Review of the ProjectWolfDragon.com
Over-Discharge Protection Circuit Board for Lithium Polymer (LiPO)
Battery Packs by GovCheese
Most airsoft enthusiast have had to make several important decisions in the past several of years as more and more innovative products have made it into the market to make the game more enjoyable and affordable. Tokyo Marui or ACM? MARPAT or Multicam? AEG, Spring or Gas Powered? NiCAD, NiMH or LiPO?
In terms of technological advances, airsoft has lagged behind other hobbies using similar technologies. Radio controlled enthusiasts have known about LiPO batteries for years, but they have only been recently endorsed and utilized by the airsoft community, with somewhat mixed feelings. Many of these feelings are due to misconceptions, but some are based on prior experiences and what people read online or see on youtube. You don’t have to search far to find a video clip of a LiPO battery violently exploding or catching on fire and spewing toxic gas.
Now for the public service announcement: LiPOs CAN and WILL be more dangerous than traditional NiMH or NiCAD batteries if handled improperly. Damaged cells could melt, catch on fire, explode and expel toxic gas. In order to prevent these, certain measures should be taken and specific equipment is required to properly maintain these battery packs.
You will need a Balance Charger, designed to charge all of the cells of the LiPO battery equally. Each LiPO cell is rated for 3.7 volts, and most airsoft batteries consist of either 2 or 3 cells, for a total of 7.4v or 11.1v.
You should always charge your LiPO batteries in a safe environment and never be left unattended. Damaged cells may melt or catch on fire while charging, so charging it in a sandbox, fireplace or inside of a LiPO Sac (or any other similar product) is highly encouraged.
You should NEVER discharge your LiPO battery below 3v per cell (6v for 7.4v packs and 9v for 11.1v packs). While you may run your NiCAD and NiMH battery packs down to the point where it will no longer fire your replica, doing so will damage your LiPO pack and could possibly cause one of the dangerous scenarios listed above.
This one is optional, but I would highly encourage you to install a MOSFET unit and a Deans type connectors to prevent wear on your trigger switch and to take advantage of your LiPO by getting rid of the major bottleneck.
1, 2 and 3 are VERY important and must be followed to ensure that you don’t have any accidents that may harm or damage users and or property.
The third rule above can be achieved by several different ways, but the easiest way is to get a LiPO alarm, such as the WolfDragon LiPO PCB unit. There are other products on the market, but none are designed exclusively for the airsofter, by an airsofter.
Kevin Stewart is the designer, and knows his electronics. He graduated from Virginia Tech (Go Hokies!) with a Bachelors in Aerospace Engineering with a background in Electrical and Mechanical Engineering. His full time gig is working for a company that makes and repairs Space Shuttle components!
There are a couple of different options for the PCB Lite product that Kevin offers through his website (www.projectwolfdragon.com). You can get it with either a buzzer, or a bright red LED. The buzzer will likely be the better option for most of you, as these will likely be hidden away in the battery compartment. Also, a small LED is a part of the PCB board itself, so getting the model with buzzer will also give you visual cues if you happen to place the unit in a visible area.
With the order, you receive two packets. One will include the unit and the LED or Buzzer and the other will include some JST connectors and wires, which connect onto the balancing port or your LiPO pack. You will need some simple soldering skills or take the unit to a local electrician to assemble the unit. Obviously, you will also need a soldering iron, solder and some flux if you plan to assemble it yourself. I would have preferred to have a pre-assembled unit, as I wouldn’t trust many others to solder this together, especially given that you’re working with very small parts. The wire lengths are also very long and needed to be trimmed, which may or may not help you but definitely leaves more room for installation in locations other than just the battery compartment. Other units that I have tested previously have had the buzzer integrated into the unit. You can configure the WolfDragon unit the same way, but I assembled it in the same configuration as shown on the website. Also, installation and assembly instructions were not included in the package. You must go to a specific website which has a PDF file with detailed instructions and many color illustrations, but much of the content was not for this product or configuration. While I found it to be useful, I would have preferred to have a printed out instruction in the packet, with only the information about the product that was ordered.
The unit itself is well designed and small enough for it to fit in most battery compartments, along with the battery. I have tested the unit in a Tokyo Marui SG552, which has a very tight battery compartment designed for a small 8.4v NiCAD or NiMH battery. I removed the battery “guide” piece to give it the compartment a little more room. It was a snug fit, but it did fit.
Now the problem with most other units was that because they weren’t designed for use with airsoft replicas, they didn’t function properly in them, often resulting in premature alerts due to discharge spikes, especially in upgraded AEGs. The WolfDragon unit solves this problem. I am not very technical, so I don’t know how it was done but Kevin has designed a unit that will only detect when the battery pack or individual cell has dipped below the safe level but ignore the temporary dips in voltage rates caused by a discharge spike that may occur with your AEG.
When you first plug the unit into your LiPO pack after proper assembly, you get a few chirps from the buzzer along with some LED flashes. This lets you know that everything is working properly.
To test the unit, I conducted several different tests.
First, I plugged the unit into two different 11.1v LiPO packs, one that was fully charged and another than was used to shoot approximately 750-100 rounds in my Systema PTW Max. Neither set off the alarm. The reading for the fully charged battery was 12.4v and the other was 10.9v.
I then place the slightly discharged battery and the unit into a Tokyo Marui SG552 and shot off about 200 rounds. The alarm still did not chirp and the reading had only dropped to 10.8v. Since it was getting late and the wife and baby were sleeping (and to conserve ammo), I did not want to shoot a couple of thousand BBs to bring down the voltage. Fortunately, my LiPo (all-purpost) charger has a discharge feature, which can bring down a 3 cell 11.1v pack to around 9.0v.
I discharged the pack in the LiPO setting (which requires me to plug both the Deans (main connector) and the JST (balancing connector) to the charger to 9.0v and plugged in the PCB Lite unit. After the initial boot up sequence, it detected that my battery was too low and started chirping and flashing after about 3 or 4 seconds.
Then, I decided to do a different test using the other 11.1v pack to simulate a real game situation. I plugged in the main connector to the charger and set it for regular (NiMH/NiCAD) discharge, while plugging the JST connector to the PCB Lite unit to see when it would trigger the alarm.
After about 35 minutes, I heard the chirping and went to my basement to check it out. To my surprise, it was triggered around the 9.8v mark on my charger, which was higher than I thought. I then plugged it into the LiPO meter to see if my 9.8v reading was correct and it was. However, because I didn’t use the LiPO setting on the discharge, the discharge process was not balanced (it was drawing more power from one cell than others), which is probably a very likely scenario during gaming. Because of this, one of my cells had actually dropped below the very important 3.0v per cell limit. It’s great to know that this unit will actually measure each cells voltage and alert you, not just when the entire pack drops below this threshold. Having this attached to my LiPO while discharging under the non-LiPO setting probably saved my pack, and perhaps prevented something bad from happening in my basement.
Overall, despite the minor complaints (assembly required, no instructions, etc…), I would HIGHLY recommend this product. This unit is available on www.projectwolfdragon.com for $17.50. The LED unit is available for $15. If you have a mosfet installed, there is an advanced version called the PCB V3.X available for $35, which adds some additional features. You can contact Kevin at sales@projectwolfdragon.com.
- END ADM
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Everything
is In Our Opinion Only - We lay no claim to any of these ideas,
suggestions, tunes, etc. We learned, in person and online, from
people who are a lot smarter than us and we merely use and try to
improve upon what we consider to be useful. ADM
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