Thursday, July 21, 2016

Battery Powered

I have always taken a unique approach to powering my radios, compared to the rest of the hobby. I have never *once* made a QSO with my own gear on anything that wasn't battery powered. I simply don't own any power supplies, and have never had the need or desire to get one. Now obviously I use AC power to charge my batteries, and I have tapped into the big battery on my Jeep (even going to so far as to run powerpoles to two different place in it) but the fact remains that when it's time to actually turn electricity into RF, it has always been a battery that is providing the juice to do it.

I've got several different versions, for depending on what I'm up to. For 'normal' everyday usage on HF with my 857 I've got a pair of Werker 35AH Deep Cycle lead batteries (left most in the picture). They work well, and I can use the 857 at the full 100W on one or both of these for a day's worth of contacts. Next I've got a smaller Werker Deep Cycle, rated at 12AH (furthest to the right) that I use for slightly smaller jobs. It doesn't quite have the capacity to handle a full 100W HF load (on especially something like 6m) on the 857, but at lower levels < 50W it works well. This battery is nice for quick "hamming in the park" or NPOTA application where I'll only be on the air for a few hours, and don't necessarily need full power. The SLABs (Sealed Lead Acid) are my workhorses, and do most of the heavy lifting when it comes to powering my different rigs.

Finally, I've got the sports car of the bunch - my Zippy 8.4AH LiFePo4 Battery Pack (The blue battery in the middle). This thing is stripped down with no fanciness, but weighs about 1/4 of what the SLABs do for equal power, and the Lithium chemistry will hold full voltage even under the full load of 100W 6M FM from the 857. It is what I find myself using more and more of these days, because it's just so light and powerful. When it goes dead though, you REALLY have to watch it, cause voltage will fall from 13.2V to < 12V in a matter of minutes - and when it does, the battery is dead and it's time for a recharge.  

Downside of the LiFePo4 pack, is while it's stripped down and efficient, it's made up of multiple cells that have to be kept relatively close in voltage or else bad things will happen. This requires a special charger. Luckily they're pretty cheap, and are adaptable. Here I've got it hooked up to the powerpoles in the Jeep, so it's slurping juice from the alternator and the starting battery. The LiFePo4 chemistry in addition to dumping it's juice quickly, will also accept a charge very quickly as well. My particular charger will do up to 7A of DC charging ability (while keeping the cells balanced) which means I can get the battery back up to full power from near dead in just over an hour. When on the road and navigating summit to summit, this is a huge bonus.

Since power is a consumable quantity in my trade, knowing how much you've used, and how much you have left is huge... especially on the little lithium. That's why these inline power meters are practically essential. They give you current voltage, amperage use, and how many AH you've used since you plugged in. It's a great way to watch how much juice different modes and styles of operating pull as well. I highly recommend them when you're a battery only ham like I am. 

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