shdesignsPowered By Infinite Improbabilty Drive Premium Member join:2000-12-01 Stone Mountain, GA (Software) pfSense ARRIS SB6121
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Re: battery backup lightsI have one I used: » shdesigns.org/gcellchg.htmlI set it to 13.4V. Will charge fast for the the first 75% then ramps down to 0. It is what is called a "float charger". |
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Subaru1-3-2-4 Premium Member join:2001-05-31 Greenwich, CT |
Subaru
Premium Member
2013-Feb-21 10:49 am
That design looks good and the LED is a nice touch so after I get my battery (might use one I have already) I just find what the charge settings are and just set it to that? |
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shdesignsPowered By Infinite Improbabilty Drive Premium Member join:2000-12-01 Stone Mountain, GA |
shdesigns
Premium Member
2013-Feb-21 11:11 am
Yes, see what the OEM says for float charge voltage. |
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Subaru1-3-2-4 Premium Member join:2001-05-31 Greenwich, CT |
Subaru
Premium Member
2013-Feb-21 11:15 am
I will have a check, I hope it's listed on the battery, btw nice use of off the shelf parts, I have everything listed but the heatsink and the N22222A
My project box may be a little small but I have at least 3 sizes laying around |
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shdesignsPowered By Infinite Improbabilty Drive Premium Member join:2000-12-01 Stone Mountain, GA (Software) pfSense ARRIS SB6121
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shdesigns
Premium Member
2013-Feb-21 11:35 am
Nearly any general purpose NPN transistor will do.
Will need a heat sink. I used a box about the size of a biz card and 1" tall. I replaced the cover with an aluminum plate that doubled as a heat sink.
Works best with about 16V in, higher is just wasted as heat. I use it with a solar panel to keep my riding mower batt charged. |
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Subaru1-3-2-4 Premium Member join:2001-05-31 Greenwich, CT |
Subaru
Premium Member
2013-Feb-21 2:26 pm
did you take any measurements of the heatsink? I don't know if I have any spare transformers but say it had a 15-17 Vout voltage.. trying to get an idea if that's too hot to run in a case without a aluminum plate but with a heatsink on it..
if it's really bad I could add a small 40 mm fan to the case |
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SmokChsrWho let the magic smoke out? Premium Member join:2006-03-17 Saint Augustine, FL |
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said by shdesigns:I set it to 13.4V. Will charge fast for the the first 75% then ramps down to 0. Nice little design, The one thing I think I would add is an isolation diode so that the charging circuit didn't become an additional load upon failure. (especially if you need the 1K for the LM317) Of course you would have to compensate for the diode drop with the regulation setting. |
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shdesignsPowered By Infinite Improbabilty Drive Premium Member join:2000-12-01 Stone Mountain, GA |
The design was parts I had laying around.
Id probably do a switching reg if i was doing one from scratch. |
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