My DIY Lipo Battery Back Experience Share for You

Superior monolithic battery may not produce high quality Lipo battery pack for RC aircraft, but excellent RC aircraft battery pack necessarily need superior lipo cell to produce. This is particularly true if you need a battery pack to regularly power equipment such as remote controlled (RC) cars or aeroplanes. Batteries such as nickel cadmium (NiCad) or nickel metal hydride (NiMH) are popular choices for RC car enthusiasts, while lithium polymer (LiPo) batteries are chosen by RC aeroplane enthusiasts, due to the that battery's lighter weight and higher output voltage. Make a rechargeable battery pack wired in series to increase output voltage: RC models need about 10-volts to operate, although it varies by type. Wiring in series combines the output voltage of each battery in the pack.

I have two gens ace lipo 6S 5000 mAh battery packs. One pack has one defect cell. I remove the defect cell and one of the good cells from the defect battery pack and thus get a 4S pack.

I connect the 6S and 4S packs lipo battery 5000mah together in serial to get a 10S battery pack. Wiring diagram is shown below.

I also cheek each battery pack using RC LI-Po battery tester. The RC Li-Po tester clearly indicates how many cells there are in the battery pack  (including the Voltage of each Li-Po battery cell). However, this particular RC Li-Po tester can only test up to 8 battery cells. Fully charged battery cell has a voltage of nearly 4.2V. The pictures below depict the testing of a 6S (number of cells) and a 4S (voltage of a single cell in a pack) battery pack. When I connect everything together, I get a 10S 5Ah 36V Li-Po battery pack. I put the pack into the triangle bike bag for easy fitting on to the bike. Total weight of the battery pack is only 1,42 Kg.

So far in the auctions I have won on Genstattu, I have paid an average of $8.94 per cell, including shipping and handling charges! The 6-cell Lipo pack that I will build in this How-To cost me a grand total of $54.87 including the cost of the 6 cells, the Deans Connector, the 12 gauge wire and the tape used to hold everything together. If you decide to add a balance connector, this will add about $2.00 to the cost of the build.

The 6 cell pack built here has a open circuit voltage of 6 x 3.7 volts per cell for a total pack voltage of 22.2 volts, and has a capacity of 2300mah. The pack can deliver 30C continuous (69 Amps) with burst capability of 40C (92 Amps). I am currently running them in my 150% F-4 and 166% F-18 ParkJets and in both planes I am pulling 35 Amps (15.2C), and getting 5-6 minute flights with 300-400mah left in the lipo battery pack at the end of the flights. At this current draw, the Gens Ace 6-cell pack delivers 22.2 volts or 2.867 volts per cell. In this application, the packs are delivering 22.2 volts x 35 Amps or 602 watts, which is pretty good for a battery pack that weighs just 1 pound!

I think that I may be somewhat alone in my continued usage of Gens ace lipo batteries. If you care to join me, you can buy factory assembled Gens lipo battery packs from numerous vendors. Those of you comfortable with heavy soldering can save a few bucks by assembling your own packs from individual cells. In fact, most of my Gens Ace lipo battery packs were built with cells scavenged from certain DeWalt cordless drill batteries. Also note that Gens Ace lipo battery cells require specific chargers.