Sponsored by the post - the company. SolarUA.
Buying a solar panel to power and charge multiple devices in field conditions, many believe that solved all our problems in this area. But, as practice shows, it was not there - it is not charging, the power is not enough, what a surprise it has manifested.
How is ' right' to use the solar panel to get the most out of it, that it can give? .
The first thing you need to understand that the energy obtained from solar cells - is still a kind of semi-finished product, in many cases unsuitable for many power devices. Only the most ' nekapriznye ' it from them may be ' digested ', mainly batteries, and even then, not all types.
Poor power quality is, first, the instability of output current and voltage, and secondly, in a small amount of this energy is clearly smaller than those tsiferok that are present in the description of solar panels.
For proper use of solar panels to follow two basic rules:.
Solar panel has as much time in the sun and work, work, work... to give all that it can.
There must be a device that stores all the energy that produces solar battery. Most often, this is either battery or a more complex drive.
Using these two simple principles to reduce the requirements for solar power several times, and still provide a guaranteed charge their devices, even when the sun does not.
Now, more.
The first step. solar cell.
For example, take a flexible solar panels 6 W and 8 W from a company SanCharger. Their power is sufficient to meet the needs of tourists with a set of PDAs, GPS, camera, radio (on average, of course, but most of this power is enough ).
Their appearance and characteristics are shown below.
6 W solar panel.
Output voltage (operating / idle) - about 6 V / 8 V.
Output current (working / short ) - about 1 A / 1. 3A.
Dimensions when folded - mm 200h195h9.
Dimensions when open - 595h195h6 mm.
Weight 400 g.
Solar Panel 8W.
Output voltage (operating / idle) - about 12. 5 V / 16 V.
Output current (working / short ) - about 0. 66A / to 0. 85A.
Dimensions when folded - mm 210h350h8.
Dimensions when open - 420h350h6 mm.
Weight 460 g.
The material solar cells - amorphous silicon. Both have built-in series diode to prevent discharge rechargeable batteries.
What can we connect directly to these batteries?.
batteries:. a) The easiest way to charge these solar usual ' fingers ', m. e. Ni-Mh or NiCd batteries.
From shestivattnoy solar can be charged from 1 pc up to 4 series-connected batteries, and from vosmivattnoy - 1... 8 pieces.
What are the ' pitfalls ' is taken into account in such a direct charge? . To a large extent it comes shestivattnoy solar cell, T. to. She and a half times more output current.
Ability to charge NiCd-NiMh batteries directly from the solar cell due to the fact that this type of battery allows the transmission of current through themselves, even in a fully charged state. This current is approximately one tenth of their capacity, t. e. through the battery capacity, for example, 2400 mAh and can be charged after ' pump ' current of 240 mA.
In most cases, the current is taken from the solar panel, much less a passport (which roughly corresponds to a hot summer day on the banks of the South Sea), there is not always a clear sky, and inaccurate orientation of the batteries in the sun, and the sun itself may not be . As a result, current from the solar cell is often not very safe for batteries greater than the value that allows us to charge the ' fingers ' directly, without the charger. And the need to monitor the overheating occurs only in bright sunshine.
b) Sealed lead acid ( gel ) batteries 6 V and 12 V can also be recharged from these solar panels. True, not from some horrible, but only on having the correct voltage, t. e. 6 The battery is only on shestivoltovoy shestivattki, and the battery 12 from the dvenadtsativoltovoy vosmivattki.
These batteries after charge by passing current through them begin to decompose the electrolyte and gradually dry up, so need greater control over their condition. T. e. At least occasionally need to run up to the tester and check the charge level.
c) Lithium batteries are also recharged directly from the solar battery can not be simply out of control, t. to. they do not allow overcharging and simply fail. If absolutely necessary, you can either charge the small portions, so that certainly does not recharge, or take a hike with a multimeter, and constantly monitor the charging voltage of the battery so that it does not exceed 4. 2 / to the bank.
As can be connected to the electronics of these solar cells? . Every time you need to check this possibility by ' spear '. Some radios are charged from 12 V.
Cell phone, especially the simple models can be charged by solar panel 6W, 8W to no longer be, t. to. Her output of 12 V, which just sleeping Phone. But when you charge your phone, please note that in the bright sun battery gives too much current, and the phone is its limit, in most models can not. Large current causes premature aging of the battery as well as just their swelling, which is really bad. So in bright sunlight with a direct charge, should put a solar panel at an angle to the sun, to limit the current.
