Slow and Steady

Sure I read it. Did you read the bit where I never run the engine, don't have any solar and get ALL my power via the bollard? Remember I'm doing an audit here, not planning my charging. Again, I'm doing a power audit here, not charge planning, but just for you... There's a difference between charging the batteries directly with the domestic alternator and using the travel power. Both run the engine. Only the travel power is designed for the constant high output lithium batteries need so no, I don't intend to charge the batteries with the alternator, but yes as I clearly said, I will be charging them by running the engine. For future ref, I'm not a complete idiot, I posted this thread to get views on calculating my USE via the bollard meter reading, clearly stating that ALL my power derives from the bollard. I must have repeated that ... several times by now.

Tony/Allen, I'm struggling to think How I could be more clear. At present I have 12v lights and pumps. Everything else is 240V, everything, all of it. Even the 12V does in that the battery charger is permanently on maintaining a couple of old leisure batteries that are probably useless in their own right. None of it presently runs via the inverter, ever, I'm permanently plugged into 240 AC residing in a marina. I do have a 3000w inverter though. That is now. That is where I am to calculate my power use. Batteries, alternators are irrelevant at this point. Yes if I ever started the engine I could charge the leisure batteries with the domestic alternator but as I never start the engine... Pointing out that lots of things have internal transformers is splitting hairs. Ultimately they are fed with 240V AC. Future Lithium battery bank providing 12v for lights and power via inverter for all the 240v ac stuff. Any advice regarding LA batteries is pointless as I won't have any. Perhaps I should list the 240V stuff, it's a small list: Fridge without ice box. 1 x phone charger for 1x phone that provides internet. Constantly on the charger. 2 x computer monitors - 12+ hours a day 2 x PC's - not laptops, proper ones. - 12+ hours a day 2 x powered speakers - could cut to average 2-3 hours a day 1 x drill battery charger - a few times a year. occasional power tool use which I can time to use via the travel power when the engine is running. Not really much, we don't have a TV. It's the constant computer/screen consumption that worry me TBH, The CPU in mine is 125w alone and when I'm making music it gets THRASHED. Mostly though it sits at about 30W so it's variable. Solar for the summer proving unknown amount of charging. Winter / supplementary charging using the travel-power supplying a 120A charger. OK yes it's got a "special" alternator powering the travel power but I'm likely to just take the belt off the domestic alternator OR maybe get an alternator controller and up my charging possibilities. I'm lead to believe charging the lithiums via the travel power and mains charger is a neat simple way to get started. Hot water - very very rarely use the 240V calorifier. Shower at marina, nick the marina's hot water to wash up - heck I'm paying. In the future yes - engine will heat water and maybe, just maybe, I'll have spare solar to heat the water a bit in the summer sometimes. No electrical high power gadgets, never use the webasto central heating. To be fair, apart from trying to run a computerised recording/mixing studio in the boat we're already on top frugal mode. My son and I live on under £10K/year including absolutely everything, we're no strangers to "not using stuff". £5k/year each. Our best year was nearer £7k and when you consider £3k goes in mooring fees and licence you get the idea - we're good at this already. TBH I expect our costs to rise quite a bit when we set off to live outside the marina. Nick - thanks for reading, understanding and your answer. I do surely hope I'm not burning through 7Kw a day, I very much doubt that. I'll take some meter readings and get back to this thread with some real numbers to see what I'm in for. Thanks to all for taking the trouble to post your helpful advice.

I think we're all different too - some are happy to blindly follow advice and some of us need to understand it first. If you're in the second variety forums are good, if you're in the first then heaven help you!

Exactly, they are like a paint manufacturer asking if they answered the phone quickly, packaged the tin properly and delivered it promptly without asking what you think of the actual paint. I've had 1 in 6 years and as it was impossible to use it to express my opinion I ignored it. Ergo, only happy boaters will fill it in. If they really do get a poor response % I think that says a lot.

