If I connect 12V battery to 24V battery charger, will 12V battery charge or not or it explode?
Not a good idea, the charger sees a low voltage load and put a huge amount of current on it, then you have a "boiling" battery with excess gas generation, damage to the plates and excess heat. Probably permanent damage.But if it is all that you have in an emergency (and have a healthy battery) put an H4 head lamp (filament type lamp) in series to limit current to 5 amperes or so. Always supervised the battery must recover in a couple of hours, don't leave alone, the circuit doesn't limit voltage!
Can you use a 5 volt charger to charge a 3.7 volt cell phone battery?
That’s pretty much what every cell phone and tablet does.There a charge controller in the device that works the deal; the 5V charger cannot be directly connected to the battery, though.
Is it possible to charge a 6v battery with a 12v charger?
I figure that's a 6Ah battery. 1A for 6 hours should fill it up.Here is the datasheet for the BD681.The transistor is a bit on the small side for comfort. It's only a TO-225 type rated at 4A (& 40W). A bigger TO-220 device with a rating of at least 10A would be my choice.Remember it's a very simple circuit with no safety features of any kind so it needs to be dimensioned fairly well to survive (but the 4A might survive if cooled well enough).Steel (or brass for that matter) is a very poor heat conductor and will not do at all as a heatsink material. Aluminum and copper are the only common metals that'll do.An aluminum "sheet" would also need to be at least 3 mm thick and 20 x 20 cm to come close to being up to the task. Copper is much better and can be thinner (1mm).You might even consider water cooling (like a small pan, if you dare).. PVC tape is also a very poor heat conductor, as you noticed. If the heatsink is well protected from touching anything else then you can do without transistor insulation.A small drop of (cooking) oil between the transistor & the heatsink/ underside of the pan could make do as a heat transfer improver.Anyway, this charger may help you Liang's FM Transmitter,the Best Wireless Bluetooth Handsfree Car Kit/Adapter, with USB Port/Car Charger for Cellphones Power Charging iOS & Android iPhone, try it7ATest the output voltage of the circuit first without connecting the battery. The battery, being small, will not draw as much current as a car battery does, fooling the indicator.A battery resting voltage of 5.8V means it's very flat indeed. 6.4V would mean it was full however (not much of a difference).For measuring currents you usually have to move the red test lead to a separate socket on the meter (and remember to move it back before measuring Volts again).
What factors in a charger control charge speed?
The factor that mainly affects charging speed is charging current, i.e the output current of the charger.Most wall charging units (called a travel adaptor) produce ~ 0.5 A.(usually higher if meant for tablets)Usb docks/portable usb chargers/pc ports produce ~0.25 A..So if you're ever in a hurry, use the travel adaptor instead of the usb port of your computer, its 2 times faster.Its a misconception that usb sources allow you to charge faster..Note: all travel adaptors and usb sources produce a voltage of 5V, so voltage is obviously not a factor.
Can I use a 24 V solar panel to charge a 12 V battery?
Yes, you could do it. The voltage isn’t too much of a concern, it is the current the panel can provide.What is commonly known as a 12V panel is usually a 36-cell module with an open-circuit voltage of 22V, making maximum power at 18V. Traditionally so-called 24V panels would have double the cells (72 cells), and they’d make 36V-44V at the top end. Lately there is also a lot of 60-cell modules that make somewhere between 30V and 40V, which is also sometimes called “24V-panels”. As you can see though, 12V panels aren’t really 12V and 24V panels aren’t really 24V. They are usually designed to put out at least 30% more than the batteries they are intended to charge.This works perfectly well because a PV module is (at a constant light level) a constant current device. If you look on the back, you will see it has ratings for Isc (short circuit current) and Imax (maximum current). These two values are usually fairly close to one another. Now… hang on to your hats: This is the current at which it will charge regardless of what voltage you charge at. Remember that you are already doing this when you wire a “12V panel” to a 12V battery, because you are in fact pulling the 22V of the panel down to 12V.It is not a very efficient thing to do of course. Let me explain. Let’s say you have a 300W module with 72 cells. Vmp should be around 36V, and Imax should be around 300/36 = 8.3 ampere.If you wire that module to a 12V battery, it is going to charge that battery at 8.3 ampere, and pull the voltage down to whatever the battery can handle. If the battery is pulled up to 14.5V for example, you will charge at 14.5*8.3 = 120 watts.Woah, where did the rest of the power go? It got lost because the module is constant current, and you’re doing the work at too low a voltage.This is where an MPPT comes in. An MPPT is essentially an auto-adjusting DC-to-DC converter that aims to run the PV module at the optimum power level (36V in our example), and then down-converting the voltage (swapping volts for amps like a transformer does), and then charging the 12V battery at the full 300W, or 300/14.5 = 20 ampere.So getting back to the question: Can I connect a 24V solar module to a 12V battery? Sure… as long as the Imax specified on the back of the panel won’t damage it, you can do that. But it would be terribly inefficient. The better option would be to use an MPPT-based charge controller.
If I connect a 5v and a 2v battery in parallel, what is the net output voltage?
5 volt. If you connect these two batteries in parallel the output voltage would be 5 volt. the batteries has there own internal resistances hence there will be a power flow from 5 v battery to 2 v battery.
Does different charging voltage impact battery life? If so, how?
Charging under high voltage also affects the battery life . You can see the table below. It shows that, batteries charged under high voltage significantly suffers through loss in cycles.(source: Battery University)When batteries are charged at high voltage, they heat up and affect the battery capacity permanently.All battery types, be it lithium or lead acid, degrade in heat. so they must be stored in cool and dry places (18–25 C).When rechargeable batteries are exposed to high temperature or charged at high voltage , they suffer stress. This also affects capacity and cycle life. Elevated temperature might cause permanent loss of capacity.(Source: batteryuniversity): In the table above, You can see how elevated temperature affect on battery capacity.
My batteries were overcharging in my freightliner,but my volt meter showed 14 volts why?
I agree its the regulator not senseing battery voltage and responding accordingly, replace it.