cheesegas

Yep, the manual references 'van roof' a few times, I suspect the motorhome market is much bigger than boats too. To be honest I like the idea of venting the exhaust outside as it'll cut down on moisture in the air in winter, and keep the boat cooler in summer, but without a big bit of trunking dividing the galley I can't see it being possible. The drawing on page 4 appears to show the vent going through a wooden countertop. Thanks for the advice all, come to the conclusion it's ok to vent to the inside with a short piece of flue pipe, especially because it's just over 1kw - a lower output than the many conventional 50 litre ovens which don't have an external flue. The Thetford 420 oven I also linked to is designed to be built in too, but it doesn't have an external flue and the instructions specifically say the enclosure it's in needs to be sealed apart from a hole at the bottom. I suspect the exhaust comes out the front via the holes above the controls, and there's no exhaust vented out the back.

Fully aware of how airflow works...thank you. Some ovens take the air from below and need ventilation behind, like the Thetford. This Dometic however appears to take the air from the grating on the front, so the only reason you need to give clearance behind is to prevent heat build up rather than for air intake.

I think @MtB is correct, referring to domestic as in domestic vs commercial. The gas regs say that anything over 7kw needs to have a flue - anything that powerful will be a commercial oven. I've linked to the instructions in my post, 2nd paragraph, 2nd sentence. Let me know if it's not working for you and I'll screenshot the pages. It says that needs to have a certain clearance around the oven when installed, but it doesn't mention air intake oddly, just the exhaust.

Let's do some maths... Data from my system from 1st Nov 2024 to today is 90kwh consumption, 36kwh solar. 55kwh deficit which was made up by engine/generator - if that were to be stored in a battery, that's 4200Ah at 13v! This also doesn't include the energy you'd need to get through this month. Ten 560ah Fogstars would be £13,000. Quite a lot of money; that would buy around 8 years of 4 month winter stays in a marina with shore power. (I can't use the data from 2023-2024 because I was out the country for work for a lot of winter and the boat was sat empty in a marina!)

Very loose rule of thumb is that if you live aboard year round without shore power and have a fridge, you'll want as much solar as you can fit on the roof. It still won't be enough in winter. You can get away with less if you have a different use case. eg in a marina on shore power for most of the year, going on cruises in summer, moving every other day.

Hi all. I'm finally getting round to replacing the bit of my kitchen with the hob/oven/fridge in it. Decided on a new hob and fridge, but a built in oven is proving tricky. The Dometic OG2000 looks good - nice and small, built in, 12v light and ignition, designed for mobile use. However, looking through the manual, it's got a flue which needs ducting. Page 4 seems to show it going through a wooden counter top, but page 31 mentions that it should go out through the roof. The part number on page 4 for the cowl is one made for external use. I'd rather not make another hole in the roof though. Is this due to a new regulation, or simply a good feature to reduce condensation in the boat? Similar ovens like a Thetford 420 don't have this, despite having a similar power output. I've emailed Midland, who said to contact Dometic but they aren't getting back to me. I can't find any new boat related regs saying that ovens need a flue, and it's below the 7kw rating for which domestic gas things need a flue.

Indeed, there's a lot of people who have done the certificates and wave them around! The BMET is the worst offender for this, I see people touting this qualification like it's difficult to get and worth something, when in reality anyone who's done a bit of boat electrical DIY can pass it. I don't see what the greater risk to the insurance company is though? Increased value of the boat perhaps? If I were an insurance company, I'd charge a higher premium for having an e-scooter/bike charged on board, as they have a pretty bad track record of safety, unlike an LFP leisure battery.

That's exactly my point. There is currently no qualification which defines what a capable person is in the eyes of insurance companies etc. Personally, I'd define it as someone who installs according to the Small Boats ISO and BSS, and has had product-specific (eg. Victron) training if needed. Even still, the ISO isn't all encompassing on best practices, which have to be learned elsewhere.

That's not what we're saying. There are lots of people who are capable of fitting a lithium battery system to your boat, that's no problem. However, there is no qualification to prove to your insurers on paper that the person is capable of doing it in a safe manner. As I mentioned earlier, the British Marine Electrical Technician qualification is a very basic 2 day affair which is impossible to fail, and doesn't cover lithium batteries at all. It's just a formality which you need to have in order to get liability insurance so you can do electrical work on boats.

