Servus, I would like to replace the lead acid battery under the passenger seat with a lithium battery. The following situation: During the ride, start and second batteries are charged in parallel. Separated from a simple separation relay, so that the first battery is not discharged from the second battery in the stand. When camping with mains power supply I have a Fraron charger (20A, two charging outputs). The original Westfalia charger has said goodbye before longer. the LiMa with max 90A and 13,8 – 14,5V, depending on what is running on the side. And the Fraron charger charges with 14.4V, max 20A. Both voltages are too high for a LiFePO4 battery. Now I have only found charging booster with solar function etc for 150€+ and am not even sure if this is the right thing for me. Therefore I wanted to ask if there is simply a voltage converter or something that is hanging directly in front of the second battery and which regulates the charging voltage to 13.2V ( On the battery is 13.2V Normarlspannung). I hope there is a relatively simple solution. Thank you!