System components - will it work?

DIY
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1

I intend to light up an off-grid cabin for a few hours per day between April and October, and wanted to build a little system from the following components:

COB LED strip, 30W, 24V, 1.25A
LiFePo4 rechargeable battery 24V, 12Ah
Solar panel 180W, Vmp 23.4V, Imp 7.7A
Solar charger victron energy BlueSolar MPPT 75/10
DC-DC converter buck-boost 24V, 3A

I am under the impression that one needs to connect the LED strip to the BlueSolar’s load output terminals with the DC-DC converter in between to ensure a steady 24V supply to the LED strip. Is that correct?

Is the Vmp 23.4V of the solar panel sufficient, or should the voltage be higher to charge a 24V battery via the solar charger? If so, how much higher?

Apart from that, anything else that’s wrong?

Many thanks in advance!

2

Solar needs to be 5v above battery voltage to start the mppt,

Wire two of those panels in series or use a bigger panel with higher voltage

But if you have shading voltage may not reach the required level to start

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3

Thanks, so all I have to do is to find a solar panel with Vmp 30V or in that region.

4

In addition to the panel voltage check your battery is OK to be charged at 6 to 7A it should be but best to be sure. Most of the Victron MPPTs can have the output current reduced if required.

5

I found a solar panel with 100W, Vmp 39.6V , Imp 2.53A so that should be sufficiently higher than the 24V rechargeable battery voltage. I have to use only a single solar panel to fit to the tracker the previous owner left behind.

6

With even lower current it would be much harder to get your battery charged..

Are you limited by size of the panel?

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7

Yes, there’s only space for a panel of around 130 x 70cm, maybe a tad larger. I was hoping to find a panel that is not too large and not too heavy (increased wind load, increased strain on the tracker motor/assembly), yet delivers 5V above the 24V battery voltage, as you mentioned above. I guess I just have to keep searching to find one that also delivers a high enough current (just started).

8

Found another one with 240W, Vmp 34.32V , Imp 7.43A at 131 x 99cm. Would that be sufficient current?

9

It think it will!

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10

Thanks, I ordered all the parts.

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