ppm
Bearings: 21, 15 ppm

Having said that these are the automotive industry targets, they do not excuse defects. You will still get customer complaints, and possibly worse (e.g. containment inspections at your expense) if you ship defective product -- even one piece, in some cases.

Again, thanks for your candor. However, you have a ways to go to every supply to the automotive industry.
Knowing your competitive status is nonetheless helpful. It would be good to have similar numbers for your products.

Bill
Nov 29, 2014, 10:10 AM
Registered User
I love my Multi4 and use it all the time for smaller packs.

I don't think your comparison of the auto industry, or most electronics industries, is at all valid. In most of those cases the consumer never interacts with the item in any way similar to a lipo charger. The nature of this hobby makes user error much more likely than in any other consumer electronics device.

As Jamie stated the return rate "include all chargers returned to FMA/REVO for any reason including user error such as over voltage". I'm going to guess that at least half of the returned chargers were damaged due to user error not manufacturing defects.

I guarantee you the defect rate on most other brands is many times higher. Just go look at the HobbyKing forums, or even the iCharger forums.
Nov 29, 2014, 12:16 PM
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Prof100's Avatar
Quote:
Originally Posted by grimbeaver
I love my Multi4 and use it all the time for smaller packs.

I don't think your comparison of the auto industry, or most electronics industries, is at all valid. In most of those cases the consumer never interacts with the item in any way similar to a lipo charger. The nature of this hobby makes user error much more likely than in any other consumer electronics device.

As Jamie stated the return rate "include all chargers returned to FMA/REVO for any reason including user error such as over voltage". I'm going to guess that at least half of the returned chargers were damaged due to user error not manufacturing defects.

I guarantee you the defect rate on most other brands is many times higher. Just go look at the HobbyKing forums, or even the iCharger forums.
FMA is a great brand and as I said I have owned both Cellpro 4S and PL8 but user interface is not an excuse for high failure rate if your goal is to design a robust charger. Robust is defined a suitable for use and function. The system faults experienced by fellow flyers with the Cellpro 4S resulted in dissatisfaction, new charger (different brand) and gifts to me to try to see if I could use any of them or repair them. One was simply dirty contacts and I cleaned the contacts. So, while I still use mine I don't recommend them any more. I would recommend the PL8, it is worked flawlessly, but most people don't want to pay for the PL8.

The reality is that the return rate is not an indicator of true failure rate. Many owners won't take the time to return to manufacturer or retailer. In this case, the Club President sent his Cellpro 4S in and got back a no trouble found response. Like it or not, the word spreads that FMA rejects claims with the ubiquitous "no trouble found"

And, of course, I have bought, tried and and shook my head at failures of Turnigy chargers especially the one that started out with a squeaky fan from the beginning.
Last edited by Prof100; Nov 29, 2014 at 12:43 PM.
Nov 29, 2014, 09:52 PM
Registered User
Quote:
Originally Posted by Prof100
FMA is a great brand and as I said I have owned both Cellpro 4S and PL8 but user interface is not an excuse for high failure rate if your goal is to design a robust charger. Robust is defined a suitable for use and function. The system faults experienced by fellow flyers with the Cellpro 4S resulted in dissatisfaction, new charger (different brand) and gifts to me to try to see if I could use any of them or repair them. One was simply dirty contacts and I cleaned the contacts. So, while I still use mine I don't recommend them any more. I would recommend the PL8, it is worked flawlessly, but most people don't want to pay for the PL8.

The reality is that the return rate is not an indicator of true failure rate. Many owners won't take the time to return to manufacturer or retailer. In this case, the Club President sent his Cellpro 4S in and got back a no trouble found response. Like it or not, the word spreads that FMA rejects claims with the ubiquitous "no trouble found"

And, of course, I have bought, tried and and shook my head at failures of Turnigy chargers especially the one that started out with a squeaky fan from the beginning.
You cannot determine the failure rate until you determine the cause of failure. As grimbeaver mentioned above, improper use by the end-user is not the fault of the product.