PDAs and Communicators. 95% of the models ( and maybe more ) to charge directly from a 6- watt battery will not work, but to an 8- watt, as well as cellular, can not even connect. Inability to recharge due mainly to two reasons. First, the failure of the current solar cell (mainly for hungry CCP), which results in a voltage drop at the output of the battery below the permitted scheme and charging handheld stops, assuming that something is wrong with power supply. Second, even if the current is sufficient, then the voltage from the solar cell is unstable, and many devices have a very narrow limits of the allowable input voltage, for example, from 4. 8 to 5. 5B. And once we go beyond these limits cease charging. T. e. physically could take charge, but, alas, is prohibited by the developer gadget.
step two. Improving solar cell.
It is clear that such problems of the real charge more or less complex devices, no organized. Therefore, the easiest way to remedy the situation was the use of electronic voltage stabilizers at the output of solar batteries.
The stabilizer does not allow the voltage to rise above that and so disappears the risk to burn their high-voltage device.
First stabilizers were linear, r. to. just cut off the excess stress, not allowing him to pass to the consumer. Then, developers quickly realized that sin is converted into heat and so little energy from the solar battery, and started doing the type of pulse stabilizers. This stabilizer is simply converts the voltage and current of one level to another with minimal losses ( efficiency of about 80... 90% ), t. e. it can take a 12 0. 5 A from the source and issue 6, but an A consumer ( ideally, without regard to efficiency).
Using such a regulator, we can not worry about what will be the output voltage of the solar battery, if only it was not less than needed gadget.
By the way, car cigarette lighter adapters are a switching regulator is the same, but with a fixed output voltage, calculated for a particular device. Unfortunately, most of them starts to work only on the voltage of about 8V, which prevents the use of solar cells at 6 watts, only 8 vattku.
T. of. the use of the stabilizer can be used to charge PDAs, cell, player, or other ' naughty ' to power devices like solar cells at 6 watts, and at 8 W.
step Three. ' Fat ' Gadgets. Well, part of the problem of ' feeding ' gadgets we decided - the process was safe, and it became possible to feed them from any solar. But what happens when the sun seems to be true, but not enough for a normal charge? . e. physically, we could charge our PDA even for a long time, but, in fact, electronic handheld forbids us to do this, t. to. We can not provide sufficient on its ' understanding ', the current.
Yes, of course, you can buy a more powerful battery, but the output is it? .
Another disadvantage of using only solar cell with a stabilizer for power gadgets is the one that in those moments when the gadget is partially charged, he did not take all the current from the solar battery and the current is simply lost.
A more reasonable solution is to use a buffer battery or accumulator. Storage is called a battery combined with the electronics, which would be followed to correct the charge / discharge, stabilized output voltage, as well as perform other functions that make life easier to the user.
This drive consumes almost all the current that can develop a solar cell.
By analogy, the drive - it's a large bucket into which the stream flows of energy from solar. And the power of the jet can vary by tens of times, it does not matter - will fit any thread for filling buckets - anything that might give the solar panel, all stored in the storage batteries.
When the need to feed some gadget, it is simply connected to the drive and draws from it as much energy as fast as it is convenient, and ' eaten ' fall off, rather than waiting for the same solar panel deign to draw some for him to appropriate a portion of.
Graphically, the difference in charge with the drive and without are shown in the figure below. The graph shows the maximum output current of solar battery for some time, and times when it can be recharged and drive gadget.
The area shaded in red represents those moments when the solar array produces enough current to power a real PDA directly from the solar battery.
The amount of green and red regions, respectively, a time when there is a charge storage device.
When building a schedule, I tried more or less to comply with the scale of real currents and their relationship. For example, some PDAs have bad charging at currents below 1. 2A, in particular, the discharged battery. Here, for example, used even less current - 0. 5 A. The drive also, for example, ' Vampirchik - Li ', begins to charge their batteries from the current 10 mA, but with a reserve schedule ukazno - 50 mA.
T. e. We can see from the figure that using solar panel in direct charge of many devices, the entire green area is simply discarded, t. to. Gadget can not often take a very small current. The drive also eats almost everything, and ' mature red ' and ' green nedorosshee '.