Indeed, but someone who has the knowledge to repurpose an NMC vehicle battery will also know about its chemistry - these batteries aren't an easy swap like an LFP with a built in BMS. There's data lines to connect up, protocols to translate, a lot of very in depth bespoke work to get it to be usable in a boat. It's well beyond the realms of your average boat DIYer, it needs a good chunk of electronics and IT knowledge. I agree that there should be a check in the BSS to ensure that they're LFP, but I'm yet to see a non-LFP fitted to a boat. The exception at the moment seems to be the larger power banks, most of which have LFP cells inside but some of the medium sized ones have NMC.

Here's my usual spiel when this sort of thing is posted - EVs use NMC or or NCO li-ion batteries, very different to LFPs used in boats. It's not really relevant to this discussion. I can't be bothered to copy and paste my usual sources, there's plenty of info online.

It all depends on what you use it for. For example, I upgrade my laptop every 3 years or so as I do a lot of CAD rendering for work so a more powerful machine = quicker workflow, and since it comes everywhere with me it tends to lead quite a hard life. I agree that some people buy the newest stuff for look and feel or image, but that's not always the case. Likewise, I have a remote monitoring system on my boat. It's useful to turn the diesel heater on if it's -1 outside and I've been away for long enough for the stove to go out. And knowing the battery % from 30 miles away is useful; I can tell if it's been a good couple of winter days with solar, so I might not need to rush home at the end of the week to start the generator/engine. If it's been a good week on solar I might plan to do something else that evening.

Sorry, I was unclear. The BMET is a qualification for electricians who want to work on boats, it's needed so the electrician can get PLI in order to work on boats. Incidentally, it doesn't mention lithium at all.

The problem is that there's no decent universal qualification for boat electrics. There's the BMET one, which is pretty useless as it includes very little info and only lasts two days; the sort of course you can't fail, and is done purely so you can get PLI. All depends on how you use the boat. For someone who's on shore power most of the time, maybe doesn't live aboard, has a decent bit of solar and only goes on cruises in summer, moving every other day, there's not many benefits to lithium. However, for someone who lives aboard year round, doesn't have shore power and moves maybe once a week, there's much more benefits. The main one is faster charging; lead needs a long period of constant voltage, low current charging to get from ~80% to full. Lithium will charge at high current, taking all the power the source can supply, right up until 98%. Fast charging is important if you're using a portable generator or the engine to charge, like in winter. That means you can take 60ah out of a 100ah lithium battery and it'll take just over an hour to recharge with a 60a charger. Lead would take probably take four times that. The other good thing is that lithium can be left at a partial state of charge indefinitely with no damage; this would soon sulphate a lead battery and kill it. My 560ah litihium has only been up to 100% a couple of times since October! You can also discharge it deeply again and again with no ill effects. Taking a lead acid down to 20% repeatedly and not recharging for a few days would kill it, but not so with lithium. As they can accept high current right up until they're almost full, solar yields are higher in winter - a burst of sunshine can be fully utilised if the battery is at say 80%, rather than simply taking the voltage up to CV point as would happen with lead.

Being a little pedantic here, but that's what insurance companies etc tend to catch you on - it's perfectly fine to charge a lithium direct from the alternator. The difference is that you shouldn't do it with a standard alternator with an internal regulator as it's liable to overheat, and it'll hold the lithium at too high a voltage for optimum lifespan. It's perfectly fine to charge directly from the alternator as long as you have an external regulator to monitor the alternator temperature and vary the output voltage as required by the battery.

Yep, I expect they may break some standards but they are available. IEC 60061 lists the GU10 base as type 7004-121-2, but I don't know if it includes a voltage standard along with the base. Like all IEC standards, the PDF isn't free to download so I can't check...

