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Mikael avatar image
Mikael asked

Charging a 12v battery from 48v system

I have a 48v system and what to charge a 12v removable battery. But don’t seem to exist an Orion DC-DC Charger 48 to 12v. Any tips on how to accomplish this?


I was thinking if it would be possible to just buy a small MPPT like 75/10 and feed 48v as PV in and the charge the 12v battery through that.



Or should I buy an Orion DC-DC Charger 12/12 and connect it to my existing Orion DC-DC Converters output of 12v



I would rather not use the Multiplus for charging the 12v battery as we usually turn it of when we are not there.



PV 3500w

SmartSolar 250/100

VenusGX

Multiplus II 3000 35-32

2 x Pylontech US2000

2 x Orion DC-DC Converter 48-12/9A




battery charging
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3 Answers
safiery avatar image
safiery answered ·

We install a similar setup with MultiplusII , Dyness Lithium on CANbus to Venus, Smart Solar and Orion 48/12 units to a 12v buffer battery. We choose a small 40-60A Lithium stand-alone. We select the Orion size to match 90-95% of the maximum 12v load if all devices like LED and fridge and water pump were all on. Then we set the Orion Output voltage to keep the lithium at 40-70% SOC which is around 13V. This SOC is perfect for long Capacity storage life of the Lithium. we have several systems installed like this without any difficulty.

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Mikael avatar image Mikael commented ·

@safiery So if I understand you correct you have the 12v battery on the same Orion as your 12v loads as buffer? Ang you just hang the battery on after the Orion with adjusted voltage in parallell with the load?

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luckybeanz avatar image luckybeanz commented ·

Are both banks connected to the Venus via CANbus and can the Venus distinguish between the two or is it just the dyness? How do you then monitor the 12v?

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thtruck avatar image
thtruck answered ·

I charge a 80ah battery with a smart solar MPPT 75/10 with power from a 24 volt battery bank. Works flawless.

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Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

I think using a small MPPT would be the easiest solution and should work.

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luckybeanz avatar image luckybeanz commented ·

I agree, but there is a lot of talk on these forums and in the MPPT FAQ section about not doing this.

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