Diodes for 12v battery charging
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From: Stumpy on 31 Jan 2010 18:15 >> >> I don't even know how that 45volt rectifier could be used as a diode. >> This is a link to the regulator I have. >> >> http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96728 >> > > > If you put diodes in series with the output of the regulator, the volt > drop of the diodes might result in under-charging. > > The ideal solution would be to give each battery its own regulator. > > If you only want to use one battery at a time then you can connect the + > terminal with an alligator clip, if you want the full capacity from all 3 > batteries at once, you'll need output isolating diodes to feed the + > terminals to your load - these diodes will need to be rated considerably > more than 7A !!! I'm getting confused. The 3 batteries are in 3 separate vehicles. It might be convenient to have no diodes so that the other 2 batteries could act as "jumpers" when starting one, but then I would risk having one battery fail and drain the other 2 during a possible 2 month period with no attention. It seems safer to isolate the batteries from each other, yet allow a single solar panel to charge all 3 simultaneously. I assume that a 25 watt panel would supply ~2 amps at 12 volts .:. the Radio Shack diode http://www.radioshack.com/product/index.jsp?productId=2062591# would be OK for charging and for reducing risk from an unexpected discharge. I was looking for some confirmation because I am a trial and error sort of fellow and an error can mean a bad trip and added expense. Thanks for considering my problem.
From: Jamie on 31 Jan 2010 18:51 Paul E. Schoen wrote: > "Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net> wrote in message > news:G8l9n.11539$3n2.9167(a)newsfe01.iad... > >>Stumpy wrote: >> >> >>>I put in a 12v solar panel to charge up 2 ATV's and a mini tractor. Ran >>>some speaker wire and battery clips to charge all of them in parallel. >>>The tractor battery seems to not hold a charge very well. I'd like to >>>add 3 diodes to protect the other 2 batteries in case at night with no >>>input current, the low battery would siphon off power. >>> >>>The setup is in a very remote location with no power lines and I've >>>misplaced to specs for the panel and the 7amp regulator, but they both >>>came from Harbor Freight. The bigger battery is 14 amp-hr, the 2 >>>smaller ones are 10 amp-hrs. >>> >>>Can someone please suggest an appropriate diode to purchase at Radio >>>Shack or Fry's that will handle up to 7amp and not waste too much >>>charging ability? >> >>http://www.frys.com/product/1003123?site=sr:SEARCH:MAIN_RSLT_PG >> >>from Fry's >> NTE6083 >> >> Make sure you mount these to a heat sink. >> >> Also, not sure about your charging unit, it may be regulating voltage >>to a close degree. You'll get a slight drop in voltage to the batteries >>if the charge regulator does not ramp up to maintain current. >> Drop will be around .7 volts. > > > The picture of the rectifier shows a three-lead TO-220, but description > says two-lead. > > Drop will decrease to about 0.3V at low current when regulator goes into > float voltage mode. > > You might be able to cannibalize a Schottky rectifier from a computer power > supply. Maybe a three-lead diode which can be used in parallel for even > less voltage drop. > > Here is the manual for a 7A Harbor Freight charging unit: > http://www.harborfreight.com/cpi/ctaf/manuals.taf?f=form&ItemID=96728 > > Paul > > Many sights use generic images for their parts. They look at the TO-220 and think they're all the same. AS far the manual, it really does not give much info to break down the circuit how ever, it does state (+.5) above 14V, so I think it should still charge the batteries, just maybe a little slower, which could be a good thing if it's left to keep the units at float.
