What is an ADM battery? For the majority of passagemakers the weight of batteries is inconsiquential. The weight can be distributed down low--I have voyaged many thousands of miles in a vessel which had a box keel--over 3 feet wide--where the batteries were down in the keel (precautions were taken to prevent sea water from getting to them)--and acted as ballast. When running the main engine, generation capacity is not an issue; but at anchor, which is the majority of time, even in most passagemakers, running a large gen set several hours a day can accomplish all of the chores necessary. These include running a compressor to pull holding plates down, a water maker, water heating, and generation of DC power (it does not make much difference if it is from an alternator on the genset, or battery chargers--we used a combination of 150 amp alternator and 130 amp battery charger. However, it seems like many modern passagemakers need the luxary of air conditioning. Although there are air conditioning units which can run on DC power, and perhaps more effecient units using chilled water, it still remains a problem to provide adequate airconditioning. (We voyaged in motor sailors, and never required air conditioning in any parts of the world--as long as there was a breeze) Many power passagemakers do not have adequate ventillation. An example of this problem was the Nordhavn 40 around the world. As I recollect, the original plan was no generator and minimal AC off the inverter--but reality set in, and the Generator had 2776 hours compared to the mains 4697 hours. Unfortunately I cannot pull up on the Nordhavn site the comments or forum about the air conditioner (only the later material was available). Bob Austin

>Bob Austin wrote: What is an ADM battery? For the majority of passagemakers the weight of batteries is inconsiquential. REPLY Hi bob, that remark by me was addressed to power cats where weight becomes more of a factor. I admit that a full displacement hull is not going to be especially sensitive, unless of course the placement is not convenient in terms of proximity to generation equipment or inverters. Long cables for low voltage DC is simply an invitation to excessive losses. Bob wrote: The weight can be distributed down low-- <snip>--and acted as ballast. REPLY I guess its relative. Where do you place your 2000 pounds of house bank on your power cat? < VBG> Ballast on a power cat? How much is used and where placed? Bob wrote: > However, it seems like many modern passagemakers need the luxury of air conditioning. Although there are air conditioning units which can run on DC power, and perhaps more efficient units using chilled water, it still remains a problem to provide adequate air conditioning. > Bob Austin REPLY Now you hit the nail on the head! This is indeed one of the biggest stumbling blocks to providing adequate electrical power on board. People like Steve Dashew have posted a number of articles on how they avoid the need for constant A/C. However we do not see too many designs that incorporate his excellent ideas. From various discussions I get the feeling that in most cases it is the wife that insist on A/C throughout th eboat. I have also been told that the Dashew boat was considered somewhat minimalist and that the person's wife would not put up with such a setup. This sounds more like a speculative opinion rather than one based on past experience. In most cases, the energy budget for a design reveals the A/C is more than half and sometimes more than 3/4 of the total energy requirement. Eliminate that and you can reduce the total cost of the electrical system by huge factor. Arild

Has anyone had the opportunity to compare a holding plate freezer to a conventional freezer system in terms of energy consumption over a 24 hour period? Arild