Gen 1 battery charge rate increase

I am wondering how I could increase the charge rate on a Gen 1 inverter/battery. I am upgrading to have 1 x8kWh and 2 x 5kWh batteries but the maximum rate is 2600w. Which I think would require circa 7 hours to charge the batteries from empty to full.
I have a 3 hour window at a highly reduced rate which will only allow for around 7.8kWh.
Someone recommended me to use something like the following but would this work with GIVenergy batteries?
Any other options?
https://www.aliexpress.com/item/1005003755306962.html?spm=a2g0o.order_list.order_list_main.43.59641802Dfdob4

bignelly The limiting factor on your charge rate is your inverter. The Gen 1 inverter is limited to 2.6kW charge and discharge rate. The only practical way you can increase this is to change the inverter for a Gen 2 or Gen 3 which have a 3.6kW rate, but at about £1000 for a new inverter its not a cheap option.

A number of people have reported that the batteries slow down their charging if the internal cell temperature is less than 20 degrees, particularly so on the latest BMS firmware 3017. A heater such as the link you supplied may prevent this from happening if it can keep the battery cell temperature high enough, but you’d probably need one heater per battery and a 48V power supply for it all. I know some people have tried insulating their batteries but haven’t heard of anyone using a heater like this.

bignelly Have you considered getting AC coupled batteries rather than putting more behind the hybrid inverter? Not sure of costs with this route compared to additional batteries (although GE are doing half price inverters with low-valtage batteries at the moment) is, bit worth a thought

Have a Gen 1 and 5.2 battery. This morning happily charged at 2.4kW or so from cold at 6 Deg C before warming to 12 Deg C