We have 1993 Grand Marquis Beaver with drives like a dream except for the voltgage coming off the altenator, no load around 12.5v, overhead panel shows 12.2v for coach with +12 amps and 13.2v with + 6 amp on chassis batteries. As soon as you start loading the altenator up, AC fan, head lights etc, the volt meter continues to drop below 12v. Just put on the secong new altenator in two years (160 amp), replaced both chassis batteries, ( one had a bad cell) found a frayed wire shorting against the engine block. But still have same issue. As a side note,the inverter voltage is only reading 105V with the engine running, with shore power or generator operating, it reflects the ac line voltage. We have had the Coach for almost four years and are still learning, do I have an invertor that is sucking all the power from the altenator or is it something else? Thanks for your help Rick Mayer 605-321-0966