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On Wed, 05 Nov 2003 18:09:46 -0500, Bruce W...1 wrote:
mcalhoun wrote: Although their normal price is about $15, float battery chargers (wall wart, coiled cord, little black box with LED, two cords with large alligator clips on the ends) are often advertised in Harbor Freight catalogs for $7.99. I must have half a dozen of them now, keeping batteries here and there up to snuff. I've never measured them, but they seem to do a real good job, and they're hard to beat at that price! I have no connection to Harbor Freight except as a satisfied customer, Ditto to all of the above. You don't say! Have you ever measured their voltage? Or is it written on the case? Mine vary between 13.5v to 13.6v. If you open the little plastic box between the transformer and the battery terminals you will find a little adjustment that will let you tweak the voltage. I have two different styles, one with curly coiled leads and one with straight leads. I think the straight lead is older and has been obsoleted. Too bad, because they made a nice low-current adjustable power supply. :) The curly lead ones don't. But they both seem to do a fine job of keeping lead acid batts up to snuff. I have a couple on my bench. One set to 13.6v and one to 14.1v. I put a gel cell on the 14.1v to charge after use, then on to the 13.6v to maintain ready for next time. I have one in the barn. I cut off the clamps and put on a pair of anderson powerpole connectors. A matching connector on my lawn tractor allows me to easily attach with no concern for polarity mismatch whether it is me or anyone else. I got 5 seasons from the last battery, which is pretty good for a lawn tractor that sits pretty much unused october thru april. sdb -- | Sylvan Butler | Not speaking for Hewlett-Packard | sbutler-boi.hp.com | | Watch out for my e-mail address. Thank UCE. change ^ to @ | It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end, for they do so with the approval of their consciences. -- C. S. Lewis |
mcalhoun wrote:
Harbor Freight $7.99 float chargers: You don't say! Have you ever measured their voltage? Or is it written on the case? I never had, so I went out (to the garage; brrrr!) and measured one: 13.58 volts. FWIW, the wallwart says "15VAC at 600 ma", but there's a little plastic box on the wires between the wart and the battery clips. --Myron. -- Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTX). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) ================================================== ======== Now we're getting somewhere. Myron said 15VAC at 600 ma. C/100 is about 700 mA. Any idea what's inside the little voltage adjustment box? |
mcalhoun wrote:
Harbor Freight $7.99 float chargers: You don't say! Have you ever measured their voltage? Or is it written on the case? I never had, so I went out (to the garage; brrrr!) and measured one: 13.58 volts. FWIW, the wallwart says "15VAC at 600 ma", but there's a little plastic box on the wires between the wart and the battery clips. --Myron. -- Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTX). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) ================================================== ======== Now we're getting somewhere. Myron said 15VAC at 600 ma. C/100 is about 700 mA. Any idea what's inside the little voltage adjustment box? |
"Bruce W...1" wrote in message ...
This is not ham radio related but I know you guys have the answer. I need to store a car unattended for a winter in the midwest. And I want to put a tricke charge on the battery. I'd rather not buy a fancy trickle charger because it would probably get stolen. On the other hand I have a vast array of wall wart transformers. If I connected one of these transformers how many milliamps should it put out at 12V? Or rather what's the least current that would do the job? It seems that lead acid batteries can dissipate too much current as heat. In other words I could probably feed it one amp continuously. But would 100 mA at 12V do the job? I'd hate to lose a 1-Amp wall wart. Thanks for your help. Hi Bruce, you have been given heaps of technical suggestions, heres mine. 1.Pull the battery out of the vehicle and take it back to your place. 2.Every week or so, check specific gravity with a hyrometer (sp) and if it needs charging, do so. This solves the problem of someone stealing the car unless they are really keen, is simple, easy, and lo tech. 73 de VK3BFA Andrew |
"Bruce W...1" wrote in message ...
This is not ham radio related but I know you guys have the answer. I need to store a car unattended for a winter in the midwest. And I want to put a tricke charge on the battery. I'd rather not buy a fancy trickle charger because it would probably get stolen. On the other hand I have a vast array of wall wart transformers. If I connected one of these transformers how many milliamps should it put out at 12V? Or rather what's the least current that would do the job? It seems that lead acid batteries can dissipate too much current as heat. In other words I could probably feed it one amp continuously. But would 100 mA at 12V do the job? I'd hate to lose a 1-Amp wall wart. Thanks for your help. Hi Bruce, you have been given heaps of technical suggestions, heres mine. 1.Pull the battery out of the vehicle and take it back to your place. 2.Every week or so, check specific gravity with a hyrometer (sp) and if it needs charging, do so. This solves the problem of someone stealing the car unless they are really keen, is simple, easy, and lo tech. 73 de VK3BFA Andrew |
According to the manual the Harbor Freight charger is 15.5V. That
seems a little high for a float charge to me. 12-volt LA batteries are generally float charged at 13.8V. Did you guys measure the voltage with it connected to the battery or under "no load"? |
According to the manual the Harbor Freight charger is 15.5V. That
seems a little high for a float charge to me. 12-volt LA batteries are generally float charged at 13.8V. Did you guys measure the voltage with it connected to the battery or under "no load"? |
On Thu, 6 Nov 2003 18:37:30 -0500, Bob Lewis (AA4PB) wrote:
According to the manual the Harbor Freight charger is 15.5V. That I think that's the wallwart, not the voltage applied to the batt. seems a little high for a float charge to me. 12-volt LA batteries are generally float charged at 13.8V. Did you guys measure the voltage with it connected to the battery or under "no load"? Either way measures the same. The little box is a basic voltage regulator circuit. sdb -- | Sylvan Butler | Not speaking for Hewlett-Packard | sbutler-boi.hp.com | | Watch out for my e-mail address. Thank UCE. change ^ to @ | It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end, for they do so with the approval of their consciences. -- C. S. Lewis |
On Thu, 6 Nov 2003 18:37:30 -0500, Bob Lewis (AA4PB) wrote:
According to the manual the Harbor Freight charger is 15.5V. That I think that's the wallwart, not the voltage applied to the batt. seems a little high for a float charge to me. 12-volt LA batteries are generally float charged at 13.8V. Did you guys measure the voltage with it connected to the battery or under "no load"? Either way measures the same. The little box is a basic voltage regulator circuit. sdb -- | Sylvan Butler | Not speaking for Hewlett-Packard | sbutler-boi.hp.com | | Watch out for my e-mail address. Thank UCE. change ^ to @ | It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end, for they do so with the approval of their consciences. -- C. S. Lewis |
The recommended float voltage differs a fair amount with temperature and
with battery type (liquid, starved, or, now very rare, gelled electrolyte). I'd check the manufacturer's specifications for the specific cell. Most are on the web these days. If I were floating a battery outside or in any other environment with substantial temperature variation, I'd want to use a temperature compensated charger, with the charger close to the battery. Roy Lewallen, W7EL Bob Lewis (AA4PB) wrote: According to the manual the Harbor Freight charger is 15.5V. That seems a little high for a float charge to me. 12-volt LA batteries are generally float charged at 13.8V. Did you guys measure the voltage with it connected to the battery or under "no load"? |
The recommended float voltage differs a fair amount with temperature and
with battery type (liquid, starved, or, now very rare, gelled electrolyte). I'd check the manufacturer's specifications for the specific cell. Most are on the web these days. If I were floating a battery outside or in any other environment with substantial temperature variation, I'd want to use a temperature compensated charger, with the charger close to the battery. Roy Lewallen, W7EL Bob Lewis (AA4PB) wrote: According to the manual the Harbor Freight charger is 15.5V. That seems a little high for a float charge to me. 12-volt LA batteries are generally float charged at 13.8V. Did you guys measure the voltage with it connected to the battery or under "no load"? |
Alright, so I built a voltage regulator with parts that I have around,
an LM7812 with a few diodes connected to a 500 mA 12VDC wall wart. I hope you guys are happy now. However I still maintain that a properly sized wall wart could do the job with no voltage regulation. |
