Lithium 12v to 24v Step up converter

[Sailbrandison]

I am wondering if anyone has any advice on what is a good, QUALITY, reliable step-up converter for converter TWO 12volt lithium battery power banks into one 24volt power feed. I need to go from two 12 volt lithium banks (that CANNOT BE wired in a series) to 24 volts into a Schneider Inverter/Charger. This would be easy if I could go in a series, but I need to step up the voltage. I can wire all the batteries in parallel or create two 12v banks with a relay or step up....Here's the complex part. I need it to be 350-400amps capacity for safety. Any tips?

[john61ct]

Such a device designed for marine use would likely cost almost as much as replacing the inverter, or maybe even the LFP packs.

Could you link to what batteries you bought, that "can't" be put in series?

Otherwise, I would contact Victron and see which of their converter lines can be put in parallel to handle that size current.