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FAQS | CELLPRO MULTI4 CHARGER AND ACCESSORIES

Multi4 Firmware v1.55 Definition:

Added Autostart feature which can be activated in the Options tab of the CCS or via a new Options menu accessible by pressing and holding the MODE button on power up. Power Supply input current limit is also now adjustable at the charger as well as in the CCS.

Multi4 Firmware v1.52 Definition:

Pack Removed requires 2V drop when charge is complete to prevent erroneous safety code.

Multi4 Firmware v1.49 Definition:

Added PC Remote Control to the charger. Customer can now select presets and Start/Stop the charger from the CCS "Cells" tab, all without the need to touch the charger's MODE button. Also, maintenance item: preset library starts with the first for forward button press and last for reverse button press.

Multi4 Firmware v1.48 Definition:

LCD now displays Low Volt Restore when the battery requires this special mode. Trickle charge for Ni chemistries can be set up to 300mA in the PC software. Firmware versions prior to v1.48 still limited the trickle charge to 100mA. This limitation has been removed so that the charger will track what is programmed in the CCS. Adjusted Safety Code #96 setting to help prevent false positive for this code.

Multi4 Firmware v1.47 Definition:

Fixed 1mA rounding below 1000mA so that charge rates match set points in the charger and the CCS. Adjusted threshold for Safety Code 96 to prevent erroneous safety code. Empty Presets can now be hidden. Adjusted threshold for PACK REMOVED to prevent erroneous safety code. Full batteries will show charge complete in Store Mode.

Multi4 Firmware v1.45 Definition:

VERSION 1.45 Changed BSL configuration - this changed a programming setting
so that the likelihood of losing the oscillator calibration due to
production problems is lower. Again, this has nothing to do with chargers
in the field or that have already passed production QA.

Multi4 Firmware v1.44 Definition:

VERSION 1.44 Locked Presets wont be over written by the Library. Holding
Button while powering on show a Supply Limit override screen. Previously,
if a preset was set to "locked" in the CCS, you could still overwrite it at
the charger from the charger's library. The ability to display a screen
showing Supply Limit override on startup was an enhancement.

Multi4 Firmware v1.43 Definition:

VERSION 1.43 Added an 16MHz oscillator calibration utility. - this has
nothing to do with actual charger operation per se. If during calibration,
the charger has a shorted uC, it's possible for the default oscillator
setting to get whipped out (a TI bug actually). We corrected this by having
the firmware be smart enough to recognize the oscillator is not set properly
and to adjust it through utility in the charger. This is only for
production problems.

Multi4 Firmware v1.42 Definition:

VERSION 1.42 Fixed default oscillator - this was a minor bug fix to massage
the internal oscillator value so that all chargers in a batch pass
calibration and testing. We fixed this before the first unit went out the
door I think.

Why are there up to 50 library presets in the Multi4 charger?

The Multi4 charger will store up to 50 library presets. Libary presets can not be edited by the customer directly unless they are first copied to the user bank. At this point, they become a user preset and all parameters can be edited. The first 25 library presets are identical to the first 25 user presets. The reason for this is that if a customer clears a user preset at the charger, he will always be able to re-load it later if he decides he needs it. Also, additional presets are included that are not a part of the statndard 25 user presets and the list will grow over time to support newer battery types or special requirements. Library presets are, in part designed so that the customer always has access to known-good presets that have been qualified by the manufacturer. When new Charge Control Software (CCS) updates become available, they may carry new firmware updates as well as new library presets. Additionally, if the total number of "qualified" library presets exceeds the capacity of the charger (50), additional library presets could become available in the FMA Library on the PC. Access the full library using File > FMA Library Presets. One simple way to keep your charger updated with the latest library presets is to initiate a Factory Restore from the CCS Firmware tab. But please recognize that Factory restore will update all user presets, all library presets, and all options in the charger to the latest factory settings. If you have made custom changes to your user presets, remember to save them down to your computer's hard drive before initiating Factory Restore. This way, you will be able to restore them again after Factory Restore completes. The same thing applies to Options. You can save customized options to your PC hard drive and recall them from the Options tab in the CCS.

What type of parameters can be programmed at the charger?