Alright, so I built a voltage regulator with parts that I have around,
an LM7812 with a few diodes connected to a 500 mA 12VDC wall wart. I hope you guys are happy now. However I still maintain that a properly sized wall wart could do the job with no voltage regulation. |
Alright, so I built a voltage regulator with parts that I have around,
an LM7812 with a few diodes connected to a 500 mA 12VDC wall wart. I hope you guys are happy now. What sort of open-circuit voltage are you getting out of it? However I still maintain that a properly sized wall wart could do the job with no voltage regulation. Hey, it's your battery (or your neighbor's) - if you want to experiement and see if you can figure out whether that sort of charging regime will appreciably shorten the life of the battery, go for it! I just figure that doing the job right isn't really very much harder than doing it "maybe right, or maybe we shorten the battery's life by a year?". [and I really do like the idea of those Harbor Freight float chargers... $7.95 for a tweakable-voltage half-amp charger is so low I don't see much sense in homebrewing my own any more! I'll have to pick up a couple.] -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
Alright, so I built a voltage regulator with parts that I have around,
an LM7812 with a few diodes connected to a 500 mA 12VDC wall wart. I hope you guys are happy now. What sort of open-circuit voltage are you getting out of it? However I still maintain that a properly sized wall wart could do the job with no voltage regulation. Hey, it's your battery (or your neighbor's) - if you want to experiement and see if you can figure out whether that sort of charging regime will appreciably shorten the life of the battery, go for it! I just figure that doing the job right isn't really very much harder than doing it "maybe right, or maybe we shorten the battery's life by a year?". [and I really do like the idea of those Harbor Freight float chargers... $7.95 for a tweakable-voltage half-amp charger is so low I don't see much sense in homebrewing my own any more! I'll have to pick up a couple.] -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
Andrew VK3BFA wrote:
Hi Bruce, you have been given heaps of technical suggestions, heres mine. 1.Pull the battery out of the vehicle and take it back to your place. 2.Every week or so, check specific gravity with a hyrometer (sp) and if it needs charging, do so. This solves the problem of someone stealing the car unless they are really keen, is simple, easy, and lo tech. 73 de VK3BFA Andrew ================================================== ==== Screw that. This is a charity case to begin with. There's no way on God's green earth that I'd haul the battery back to my place. |
Andrew VK3BFA wrote:
Hi Bruce, you have been given heaps of technical suggestions, heres mine. 1.Pull the battery out of the vehicle and take it back to your place. 2.Every week or so, check specific gravity with a hyrometer (sp) and if it needs charging, do so. This solves the problem of someone stealing the car unless they are really keen, is simple, easy, and lo tech. 73 de VK3BFA Andrew ================================================== ==== Screw that. This is a charity case to begin with. There's no way on God's green earth that I'd haul the battery back to my place. |
Roy Lewallen wrote:
The recommended float voltage differs a fair amount with temperature and with battery type (liquid, starved, or, now very rare, gelled electrolyte). I'd check the manufacturer's specifications for the specific cell. Most are on the web these days. If I were floating a battery outside or in any other environment with substantial temperature variation, I'd want to use a temperature compensated charger, with the charger close to the battery. Roy Lewallen, W7EL ================================================== = Hmmm, temperature compensate at a certain distance from the battery. Can you model this Roy? |
Roy Lewallen wrote:
The recommended float voltage differs a fair amount with temperature and with battery type (liquid, starved, or, now very rare, gelled electrolyte). I'd check the manufacturer's specifications for the specific cell. Most are on the web these days. If I were floating a battery outside or in any other environment with substantial temperature variation, I'd want to use a temperature compensated charger, with the charger close to the battery. Roy Lewallen, W7EL ================================================== = Hmmm, temperature compensate at a certain distance from the battery. Can you model this Roy? |
LMAO! How many people does it take to screw in a lightbulb, or in this
