Adding more batteries away from main battery

Mojn

We got 300Ah battery (LiFePO4 from Roamer) in our motorhome and we are finding that are struggling a bit. So therefore would like more power. Though the location is not big enough to add a bigger or more batteries next to the original battery.

We got ample of space elsewhere in the motorhome, about 3-4m cable run away. Would adding 2 more batteries in parallel, be a problem at distance so to speak?

Sadly Roamer do no make the 300Ah battery anymore so we can’t add like for like. But Roamer said that by using a Vittron SmartShunt, there shouldn’t be an issue with adding a different size to the system.

We are looking at the FogStar Drift ECO 628Ah (two of them cost just about £200 than the one 300Ah did a few years ago:) )

Thanks for your inputs.
woollypigs