It’s finally time for a battery upgrade. When I first started with my little FT-817 I made use of a small 4.2 Amp Hour VRLA, what’s more commonly known as a Sealed Lead Acid Battery, or SLAB. The battery, an SH4.5-12, was given to me by my father in-law, who I think got it at a garage sale, before I even had the radio. Looking at the date code stamped in the base it was made in April 2012, so it must have been newer than I thought when I got it.
SLAB Date Code
It finally died, which forced me to upgrade. After some research I chose to go with an LiFe battery. LiFe at full charge is 3.6v / cell, or 14.4v for 4 Series Cells, which is within the voltage range of the FT-817. The alternative was LiPo. But LiPo have a fully charged cell voltage of 4.2v, or 16.8v for 4 Series Cells, which is more than the FT-817 is rated for. I also saw multiple people say that the LiFe is easier to manage, so safer than LiPo. Though care still needs to be taken with charge and discharge. Safer doesn’t mean risk free.
I selected a Zippy 4200 from HobbyKing. It’s about the same power rating as the SLAB, but a full kilo lighter. I paid $59, and today I see they are selling for $10 less. 😦 Note that HobbyKing’s AU prices are all listed ex GST, which can be a trap when you get to the checkout stage.
The new battery is about the same power rating as the older one, but a full kilo lighter. First use was New Years day. I ran the radio for about three hours, admittedly with alot more RX than TX, and only dropped about 0.2V, so lots of run time left still when I packed up.
Zippy 4200 LiFe Battery
An updated battery needs a proper charging system. I chose the imax B6AC v2. It has specific LiFe mode and can be powered via AC or DC input. It also seems to do lots of other stuff, which I’m still to work through.
IMAX B6AC v2
I also purchased Turnigy Watt and Power meter to help keep an eye on the minimum voltages. There’s much smaller units that only show voltage, or an alarm. I might add one of those into the next order. I think if I was being really weight conscious I’d just use the volt meter in the radio.
Turnigy Watt Meter
The battery came with 5.5mm bullet connectors. The most common connector used on radios seems to the the 30amp Anderson connector. It’s a conversion I still have to make, so for now all the connectors are bullets, as that was cheap and easy.
If I’m in a park and don’t have to carry the gear any distance, I use a 20Ah AGM battery. I originally bought it for a mower. It was a lot bigger than the mower really needed, but I never had any problems getting it started. 🙂 The mower was on its last legs and since died, leaving the battery free for radio. At 5Kg, it’s too heavy for much of a walk. It’s got enough grunt to last at least a day in the field, even with a heavy TX cycle.
20Ah, 12V, AGM Battery
Now I just need to get out there an use them.