Battery power in Bareboat Charter boats

[Mithril Bham]

Originally Posted by kas_1611

400amp/hrs on a charter boat Christ that seem ridiculously high. Given we manage 2 days on anchor witg the fridge running on a single 135amp/hr battery.

Depends on the boat. You have an efficient fridge.

[Cadence]

Maybe I am wrong? The charter co, has no vested interest, Someone has been sold a bill of goods about owning the boat after X no. of years. There ain't no free lunches.

[Reefmagnet]

Flat batteries aren't as common as you think. If a charterer can't get their boat started the charter company needs to send out the service team to give them a jump start. It might be region dependent to an extent, but around my way most "actual" problems occur with broken alternators, mounts, fan belts, tripped breakers or simply getting the battery switches wrong. There are those, however, that like to party most of the night with the fridge open and lights blazing like the Titanic. They tend to wake up next morning to flat batteries. Fortunately they're in the minority.

[Rapanui]

Our boat was in charter until a few days ago, and as an owner and user, I recognise many of the problems identified. We wanted to fit solar from the start of ownership but were dissuaded by the company on the grounds of complexity (for them) and possibilty of physical damage to the panels. They were also not keen on additional complexity in the charging system, first diagnosing problems and then the supply chain to repair or replace defective bits. You have to realise that there is a very extensive supply chain required to service huge numbers of charter boats. Virtually any defect or damage can be and has to be fixed in less than 12 hours.
Having said that, our house bank is 3 off 110 Ah sealed leisure batterries, and that lasted 4 years despite the use and abuse of intensive chartering 6 months of the year, which I think is pretty good going. That set up allowed us to stay at anchor for up to 2 days with fridge, lights etc without goung below 50%. I would suggest that the OP has either a fridge, battery or useage problen if his much larger battery bank could not cope.
Over the last few days, we have fitted 480W of solar, the new Outback FM 40 controller and replaced the batteries again with sealed leisure batteries. I know these are certainly not the best battery technology or capacity, but we needed sealed and was not prepared to fit AGM based on MainSails excellent website. It will be interesting to see how long they last.
As I write this in Croatia at 0730, the sun is about 10 degrees altitude and over 6A is going into the batteries, making a lot of hard work worthwhile!

[Gamechanger]

Originally Posted by kas_1611

400amp/hrs on a charter boat Christ that seem ridiculously high. Given we manage 2 days on anchor witg the fridge running on a single 135amp/hr battery.

Since most reasonable efficiency decent sized fridges consume at least 3-4 amps per hour (most consume much more than that), that's 72-96 AH per day. With a 135 Ah capacity house bank you're already used more than 50% capacity after only one day!! I can only assume that you accept a battery lifespan of only 1-3 years versus a lifespan of 10 years if you treat your battery bank reasonably well.

[kas_1611]

Originally Posted by Gamechanger

Since most reasonable efficiency decent sized fridges consume at least 3-4 amps per hour (most consume much more than that), that's 72-96 AH per day. With a 135 Ah capacity house bank you're already used more than 50% capacity after only one day!! I can only assume that you accept a battery lifespan of only 1-3 years versus a lifespan of 10 years if you treat your battery bank reasonably well.

72 watts over 12v gives 6 amps so yes if the fridge is running continuously it would drain 144amps from the battery over 24hrs. But with extra insulation fitted it runs for 10mins per hour to maintain temps between 0-8ºC which means our fridge only draws 24amps over a day.

As it is our house battery is now 3 years old and still happily holding full charge. We leave a 35w solar panel hooked up to trickle charge when away and have 2x35w panels for when onboard to add in extra amps.