I have a solar light of 300W
DC voltage 6.4V
Battery capacity 25000mah
Solar panel details. (Pmax 50W, Vmp 10V, VOC 12V
Can I extend the run time of the solar light by connecting a second battery of same type parallel. Now light run up to 4hrs. I need to extend up to 10hrs.
or remove battery and solar panel and connect external SMPS power supply equal to the battery.so it will take only little current.
Pls advise

 

There is something wrong with the numbers you quote. A 300 watt light with a 6.4 volt battery will take close to 50 amps. 50 amps from a 25 AH battery would discharge it in half an hour. In practice this would be less than half an hour as the battery capacity will be less at such a high discharge rate. This does not agree with your quoted run time of 4 hours. Connecting an extra battery of the same capacity would double the run time but it would also double the time required for the solar cells to recharge the batteries. I don't understand what you mean in your last sentence when you say "so it will take only little current." A switch mode power supply would need to be rated at least 50 amps to provide 300 watts at 6.4 volts.

Les.

 

There is something wrong with the numbers you quote. A 300 watt light with a 6.4 volt battery will take close to 50 amps. 50 amps from a 25 AH battery would discharge it in half an hour. In practice this would be less than half an hour as the battery capacity will be less at such a high discharge rate. This does not agree with your quoted run time of 4 hours. Connecting an extra battery of the same capacity would double the run time but it would also double the time required for the solar cells to recharge the batteries. I don't understand what you mean in your last sentence when you say "so it will take only little current." A switch mode power supply would need to be rated at least 50 amps to provide 300 watts at 6.4 volts.

Les.

I have attached photo for the reference from the solar light label. as the day light is less you are right that battery needs more time to get recharged. either option #1 remove solar panel and connect a external DC adaptor to get battery recharged or Option # 2 remove battery and solar panel and replace the battery with a external DC power supply same as the power of battery. Is it possible. If so what would be the power needs for the adapter which replacing the battery. Will it draw more current which increase my electricity bill.

 

Your LED lamp says 8Hrs on a 25Ah battery, that is 3Amps @6.4V is 19W power.

So two 25Ah fully charged batteries will give you 16Hrs.

 

The type VT-300W is misleading.
The lamp is 50W.
https://v-tac.eu/led-lights/lights4...r-panel-with-led-floodlight-6000k-detail.html

 

I think the model number is made to make people THINK it is 300 watts. From the information on the label it will be about 20 watts. (25 AH x 6.4 volts divided by 8 hours) It will take a current of 3.125 amps so a 4 amp power supply would be enough. I would not trust the values shown on the label. I would make my own measurements.

Les.

 

I think the model number is made to make people THINK it is 300 watts. From the information on the label it will be about 20 watts. (25 AH x 6.4 volts divided by 8 hours) It will take a current of 3.125 amps so a 4 amp power supply would be enough. I would not trust the values shown on the label. I would make my own measurements.

Les.

Thanks dear
from the label information, to replace the battery and work on DC power supply directly. 6VDC and 4amp SMPS Power supply will do? Please advice. Then light will run continuously without stopping and may we need to connect a photoelectric switch to operate automatically off in the day time and On at the night time.

 

The type VT-300W is misleading.
The lamp is 50W.
https://v-tac.eu/led-lights/lights4...r-panel-with-led-floodlight-6000k-detail.html

yes your right. it is misleading.

 

yes your right. it is misleading.

I would go beyond calling that label "misleading", and call it a work of fiction. 25000 MAh =25 amp-hours and that would be a large battery, Adding a second battery in parallel will certainly extend the time that the light is available, and it may double the time, possibly.
If you have a way to measure the actual current then we should be able to provide some useful suggestions. Note the frequent use of the term "max", which is an indicator that the number is different from average or typical. Also, can you provide approximate dimensions of the battery, which will help us understand what the actual capacity is likely to be.
If you were able to use a small switching power supply instead of the battery that might be a less expensive option.

 

I would go beyond calling that label "misleading", and call it a work of fiction. 25000 MAh =25 amp-hours and that would be a large battery, Adding a second battery in parallel will certainly extend the time that the light is available, and it may double the time, possibly.
If you have a way to measure the actual current then we should be able to provide some useful suggestions. Note the frequent use of the term "max", which is an indicator that the number is different from average or typical. Also, can you provide approximate dimensions of the battery, which will help us understand what the actual capacity is likely to be.
If you were able to use a small switching power supply instead of the battery that might be a less expensive option.

Attached photo of the battery fixed inside the light.(blue color is the battery pack). 10numbers of "C" type battery in one pack. I measured the voltage out put to the circuit board from the battery is 6.7V DC and the voltage received from Solar Panel is DC10.9V for charging. I hope that 6V DC 5amp external power adaptor can be used for replacing the battery and solar panel. ie we can run the light directly from the power supply.

 

Can I use 6V DC 5amp external power adaptor for replacing the battery and solar panel. Kindly advice. Details as given above.
"10numbers of "C" type battery in one pack. I measured the voltage out put to the circuit board from the battery is 6.7V DC and the voltage received from Solar Panel is DC10.9V for charging"

 

It seems that every thing flows into or out of a circuit board so my wild guess is that 6V should work. At a utility rate of US $ .12, then one night
with a line operated timer, would cost about 6 cents.

 

Adding a second 25A hour battery will also mean it will take twice as long to charge it up. The solar panel says it outputs 10V at 5A. To charge two 25Ah batteries (50Ah total) if fully discharged, would take about 10 hours. This assumes full solar output (full sun).
So, not only do you have to consider runtime, you also have to consider charge time.