CHARGING MULTIPLE BATTERIES

I charge 15-20 batteries at a time. Here's how.

SORT THE BATTERIES

Read the voltage of all used batteries with a voltmeter. Sort the batteries into one of 3 piles:

     First pile:       3.69 Volts or less

     Second pile:  3.7 to 3.79 Volts

     Third pile:      3.8 Volts or more

The bulk of the batteries I charge are in the second pile of 3.7 - 3.79 Volts. This is because I fly for 6 minutes per battery, timed, and then stop flying and change battery at 6 minutes. This leaves about a 15% remaining charge in the battery. 

Yes, I know. The UDI manual says, "6 to 9" minutes flying time. However, at 9 minutes the batteries would probably be at or below the critical voltage of 3.209V. I choose to use more batteries and for a shorter length of time. 

Remember, these are 1C batteries. 1C means they can ONLY be charged at the rate shown on the battery and NOT at a higher rate. All my batteries say 600 mAh. The maximum charge rate is 600 mAh.

     When multiple batteries are in parallel, the maximum rate of
     all batteries works out to the same 600 mAh per battery as the
     charge load is "spread out" over multiple batteries.

CABLE TO QUICK READ BATTERIES

Get a volt-ohm-meter (VOM). About $10.00-$15.00. Harbor Freight, Lowes, Amazon, eBay, etc. Set scale to the next step higher than the battery voltage to be read.

I use the 20 VDC scale. VDC means: Volts, Direct Current. All batteries are DC or direct current. Don't use AC scale. Readings will be incorrect if you do. See picture below for custom adapter cable. Click on pic for larger view.

 

I made mine from:

     1) 1 each 12" long jumper cable with alligator clips on each end.

     2) Cut this cable in half.

     3) Solder each half of the cable to a scavenged JST female plug with wires. I got mine off an damaged quad. Note the silver dot on the JST. All my batteries are "indexed" in this fashion. See other posts for more information. 

Prior to soldering, I inserted two 1" length of heat shrink (HS) tubing. After soldering, I positioned the HS and shrunk them with a cigarette lighter flame.

     4) Add some electricians tape to HS connections to "beef it up". I slipped on a larger piece of HS tubing and shrunk it into place.

     5) Clip the alligator clips to the red and black leads of the VOM. Ignore polarity for now. Set VOM to 20 VDC or next highest setting above 3.7 volts. 

Note: My meter (above) has a black triangle inked on the meter's side just opposite of the 20 VDC setting. Insert a battery into the JST fitting.

     6) Read voltage on meter. If you see a minus (-) sign (see pic above), the cables are hooked up incorrectly. Swap the red/black leads. Meter should now read voltage with NO minus sign.

Polarity is now correct. VOMs will read DC voltage with cables reversed or normal. If the leads are reversed, the (-) or negative sign shows up.

     7) Add a 1 inch piece of Black electricians tape to the black lead of the VOM. See picture. The black lead is always ground or negative or minus (-). The BLACK tape alligator clip now goes to the negative jack of the VOM.

ATTACH BATTERIES TO THE 5-WAY

You can attach up to 5X batteries one a 5-way cable. Here's a seller with 5X 600 mAh batteries and a free 5-way cable on Amazon. The battery/connectors fit the UDI U818A:

5-WAY CHARGER CABLE

Here's a seller that sells only the cable. It also fits the UDI U818A:

ANOTHER CABLE, NO BATTS

Use one charger for each 5 way cable. I have 3X 5-way cables and 3X chargers. All identical.

B6 LiPo DC CHARGER

I use these:

B6 LiPo CHARGER 

I use an AC adapter (wall wart) with output voltage of 12 volts (12-18V is ok) and with an output current of 2 Amps, minimum. Here's what I bought: 

B6 LiPo Power Supply

Be sure the plug diameter on the end is 5.5mm with a 2.5mm center positive (+). The above adapter meets these specifications.  One of my B6 chargers came with a 5.5mm x 2.1 center. The above adapter will fit both.

CABLES

Locate in the "Banana plug" cable in the charger box.  Banana plugs have a gold plated fluted spring connectors on one end and "T" shaped male plug on the other. This cable is about 12" long.

The above pic (click for larger) shows 1 battery on the cable end. Substitute the 5-way cable to charge 5 batteries. Locate the JST / "T" shaped female jack cable (about 5" long) and plug it into the Banana cable.

You now have a cable setup to be plugged into the charger that has a JST jack at the end. Don't plug in the cable, yet.

