What can I use to charge a 6V 4.0 Ah battery?
It depends on the chemistry of the battery. You didn’t specify, so I’ll just guess.For small SLA (sealed lead-acid) batteries, the ‘standard’ regime for charging is to maintain a small constant current (10% of the capacity in Ah) until the terminal voltage reaches 2.25 volts per cell (6.75V) — this usually takes 8 to 10 hours and at this point the battery is about 70% ‘charged’.You then hold the voltage steady at that point until the current drops to about 1% of the charge rating (40 mA). This phase will take another pair of hours, and at this point the battery is ‘full’.You can, if the situation warrants, then hold the voltage at 2.15 volts per cell (6.45) ‘forever’.Both of those voltages assume ‘room temperature’, and the first improvement in charger design would be to use a temperature sensor on the middle-most cell of the battery to adjust the voltage se point.Many ‘simple’ chargers do nothing like this – the voltage is regulated to some arbitrary set point, and the current will fall where it will depending on state of charge, and if the battery is ‘cooked’, that’s just the price you pay for a cheap charger.
How do I charge a 3.7V battery from a 1V source?
you put four of them is series. But it will take a very long time to charge any battery at 2 microamps. for example this battery cell 1.2 volts and 3 Ah ihttp://www.allelectronics.com/item/nmh-s... it would take 1.5 million hours to fully charge. or roughly 342 years. the average LED uses 18 ma which is roughly 10000 times what you cell is putting out..
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.
Can I charge a 6V 4.5 Ah battery with a 9.5V 2.5 Ah charger?
You may use this converter module to reduce the voltage to 7.5V to 8V DC and charge the battery safely.
Can I use a 9.5 volt 800MA charger to charge a 12 volt 7AH battery?
You will need a step-up (boost) converter followed by a constant current controller. The purpose of converter is to boost 9.5V to 13.4V, while constant current controller makes sure the output of boost converter is current limited to avoid damage to either charger/converter or battery.Assuming 80% converter/constant current controller efficiency, the power goes into battery is 9.5*0.8*0.8=6W. The battery is 12*7=84Wh. It can potentially take 18 to 24 hours to charge a flat battery.
What charges a battery faster: more current or more voltage?
To properly charge a battery you need a proper battery charge management system. Since the battery stores charge, the more charge you inject per second, the faster it charges (I = dQ/dT). Therefore, the more current, the faster the charging. Most batteries have a max current limit for charging. Charging beyond this will damage the battery.Coming to voltage, the terminal voltage of a battery always stays within a certain range. (For 12V lead acid it will be around 9.5V at deep discharge and almost 14V when fully charged). Therefore, if you dump a constant voltage into it, you have no control over the current you are charging it with and may damage the battery. If it is a lead acid, this may still be acceptable, but if you are charging a Li-Ion, this is unacceptable since the battery could explode if charged improperly. So your battery chemistry also affects how you charge it. Lead acids will take more rough handling than lithium rechargeables. However, like I said before, most batteries are charged by pumping a constant current till the battery voltage hits the maximum possible voltage. After this, the charging circuit switches to constant voltage mode, and maintains the terminal voltage at a particular value (typically equal to the max possible cell voltage) - this stage is called trickle charging.
Can I charge a Li-based battery (8.5 V, 1 A) by using 7.5 V and 0.5 A?
first of all I know of no combination of lithium cells that make up 8.5 volts. They are usually 3.0 to 3.7 volts and 8.5 does not fit. Lithium has very specific charging requirement. If charged incorrectly can catch on fire or explode. To charge a bettery you must go from a higher voltage into the charging battery whihc is a lower voltage. water does not go uphill. So how can a 7.5volt source charge a 8.5 volt battery