From: Jamie on 31 Jan 2010 19:02 Stumpy wrote: >>>Can someone please suggest an appropriate diode to purchase at Radio >>>Shack or Fry's that will handle up to 7amp and not waste too much >>>charging ability? >> >>http://www.frys.com/product/1003123?site=sr:SEARCH:MAIN_RSLT_PG >> >>from Fry's >> NTE6083 >> >> Make sure you mount these to a heat sink. >> >> Also, not sure about your charging unit, it may be regulating voltage >>to a close degree. You'll get a slight drop in voltage to the batteries if >>the charge regulator does not ramp up to maintain current. >> Drop will be around .7 volts. >> > > > I don't even know how that 45volt rectifier could be used as a diode. This > is a link to the regulator I have. > > http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96728 > > Harbor Freight doesn't seem to carry the solar panel any more. I guess I'll > just gamble with a 2 legged diode. > > http://www.frys.com/product/1001633?site=sr:SEARCH:MAIN_RSLT_PG > > http://www.radioshack.com/product/index.jsp?productId=2062591# > > Don waste your money on that part at Fry's, its not what you need. that is a protection diode and has nothing to do with what you need. The one at Radio shack that you have pointed out would most likely work , even though its under rated by 1 amp and also, likely will have a higher forward voltage than what I pointed out. I picked the one at Fry's because of your 7 Amp unit you have and keep the voltage loss down. The diode from the shack will most likely get a little warm, the Fry's one, you can mount it to some AU to extract the heat and it's simple to hook up with an iron. It's up to you.
From: Michael A. Terrell on 31 Jan 2010 19:05 Stumpy wrote: > > >> > >> Can someone please suggest an appropriate diode to purchase at Radio > >> Shack or Fry's that will handle up to 7amp and not waste too much > >> charging ability? > > > > http://www.frys.com/product/1003123?site=sr:SEARCH:MAIN_RSLT_PG > > > > from Fry's > > NTE6083 Here is the data sheet: http://www.nteinc.com/specs/6000to6099/pdf/nte6083.pdf > > Make sure you mount these to a heat sink. > > > > Also, not sure about your charging unit, it may be regulating voltage > > to a close degree. You'll get a slight drop in voltage to the batteries if > > the charge regulator does not ramp up to maintain current. > > Drop will be around .7 volts. > > > > I don't even know how that 45volt rectifier could be used as a diode. This > is a link to the regulator I have. A recitifer is a diode. Look at the data sheet. The terminal marked 'K' is the cathode. This is the same as the banded end of a typical diode. The other lead is the anode. > http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96728 > > Harbor Freight doesn't seem to carry the solar panel any more. I guess I'll > just gamble with a 2 legged diode. That website is for their retail stores. http://www.harborfreightusa.com/ is the main site, and there is another site for their "Inside Track Club" members. The site you referenced only lists the most popular items. They have a printed catalog with more items, as well. > http://www.frys.com/product/1001633?site=sr:SEARCH:MAIN_RSLT_PG > > http://www.radioshack.com/product/index.jsp?productId=2062591# This is only rated for six amps. -- Greed is the root of all eBay.
From: Stumpy on 31 Jan 2010 19:56
>> > >> > http://www.frys.com/product/1003123?site=sr:SEARCH:MAIN_RSLT_PG >> > >> > from Fry's >> > NTE6083 > > Here is the data sheet: > > http://www.nteinc.com/specs/6000to6099/pdf/nte6083.pdf > > Thanks, I see it only has 2 leads. Now it makes sense to me. Paul pointed it out before but I needed to see the picture. >> > Make sure you mount these to a heat sink. >> > >> > Also, not sure about your charging unit, it may be regulating voltage >> > to a close degree. You'll get a slight drop in voltage to the batteries >> > if >> > the charge regulator does not ramp up to maintain current. >> > Drop will be around .7 volts. >> > >> >> I don't even know how that 45volt rectifier could be used as a diode. >> This >> is a link to the regulator I have. > > > A recitifer is a diode. Look at the data sheet. The terminal marked > 'K' is the cathode. This is the same as the banded end of a typical > diode. The other lead is the anode. > ---snip---- > >> http://www.frys.com/product/1001633?site=sr:SEARCH:MAIN_RSLT_PG >> >> http://www.radioshack.com/product/index.jsp?productId=2062591# > > > This is only rated for six amps. > I'm pretty sure that the panel can only supply ~2 amps. I'd be happy to get 3 of the NTE 6083s for $4.80 at Fry's but Radio Shack is about 5 miles closer with a $2.50 4-pack of the 274-3631s. Don't need heat sinks either. |