Cool Mini-Review of new FMA Multi4 Multi-Chemistry Charger

[BARNESJONR]

Introduction

If you had a friend just embarking on his “career” in electric flight (and I just so happen to have one JUST starting into the hobby), which charger would you recommend for him? He is just learning the differences between the various battery chemistries and really does not need to be concerned and confused by all of the technicalities of battery chargers and how to charge various chemistries. For now, he just needs to be able to plug his depleted lipoly or NiMH batteries into the charger and get them pumped back up for another flight in his Nexstar EP.

Now, lets go all the way to the other end of the spectrum. You have a guy in your club who is the go-to guy in electric flight He has been into it for several years and seems to always have the answer. His park flyer fleet is large and his battery box even larger. He can speak in great detail about the science of charging batteries and even knows the basic differences between the charge cycle of a lithium polymer battery versus that of a NiCD or NiMH battery. He is a tinkerer and is always “under the hood” tweaking and endeavoring to make his equipment even better. He knows what he wants and knows how he prefers his chargers to function. Now, which charger would you recommend for HIM? It would probably be WAAAY at the other end of what you would recommend for our newbie above ... right?!

Would you believe me if I said that there is one charger that I would recommend for both greenhorn and grizzled veteran!? Yes indeed, there is and it is FMA's new Multi4. But of course now you are shaking your head and saying NO WAY! Impossible! Bear with me and please come along as I explain why I think the new Multi4 is a charger for every electric flyer.

[BARNESJONR]

Open Architecture

The new Multi4 charger builds upon the fame and success of its predecessor, the Cellpro 4S charger from FMA. I have been using mine for years now and it is nearly unrivaled in ease of use and in the way it safely recharges and balances lithium polymer chemistry batteries. So, how do you make a great charger even better? FMA went back to the drawing board and did just that. And the main feature of the new Multi4S is its open architecture approach I. E. the ability of each user to configure it to operate exactly the way HE prefers it to operate. From the words displayed on the Welcome Screen to the number of beeps when it is done charging to the actual t screens that will be displayed while the charge is underway, you CAN change so much on this charger. FMA describes this open architecture as being “Preset Driven”. Every major parameter of its operation are defined at a preset level and you can change the vast majority of these parameters to make the charger behave and appear just as you prefer.

[BARNESJONR]

Safety

One of the most notable features of the original Cellpro 4S was its approach to safely charging the lithium polymer battery chemistry, which can be particularly volatile if charged improperly. FMA engineers have placed a huge emphasis on safety when programming the software algorithms in their charging products and the Multi4 is certainly no exception. It includes over 60 different numerical Safety Codes that are indicative of all of the safeties that FMA built into the software.

[BARNESJONR]

A Quick Walkaround

One very obvious improvement over the original Cellpro 4S charger is the fact that it now comes in a hard plastic case, which offers a little more protection that the open structure of the previous model. (In fact, FMA will gladly sell you an extra plastic case should you want to pick up an extra for your Cellpro 4S) Another marked improvement is the brightly backlit LCD display of the Multi4. There is but one pushbutton on the new charger, which is the same exact number of buttons the original one had. But there is a very good reason for that. More on that point in a few paragraphs. The actual point of connection for the new Multi4 charger, the port where you plug the battery balance connector in, is the same as the older unit.

However, there is a new port or connection on the Multi4. It is a tiny three pin connector that acts as a PC interface. Yes, and what that means is that the charger firmware can be updated over the Internet, with no need to EVER have to send the charger back to FMA for updates. This same PC interface port adds additional functionality with FMAs free CCS (Charger Control Software) program. The CCS software enables charge cycle graphing and also easy access to all of the charger settings and configuration in a convenient Windows tabular format. The CCS application is available as free download form the FMA website. The interface is known in FMA jargon as the FUIM2, 2 way P.C. Interface. FMA also makes a faster FUIM3 interface but it is primarily for another of their product lines and though it is some 3 times faster than the FUIM2, it's faster speed does not really gain the user very much in use with the Multi4 charger. Factor in its reported higher cost, and it may make sense to just stick with the FUIM2 interface.

