Portable Power
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I have three portable Elecraft rigs (K1, K2 and KX3) and up to now power them from a wall outlet (I do have the internal battery charger unit in the KX3). I want to take them out and about and do some SOTA type stuff.
So, I am looking for advice on a portable power solution. Should I bee looking at LiFePO4 batteries or Sealed Lead-Acid batteries? What are the pros and cons of each? How about charging them when they are not in use? Should they be left to run down and then charged or kept continuously on a charger? Are the Buddipole one any good (although I would have to source the same type here as they are not shippable across the pond!). I am in the UK so generic types may be more applicable than specific brands. Your suggestions would be most welcome! 73 David ============================ David Bondy G4NRT RNARS:4148 Fists:16978 SOC:1132 G-QRP: 14747 BARTG: 9123 Locator: JO01bt / WL41 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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On Mon 10 Aug David Bondy G4NRT wrote:
> Should I be looking at LiFePO4 batteries or Sealed Lead-Acid > batteries? You'll find quite a bit of discussion of batteries on the SOTA reflector, but apart from the cost, I can't see any obvious advantages of using SLABs any more. Choose an appropriate LiFePo and you'll have a battery delivering more power at a more useful voltage with rather less weight in your pack... Things get a bit more involved if you intend flying to foreign parts. Again, lots of advice on the SOTA reflector. -- 73, Rick, M0LEP (KX3 #3281) ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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+1 on the lifepo4. 4 in series gives an adequate voltage for most portable
ham radios. From just under 14v, til they emtpty at about 8v. Get or build a pack with protection circuit as over charging an discharging ruins them pretty quickly. Tons of info on the web. Just google it. As for antennas. Look at sotabeams, he i uk based and have a great selection of portable wire antennas and the stuff you need if you want to build your own. Lighter, cheaper and more efficient than the buddipole. Take a look at an linked dipole for the bands you plan on using. Good luck on you sota activation's. Hope to catch you on an s2s soon. 73 LA4TTA Erlend 2015-08-10 13:17 GMT+02:00 Rick M0LEP <[hidden email]>: > On Mon 10 Aug David Bondy G4NRT wrote: > > Should I be looking at LiFePO4 batteries or Sealed Lead-Acid > > batteries? > > You'll find quite a bit of discussion of batteries on the SOTA > reflector, but apart from the cost, I can't see any obvious advantages > of using SLABs any more. > > Choose an appropriate LiFePo and you'll have a battery delivering more > power at a more useful voltage with rather less weight in your pack... > > Things get a bit more involved if you intend flying to foreign parts. > Again, lots of advice on the SOTA reflector. > > -- > 73, Rick, M0LEP (KX3 #3281) > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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David, you might want to take a look at the article on this at arpoc.org.
the article is on the front page. On Mon, 10 Aug 2015 12:48 Erlend Grimseid <[hidden email]> wrote: > +1 on the lifepo4. 4 in series gives an adequate voltage for most portable > ham radios. From just under 14v, til they emtpty at about 8v. Get or build > a pack with protection circuit as over charging an discharging ruins them > pretty quickly. Tons of info on the web. Just google it. > > As for antennas. Look at sotabeams, he i uk based and have a great > selection of portable wire antennas and the stuff you need if you want to > build your own. Lighter, cheaper and more efficient than the buddipole. > Take a look at an linked dipole for the bands you plan on using. > > Good luck on you sota activation's. Hope to catch you on an s2s soon. > > 73 > > LA4TTA > Erlend > > 2015-08-10 13:17 GMT+02:00 Rick M0LEP <[hidden email]>: > > > On Mon 10 Aug David Bondy G4NRT wrote: > > > Should I be looking at LiFePO4 batteries or Sealed Lead-Acid > > > batteries? > > > > You'll find quite a bit of discussion of batteries on the SOTA > > reflector, but apart from the cost, I can't see any obvious advantages > > of using SLABs any more. > > > > Choose an appropriate LiFePo and you'll have a battery delivering more > > power at a more useful voltage with rather less weight in your pack... > > > > Things get a bit more involved if you intend flying to foreign parts. > > Again, lots of advice on the SOTA reflector. > > > > -- > > 73, Rick, M0LEP (KX3 #3281) > > > > ______________________________________________________________ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:[hidden email] > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > Message delivered to [hidden email] > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by David Bondy G4NRT
On Mon,8/10/2015 3:45 AM, David Bondy G4NRT wrote:
> So, I am looking for advice on a portable power solution. Should I bee looking at LiFePO4 batteries Yes. > or Sealed Lead-Acid batteries? No. > What are the pros and cons of each? LiFePO4 gives more than double the Ah capacity for their weight, AND a far better discharge curve (that is, the battery voltage stays higher until it runs down). They are also a lot more expensive, but some battery vendors are a lot more expensive than others for the same product. > How about charging them when they are not in use? Should they be left to run down and then charged or kept continuously on a charger? They should be charged using a proper charge controller. > Are the Buddipole one any good Buddipole is one of those too expensive vendors of LiFePO4 batteries. The good vendors in North America are http://www.bioennopower.com/collections/12v-series-lifepo4-batteries and http://www.batteryspace.com/128vlifepo4batterypacks.aspx I bought a BLF-1220W from Bioenno. My neighbor bought a similar pack from Battery Space. UN 38.3 is a safety Standard for Li batteries, and is required for air transport of batteries. > (although I would have to source the same type here as they are not shippable across the pond!). I suggest that you send email to those two good vendors and ask for suggestions about how to buy in the UK. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by David Bondy G4NRT
