Are you the type of American RV owner who uses large camp sites that supply a 16 amp hook up? If you this is you, then inverters and efficient chargers are not what you need. On the other hand if you are one of the American motorhome owners who travel to places where there is no electric hook up, then a good inverter charger (combi unit) could be very useful.
For one of our customers LAS had to fit a 3kw inverter to its maximum, in order for the customer to be able to use as much 12 volt power as possible.
As with many things they all fringe on a budget. This case study will try and explain to you what can be done, ignoring to some extent a budget and concentrating on the customers needs.
First of all AGM batteries are used because they maintain their usable voltage for longer, although they do need to be charged at a higher rate. American motorhomes will charge their leisure batteries when travelling by using some of the alternator output. AGM batteries need to be charged at 15 volts, with an alternator only delivering 14.2 volts. An A to B charger was used to increase the alternator voltage going to the leisure batteries. A combi charger was wired into the 230 volt side of the RV to power TV’s etc. This combi unit was used for two reasons, the first was to charge the batteries at the correct voltage and also monitor them. The second reason was that if only a limited amount of ampage was available from a landline, then the inverter could supply the extra by using the large capacity stored in the batteries. This power could then be replaced by the battery charger when the large demand was not required, or the generator was used.
So to recap the motorhome had 1000 amps of 12 volt power, a 3kw inverter to supply the 230 volt system, and a computerised charging system to keep the batteries at their optimum. The technicians at LAS also fitted an A to B charger which allows the alternator to charge the AGM batteries at the correct voltage.