I decided to build a lithium battery for my Yaesu FT-897D because the official Yaesu Ni-Mh batteries are far too expensive to import here (Then you need the special charger too!)
At present when operating portable, I have been running a lithium battery external to the radio (often a higher voltage battery through a little power supply)
So I grabbed some battery packs made up of four 2200Mah 18650 cells each, three of these adds up to 11.1v at 8.8Ah, this is plenty for my short trips !
I planned out how to fit them inside, and there’s more than plenty of space, see image 🙂
My preliminary notes were:
The three packs are each four 18650 cells in parallel
Totalling up to 8.8Ah per pack at 3.7v
At full charge it will be at 12.6v and at empty about 9-10v
I have measured how much power the radio draws, and on monitoring it draws around 8w, on transmitting around 18w (at 10w TX power, go figure) so that’s only 1-2 amps, super easy for these lithium batteries.
I’m just waiting for my BMS to arrive from China (battery management system)
As that has over current protection, over charge protection, over discharge protection and short circuit protection for the batteries
Then I’ll use some padded sticky foam to mount them in such a way they’ll get ventilation from the existing fans and good to go!