The Multi4 concept is based on keeping the charger as simple as possible to operate while in the field. Therefore, the parameters that are programmable at the charger are limited to 1) the ability to recall any one of 25 user presets; 2) the ability to change the charge rate setting for a preset; 3) the ability to clear presets from the charger to "open up" a blank preset; and 4) the ability to over-write a user preset with a library preset so it can then be used to charge a battery. All other parameters require the use of the Charge Control Software (CCS).

What types of parameters can be programmed using the Charge Control Software (CCS)?

There are over 70 basic editable parameters that can be edited using the CCS for each of 25 user presets. This does not take into account the fact that a single parameter might consist of pulldown lists containing hundreds of settings. In the charger, depending on how the preset is set up, charge rates might be selectable between 0.25A and 4.0A in 0.25A increments. But in the CCS, the charge rate settings are 50 times finer, or adjustable in 5 mA increments. The actual number of editable parameters are too many to list in an FAQ, but include things like editing a preset name, showing, hiding, or clearing a preset from the charger LCD, choosing a library preset, locking a preset so it cannot be edited, adjusting low votage restore settings, setting cell detection between Auto or a specific number of cells, selecting between Auto or fixed charge rate, setting manual charge rate, end charge voltage, cold weather on/off, cold weather end charge voltage reduction, cold weather temperature set, choose between proportional of digital balancing method, balance speed, balance start voltag, balance set point, whether or not to balance the entire charge, balance dead band, balance current limit, termination mode (lithium, delta fallback, reaches end charge voltage), C/? termination value, whether or not 100% balancing is required, whether or not all cells must reach full charge voltage, C.V. timeout (in minutes or hours), screen order, information, or show/hide LCD screens at the charger, pack capacity (if available), whether or not to use a Fuel Table (lithium only), sound a beep at xx% capacity reached, start Auto amps, max auto amps, individual fuel table levels at 10%, 20%, etc., charge timeout, max auto C rate, and other safety settings.

What is Fuel Gauging and how is it improved on the Multi4?

Fuel Gauging is a technology pioneered by FMA. As a lithium battery charges, the plot of voltage vs. capacity during a charge (or discharge) is very predictable and repeatable. FMA took advantage of this phenomenon to enable our chargers to notify the customer of the capacity that remains in the battery soon after it is connected to the charger. As charging progresses, the charger closely monitors this fuel level and improves the accuracy of the fuel level reading. Additionally, fuel gauging technology is what allows us to offer AUTO charge modes. As the charger monitors the capacity of the battery increasing over the charge process, it can adjust up or down the charge rate to closely match the ideal charge rate selected. For example, if an AUTO charge setting of 1C was initiated on a 2000 mAh battery, the charger will gradually ramp up the current. As it does, it watches the capacity increase by carefully monitoring the battery's voltage. Within 20 minutes or so, the charger knows the capacity of the battery to within about +/- 10% accuracy. So it will charge the 2000 mAh at 2A as it should without the user ever entering a charge rate. The advantage is that if the customer has multiple batteries with varying capacities, or does not know the capacity of the battery, the charger will choose the ideal charge rate automatically. But Fuel Gauging technology has some limitations. As newer lithium batteries began to emerge with newer chemistries and higher C discharge rates, the charge curves began to change. The accuracy of the fuel gauge did not match the single fuel table the older charges held. So, with the Multi4, each preset can be designed and optimized for a specific chemical composition, brand, or C rate discharge. This way, whenever the customer is charging brand X lithium, he calls up the brand X preset and the corresponding fuel gauge readings and AUTO mode charging will be highly accurate. Additionally, by using the CCS to monitor a single charge with a charge rate set manually to 1C and recording the data, the CCS can then "learn" the actual fuel table values for the particular battery type. Using simple tools in the CCS, this fuel table can then be extracted from the data file and imported into the current selected preset. From this point forward, this preset will always charge this type of battery properly in AUTO mode.

How do I create a custom fuel table for the Multi4?

The following instructions assume you will be using the Charge Control Software exclusively to perform this procedure. Some steps can also be performed at the charger. For this example, we will utilize one of the EMPTY presets in the user bank to create a new preset. We will begin by copying an existing preset, which most closely resembles the custom preset we are striving to create.

