diy solar

diy solar

Buck converter

san8ra

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Nov 17, 2021
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I have a 495W solar panel that has an open circuit voltage (Voc) of 45,46V and max power voltage (Vmp) of 38.17V , with short circuit current (Isc) of 13.86A and max power current (Imp) of 12.97 and I would like to connect it to a MPPT with Max. Solar Input Voltage of 25V. Can you please advise which dc-dc buck converter I need .
 
Do yourself a favour and invest in a quality SCC.

If your current SCC will only accept 25V, it is highly unlikely that it will use MOST of the power from your nice big panel:

495W / 12.8V battery can produce 38.6A charging. Does your SCC charge at that rate?

If you can afford a little more and need everything from your big panel, get a 40A or larger SCC.

How much power do you want/need from your panel? Any usage details might be helpful to anybody making further recommendations.
 
Thanks for coming back.
i have already invested into Renogy's DC to DC MPPT on-board Battery Charger that can charge with 50A. And am hoping for a quick solution that is comparable with both complements ( solar panel and MpTT)
 
DC to DC MPPT and solar charge controller MPPT are two different things
 
DC to DC MPPT and solar charge controller MPPT are two different things
This is the unit in question.
Its a dual function mppt solar charge controller and battery to battery charger.
It's 3rd bonus function is causing pain in the back of the pants.
 
This is the unit in question.
Its a dual function mppt solar charge controller and battery to battery charger.
It's 3rd bonus function is causing pain in the back of the pants.
Thanks for the link! This dual function charger will be ok
 
This is the unit in question.
Its a dual function mppt solar charge controller and battery to battery charger.
It's 3rd bonus function is causing pain in the back of the pants.
Yes that is the one. So is there any way I can keep my solar panel and this charger?
 
Yes that is the one. So is there any way I can keep my solar panel and this charger?
Yes but you REALLY need a different SCC. Your panel can provide about 38A of charging power so get an SCC that can use as much of that as you need.

Your DC-DC charger can still function as a dedicated alternator powered charger. I think it’s fairly respectable in that capacity (it really falls down as an SCC).

If you have a budget or other constraints (space, want Bluetooth…), make them known so folks can suggest appropriate SCCs.
 
Last edited:
Yes but you REALLY need a different SCC. Your panel can provide about 38A of charging power so get an SCC that can use as much of that as you need.

Your DC-DC charger can still function as a dedicated alternator powered charger. I think it’s fairly respectable in that capacity (it really falls down as an SCC).

If you have a budget or other constraints (space, want Bluetooth…), make them known so folks can suggest appropriate SCCs.
Thank you very much.

I have lifepo4 280ah ( that i have build from four 3,2v cells) connected to a 12v system.
Bluetooth is not essential, but space is (not much space left in the van)
Would really appreciate suggestions on SCC
 
6C7BC924-60A7-43BC-8FCC-0C2C88D4D270.jpegThank you very much.

I have lifepo4 280ah ( that i have build from four 3,2v cells) connected to a 12v system.
Bluetooth is not essential, but space is (not much space left in the van)
Would really appreciate suggestions on SCC
This is my solar panel
 
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