Sure, but if you read my boring posts... I suggested using 13 instead of 12v I don't have a laptop. I won't be directly charging batteries using an alternator. Charging losses are somewhat irrelevant to consumption. I'm trying to get a figure for consumption.

Thanks for taking the trouble to provide that detailed answer Tony. Obviously at present I don't use the inverter at all, I feed mains equipment with mains from the bollard and lights/pumps from the battery bank for which the charger is permanently on. No solar complicating the calculations at present which is partly why I want to do this now. I think I'd be near enough and more accurate by assuming all my current use is via the 240V supply because the vast majority including the fridge is. As we know it takes more energy to charge the batteries than I get out of them, the lights pump part would calculate out on the safe side as the 240 supplying the charger is more than the consumption? So, meter reading converted to KWh x 1,000/12 x running inverter losses + a chunk of standby inverter losses would be not too far out? Maybe divide by 13 (12.7) rather than 12 to be safer? Then assume the worst and multiply the final answer by for example 120%... or even 150% to be sure I'm over-estimating. The aim here is not to penny pinch on the system if it means I then have to limit my normal day to day consumption to fit the system I install. At the same time I'm very aware that my present consumption may well be unfeasible and I might have to have a good hard think about how I live. Hence this wish to do the rough calculation. I have no idea if I can survive on LA as TBH their only function at present is to provide a way for the shore power to convert to 12v via the charger. Doing this I've probably already ruined the batteries but in this situation that literally doesn't matter. Plan is yes to survive out in the wild on solar in the summer and charge Lithium via Travel power/mains charger in the winter. I won't be fitting all this complex lithium malarky myself, the plan is to ask Four Counties Marine to install the Lithium and organise/wire the charging but before I talk to him (to save wasting his time) I do need a good idea of the size of system I want and whether the panels required will fit on the roof etc I'm pretty sure his first question would be "How much power do you use?"

I got the strong impression that he totally understood that which is why he asked for approx dimension as he had no idea and hasn't even got a boat. No boat = no possibility of an accurate answer so why bother asking him for details? If his design doesn't fit it's no skin off our noses is it?

He asked for an approximate dimension, it really wasn't difficult to say "1m". I didn't even get up and measure, I guessed. Advising he takes a tape measure to the canal and measure boats himself? That's a wind up!

I'm happy with anecdotal + some tech reasoning to make sense of it like Alan's "not enough volts = no charging" example above. That's useful information despite not being a laboratory controlled experiment.

Last bit - my batteries are always fully charged and by "going Lithium" I would avoid most of the state of charge / charging while discharging complexity? But yes, I would be attempting to keep up with battery use through the lossy inverter and whatever losses in the charging system. I would be looking to over-cook the whole system a bit, I wouldn't be happy having to fully charge/fully discharge the batteries every day, but as a start point I do need to know approximately what my current unfettered use is which is a sort of bad as it gets state. From what I've read, it's far easier to predict all this stuff with Lithium batteries. So, I'm just looking for an equation to get a rough but reasonably realistic figure to start thinking from, not one to design from at this stage as all I need to know right now is whether my lifestyle is remotely sustainable or simply a non-starter. All I know at present is that £100 in the meter lasts "quite a while".

I'm plugged in on a marina with an accurate meter on the supply bollard. This provides for 240V and battery charging. Most of our use is 240v. Just lights and pumps on 12v. If I were to note a week or a month use on the bollard meter, is there a formula to translate that into the expected use powering everything via batteries / inverter / inverter losses? I think if there is, that would be good start point to assess whether it's even possible to live with solar / engine / Lithium. Possibly more realistic than guessing our use and power requirements for each separate item on board. I'm sure the standby and loss figures for the inverter I have are in the blurb and we are creatures of habit regarding power use so every day would be more or less the same usage. Thanks for reading.

