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Topic: Which diode should i use with three solar panels? (Read 440 times) previous topic - next topic

dennis_arduinouser

I have these diodes and googled alot but still dont know what exactly the difference is between the diode i have. Here are the specs:

1.Wattage: 1W
2. Diode/rectifier type: DO-41
3. RoHS: Yes
4. Standard Recovery Power Rectifier
5. Repetitive Reverse Voltage Max, Vrrm: 50V
6. Forward Current,IF(AV): 1A
7. Forward Surge Current Max, Ifsm: 30A
8. Forward Voltage Max, VF: 1.1V
9. Current Rating: 1A
10. Mode: IN5822, IN5408, IN5399, FR207, FR107, IN5819, IN4007, IN4148

25 x IN4148 Diodes
25 x IN4007 Diodes
10 x IN5819 Diodes
10 x IN5399 Diodes
10 x FR107 Diodes
10 x FR207 Diodes
5 x IN5408 Diodes
5 x IN5822 Diodes

What i am trying to do is connect 3 solar panels (5V 250mAh) together to create at max 15V 750mAh.
But im lost do i even need a diode cant i just connect them together like placing 2 batterys together to double the voltage?

jremington

#1
Oct 29, 2017, 05:01 pm Last Edit: Oct 29, 2017, 05:01 pm by jremington
You can connect solar panels in series without using a diode.  The diode is usually used to prevent battery discharge when it is dark.

"mAh" is a measure of battery capacity. You are thinking of current, measured in A or mA.

slipstick

#2
Oct 29, 2017, 05:24 pm Last Edit: Oct 29, 2017, 05:24 pm by slipstick
What i am trying to do is connect 3 solar panels (5V 250mAh) together to create at max 15V 750mAh.
That's not going to work. Apart from the fact that you mean mA (current) not mAh (capacity), when you connect these in series ONLY the voltage increases. So you'll end up with 15V but still only 250mA (and you'll probably only get that in in midday summer sun in the middle of the Arizona desert).

Steve


MarkDerbyshire

#3
Oct 29, 2017, 06:33 pm Last Edit: Oct 29, 2017, 06:34 pm by MarkDerbyshire
What i am trying to do is connect 3 solar panels (5V 250mAh) together to create at max 15V 750mAh.

So you have a choice with your panels to get either max 750mA @ 5V or max 250mA @ 15V you can't have both with your selection

MarkT

What i am trying to do is connect 3 solar panels (5V 250mAh) together to create at max 15V 750mAh.
mAh is a measure of charge used for battery capacity.

I think you mean 5V 0.25A panels.

You can't generate 9 times the power from 3 times the panel.

Either you put them in series and get 15V 0.25A, or in parallel and get 5V 0.75A.

For series you need a diode across each panel capable of 0.25A continuous.

For either setup you need a single diode on the output to prevent back-driving, and that will
need to be 0.75A rated for the parallel case.

Schottky diodes are preferred due to the much lower forward voltages and power dissipation.

[ Those 1N5819's should do ]
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

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