case to charge a battery? Sylvan Butler d wrote in message boi.hpZ.com.invalid... On Thu, 6 Nov 2003 18:37:30 -0500, Bob Lewis (AA4PB) wrote: According to the manual the Harbor Freight charger is 15.5V. That I think that's the wallwart, not the voltage applied to the batt. seems a little high for a float charge to me. 12-volt LA batteries are generally float charged at 13.8V. Did you guys measure the voltage with it connected to the battery or under "no load"? Either way measures the same. The little box is a basic voltage regulator circuit. sdb |
LMAO! How many people does it take to screw in a lightbulb, or in this
case to charge a battery? Sylvan Butler d wrote in message boi.hpZ.com.invalid... On Thu, 6 Nov 2003 18:37:30 -0500, Bob Lewis (AA4PB) wrote: According to the manual the Harbor Freight charger is 15.5V. That I think that's the wallwart, not the voltage applied to the batt. seems a little high for a float charge to me. 12-volt LA batteries are generally float charged at 13.8V. Did you guys measure the voltage with it connected to the battery or under "no load"? Either way measures the same. The little box is a basic voltage regulator circuit. sdb |
"Bruce W...1" wrote in message
... Alright, so I built a voltage regulator with parts that I have around, an LM7812 with a few diodes connected to a 500 mA 12VDC wall wart. I hope you guys are happy now. However I still maintain that a properly sized wall wart could do the job with no voltage regulation. Hey, you came to the group asking for help. It has been dispensed by several responders who, by all indications, know and understand the technology of batteries and charging much better than you. I've said to several others like you, and I'll extend the advice to you as well... "If you can't live with the answer, don't ask the question". The responses to your question have been pretty much "spot on" correct. If you don't want to take the advice of those who offered you help, then please leave and revel in your own obstinance. If you had taken the time to use the web and done a bit of research into batteries and proper charging techniques, you would have saved several helpful people a bit of wasted effort on your behalf. Cheers.... -- Tweetldee Tweetldee at att dot net (Just subsitute the appropriate characters in the address) Never take a laxative and a sleeping pill at the same time!! |
"Bruce W...1" wrote in message
... Alright, so I built a voltage regulator with parts that I have around, an LM7812 with a few diodes connected to a 500 mA 12VDC wall wart. I hope you guys are happy now. However I still maintain that a properly sized wall wart could do the job with no voltage regulation. Hey, you came to the group asking for help. It has been dispensed by several responders who, by all indications, know and understand the technology of batteries and charging much better than you. I've said to several others like you, and I'll extend the advice to you as well... "If you can't live with the answer, don't ask the question". The responses to your question have been pretty much "spot on" correct. If you don't want to take the advice of those who offered you help, then please leave and revel in your own obstinance. If you had taken the time to use the web and done a bit of research into batteries and proper charging techniques, you would have saved several helpful people a bit of wasted effort on your behalf. Cheers.... -- Tweetldee Tweetldee at att dot net (Just subsitute the appropriate characters in the address) Never take a laxative and a sleeping pill at the same time!! |
"Bruce W...1" wrote in message ...
Andrew VK3BFA wrote: Hi Bruce, you have been given heaps of technical suggestions, heres mine. 1.Pull the battery out of the vehicle and take it back to your place. 2.Every week or so, check specific gravity with a hyrometer (sp) and if it needs charging, do so. This solves the problem of someone stealing the car unless they are really keen, is simple, easy, and lo tech. 73 de VK3BFA Andrew ================================================== ==== Screw that. This is a charity case to begin with. There's no way on God's green earth that I'd haul the battery back to my place. Well screw you too, Bruce. It was a reasonable suggestion, how much longer do you want to **** around looking for a "no effort, no brains required" solution, or do you want someone to come around and do it for you. Glad I am not asking you to look after my dog for a few weeks, it would die of starvation while you stuffed around looking for an automatic feeder to save you from getting up off your arse and actually putting in some of your own effort. de VK3BFA |
"Bruce W...1" wrote in message ...
