IanD

We've got a walk-through bathroom with doors on both sides between saloon and bedroom which is an even better solution and gives more bathroom space, I'm surprised they didn't do that... 😉 (needed for us anyway since the sofabed in the saloon is where guests sleep, so two bathroom doors are essential...)

So that the early bird can sleep more quietly with the door closed while the night owl is watching TV or listening to music/radio in the saloon -- and the reverse in the morning?

What distinguishes them (and BYD, and maybe some other true "pro" vendors) is that they don't use MOSFET switches in the batteries -- which are cheap but don't like high currents -- they use expensive contactors (a 500A one from a reputable supplier is typically £175) controlled by the BMS -- or in Victron's case built-in to the Lynx Smart BMS (about £800 for the 500A one). Once you have that, how the charging decisions are made is just down to the software/firmware, which is some cases (e.g. Victron) can be remotely upgraded as improvements are made. The key is to have the BMS being the boss of the system which can start/stop charging from all sources (shore/solar/alternator/genny), usually by changing CVL and CCL (Charge Voltage Limit and Charge Current Limit) and turning MPPTs off -- here's an example for the last couple of days, including a balancing/SoC reset charge.

Which is why if you want high currents you either use multiple drop-in battery/BMS in parallel (e.g. 3 x 200A) or a contactor-based solution like REC-BMS/Victron NG... Making parallel/networked BMS synchronise and work together reliably is not a trivial job, "proper" suppliers like BYD/Victron will have invested a lot of time/effort/money into making this work because they're targeting large-scale systems like off-grid housing/industrial backup -- and the issue is not just getting it to work, it's making it fault-tolerant so one component failure doesn't bring the entire system down. It's possible that small companies like Seplos and JK could do this but I also doubt that they have the resources/knowledge to do this, and they're probably not going to spend enough to do it properly either because they're selling cheap (~$100) BMS not expensive (~$10k) LFP battery systems...

Fogstar drop-ins are certainly much quicker and easier than DIY, and probably not much more expensive. So long as you don't push the current rating close to 100% -- it's never a good idea! -- and have enough in parallel to easily deal with the maximum load, there's no reason they should be unreliable. I can believe small cheap RV LFPs with possibly low-quality BMS could be unreliable and die after a few years of heavy use, but there's no reason to think a properly specced boat system will do the same.

There are quite a few boats from the bigger hire companies which also have solid fuel stoves, but these tend to be in the most expensive "luxury" boats. For two people this is a nice boat: https://www.anglowelsh.co.uk/admiral-2-class-narrow-boats/

Or use a BMS which doesn't have MOSFET switches but drives a contactor -- for example REC-BMS or Victron NG, or build your DIY system the same way... 😉

True. They are also generally a bit cheaper than the high-end "luxury" narrowboats from the bigger operators, possibly because the purchase cost is being met by the sponsors rather than the hire company.

That works for a single series string of cells, it doesn't work when there are cells in parallel since they all share the same voltage -- if one has a higher resistance connection then it will source or sink less current than the others in parallel and the connection may heat up, but the voltage won't change significantly because LFP cells have very low series resistance. A good BMS which also measures cell internal resistance may be able to spot the problem (depending how many cells are in parallel), but most won't. The best solution is to not use parallel cells, but for boats this means using ultra-high-capacity cells which most don't do. If you do have parallel cells but only one BMS (usual case) then the cells should be connected directly in parallel at each stage, not in separate strings only linked at the end, and the BMS should monitor the voltage across each member of the series set of parallel cells.

I just checked the data sheet for my Winston 700Ah cells, there are two terminals for each (tapped posts) with 45-50nm recommended bolt torque, so I don't think connection resistance or heating is likely to be a problem. But then they are rated at 3C continuous which is 2100A... 😉

Do bear in mind that buying a boat like the Aqua ones isn't going to be cheap, they're currently about £170k new, but they do give a better idea of how you might live on a well-cared-for liveaboard boat than many hire boats do -- though boats affordable to buy are unlikely to be as expensively fitted out or in such good condition... 😉 Also their boats are deservedly popular, there are only 3 for hire at the moment, cost is around £2k per week, and they're mostly booked up until the end of September... 😉 https://www.aquanarrowboats.co.uk/narrowboat-hire/#prices

Fogstar have a temperature sensor on the terminal to flag poor/hot connections (reading 45C) as well as the normal one inside the battery (reading 27C). Having seen the damage that can be caused by a high-resistance connection in a high-current path -- gets hot, oxidises more, increases resistance, gets hotter, melts insulation and then starts to emit smoke -- I think this is a good idea... 😉

If you want to get a better idea of what living aboard might be like, I would suggest hiring a boat that is fitted out more like a decent liveaboard boat built for an owner than a typical hire one. The boats from Aqua Narrowboats (Barton Turns marina, Trent & Mersey) spring to mind, because these actually *are* built for owners on a sponsorship model, they're hired out/maintained for 5 years (with income for the owners) and then become their full-time boat. As a consequence they're extremely well built -- we've hired many boats over the years from many hire companies (including Shire and all the other top-rated ones) and the boat we hired from them was undoubtedly the best, and I actually considered going down the sponsorship route with them before deciding to get a boat built from scratch. [for clarification -- I've no link to Aqua, except as a satisfied hirer] Not the location you were looking for, but then West Yorkshire is rather a problem at the moment -- and has been for the last couple of years -- due to unplanned stoppages. Also the canals there are undoubtedly some of the most beautiful in the country with some fantastic towns and pubs, but are hard work for beginners/small crews due to the large number of locks and poor maintenance. I'm sure others can come up with similar "liveaboard-like" boat suggestions from other hire bases... 😉

And now the costs for a 5G Huawei-based solution, including 2 4x4 MIMO antennae (to cover 4G and 5G) with decent gain... <drum roll> ... 😉

I've said many times that the SIM socket is a known weakness of the NR5103E -- and yes, some people have had problems, but also many haven't -- and you only ever hear about the few who have a problem, not the many who didn't, I know the source I bought mine from sold hundreds of them with few returns, but then they also tested them before despatching them. Apart from this negative point it's a pretty good router, especially for 4G/5G 4x4 MIMO use with *one* external antenna... 😉 If you don't like the NR5103E SIM slot, buy something else instead e.g. Huawei. If you don't want a locked router, pay more for an unlocked one. If you want a robust unlocked router which doesn't need hacking, works with one antenna, and has two robust SIM slots, pay 3x as much and get a Teltonika. As usual, there's no perfect and cheap solution, you pays yer money and you takes yer choice... 🙂

None of the NR5103E are new, unlocked secondhand ones are a quarter the price of new ones, as are plenty of unlocked alternatives. If you want to save a few quid buying a cheap locked router, I don't see how you can then complain because it's locked -- if you want unlocked, pay a bit more... 😉

Just because the name starts with Three_ doesn't mean it's locked, the name and lock status are not related (name can usually be changed). If Vodafone are still locking routers then they're going against the trend, Three haven't done for some time now -- how old is your Huawei? Of course anyone buying a secondhand router should check whether it's locked or not -- but most aren't. Doesn't stop people selling "unlocked NR5103E" for more money though, even though they're just the same as all the cheaper ones which don't specifically state this. Sometimes the same vendor sells both, which is basically a tax on the uneducated... 😉

Good news that existing SIMs will work across both networks -- it'll be interesting to see how much better coverage the combined network has... 🙂 Are you sure about the locked routers? AFAIK all the 3 ones (e.g. NR5103E) are unlocked as are the EE versions -- don't know about Vodafone but I'd be surprised if they're any different.