LOAD THE 5-WAY

Load 5X LiPo batteries onto each of the 5-way cable(s) taking only the batteries from the same pile. Do not load other batteries of different voltages from the other 2 piles. Single batteries are charged individually.

After I load all the 5-way cable, I charge the remaining odd batteries, individually. That leaves 30 minutes or so for the batteries on the 5-way cable(s) to equalize their individual voltages somewhat.

CALCULATING TOTAL AMPERAGE

All batteries should be the same or near same mAh setting. All mine are 600 mAh. Charging 5X at a time, you multiple the number of batteries to be charged on the 5-way by their individual mAh to arrive at the total maximum allowable  current (amperage) to be used during the charging process.

You are charging in parallel so the LiPo voltage of 3.7 VDC +/-  is near the same for all and the total current allowable is the sum of all the batteries mAh to be charged.

You CAN use less than the total maximum calculated amperage if you like. But, NOT more! Charging will take correspondingly longer with lower charging current.

TOTAL MAXIMUM CALCULATED EXAMPLES:

      
   5X 600 mAh = 3,000 mAh or 3.0 Amps & does 5 batteries.

   4X 600 mAh = 2,400 mAh or 2.4 Amps & does 4 batteries.

   3X 600 mAh = 1,800 mAh or 1.8 Amps & does 3 batteries.

   2X 600 mAh = 1,200 mAh or 1.2 Amps & does 2 batteries.

   1X 600 mAh =    600 mAh or   .6 Amp & does 1 battery.

PLUG IN SETUP CABLE

Red plug goes into Red jack, Black plug goes into Black jack. Double check! You now have a cable plugged into the charger that has a JST jack at the end. Charger cabling is now setup, but 5-way batteries are NOT connected at this time.

POWER UP

Plug the power supply into the charger. Then plug the power supply into the wall. The charger will power up and display a message. Following the printed directions in the charger manual.

SHORT SETUP VERSION

The display should say "LiPo CHARGE" or "LiPo Fast Charge". If it doesn't, follow the manual and set it to " LiPo CHARGE" or "LiPo Fast Charge". Then press START button, once. The AMPS setting will now flash.

The next 2 buttons to the right are the "setting up" and "setting down" buttons.  Press INC or DEC until it says 3.0A. Then press 
START. That will set the AMPS.

AMPS will now flash at 3.0A. Press START. AUTO may/will now flash. Press START. If nothing flashes this indicates charger is set to charge. You are now set up for charging. 

Connect the 5-way cable with the batteries - now.

The reason for putting the batteries in last is if you make a mistake programming the charger, you will not charge at the wrong settings. The button pressing sequence is not complicated but you will need a little practice to learn how to make the selections using the 4 buttons.

CHECK AND START CHARGER

To start the charging sequence, press START and hold for 3 seconds. The words "BATTERY CHECK WAIT..." will appear. 

If the charger is set to AUTO, it will check the cell voltage of the battery and if all is correct it will start the charger.

If no autostart (AUTO) shows, look at display. You should see 2 of these: 1SEL.

If there are 2 sets of xSEL numbers, both must be (2) identical. Example: battery is detected as 1SEL and charger is set to 1SEL. This is correct. The charger sees any number of cells on the 5-way cable as one cell or 1SEL. 

This is because the batteries are in parallel. The charger may or may not show more than 1SEL. There are at least 2 models of the B6 charger. See your manual.

I have one charger that only shows 1SEL (once) and also shows the word,  "AUTO". I have another charger that shows 2x 1SELs and no AUTO. This charger MUST be started manually by pressing the START button.

Just be sure you are charging a 1SEL or single cell battery. Again, the 5-way with 1 to 5 batteries is "seen" as a single sell or 1SEL.

If you see 1SEL and 2 SEL or 3 SEL on the same screen - something is wrong. Disconnect the batterie(s) and start over. When there are 2x 1SELs, or 1x 1SEL and AUTO, the charger can be started. 

If in AUTO mode, the battery will do this checking automatically and start the charger for you. Any questions? Consult your manual.

NOTE

I have 3X chargers. One acts slightly different than the other 2. Most likely due to a slightly different operating system. All do the same thing.

All chargers shut off automatically at 4.2V which is maximum allowed voltage for LiPo batteries. I don't use "fast charge" as sometimes it will shut off early (4.17 volts) if the batterie(s) are near full capacity when put on the charger.

KEEP ON FLYING!