Is there any way a battery can charge other battery through isolated Charging circuit powered by a battery?

Hi Uche,

I'm a master power electronics engineer and I specialize in DC-DC converters, solar charge converters, DC-AC Inverters, Power Supplies, and battery chargers. Yes, you can charge a battery from another battery, if that's what you're asking. I don't know why you need it isolated. However, I've got to agree with D2113F with reference to your other replies to this post. To me, it sounds like a perpetual motion machine wheras you have two batteries that are each connected to relays that can switch the individual batteries to either a load or to a a charging circuit fed by the other battery. Here is the problem. Battery-1 is connected to a load and is discharged to the point that you want to rechage it from the other battery that's been idle. Battery-2 recharges Battery-1 thru a dc-dc converter with a control to ensure that it's not overcharged. Now, Battery-2 is discharged and Battery-1 is charged, therefore, the relay or relays setup the circuit such that Battery-1 recharges Battery-2 and now Battery-1 is again discharged. Hopefully, you see where I'm going with this. It's an (almost) endless loop of the batteries charging and discharging each other. And if you powered a load first, discharging Battery-1, then recharged it with Battery-2, Battery-2 is now discharged and you can power the load only one more time with Battery-1. But now, you can no longer recharge Battery-1 with Battery-2 since Battery-2 is discharged, The only way around this is if you have some additional power from another Battery, or a Solar Cell, or from an AC-DC Power Supply to put the lost energy back into the system.

One of the first things you should have learned in physics is that there is no such thing as a perpetual motion machine. Since you used the energy in Battery-1 to power the load and the energy in Battery-2 to recharge Battery-1, and since you used-up the energy in Battery-1 again powering the load after the recharge, you are out of energy as both Battery-1 and Battery-2 are discharged. Does this make any sense to you? I hope so, but if not, please feel free to reply here or send me a message using the Element-14 internal messaging system.

Best regards,

Kamran Kazem

What about if the other power source is a third battery on the same circuit?

It doesn't matter if the other power source is a 3rd battery on the same circuit. This kind of cross charging can be done and it will work. What it won't do, however, is to make a perpetual motion or free energy or over unity situation. There are few situations that will even theoretically work that way. One is LENR (low energy nuclear reaction) and another is energy harvesting from existing mechanical, electrical, or thermal energy sources. Like using ocean wave energy to generate electricity or using geothermal energy or wind energy to turn a generator and make electricity. Another example is capturing electromagnetic energy (RF) in wireless form to generate electrical power and this is easily done, but not very practical unless one is near a high-power radio station or HV power line. This is not perpetual motion and it does not violate the laws of physics. It's simply a conversion of one form of energy to another, usually using some excess or easily available energy source. Unless the laws of physics change, nobody will ever take a separate motor and generator, and use the motor to turn the generator to charge the battery that powers the motor to get free, over unity energy. The best one can do in that situation, is to extend the time the motor will run till the battery goes dead for a given apparatus.  

It doesn't matter if the other power source is a 3rd battery on the same circuit. This kind of cross charging can be done and it will work. What it won't do, however, is to make a perpetual motion or free energy or over unity situation. There are few situations that will even theoretically work that way. One is LENR (low energy nuclear reaction) and another is energy harvesting from existing mechanical, electrical, or thermal energy sources. Like using ocean wave energy to generate electricity or using geothermal energy or wind energy to turn a generator and make electricity. Another example is capturing electromagnetic energy (RF) in wireless form to generate electrical power and this is easily done, but not very practical unless one is near a high-power radio station or HV power line. This is not perpetual motion and it does not violate the laws of physics. It's simply a conversion of one form of energy to another, usually using some excess or easily available energy source. Unless the laws of physics change, nobody will ever take a separate motor and generator, and use the motor to turn the generator to charge the battery that powers the motor to get free, over unity energy. The best one can do in that situation, is to extend the time the motor will run till the battery goes dead for a given apparatus.