In that case, which I'm aware of, I think I'd be looking for higher voltage panels in the first place rather than wiring low voltage panels in series... if they even exist - the mass market does seem to be aimed at smaller installations. I'm still at the pre-planning stage myself and I'm glad not to have jumped earlier as no doubt I'd have ended up with low volt panels and LA batteries. Looks to me like High volts and Lithium is the way to go. I'm more interested in the practical usefulness than the initial cost, I like to run a fridge, computers and powered speakers all of which are constant drains and need 240v AC so there is the conversion and standby losses there too. Laptops are not powerful enough for my use and the ones that approach it, the batteries last about 30 minutes so in effect they are mains powered, noisy and hot. None of my uses are high power consumers like a microwave, kettle, washing machine etc but the hours add up to a substantial daily total.

Good answer! So... higher voltage panels for the win? Are their any downsides that you're aware of?

OP is buying a boat "in the future" and wants to name it and design the lettering etc himself in advance. So the actual boat is irrelevant hence asking for a rough dimension. TBH as he/she can scale whatever design they come up with to fit anything it's a bit of a pointless question but perhaps nice to have a vague idea of how big the letters etc will be.

My impression is that he's looking for some rather basic info on the difference the panel voltage makes to the expected output in various, but particularly low light conditions. I agree with him that this basic element of panel choice is rarely if ever discussed and I also wonder why that is. Maybe it's because it actually doesn't make much difference apart from high voltage/low amp panels not requiring such beefy cabling as low volt/high amp panels. If that's the case you could infer that the higher the output, the more gain to be had from high volt/low amp panels in terms of less bulky/expensive cables and losses in the cables.* *I'm armchair at this, a grownup will be along to clarify hopefully.

He doesn't get on with/understand women? I get that to an extent- I like women but wouldn't want to be trapped on a boat with one.

From the thread title I was expecting Youtube video of a punch-up over a mooring spot. Disappointing really.

I couldn't do that, maybe that's why my tiller extension is only about a foot long, I'll have to check!

Does it? Mine doesn't, it's trad stern but the tiller doesn't overlap the cabin.

^Well mine is anyway which makes sense when builders have to consider best use of 2m wide sheets of steel.

1m

The idea that all that's needed is to "do DIY, forage in skips, go on holiday for £9.50" is indeed condescending. Those "tips" are fine for people that are "feeling the pinch" but completely ignore that this level of financial hardship is a tier UP from the misery of real poverty. It's fashionable middle class poverty.

New repair panels for old (70's) vehicles, both being 0.8mm (they are the worst). If one butt welds them together, the new panels expand more than the original steel and rumple up while the original stays flat. One makes allowances of course and frankly I'm glad I gave this up several years ago! I really do think they must be "different" steel in some way. Maybe even the rolling process makes a difference but as I say I'm no expert. On the sill thing, it took the originals, chipped here and there 40 years to rust through, it was shocking to find a hole after just 2 years. I would admit that VW had a better paint process than I did though, they had a very, very tough, very thin primer layer that seemed as hard as plating though obviously wasn't. Not sure what that was but I guess chips would possibly not get through that. Anyway, the main point was the amusing surface corrosion picture I posted, I only mentioned the shrinking/bendy aspect in case it was somehow related. ...and of course I am very fussy when welding old vehicle half panels - fractions of mm's seem massive to me, though funny how the general public seem to think it's easy. 0.1mm height difference butt welding is a step in my eyes and very visible, it's a far more exact science than it's given credit for... much the same as boat welding - we laugh at the agricultural nature of it, but it must be very hard to make a good one.

I can only think the makers deliberately buy "soft" steel because it's easier to stamp out the panels? Some suppliers (makers) are much worse than others. The 1968 was original VW painted steel, no rust(I cut the rusty bit out). The old shelving was (smelt like) oil based paint and again no rust. Both those were cleaned with a poly abrasive disc then degreased with cheap cellulose thinners (gun wash). The 2010 was transit paint that washed off with same cellulose thinners leaving shiny new metal. I can't really agree with your 50 year prognosis - a small paint chip in a 1.2mm thk sill I had (new) rusted to a hole in 2 years.

I actually said exactly the opposite, I find that new car panels are soft, bendy and expand/shrink MORE than the old stuff when welded.