RE: [Elecraft] KBT-2 out of radio battery charging
GM, Powersonic sells automatic chargers for SLA batteries that do just what you described, Don, The PSC 12500A is the right charger for the KBT-2. That's the 0.5 amp charger. I keep my KBT-2 on float/charge with the PSC 12500A with the battery switch off unless I am on battery power, and it seems as good as new. It was purchased with my K2 S/N 462 in 1999. It has two lights; both light when it is in the stage 1 or 2 modes, and a single light stays on when it is in the stage three mode. 73, Chas At 11:36 PM 9/7/2005, W3FPR - Don Wilhelm wrote: Vic, Thanks for adding that - in my haste, I forgot to say that indeed for a Smartcharger, the current must be set with consideration for the battery. OTOH, I believe the thing that is usually adjusted is the 'bulk current' which is the high current part of the 3 stage charging cycle. Reviewing the UC3906 3 stage controller chip, I found that Stage 1 was the bulk current stage - where the resistance can be changed to limit the maximum current. When the terminal voltage reaches 95% (13.7v) of the full charge voltage, stage 2 is triggered which increases the voltage (to 14.4 volts for a 12 volt SLA), and the charging continues until the current drops to a small value - then stage 3 begins which limits the voltage to 13.8 volts (trickle charge value). 73, Don W3FPR -Original Message- W3FPR - Don Wilhelm wrote: Of course, an even better system is to use a 3 stage charge controller specifically designed for SLA batteries - something like the A A Smartcharger would do a fantastic job. Keep in mind that the Smartcharger (and most likely other 3-stage chargers) has an adjustment for the amount of trickle current. If the charger is designed for an automobile battery this will be too much for a small gel cell and will destroy it. How do I know? Because I have a Smartcharger and I made an error in arithmetic when I selected the value of the resistor that controls the trickle current, and the rest -- including my 4ah gel cell -- was history. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] KBT-2 out of radio battery charging
Jack, I don't know the specs for that Sears charger, but many of those designed for automotive batteries are nothing more than a cheap power supply. A gel cell can be maintained at a 'float voltage' level of about 13.8 volts at its terminals and will do well - many security systems and small emergency lighting systems use that method for the backup battery. Of course, an even better system is to use a 3 stage charge controller specifically designed for SLA batteries - something like the A A Smartcharger would do a fantastic job. 73, Don W3FPR -Original Message- Now I have a question for the list regarding charging the K2 battery. I have the battery out of my K2 (while the KPA100 is installed), and I want to make sure the battery is charged. I have a Sears 1.5 Amp Fully Automatic Onboard Battery Charger Maintainer that is designed to mount in a car well to keep a battery maintained when the car isn't driven for long periods of time. Should I use this with the GelCell in the KBT2, or should I find some other method? I just want to make sure the battery doesn't die from not being charged so that next time I need it, it is ready to go. Thanks! -Jack Brindle, W6FB === -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.344 / Virus Database: 267.10.18/91 - Release Date: 9/6/2005 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] KBT-2 out of radio battery charging
W3FPR - Don Wilhelm wrote: Of course, an even better system is to use a 3 stage charge controller specifically designed for SLA batteries - something like the A A Smartcharger would do a fantastic job. Keep in mind that the Smartcharger (and most likely other 3-stage chargers) has an adjustment for the amount of trickle current. If the charger is designed for an automobile battery this will be too much for a small gel cell and will destroy it. How do I know? Because I have a Smartcharger and I made an error in arithmetic when I selected the value of the resistor that controls the trickle current, and the rest -- including my 4ah gel cell -- was history. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] KBT-2 out of radio battery charging
Hi You could use one of my solar controller kits and a 15-18 volt wall wart or power supply in place of the solar panel. You would just need a 5-10 ohm 10 watt resistor in series with the wall wart to limit the current and make the supply simulate a constant current source like a solar panel. I still have a few of the low current 1.5 amp versions left at $16 or the 16 amp version at $30. For this application the low current version would be fine. This controller is designed to keep a SLA battery charged and can be left connected to the battery indefinitely Don Brown - Original Message - From: Jack Brindle [EMAIL PROTECTED] To: Elecraft List elecraft@mailman.qth.net Sent: Wednesday, September 07, 2005 5:14 PM Subject: [Elecraft] KBT-2 out of radio battery charging Now I have a question for the list regarding charging the K2 battery. I have the battery out of my K2 (while the KPA100 is installed), and I want to make sure the battery is charged. I have a Sears 1.5 Amp Fully Automatic Onboard Battery Charger Maintainer that is designed to mount in a car well to keep a battery maintained when the car isn't driven for long periods of time. Should I use this with the GelCell in the KBT2, or should I find some other method? I just want to make sure the battery doesn't die from not being charged so that next time I need it, it is ready to go. Thanks! -Jack Brindle, W6FB === ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
RE: [Elecraft] KBT-2 out of radio battery charging
Vic, Thanks for adding that - in my haste, I forgot to say that indeed for a Smartcharger, the current must be set with consideration for the battery. OTOH, I believe the thing that is usually adjusted is the 'bulk current' which is the high current part of the 3 stage charging cycle. Reviewing the UC3906 3 stage controller chip, I found that Stage 1 was the bulk current stage - where the resistance can be changed to limit the maximum current. When the terminal voltage reaches 95% (13.7v) of the full charge voltage, stage 2 is triggered which increases the voltage (to 14.4 volts for a 12 volt SLA), and the charging continues until the current drops to a small value - then stage 3 begins which limits the voltage to 13.8 volts (trickle charge value). 73, Don W3FPR -Original Message- W3FPR - Don Wilhelm wrote: Of course, an even better system is to use a 3 stage charge controller specifically designed for SLA batteries - something like the A A Smartcharger would do a fantastic job. Keep in mind that the Smartcharger (and most likely other 3-stage chargers) has an adjustment for the amount of trickle current. If the charger is designed for an automobile battery this will be too much for a small gel cell and will destroy it. How do I know? Because I have a Smartcharger and I made an error in arithmetic when I selected the value of the resistor that controls the trickle current, and the rest -- including my 4ah gel cell -- was history. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco -- -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.344 / Virus Database: 267.10.18/91 - Release Date: 9/6/2005 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] KBT-2 out of radio battery charging
W3FPR - Don Wilhelm wrote: [re the AA Engineering Smart Charger] OTOH, I believe the thing that is usually adjusted is the 'bulk current' which is the high current part of the 3 stage charging cycle. Yes, you're absolutely correct -- it's the bulk current that's adjustable. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