1. Launch the Multi4 CCS and check to see that the software is communicating properly with the charger. “Waiting to Start” should appear at the top of the CCS program window. The presets and options should upload from the charger into the CCS options and presets tabs.

2. Activate the tab “Presets” to see the list of charger user presets and library presets. All of your work will be done in the user preset bank as the library presets can not be altered by the customer unless or until they have been copied into the user preset bank.

3. Click in an empty preset title field from within the 25 user preset bank.

4. Make sure the checkbox titled “Advanced Properties” above the preset list is checked.

5. From the main menu, choose File > FMA Library Presets > Open File to Preset # (where # would equal the preset number of the empty preset you selected).

6. Navigate to the folder that contains the preset most closely resembling the new preset you will
create. For example, if you want the most accurate charge possible with a 1C AUTO charge as the default, then locate the preset file “LiPo Generic Accurate Charge” in the folder titled “Generic LiPo”. For detailed information about the available user presets that come with the Multi4, check the Cellpro Multi4 manual.

7. In the selected preset title field, highlight and re-name the preset to match the battery which requires a custom fuel table. For convenience, the carrot above the preset name field shows you where the name will be broken on the charger’s 2 line, 16 character LCD when the charger scrolls the information.

8. Next, click the Charge tab in the preset parameters pane to the right of the preset list.

9. In order to generate a custom fuel table for the new preset, you must first charge the battery that will utilize the new preset at a manual 1C charge rate. Therefore, click the pull-down next to the parameter titled “Auto Chg. Rate” and select the parameter “Manual Charge”.

10. Next, calculate the correct manual charge rate setting for the battery in question. Let’s say the battery has a capacity of 2100 mAh. A 1C charge rate for this battery would be equal to (1 x the capacity), but expressed in either milliamps (mA) or amps (A). So in the Charge Amps parameter, pull down and select 2.1A because (2100 mAh x 1 = 2100 mA or 2.1A). There are 1000 mA in 1A. If the exact current is not available, use the next closest value; higher or lower.

11. Click the “Update Charger” button below the preset list. The charger will beep when the preset
is saved to the charger and “Saving Presets….done” will appear near the bottom of the CCS program window.

12. Make sure the battery is discharged, then attach it to the charger’s output and start the charge. If you do not know how to start a charge, refer to the charger’s manual.

13. Once the charge is initiated, the File Save dialog box will open. Choose a name for the data file that you are about to record and save it to your hard drive in a location where you will be able to find it later. During the charge process, you may select other tabs and view information or data graphs as the charge progresses.

14. Allow the charger to finish the manual rate charge on the battery. The charger will display DONE on the LCD. If you do not allow the charge to complete, the procedure will fail when you attempt to import the fuel table data.

15. Make sure that the new preset is highlighted in the preset tab of the CCS.

16. From the CCS main menu, choose File > Import Fuel Table to Preset # (where # would equal the preset number of the newly created preset which is highlighted) > Import Fuel from a Manual Current 1C Charge Graph… Navigate to the folder where you stored the 1C manual charge data, and select the file.

17. The new fuel data will be derived from the data file you created. The data points are stored in the new preset and can be seen in the Fuel tab. If you receive any errors, click the errors tab, check the error, then double click on the error. The CCS will automatically take you to the parameter which requires adjustments.

18. Return to the Charge tab and choose 1C from the “Auto Chg. Rate” parameter pull-down.

19. Click the Update Charger button to save the new custom preset with custom fuel table to the charger.

20. With the new preset highlighted in the Preset tab, From the CCS main menu, choose File > Save Preset # to File… choose a location on your hard drive to store the preset and choose “Save”. This way, if you ever need to restore factory defaults on the charger, you can easily reload the custom preset you just created.

21. Discharge the battery again and re-charge it using the new preset but this time with AUTO mode selected. Whether AUTO is set for 1C, 2C or 3C, the AUTO mode should now choose the charge rate more accurately than it did using a Generic preset. Fuel readouts should also track better. As long as the chemical composition of the battery is the same among various packs you have, this new preset should handle AUTO charge properly for any capacity pack you attempt to charge. However, bare in mind that just because brand X 800 mAh pack charges great on the new preset, brand X 3200 may come from a different LiPo vendor. The name on the battery does not necessarily mean the chemical composition are the same. For more information about the expected accuracy and charging characteristics, refer to the Multi4 manual.