[BARNESJONR]

Understanding Presets

The Multi 4 uses the word “Preset” quite a bit. Primarily, there are two types of presets: Library Presets (unchangeable by the user, well at least as long as it remains a Library Reset!)) and User Presets. Library Presets, which number 50, are defined as the starting point for creating all User Presets. FMA configures the 50 Library Presets with the optimal charger characteristics for many different batteries (Lipoly, A123, NiMH, etc) and different charging strategies (Accurate charge, quicker charge, etc) You can change a Library Preset into a User preset but not vice versa. Think of Library Presets as hard coded recipes, written by FMA, for charging different types of battery chemistries ... AND different ways of cooking, er, I mean charging the battery. In the same way that one person likes their chicken fried and another baked, one user may prefer to use the “Long Life” preset, which limits the charge to 4.1 volts per cell but at the small expense of shorter flight time. Other users will prefer the “well charged” recipe or preset, which maximizes the cell voltage to 4.2 volts but can shorten the overall life of the battery a little.

Once you move a Library Preset into a User preset, you gain access to some 80 parameters and you are now able to make changes to the preset. It is also possible to restore the original factory Library Presets by using the CCS software and PC interface. In fact, most of the editing and programming changes you will be making will occur within the CCS application. The changes that can be made by using the solitary pushbutton on the Multi4 are deliberately limited to basic editing only. The reason for this is to prevent the operation of the Multi4 from getting too confusing. Some of the changes that CAN be made, without using the CCS software, are changing the charge rate of a preset, clearing out a User Preset and moving a Library Preset into a User Preset. Using the CCS software permits more advanced programming changes. All Presets can be altered, the order can be rearranged, Presets can be saved and loaded to your PC hard disk, the display screens that appear on the LCD while the charge is underway can be reconfigured for each and every User Preset, the firmware can be updated, real time graphing of the charge cycle is possible, the chargers audio and display global settings can be altered and the individual cell voltages and power supply voltage can be monitored, and even limited if the power supply you are using cannot supply enough current to the Multi4.

[BARNESJONR]

Advanced Features

One especially noteworthy advanced feature sure to please the under-the-hood types is the ability to generate custom fuel tables. Each type of battery and each manufacturer of battery will have it's own charge profile I.E the way it reacts and responds during the charge cycle. FMA has included specific fuel tables for their own house brands of Revolectrix lipoly batteries but these fuel tables are not necessarily the best for other manufacturers lipoly batteries. I t is thus possible for the user to create a custom fuel table and then save it to a preset for future use on that particular manufacturers battery. It is not entirely necessary to do so, as FMA provides generic presets that will function for all lipoly batteries but the advantage of custom fuel tables is that the charge cycle will be tuned for that type of battery and will choose the charge rate more accurately than it did using a Generic preset. Fuel readouts, FMAs way of predicting the percentage of charge in the battery, should also track better and more accurately.

For an in-depth explanation of custom fuel tables, have a peek at the Multi4 FAQ:

Multi4 FAQ

Another interesting advanced feature is the ability to share presets with other Multi4 users. Perhaps you have come up with a very efficient custom fuel table for Brand XX battery. You being the good friend you are to your fellow club members, you will undoubtedly want to share the “special” preset with them too!

[BARNESJONR]

A Charger to Start With, a Charger to Grow With!

The Multi4 is designed to be super easy to use. Connect the battery to be charger, push the Mode button a few times and you are charging. It can't get much easier! But the Multi4 is also a charger to grow with. One reason is it's extreme versatility in the different battery chemistries it can charge. However, battery chemistry is sure to keep changing and evolving. And as it does, FMA engineers will be able to create new Library Presets. These updates will include both new battery brands and also new battery chemistries that will undoubtedly develop. Since these Presets are contained within the CCS software, a fresh version downloaded from FMA will be the mechanism in which to receive these updates. Another reason that the Multi4 is a charger to grow with is that there are so many different areas of interest in the world of radio controlled crafts, each with their own favored type and chemistry of battery. As a user's specific areas of interest and battery needs evolve, the Multi4 should be able to service their recharging needs. As ones knowledge of battery chemistries and charger functionality evolve, they will be able to reconfigure their Multi4 to display the data that is most important to them.