Let's stamp out this bad idea. ALWAYS recharge as soon as possible after
use. The further you discharge a battery the more you shorten its useful lifetime. This is true of all battery technologies. I know you have heard clueless vendors say you want to completely discharge a battery before recharging. Perhaps they are trying to increase sales. Furthermore, larger lithium type batteries are not only damaged by total discharge, they also become unstable when totally discharged. They are potential bombs if totally discharged. Therefore the manufacturers embed a microprocessor and a discharge mechanism inside the battery so you can not totally discharge these batteries if you wanted too. Yes the so called 'gas gage' may show zero charge remaining. Internally there is really 20 to 30% charge you can not access. This questionable practice of total discharge was started with NiCad batteries in order to equalize charge. It didn't work and shortened battery life so it was soon abandoned. Unfortunately many dealers did not get the message. 73 Fred, AE6QL -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of David Bondy G4NRT Sent: Monday, August 10, 2015 3:46 AM To: [hidden email] Subject: [Elecraft] Portable Power <Clip> Should they be left to run down and then charged or kept continuously on a charger? <Clip>< ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Erlend Grimseid
I'm sure that LiFePO4 is by far the best choice for ham gear and
weight. I ran a 2.4 Ah 4S1P on my K2 on receive with a recording voltmeter knowing that the K2 would shut down before the battery was over-discharged. Fully charged, it started at 14.2 V, which dropped to 13.8 V very quickly ... ~20 min. Thereafter, the voltage remained stable, declining very slowly and linearly until it reached about 12.1 V, at which point it took on the glide angle of a brick and the K2 shut down. This sequence took about 10 hours. K2 receive drain was just over 200 mA ... I don't have many add-ons in it. For my second test, I repeated the above watching for when the voltage reached 12.4 V. At this point, I began to transmit [CW] into a dummy load at 5 watts output. The battery maintained a useable voltage until it reached the sharp "knee" and the K2 died. IOW, because of the flat discharge curve I could still get usable energy from it [to transmit] even though it was nearly depleted. I have a 5 Ah SLAB, and I conducted the same two tests. It took longer on the RX-only test of course, but nowhere near twice as long as the LiFePO4. The TX test, with the voltage at 11.9, shut down the K2 when I tapped the paddle once. I conclude that I could get nearly as much total usable energy at usable voltages from the 2.4 Ah 4S1P as from the 5 Ah SLAB. The SLAB may have twice the "rated" energy capacity as the LiFePO4, but its internal resistance is significantly higher. When the voltage drop through that resistance reduces the voltage to an unusable value, the remaining energy might as well be stored on the moon. There is a safety caveat with extremely low resistance battery chemistry such as LiFePO4 and Li-Poly: With such microscopic internal resistance, they will deliver their entire energy capacity about as fast as the external circuit can accept it. If the external circuit is a dead short, which may be close to the internal resistance, that can be upwards of 20C - 30C, where C is the capacity of the battery. This can be good for a variety of electrical displays, none of which are particularly useful. My 4S1P is TSA-certified for carry-on luggage. Make sure there is absolutely no way the battery can be shorted and I think you're OK. Fred K6DGW --Northern California Contest Club --CU in the Cal QSO Party --3-4 Oct 2015 2015-08-10 13:17 GMT+02:00 Rick M0LEP <[hidden email]>: >> On Mon 10 Aug David Bondy G4NRT wrote: >>> Should I be looking at LiFePO4 batteries or Sealed Lead-Acid >>> batteries? >> You'll find quite a bit of discussion of batteries on the SOTA >> reflector, but apart from the cost, I can't see any obvious advantages >> of using SLABs any more. >> >> Choose an appropriate LiFePo and you'll have a battery delivering more >> power at a more useful voltage with rather less weight in your pack... >> >> Things get a bit more involved if you intend flying to foreign parts. >> Again, lots of advice on the SOTA reflector. >> >> -- >> 73, Rick, M0LEP (KX3 #3281) >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2015.0.6086 / Virus Database: 4392/10407 - Release Date: 08/09/15 > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Jim Brown-10
On 8/10/2015 10:14 AM, Jim Brown wrote: > On Mon,8/10/2015 3:45 AM, David Bondy G4NRT wrote: > How about charging them when they are not in use? Should they be left > to run down and then charged or kept continuously on a charger? > > They should be charged using a proper charge controller. > To expand on Jim's answer, LiFePO4 packs need to charged with a cell-balancing charger designed for LiFePO4's. My battery plugs into the charger with a multi-conductor plug separate from the power leads that go to the radio. The charger tells me the voltage on each cell as charging takes place. For longest storage life, they like to be put away at about 85% or so charge. My charger has a" LiFePO4 Storage" charge setting. My charger is from Revolectrix, I can give you the model # if you want, we're moving and I need to go find it. Fred K6DGW --Northern California Contest Club --CU in the Cal QSO Party --3-4 Oct 2015 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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