Hi there, my System has a large 60V LiIon battery bank but I want to convert this to 24, 12 and 5 Volts for meaningful use in the home. For that I install a 24V Lead Acid buffer battery (mandatory) and I want to charge it from the 60V bank without using 230V.
Using this voltages, Victron offers only DC Converters, no chargers. So can I use a MPPT Charger for that? Or will there be a 48 to 24V charger in the foreseeable future?
Other suggestions? Thank you!
No, you can't. The MPPT will in some situations just short the PV terminals. No problem with solar panels, they can't exceed the max amps they can provide, and you need to remain within the controller specs.
But without a PV, and a battery bank instead, nothing is preventing the 60V pack to (try) to provide full current to the PV terminals, thus overloading the MPPT and destroying it. You need to apply some kind of current limiting so even in case of a short, it won't exceed the max rating of the MPPT.
Also keep in mind the 60V is probably the nominal voltage, and may be more like 70V when fully charged..
You might consider a 72V to 12V converter:
https://daygreen.com/collections/48v-60v-72v-to-12v-13-8v/products/48v-60v-72v-to-12v-30a-360w-dc-dc-step-down-converter-voltage-regulator-w-acc-swtich
And connect a Orion TR Smart 12-24/15 to it.
That would 'build' you a 24V 15A charger with the proper charge profiles for your lead battery bank.
Another option is https://daygreen.com/products/72v-to-24v-40a-960w-dc-dc-step-up-converter-voltage-regulator which allows you to run 2x Orion 24-24/17 in parallel providing you 24V / 34A charge capacity.