Indeed - I was just pointing out the downside of LED tape, which may or may not apply to the OP as they may have shore power. I have a compromise - LED uplights on the wall, pointing at the white ceiling. Less power but also not glaring in your face. Incidentally, at work LED tape is pretty much a disposable item - gets used for a two day event and then goes in the bin, often 50m or so on a stage or exhibition stand. I remember a stand at the boat show in the Excel used so much under the steps, it filled a 1000 litre wheelie bin, such a waste. I used to hoard the stuff... It's possible to get GU10 12v DC LED bulbs, which expands your choice of lamp holders significantly. https://www.ledkia.com/uk/buy-1224v-led-bulbs/107979-1224v-gu10-led-bulb-6w-600-lm.html

It's fine if you're on shore power, but LED tape is pretty inefficient making it unsuitable if you're off grid. The usual stuff has 60 LEDs per metre which equates to about 5w per metre. If you have a 3m saloon and use the tape on both sides of the boat, that's about 30w. Quite a lot compared to a couple of 4-5 LED dome lights!

Interesting - I looked at a few from around that date, and they all had 8mm baseplates, a few 10mm. I did see one with a 10mm baseplate full of massive pits as the owner hadn't blacked the base, and it had been rotting away in a marina without an iso trans/galvanic isolator.

My 1992 Liverpool has an 8mm base plate, 6mm sides and 4mm cabin, same as most builders from around that time. I'd say that hull condition depends more on how it's been looked after than the builder however. Mine has some overplating on the waterline at the bow - others I saw of a similar age and a premium builder have more overplating, others have less.

I don't think it's related, I think it's an age thing. The Eco and Pro versions came along much later than the Drift, I haven't personally had any experience with the Eco versions though. All models of the 4 cell JBD has the Bluetooth bits on a separate PCB about the size of a stick of gum which connects to the UART port on the main board - I expect to save costs, they just miss the little board out. However, there's also an even cheaper JBD board around, which has no UART port and no means to program it. This one tends to get used in all the super cheap Amazon specials, but may also be in the Eco.

The JBD BMS SOC is odd, compared to how Victron BMV works. It doesn't appear to need to be taken up to 100% to reset/sync it...it does *something* based on cell voltages and amp hour counting. In the app, you can set in millivolts what 10%, 20% equates to per cell, all the way to 100%. The later firmware revisions are pretty accurate, even though Fogstar claim otherwise. Mine (new firmware, can't remember the revision off the top of my head) sees a variety a low and high currents throughout the day, but even though I rarely charge to 100% in winter, it doesn't deviate more than a few % from the BMV. I suspect it counts amp-hours in and out, and corrects itself by referencing cell voltages when the current is low. Older JBDs had the same cell voltage % settings, but the SOC wasn't accurate and would frequently jump to 100% if charged with high current, even though it was actually much lower. Fogstar batteries have shipped with at least two different revisions of BMS firmware to my knowledge. The older one starts with a 2 and has crap SOC readouts. There's no way to update the firmware unfortunately, I suspect it's tied to hardware revisions.

The JBD BMS in the Fogstars doesn't make any decisions based on SOC - it's just there as an indicator. It will only do a discharge disconnect based on low pack voltage, low cell voltage, low temperature or overcurrent. Running it down to an indicated 0% has no effect, unless the cell/pack voltage drops below the threshold. Yep, I'm agreeing with you on the constant voltage hold period. Usually an hour is enough; remember, the JBD's balancers are passive and only bleed off 150ma. There's no comms between this BMS and charge sources, so it doesn't actively call for an extended constant voltage period to allow things to balance. However, it only seems to be an issue on the cheaper batteries. Fogstars seem to be pretty good at matching cells.

What seems to result from not enough 'absorption' time is a bit different, seen it on hybrid bodge installs with Lifepower branded batteries as there is effectively zero time being held at constant voltage above the knee. One cell (usually 3 for some reason, suspect internal wiring) starts to get out of balance and ends up higher than the rest. This difference then gets worse over time, especially in winter as people are more likely to charge with high current, so compared to the lower currents of solar the battery spends less time charging in a voltage range where the cell balancers are working. In the end, the high cell triggers the high cell voltage charge disconnect, usually when the battery is almost full. It then gets worse and worse, triggering the disconnect when the pack is at a low state of charge. People don't tend to notice it until winter, when the batteries don't charge until full.

Ah yep, just re-read the posts, missed that. Saw the 98% in the debugger and assumed he was trying to terminate charge at 100%.