I've owned two Multi4s, two PowerLab 8s (both original v1s), and a Dual PowerLab 8x2 for the the past year and none of my five PowerLabs chargers have ever required service.

Lastly, if I'm not mistaken, the 4S was discontinued years ago.
Nov 29, 2014, 10:12 PM
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Prof100's Avatar
Quote:
Originally Posted by Ohmic
You cannot determine the failure rate until you determine the cause of failure. As grimbeaver mentioned above, improper use by the end-user is not the fault of the product.

I've owned two Multi4s, two PowerLab 8s (both original v1s), and a Dual PowerLab 8x2 for the the past year and none of my five PowerLabs chargers have ever required service.

Lastly, if I'm not mistaken, the 4S was discontinued years ago.

First, you are conflating failure rate (i.e., does not work) with root cause. You can have multiple failures and multiple causes for each failure. See root cause analysis 101 or FMEA or Fault Tree Analysis.


I am glad you are happy with your FMA chargers, so am I except for one Cellpro 4S that required return and replacement because it had a system fault. FMA checked it out and replaced it. It was few years ago so when I was asked by others to recommend a good, safe charger of airplane lipos I always recommended Cellpro 4 series chargers. But, not anymore, apparently they are prone to having faults about 2% of the time.


Others have not been so lucky.


Your last point is nonsensical. The 4S original and its upgraded models are good basic chargers for me, however, others are not as lucky. A 2% return rate is astronomical in terms of quality assurance.


IMPROPER USE can always happen and it is the design engineer's function to mistake proof their design to prevent misuse. Why do infer failure are due to misuse? You have no evidence other than speculation. How do you attribute a failure to customer misuse? You have nothing but a supposition and NO facts.
Last edited by Prof100; Nov 29, 2014 at 10:29 PM.
Nov 29, 2014, 11:34 PM
Revolectrix Ambassador
Quote:
Originally Posted by Prof100
A 2% return rate is astronomical in terms of quality assurance.
Not in the RC Hobby industry.

I said this earlier but it was dismissed or disregarded. Connection issues exist on ALL chargers. The difference with the Cellpros is that it will not let you start the charge cycle until those issues are corrected. Other chargers will allow you to charge and may not alert you of an error. The packs end up unbalanced or perhaps one cell is overcharged. But the Cellpro takes the hit in the "perception" of failure rate. Where as the inexpensive charger with minimal safety protocols is deemed more reliable.

Fun market!
Nov 30, 2014, 04:45 AM
Registered User
Quote:
Originally Posted by Prof100
First, you are conflating failure rate (i.e., does not work) with root cause. You can have multiple failures and multiple causes for each failure. See root cause analysis 101 or FMEA or Fault Tree Analysis.


I am glad you are happy with your FMA chargers, so am I except for one Cellpro 4S that required return and replacement because it had a system fault. FMA checked it out and replaced it. It was few years ago so when I was asked by others to recommend a good, safe charger of airplane lipos I always recommended Cellpro 4 series chargers. But, not anymore, apparently they are prone to having faults about 2% of the time.


Others have not been so lucky.


Your last point is nonsensical. The 4S original and its upgraded models are good basic chargers for me, however, others are not as lucky. A 2% return rate is astronomical in terms of quality assurance.


IMPROPER USE can always happen and it is the design engineer's function to mistake proof their design to prevent misuse. Why do infer failure are due to misuse? You have no evidence other than speculation. How do you attribute a failure to customer misuse? You have nothing but a supposition and NO facts.
Did you determine the RCA for the extremely small number of samples you encountered? If so, what is the RCA for each of the samples you encountered?

So you're saying it's practical and cost effective design and manufacture a ~$60 charger capable of withstanding any misuse the end-user could subject it to?

What evidence do you have that the units weren't misused? I didn't attribute the failures to misuse, I only indicated one possible cause of the failures could have been misuse.

The 4S was one specific model. When referring to failure rates it's important to be model specific and not generalize regarding an entire product family.