Originally posted by inetdog
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Need to regulate voltage from 5.8 to 5 without battery. Any ideas?
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Apple has done some even more egregious things in regard to their new "Lightning" connector standard (smaller footprint) for their new iDevices.
They will only license the connector for use by third party charger and adapter manufacturer if the Lightning connector is the only output the charger has. They will not even allow a charger which works for both the old and the new iDevices. And of course, even Apple themselves do not make a dual output charger for the old and new connectors. They do make and license adapters from 30 pin to Lightning, but even these have a proprietary ID chip in them which handshakes with the device to tell it that it is working with a licensed accessory. And there are no Lightning back to old standard adapters that I have found.
The new USB power standard allows power-only USB chargers/supplies to deliver even higher voltages and/or higher currents, but only after handshaking with the load to negotiate what sort of power the charger is expected to deliver. (Shorting 2-3 is an early rudimentary handshake, I guess.) That handshake allows the exact same connector to be used for both the old and new USB power connections without interoperability problems.Leave a comment:
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Originally posted by cartgolfsolar View PostIt's about trying to regulate my voltage from 5.8 to 5.0 and if it is even possible.
5.8 volts in > Diode > 5.1 volts outLeave a comment:
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Originally posted by inetdog View Postrectifier in series between the panel and the load to drop ~.7 volts
Use an L7805 to limit the output Voltage, which you can feed up to 37.5V
You might find the 7805 doesn't have enough input Voltage to begin with at 5.8V, (I seem to remember they drop 1.something Volts) you'll have to experiment...Leave a comment:
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Originally posted by cartgolfsolar View PostFirst, thank you for responding. This sounds promising from what I've just researched about it, but I cannot seem to find a zener diode that fits the specs. I've tried to source it as a 4.75-5.1 volt (ex.) 10 watt zener diode and every other way I could figure with no luck. I'm lost, could you point me in the right direction. Thanks again.
Or you could just go the other route and put a forward biased rectifier in series between the panel and the load to drop ~.7 volts and a Schottky diode to drop another .2 volts. This would allow you to take the higher voltage for battery chargers that will accept it and still deliver the lower voltage on the cable to the iphone. Easy to try to see whether it works. Lower power requirements on the diodes, since they will be sinking no more than 1.5 watts at 2 amps.Leave a comment:
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Originally posted by Sunking View PostThat is what I am trying to tell you. It needs 2 amps, the new USB charging standard is 2 amps, and you have to short pins 2 and 3 together. Read up on USB charging standard. Easiest way to make a USB solar charge is to buy a 12 volt vehicle 2 amp USB charger for $7 and connect it directly to a 40 or higher watt 12 volt battery panel. (A panel with a Isc of 2 amps or greater)Leave a comment:
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Originally posted by cartgolfsolar View PostI works just fine for everything but my iPhone right now,Leave a comment:
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Originally posted by Sunking View PostIt is not going to work as the voltage is too low to be of any use. For a solar USB charger you are going to need at least 20 watts @ 7 to 10 volts panel. However will be limited to only 1 or 2 hours daily charge time unless you have a tracker. A series or shunt voltage regulator requires the input voltage to be at 1.5 to 2 volts higher than output.Leave a comment:
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It is not going to work as the voltage is too low to be of any use. For a solar USB charger you are going to need at least 20 watts @ 7 to 10 volts panel. However will be limited to only 1 or 2 hours daily charge time unless you have a tracker. A series or shunt voltage regulator requires the input voltage to be at 1.5 to 2 volts higher than output.Leave a comment:
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Originally posted by inetdog View PostThe absolute simplest circuit would be just to put a slightly less than 5 volt zener diode in parallel with the panel output. If the zener is sized to handle ~10 watts, it would draw enough current from the panel to keep the voltage from rising above the knee voltage of the diode. Any attempt by the real load to draw current at that voltage would tend to reduce the voltage from the panel to the point where the zener would draw less and less current.
As the load tried to pull more current, the voltage would drop enough that the zener was not conducting at all and all of the panel power was going to the load.
Since you do not have anything else to do with the excess power from the panel, the wasted energy would be of no concern.
My guess is that with a properly sized zener, you could go from full current to zener to full current to load over a range of only one or two tenths of a volt.Leave a comment:
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Originally posted by cartgolfsolar View PostI have a 10W/5V panel with an output that measures right around 5.8V. I am running it through a power only USB charger hub for mobile/handheld devices. This works fine for most but Apple seems to only recognize/charge when voltage is right at or just below 5.0V. I only need this to work when the weather is nice so I do not have a battery or controller in the line. I would use a converter but the input is not >3V. I am going to use a 10/18V to 12/24V to 5V dc/dc to hub in the future but have quite a few 10W/5V panels I would really like to be able to use in the same fashion. I apologize in advance for lack of knowledge/info provided, I am very green in this field... no pun intended.
Thanks,
As the load tried to pull more current, the voltage would drop enough that the zener was not conducting at all and all of the panel power was going to the load.
Since you do not have anything else to do with the excess power from the panel, the wasted energy would be of no concern.
My guess is that with a properly sized zener, you could go from full current to zener to full current to load over a range of only one or two tenths of a volt.Leave a comment:
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Need to regulate voltage from 5.8 to 5 without battery. Any ideas?
I have a 10W/5V panel with an output that measures right around 5.8V. I am running it through a power only USB charger hub for mobile/handheld devices. This works fine for most but Apple seems to only recognize/charge when voltage is right at or just below 5.0V. I only need this to work when the weather is nice so I do not have a battery or controller in the line. I would use a converter but the input is not >3V. I am going to use a 10/18V to 12/24V to 5V dc/dc to hub in the future but have quite a few 10W/5V panels I would really like to be able to use in the same fashion. I apologize in advance for lack of knowledge/info provided, I am very green in this field... no pun intended.
Thanks,
Leave a comment: