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48V battery charging w/ 48V bank - DC converter, or...

almagron

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Mar 30, 2022
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I'm devising an in-vehicle solar charging hub to charge individual 48V batteries. A 48V-48V DC-DC charger would be the ideal way to do this... but I'm not having much success finding a suitable one. Has anyone else been down this road?

Alternatively, is there any reason I couldn't instead use an MPPT solar charge controller for this purpose?
 
I believe that a 48v MPPT would require a higher voltage input, than a 48v battery puts out.
 
I believe that a 48v MPPT would require a higher voltage input, than a 48v battery puts out.
Thanks, yes, the MPPT would like a higher voltage input for optimal power point tracking. For this situation though, I'm wondering if that matters?
 
I believe that the input is required to be at least 5% voltage higher than the battery output. This might work, if the input battery is fully charged. But, this will change, as charging proceeds.
 
I've heard that the PV input must be 5 volts higher than the battery voltage before the MPPT will begin charging. Once the charge has started, the 5 volt requirement is reduced.

In general, an MPPT does not work well as a DC-DC charger when both sides are batteries of the same/similar voltage.
 
Sounds like MPPT is a dud for this idea, I appreciate the feedback.

I looked at those 48V Victron Orion converters but they're not intended for battery charging, and Victron's "smart" Orion charger line only goes up to 24V (no 48V unit).

So the hunt continues...
 
This is AC to DC charger if I'm reading the specs correctly. You'll have quite a loss in converting DC from input battery to AC and then back to DC.

Victron has a 48V Orion-Tr DC-DC Converter that is designed for that purpose. But the highest power model can only drive 8A of current.

ISDT has the CM1620, an industrial DC to DC charger. A single device is rated at 20A, but these can be wired in parallel. I have no idea about the price here.

PS: Googled the price for the CM1620 and it is ~150 USD in Aliexpress. More than acceptable for such device. I would check the documentation to see how these can be paralleled if higher than 20A current is needed.

BTW the ISDT chargers are pretty good. At least the Nano Q6 that I used for top balancing my LiFePo4 cells.
 
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