Replacing generator with tesla batteries – the hull truth – boating and fishing forum f gas regulations 2015


How many cycles can it run at 50% discharge? How many can it run at a more than likely discharge rate of 80ish %? This Tesla battery stuff is pure fantasy at this point…especially for a house.Not fantasy, but also not a panacea. LiPo or LiFeMn chemistry batteries can run thousands of cycles when limited to 80% discharge and properly managed through a BMS. Telsa’s cars, for example only charge to 90% of full charge and discharge to 10%, allowing for use of 80% of the full storage capacity of the battery. This has proven effective in keeping the batteries operating at or close to full capacity for thousands of cycles vs. 500-800 for a Lead Acid system.

The concept of in house battery storage in a house is not to completely displace conventional generation (unless you are intentionally trying to go off grid, which is very expensive), rather it is to supplement the grid by allowing renewables to produce during the day when generally the wind is blowing and sun is shining, and reduce the net capacity of conventional generation resources required to augment the grid for reliability purposes. Energy storage devices help support higher amounts (as a % of total generation) of renewables without requiring huge investments in new gas fired peakers.

….really, now Gerg… we all know that there are probably _lots_ of caveats that Tesla would place on this uninformed application of their batteries. I’d expect that chief among them would be operating temperature. Without duplicating my initial read, I recall that the upper limit is 110F. That’s the upper limit of operating temp that can be sustained by whatever cooling system you have in place.OK – I’ve been thinking about this and partially recant. The "operating" T range is to 110F. In the fluff specs available from Tesla, nothing further is said about whether this is charge/discharge/storage. This would inform installation location (most likely _not_ in an engine compartment), but there might be some flex depending on use (e.g., if using for A/C at night for dehumidification, the ambient in the location of the battery would likely be lower than 110F).

Regarding inverters, the inverter requirements will be mostly determined by input voltage and output load. The fluff specs on seemed to indicate that the DC output was at a very high voltage. This will limit inverter options, even at the relatively low load one might expect when considering a modest cruiser powering A/C, a fridge, and a small entertainment system (for a few hours).

Then again, there’s the question of exposure to a humid, salty environment (fog carries salt). I’ve done a bit of aftermarket coating to harden electronics in a salt environment, but this has been for stuff I’d done DOA testing on before coating. I’d definitely want Tesla to agree to warrant these batteries for a marine app.

A quick note, as I realised after re reading the original post, you are talking more power boat. a lot of what you are asking can happen without drastically changing your electrical system, by really looking at what sailboats are doing, or the cruisers and RVers that want to anchore out or gunkhole somewhere for longer periods of time.

my biggest cost savings to date was switching to all LED lights. now with every light on the boat on, I am using less than one of the original halagen 10w bullbs, in fact the needle barely moves. there is a thing to be said for higher voltage. i switched to 24v and have noticed big changes in efficiency and power when charging and for all loads. even original equipment that was already 12v or 24v, uses less power now at 24v.

the next big power suck is refridgeration. I havent replaced mine yet. its an icebox conversion from the PO, and the insulation is old or non existant. the freezer is essentially the same coil as in a dorm fridge, it ices up quick and not very usable. I did change the control box for a newer more efficient one that accepts 24v DC or 12vAC, and that did help. at some point I will have to tear the box and my galley apart to replace insulation and rebuild the fridge. reading up and research has found that this is a major upgrade and drasticly cuts your power requirements.

either way you will need to go through your whole boat and figure out what your power requirements are for 24hours, so you can figure out how big a battery bank you need. In florida with a decent size solar system, reducing your power usage for other items and a big enough bank you could theoretically run your a/c longer, without a generator and minimal impact from charging using your engine. the bulk charge would have to be from shore power, and depending on battery bank size maybe a weekend of higher A/C use.