Thus, it appears that even in spite of the fact that the accumulation of energy in the intermediate accumulator and additional transformations is lost from a quarter to half of the energy derived from solar, we still find ourselves in a win, and repeated, in comparison with direct charging gadgets .
In addition, one of the advantages of using a buffer storage is the ability to charge at a convenient time for us, not just when there is sun. Often much easier and safer to charge your device in a tent at night than during the day on the move. Moreover, many expensive gadgets just like that, unattended, for a long time on the street will not leave.
Of course, there are other drives, for example, a lot of them presented on the site AcmePower. But, if ' Vampirchik ' designed specifically for tourists and can be powered by either solar (5... 20 V ), the possibility of charging AcmePower products from solar panels need to figure out when buying a specific model. Some of the information can be found on the manufacturer of flexible solar cell company SanCharger, where specific models are compatible storage devices and solar cells.
And finally, just give two sets to provide power in a campaign that I think are the most rational.
The first set. optimized for maximum efficiency of solar energy:.
Solar Panel 8W;.
Saving the battery;.
The pulse voltage.
The solar battery is connected directly to the battery, which eliminates the loss of a job scheme it is charged. There remain only the loss of ' chemistry ', about 15%.
The stabilizer is connected to the contacts of the battery and supplying the load. Of course, charging and power users can run simultaneously.
As the battery can be used either on the 12V lead gel, or a pack of AA fingers, in an amount of 10 pieces. Why 10 and not 8? . The ten series-connected batteries are charging voltage at the end of 14. 5, and at the same voltage 12- volt solar battery can not ' push ' them a lot of current, and it sharply decreases to a safe as the charge, which can also perform additional balancing battery. T. of. , The charging process is terminated independently and safely, without the need for any external charger.
The disadvantage of using a battery pack is that because of the difference in actual tanks, batteries with less capacity will ' wear out ' faster than the rest, especially during deep discharges. It is therefore desirable to periodically check their condition by measuring the voltage on each battery.
The second drawback, however, is very relative, such a set can be considered the desirability of using the solar battery is at 12V. However, these batteries have about twice as large size when folded than a 6- watt.
As the main advantages of such a set of three.
Lower cost of electronics compared to the second option, although, given the cost of batteries, the difference will not be too high.
More importantly, a large current of given the relatively high voltages. Moreover, current can be easily increased by using more stabilizers.
The buffer has a standard car battery voltage ( 9... 14 V ), so it can easily connect any adapters for devices powered by the cigarette lighter. ( If only they did not consume current greater than the battery can give up ).
The second point is relevant to those who use a camera, or some types of satellite phones, which are powered by voltage 8. 4 or more, consuming more than the current 1 A. Switching regulator has an output current of up to 1. 5A, and it does not matter whether it is given to current at the output voltage of 5 V or 10 V (as opposed to ' Vampirchika ', within which is an additional limiting the output power ), so the stabilizer is easy to cope with such a shock to ' high ' voltages.
By the way, attempt to power the various chargers for batteries, for example, NiCd-NiMh or lithium fingers, just off the solar panel without the buffer battery, usually ends in failure. Unfortunately, most of the memory use current pulses, and it turns out that, although the average current consumption seems to be small, but during the pulse solar cell can not cope with it and the charger is turned off. A buffer battery smoothes out these surges of current and charge is normally.
The second set. designed for the user with minimal training and is not willing to work with your hands.
Solar panel 6 W and 8 W;.
drive.
Any of these batteries simply connects directly to the drive, and he is following the charging. The user can only connect to its output to power their devices.
cons:.
Lack of some devices output to ' high ' voltage drive charges virtually all consumers using 5 - it's all PDAs, mobile etc. Dr.. But for a camera of its output current may not have been.
Large losses of about twenty per cent, compared with the first scheme, t. to. there are more changes.
Using avtoadapterov at its output is possible, but not very logically, t. to. is too much change and, consequently, loss of.
pros:.
The simplicity and compactness, the minimum wire.
No need to monitor the battery.
findings. As is evident from a review of the use of ' naked ' solar forcing to overstate its power while charging gadgets in actual use is still not guaranteed.
The use of electronics is not just desirable, but in many cases, a prerequisite of safe charging sophisticated consumers. And indeed, the very possibility of such a charge.
The buffer battery ( storage) to reduce the requirements for solar power is several times. It also provides additional ease of operation.