If and when the day comes that you feel you need more of a charger than the Multi4 can provide, you may want to take a look at the FMA Cellpro10S!! It is my other charger of choice and can handle the larger sized, multi-cell count batteries and do so in swift order!

[BARNESJONR]

I will be adding selected charge graphs and further review information as I continue to use this cool new charger from FMA!

[BARNESJONR]

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[BARNESJONR]

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[BARNESJONR]

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[jodini]

Boy if this is the "mini-review", I would hate to see the FULL review! LOL

[BARNESJONR]

Ha ha ha! Agreed BUT I believe there will be a full blown review by another RCGroups Author whom is more qualified than I to really delve into the meat of this charger.

Do not let the modest price of this little charger fool you into thinking it doesn't have very much under the hood.

There is a supercharged Hemi hiding in there IMHO!

[terencechan]

I have been using my Generation-one CellPro 4S for 4 years now. At that time, it did not come with the multi-adapter PCB for the different Lipos' charging tabs

So, I made my own 2S/3S pigtails for thunderpower lipo balance-charging tab. That pigtail 'expanded' to having two additional connectors for charging two 2S packs concurrently as if they were a 4S pack.

Then came the newer firmware with the ability to charge A123 cells. I did not send the charger back for firmware-upgrade since I only use Lipo technology.

The highly programmable feature of the new Multi4 is GREAT! The first thing I 'm gonna do with it, is to turn down the sound volume so that I can charge my 4S Lipo in my office without having its loud beeping draw unwanted attention.

Thumbs ups FMA-Direct!! You just can't go wrong getting it as your first charger!

Here's one more thing to note before you disagree.

Most good, reputable chargers out there can do cell-balancing and they have their own pro features which some may argue that they are superior to the CellPro's.

BUT these chargers normally require a wired connection to the Lipo's output (the Deans connector, JST connector or Tamiya plug for RC car's Lipo). In fact, some of these chargers won't charge unless you have connected this 'extra' cable.

This to me, is just plain-stupid!!!

Everyone who understands how the balance-charging tab work, will know that it has 2 specific nodes that will read the same series-output voltage just like the Lipo's output plug. It does not make any difference to read the voltage from the pins of the balance-charging tab or to read the voltage from the Deans Connector.

Someone will argue that it's not advisable for the charger's computer to read voltage from these 2 pins especially since high current is being pumped into the pack via these pins... OKAY point taken! But with today's technology, there are schottky diode, 1-way rectifier, zener diode and lots of sophisticated filters that can easily eliminate these 'side-effects' entirely. Well, if the FMA-Direct engineers can do it...what are we waiting for?

I'm sure any electric flyer will be happy that they can charge their my Lipo simply by plugging its charge tab to the charger.

No stinking red and black cables to hook up the charger to the deans connector! Yea! That's my Favorite Charger...you got it now!

[la528it]

Originally Posted by terencechan

BUT these chargers normally require a wired connection to the Lipo's output (the Deans connector, JST connector or Tamiya plug for RC car's Lipo). In fact, some of these chargers won't charge unless you have connected this 'extra' cable.

This to me, is just plain-stupid!!!

Everyone who understands how the balance-charging tab work, will know that it has 2 specific nodes that will read the same series-output voltage just like the Lipo's output plug. It does not make any difference to read the voltage from the pins of the balance-charging tab or to read the voltage from the Deans Connector.

The cell-pro 10s requires it if you charge over 4 amps. I thought you needed to mate the charger to primary connector (deans, tamiya, etc.) in order to feed it over 4 amps, as the balancer plug should only be used for fine tuning. Please correct me if I am wrong here, I am actually keen on learning more about this.


thanks!