Andrew VK3BFA wrote: Hi Bruce, you have been given heaps of technical suggestions, heres mine. 1.Pull the battery out of the vehicle and take it back to your place. 2.Every week or so, check specific gravity with a hyrometer (sp) and if it needs charging, do so. This solves the problem of someone stealing the car unless they are really keen, is simple, easy, and lo tech. 73 de VK3BFA Andrew ================================================== ==== Screw that. This is a charity case to begin with. There's no way on God's green earth that I'd haul the battery back to my place. Well screw you too, Bruce. It was a reasonable suggestion, how much longer do you want to **** around looking for a "no effort, no brains required" solution, or do you want someone to come around and do it for you. Glad I am not asking you to look after my dog for a few weeks, it would die of starvation while you stuffed around looking for an automatic feeder to save you from getting up off your arse and actually putting in some of your own effort. de VK3BFA |
On Thu, 6 Nov 2003 14:15:17 -0700, Sylvan Butler
d wrote: On Wed, 05 Nov 2003 18:09:46 -0500, Bruce W...1 wrote: mcalhoun wrote: Although their normal price is about $15, float battery chargers (wall wart, coiled cord, little black box with LED, two cords with large alligator clips on the ends) are often advertised in Harbor Freight catalogs for $7.99. I must have half a dozen of them now, keeping batteries here and there up to snuff. I've never measured them, but they seem to do a real good job, and they're hard to beat at that price! I have no connection to Harbor Freight except as a satisfied customer, Ditto to all of the above. You don't say! Have you ever measured their voltage? Or is it written on the case? Mine vary between 13.5v to 13.6v. If you open the little plastic box between the transformer and the battery terminals you will find a little adjustment that will let you tweak the voltage. I have two different styles, one with curly coiled leads and one with straight leads. I think the straight lead is older and has been obsoleted. Too bad, because they made a nice low-current adjustable power supply. :) The curly lead ones don't. But they both seem to do a fine job of keeping lead acid batts up to snuff. I have a couple on my bench. One set to 13.6v and one to 14.1v. I put a gel cell on the 14.1v to charge after use, then on to the 13.6v to maintain ready for next time. I have one in the barn. I cut off the clamps and put on a pair of anderson powerpole connectors. A matching connector on my lawn tractor allows me to easily attach with no concern for polarity mismatch whether it is me or anyone else. I got 5 seasons from the last battery, which is pretty good for a lawn tractor that sits pretty much unused october thru april. sdb I just picked up a couple of the float chargers from Harbor Freight. They measure 13.55 no load. 13.55 at 130 ma, 13.4 at 175 ma, 12.9 at 230 ma, 12.8 at 250 ma. Looks like they will only supply about 175 ma max and still be above 13.4 volts. At over 500 ma they will shut down and won't restart until the load is removed completely. One problem I see with them is that they draw 36 ma from the battery if they are hooked up to the battery (at 12.9 battery volts) but not plugged into the wall. If you loose AC power that will quickly kill the battery! They measure 3.6k both ways when you check the resistance but when hooked to the battery they cause much more draw than 3.6 ma. These are the ones with the curly cords. Are these internally adjustable ? I wonder if there is enough range to add a series diode? Thanks Gary K4FMX |
On Thu, 6 Nov 2003 14:15:17 -0700, Sylvan Butler
d wrote: On Wed, 05 Nov 2003 18:09:46 -0500, Bruce W...1 wrote: mcalhoun wrote: Although their normal price is about $15, float battery chargers (wall wart, coiled cord, little black box with LED, two cords with large alligator clips on the ends) are often advertised in Harbor Freight catalogs for $7.99. I must have half a dozen of them now, keeping batteries here and there up to snuff. I've never measured them, but they seem to do a real good job, and they're hard to beat at that price! I have no connection to Harbor Freight except as a satisfied customer, Ditto to all of the above. You don't say! Have you ever measured their voltage? Or is it written on the case? Mine vary between 13.5v to 13.6v. If you open the little plastic box between the transformer and the battery terminals you will find a little adjustment that will let you tweak the voltage. I have two different styles, one with curly coiled leads and one with straight leads. I think the straight lead is older and has been obsoleted. Too bad, because they made a nice low-current adjustable power supply. :) The curly lead ones don't. But they both seem to do a fine job of keeping lead acid batts up to snuff. I have a couple on my bench. One set to 13.6v and one to 14.1v. I put a gel cell on the 14.1v to charge after use, then on to the 13.6v to maintain ready for next time. I have one in the barn. I cut off the clamps and put on a pair of anderson powerpole connectors. A matching connector on my lawn tractor allows me to easily attach with no concern for polarity mismatch whether it is me or anyone else. I got 5 seasons from the last battery, which is pretty good for a lawn tractor that sits pretty much unused october thru april. sdb I just picked up a couple of the float chargers from Harbor Freight. They measure 13.55 no load. 13.55 at 130 ma, 13.4 at 175 ma, 12.9 at 230 ma, 12.8 at 250 ma. Looks like they will only supply about 175 ma max and still be above 13.4 volts. At over 500 ma they will shut down and won't restart until the load is removed completely. One problem I see with them is that they draw 36 ma from the battery if they are hooked up to the battery (at 12.9 battery volts) but not plugged into the wall. If you loose AC power that will quickly kill the battery! They measure 3.6k both ways when you check the resistance but when hooked to the battery they cause much more draw than 3.6 ma. These are the ones with the curly cords. Are these internally adjustable ? I wonder if there is enough range to add a series diode? Thanks Gary K4FMX |
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