Now that I have my SOTA radio and portable antenna setup working. Portable power options were the next item on my list. The 817nd has internal rechargable batteries, and can use AA batteries also, i have 2 battery trays for AA rechargeable batteries and the internal Ni-Mh pack, but for extended 5w operation portable, an external 12v+ source provides the best experience.
The remote control car/helicopter/aeroplane hobby scene has been a boon for hams. Modern high capacity batteries are both light and powerful, and this is the path I have gone down. a little more expensive than GelCel batteries, but much lighter for the power density. For a little more technical detail, visit VK1OD‘s explanation.
The most common type of RC battery pack these days is the Lithium Polymer (Li-Po) pack, these can be a little unstable and even dangerous, often catching on fire just because they can, especially when being charged. The Li-Fe pack is a little more stable, but still needs some care when charging and in transport. The Li-Po packs have a higher cell voltage and are less suited to portable ham use, but can still happily drive the 817nd.
I ended up with a LiFePo4 4 cell 8400mAh battery with a nominal voltage of 13.2v. The battery weights just over 1kg. I ordered the battery and charger on sunday, and it arrived from sydney via HobbyKing wednesday morning. There have been comments on a number of forums that this supplier can be a bit slow in delivery (and most times thats related to using the international warehouse), in my one experience, the australian warehouse and time taken was good.
The items came packed in a small box and well wrapped/protected, I got the special Li-Po/Li-Fe charger to allow mw to correctly charge this battery, a fire proof pouch for charging and transport (just to be safe). I also got some small plug in battery monitors, One has a low voltage alarm notification, the other is a digital Volt meter device that plugs into the monitor port of the Li-Fe battery and shows single cell voltages and the total device voltage in a cycle. These batteries can also fail if the cell voltage falls below a critical value.
A list of the items I purchased
My next tasks involve modifying the connector’s on the different items, replacing the RC car connectors with Anderson power pole connectors and some fuse protection to match my other equipment, and of course, a test operation, most likely this coming weekend 😀 – with the hamfest in ballarat, i hope to visit the two local mountains while I have day release.
Now that the cables are modified up, I set about charging the battery. I used the balance charge feature, and its taken around 2hrs to bring the 4 cells up-to the 3.6v full value from the shop (they arrived at 3.3v, that is the storage voltage. The charger was initially a little flakey and kept telling me the input voltage was too low (its connected to my big ham 13.8v supply) i suspect the device was suffering for getting hot rather than not having enough power, I lowered the selected charge current (from 3amps to 2amps, i was a little impatient) and it has been fine since, the current drops off as the voltage nears the full value. Below shows the setup, and the voltage monitor.
11 thoughts on “Portable Power for the 817ND”
Hi Andrew thanks for the detailed description. Your change over to Anderson Power Poles is really neat.
I am still gathering the bits and pieces to change over to a LiPO. I have the LiFE battery on order as well.
thanks john, It would have been nice to make it a big neater, (and have the powerpoles actually properly joined together, but the wire on the battery is 8AG, and I had to trim it down to make it fit, I did use the 45amp anderson PP inserts for this, but still not a neat fit. this was also the first answerson plug Ive bothered to ever solder, and then only to ensure the connection is well and truly secure
thus the heat shrink to protect it. alternative would be (and I seriously considered this) a 50amp (caravan) sized anderson plug and then a 30amp anderson adaptor. as a fly lead, but I went this path and it seems to work 😀
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Very good article
Could you tell me what kind of fuse I use for protection between the battery and the radio.
Thx / 73.
i just use a 5amp automotive blade fuse. nothing fancy
Many thx for your replay…
I realize you put this post up about 1 1/2 years ago, but it is quite timely for me as I get back into radio after a LONG period QRT. The details are great without overdoing it. Thanks for the effort.
the main content hasn’t really changed,
Hi Andrew. Also have the 817nd. I really like the 12v solar balance charger. Love some thoughts on how you have used it on summits etc (getting into SOTA )
I want to use the zippy as a multi use fuel source essentially. After the radio I want to switch to a 12cig female to charge my phone too.
solar chargers can produce wide HF nosie/hash, they will work, but may make HF performance bad, choose wisely.
I got one of these for my SG-2020.
The low weight is quite nice. However, charging it requires a great deal of trouble. You have to be there the whole time it’s charging to make sure no cell overcharges. Also, to be safe, you need to charge it in sand surrounded by bricks, because if it explodes, everything in the room can catch fire. That doesn’t happen often, but it happens often enough. I have a fireproof pouch, but they can fail. Then, after you have it all charged up, you need to store it in an ammo can or something similar. Some will I’m being over cautious, but I don’t think so.
It’s rated at 8.4 ah but when I’ve use it in the field, it seems to perform with a capacity less than that. One of these days I’ll get the proper meter to test it.