Our Design Partner, FMA Direct

Our in-house staff of engineers is constantly at work developing new products, and improving existing designs for the R/C industry.



I'm using Windows Vista or Windows 7 Pro 64-bit (or 32-bit). Do I have to have the FUIM2/FUIM3 connected to the USB device before connecting it to my computer? I ask because I keep getting "no driver found for your device."

1) Leave the FUIM2/FUIM3 disconnected from the Cellpro 10s and from your PC's USB port.
2) Launch the Cellpro 10s CCS application.
3) Click the download USB driver link from the application window.
4) Pick the correct driver from the web page. If your device is FUIM2, use the Driver for Win Vista x32 or x64 bit. If it's the FUIM3, there's only one driver.
5) Follow the on screen instructions. If you have attempted to load the driver before, what might happen is an uninstall first. If you see that the program wants to uninstall the driver, let it. Then go back to the website and install it again.
6) Now launch the CCS application again.
7) Plug the USB end of the interface into your USB port at this time. Win7 should tell you the driver is loaded now.
8) Plug the other end of the cable into the Cellpro 10s PC port and apply power.
9) Click the firmware you wish to install, then choose Update Firmware.

Why does the Cellpro 10s charger charge my battery at a higher rate than I expect using AUTO modes?

Fuel Gauging technology for lithium batteries as implemented in the FMA Cellpro chargers is a great way to vastly simplify the charging process. In addition to supplying the customer with a fast approximation of how much capacity remains in his battery pack when connected to the charger, fuel gauging also allows the customer to select AUTO modes. This means it is simpler to initiate a charge. The customer does not need to know any details about the lithium battery pack he will be charging. He just needs to tell the charger whether he wants to charge at 1C, 2C, or 3C. We knew AUTO charge modes would be popular, but we had no idea that Fuel Gauging and AUTO modes would become the dominant method of using the chargers.

Fuel gauging is actually fairly simple in principal. The charger looks at the battery pack voltage as it charges and compares "where it is" to a known voltage-to-percent capacity table. In other words, if the battery is at "n" volts at any particular time, it has "y" % charge state.

Recently, we have come up against a limitation to Fuel Gauging technology that we did not foresee and which we have addressed quite well in newer model chargers (beginning with the Cellpro Multi4). Previously, all of our research indicated that, within reason, all lithium batteries had very similar charge curves. It worked very well to have a single fuel lookup table stored in the charger. Actually, LiPo and A123 use two different tables. But in recent months, we have come to learn of newer, higher C batteries coming to market with substantially different voltage characteristics. Many of these are rated 25C or higher discharge. Also, we have learned that lower quality or aging batteries have substantially different voltage charge curves.

So what can happen? As noted in certain forum posts we have made over time, the chargers might jump around on current during charge in AUTO modes. Charge current might go higher than expected for up to several minutes. Fuel level percent displayed may not closely approximate the actual capacity remaining in certain batteries. Storage charge mode can also be affected as it uses fuel gauging to set the 1C charge rate in the Cellpro 10s charger.

We do not feel that some inaccuracy in charge rate has any impact on the charger’s safety. Do not be concerned if the charger delivers higher current than expected to the battery pack during AUTO modes. The setting averages out over time. It will not stay at high currents for an entire charge and it will not damage your batteries. Nevertheless, if you feel the charger is over-charging super-high rate batteries (25C and higher) consistently, please observe the following workaround:

If you experience inaccurate fuel gauge readings or you witness the charge current jumping around on certain batteries, either during AUTO charge, or STORAGE charge, note which batteries are causing the problem. Stop using AUTO mode for those batteries. Instead, set the charge current manually. In manual charge modes, the charger does not have to calculate what the ideal charge current should be. It will not exceed the charge current limit you select. You can still perform a manual storage charge on these problem batteries by watching the cells charge and removing the pack when the individual cell voltages reach 3.85v.

Alternatively, FMA has already issued newer firmware for the Cellpro 10s charger to address this issue. Firmware v2.22 will limit charge current to 4A maximum in any AUTO mode or when in STORAGE mode.

Furthermore, as of the date this FAQ was written, we are pursuing the possibility of releasing additional firmware(s) to support higher discharge (25/30c) batteries more optimally. This method would entail loading a different firmware into the charger based on what batteries you will be charging using AUTO modes or STORAGE charge mode.

When I attempt to charge two batteries with my Cellpro 10s via both the balance plugs and discharge plugs, I get the following error "No Plug Blocker". The charger will charge a single battery pack through the discharge leads and balance plugs, but not two packs.

Using a DVM set to continuity, check to see if the internal fuse between banana jacks 2 and 3 on the front panel is blown. If the fuse is in tact, you should be able to measure continuity. This fuse can be blown when a battery pack is connected across the two center banana jacks. Use banana jacks 1,2 / 3,4 for 2 packs and jacks 1 and 4 for a single pack. Never connect a battery across banana jacks 2 and 3. There is a skull and crossbones on the front panel of the charger between these jacks to remind you. The internal fuse is soldered in place and is the size of a 1/4W resistor. Value is 15A fast blow. Contact customer service at (301) 668-4280 if you determine the fuse is blown.

When I try to use storage charge on my battery pack, I get an error message saying "CH1 Bad S Count". What's going on?

The battery pack must be discharged below 50% before re-charging to storage voltage (3.8v) or the charger will error out. The charger does not have discharge capability.