Tag Archives: SOTA LiFePO4

Homemade SOTA battery for the FT-817ND 11.1V 3S1P LiFePO4

In looking around for a decent battery for SOTA activations on my FT-817ND radio, I decided that nobody was making the exact battery that I wanted. Up until now, I’ve been successfully using a Bescor 4500mAh, 12V NiMH battery. I wanted something that was slightly lighter, and also a lower pack voltage to minimize the standby current on this particular radio.

I decided on the LiFePO4 (Lithium Iron Phosphate) technology, because it has a lot of the energy characteristics of other Lithium batteries, but with less chance of fire! All my parts were purchased from BatterySpace.com. They shipped pretty quickly and I got exactly what I ordered.

Here are the parts as they arrived in the mail. (3) 3300 mAh cells, a fusible link, an over temperature link, some heat shrink and a balancing connector.


A shot of the individual cell:


The over-temperature link. I connected this between cells 2 and 3.


Here’s a shot of the self-resetting fuse. This was soldered between cell 1 and 2:


Before I soldered any of the cells, I hot glued them together. I always used to think hot glue guns were for craft folks. I now find myself using it a lot for fabricating “stuff.”


After shrink tape applied! I put 2 wraps on and alternated them. Once it’s fully tested I’ll put 1 more wrap on just to be safe.


Here’s the pack connected to the balancing board on my Thunder Power TP610C-ACDC charger. I got this charger a few weeks ago, and it’s the fanciest battery charger I’ve ever had! I’m glad I spent the money on something nice and versatile. I’ve used it for my SLABs, AGMs, NiMH packs and now the LiFePO4 pack.


View of the charger. This one is nice because it can use DC or AC as a source of power for charging. Handy if you’re at home or in the field.


View of the screen with first charge. The little carrot indicates that the charger is sensing the center taps between cells. BTW, on the balancing wires, connect the red wire to red, black to black. The Green wire, which is adjacent to the red wire on the balancing plug, should connect to the tap between cell 2 and 3. The yellow wire which is next to the black wire, should connect to the tap between cells 1 and 2. To test, measure on the balancing connector. Between black and Yellow, you should measure 1 cells voltage (~ 3.5V). Between black and Green you should measure 2 cells in series, or ~ 7.0VDC. Between black and red, you should have the full pack voltage of ~ 9-10VDC. The cell voltages will depend on the state of charge that the batteries arrived in.

Keep an eye on this battery during the first few charge/discharge cycles. It should be perfectly safe, but it’s better to keep an eye on things.


Posted in N0BCB Also tagged , , , , |