Hi Rodolphe,
A battery is a much lower impedance device than a power supply. Lets assume your SSG has a 20% duty cycle with an average measured current draw of 1 ampere. This means that it is drawing 1/20% = 5 amp pulses each time it fires. This is no problem for the battery because it's impedance is very low. A power supply, on the other hand, will struggle to produce this current pulse and will have an attendant voltage drop in it's transformer each time the transistor conducts. A very large filter capacitor on/in the power supply will help, but the performance will always be better with a fully charged good battery of sufficient size. Another advantage the battery has is that it will receive some of the radiant voltage and run down more slowly that it would with a purely resistive load. The power supply won't accept any of this radiant voltage.
You need to start out with all batteries fully charged. On an AGM that is usually around 13 volts at rest. Under a 1 amp load the primary battery will show from 12.6 to 12.7 volts at first and should run down very slowly. The charge (secondary) battery should first be discharged at the c20 rate for however long it takes to remove 1 AH. For a 12 AH battery that would be 600 ma for 1.67 hours. Do this and let it rest for about another hour before you begin charging it. It's standing voltage will probably recover to around 12.9 volts while resting.
Run the SSG until the charge battery reaches 15.3 volts under charge. This is the finish point that indicates full charge. Note the time it takes to recharge and take occasional current draw readings from the primary by switching an ammeter into and out of the primary circuit while it's running. Don't let the current go through the ammeter all the time as this will lower the results you get. Use a switch across the ammeter to short it out except to take an occasional reading.
Discharging the battery to 9.6 volts at a c2 rate is the wrong thing to do and will damage the battery. It shouldn't be discharged below 10.6 volts minimum and not over the c20 rate!
You should be working in the top of the battery's capacity range, ie between 10 and 12 AH to see the best results from the SSG. The more you take out of the battery, the longer it will take to recharge it! The idea is to measure the AH you remove from a full charged battery and then see how many AH the SSG uses to full recharge it. If you completely discharge the battery, it will take a very long time to recharge it with the SSG.
And yes, it would take my SSG at least 6 hours in generator mode to fully recharge a 12 AH battery that was completely run down. This is not a good way to use the system.
A battery is a much lower impedance device than a power supply. Lets assume your SSG has a 20% duty cycle with an average measured current draw of 1 ampere. This means that it is drawing 1/20% = 5 amp pulses each time it fires. This is no problem for the battery because it's impedance is very low. A power supply, on the other hand, will struggle to produce this current pulse and will have an attendant voltage drop in it's transformer each time the transistor conducts. A very large filter capacitor on/in the power supply will help, but the performance will always be better with a fully charged good battery of sufficient size. Another advantage the battery has is that it will receive some of the radiant voltage and run down more slowly that it would with a purely resistive load. The power supply won't accept any of this radiant voltage.
You need to start out with all batteries fully charged. On an AGM that is usually around 13 volts at rest. Under a 1 amp load the primary battery will show from 12.6 to 12.7 volts at first and should run down very slowly. The charge (secondary) battery should first be discharged at the c20 rate for however long it takes to remove 1 AH. For a 12 AH battery that would be 600 ma for 1.67 hours. Do this and let it rest for about another hour before you begin charging it. It's standing voltage will probably recover to around 12.9 volts while resting.
Run the SSG until the charge battery reaches 15.3 volts under charge. This is the finish point that indicates full charge. Note the time it takes to recharge and take occasional current draw readings from the primary by switching an ammeter into and out of the primary circuit while it's running. Don't let the current go through the ammeter all the time as this will lower the results you get. Use a switch across the ammeter to short it out except to take an occasional reading.
Discharging the battery to 9.6 volts at a c2 rate is the wrong thing to do and will damage the battery. It shouldn't be discharged below 10.6 volts minimum and not over the c20 rate!
You should be working in the top of the battery's capacity range, ie between 10 and 12 AH to see the best results from the SSG. The more you take out of the battery, the longer it will take to recharge it! The idea is to measure the AH you remove from a full charged battery and then see how many AH the SSG uses to full recharge it. If you completely discharge the battery, it will take a very long time to recharge it with the SSG.
And yes, it would take my SSG at least 6 hours in generator mode to fully recharge a 12 AH battery that was completely run down. This is not a good way to use the system.
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