22. If you need to create other new presets which utilize the custom fuel table you just created, you can also import the fuel table data directly from the new preset you just created as opposed to the original data file. The preset containing the custom fuel table needs to have been previously stored on the computer hard drive as we did in step 20 above. Highlight the preset that you wish to copy fuel table data to, then from the CCS main menu choose File > Import Fuel Table to Preset # > Import Fuel from another Preset File… Locate the preset file containing the custom fuel table data, and choose “Open”.

This concludes our tutorial on creating new presets, creating custom fuel table data files, and applying custom fuel table data to presets.

what is fallback voltage?

Fallback voltage is the term used to describe when a delta peak detection charger will shut off. During peak detection charging, precise constant charge current must be maintained. The battery voltage will rise through most of the charge. But toward the end of charge, heat begins to build in the cells as the electrolyte begins to heat. As charging inefficiencies come in to play, the voltage of the battery will begin to fall. Fallback voltage is the measure of voltage decrease during this critical time.. It is expressed in mV (thousandths of a volt) and is measured from the highest point in the charge to the lowest (the set fallback voltage). In the CCS, the NiCd preset fallback voltage is set for 8mV by default. This is a per cell figure. The charger calculates the number of cells in the pack 1) when the pack is first connected; and 2) then re-checks at a specified interval to ensure the cell count, and thus the fallback calculations are accurate. These parameters can be adjusted in the CCS. They are:

Tab Parameter

Termination Fallback Voltage
Detection Verify Cells Time

Depending on the quality and brand of cells used in a battery pack, fallback voltage may need to be adjusted up slightly to prevent false peaking. Verify Cells Time probably would not require adjustment.

A couple other parameters which are related are:

Tab Parameter

Termination Peak D. Skip Min
Termination Reduce FB 50%

Peak D. Skip helps prevent false peaking early in the charge process by ignoring erroneous peaks that often occur as a dead battery "adjusts" to charge current applied. Reduce FB (Fallback) 50% is a neat feature that will reduce the programmed fallback by 50% over a period of 1 hour during charge. This helps prevent false peaking on "difficult" batteries that tend to false peak early in the charge. The idea is to set the fallback parameter higher so that the pack will not false peak, but still peak detect on a smaller fallback so that the battery does not over-heat. In general, if the fallback voltage is set too high, in the worst case, the battery electrolyte can actually beging to boil. Ultimately, the safety vents on the battery can open venting gas from the cell to reduce pressure. Back in the days before microcontrollers, measuring the fallback with analog components was tricky. It did not always work reliably. Batteries could vent and even explode. With today's microcontrollers, it is virtually impossible to miss the peak during charge.

Why doesn't my Multi4 finish balancing my high capacity battery?

1) the pack may have been very out of balance at the beginning of charge.
Some cells may have notably higher capacity than the other cells which means
the charger has to work for a long time to balance it with the others.
2) the balancers are smaller in the Multi4 than in, for example the Cellpro
10s charger; 250 mA maximum.
3) If you check the preset parameters using the Charge Control Software
(CCS), look at the termination tab, and see that parameter "C.V. Timeout" is
defaulted to 30 min or lower. What this means is that from the moment the
charger enters Constant Voltage Mode, it will stop charging even if the pack
is not in balance within 30 minutes.
4) You can easily spot the time when the charger enters C.V. by examining
the current graph. When the current drops off steeply, that's when the
charger entered C.V. You can also see it in the voltage graph
when the first cell reached 4.2v. Of course, if you were watching the Cells
tab, the CCS will alert you the minute the charger goes into C.V. mode.

To enable the Multi4 to fully balance this battery in one charge, you would
need to increase the "C.V. Timeout" parameter to greater than 30 min;
possibly 1 or 2 hours. You should keep an eye on this battery over
time. If it continues to charge the way it did in these graphs, you can
increase the timeout parameter and it will balance in one pass, but it will
take a long period of time. Consider creating a custom preset for this
battery pack with the "C.V. Timeout" set to a longer time period.

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