stranded
Well-known member
I think that at £56 the 75/15 bluesmart mppt I bought this winter was half the price I paid for a 75/15 not smart at all mppt 10 years ago.
Lithium fears
- Thread starter Neeves
- Start date
lustyd
Well-known member
We have 200W too but 300Ah lithium. This means we have more capacity than you and our capacity fills faster than yours from the same solar. I can't see a downside, given that my lithium bank is cheaper overall than your AGM will be and won't degrade as fast or as often.
While it is slightly more complex, I can't see much of an argument the other way in 2024 aside from "it's what was on the boat when I got it"
oldbloke
Active member
Water power started the industrial revolution, you just need to add a water wheel
Sandy
Well-known member
I understand you can fill the batteries faster and will have an extra 30% of usable power, but how often do need to fill the batteries faster or run it down to 20% - I understand that's good working limit.
Looking at the numbers – 240 Ah against my 195 Ah usable amp hours.
I sized the bank before I added solar so that I can run with everything at 'full chat' for 24 hours before any need to recharge. To date the longest passage has been six weeks with a mix of engine and occasional marina charging. The next time I head off on a long adventure I won't need to plug into into a marina.
On your last point, the boat had 'bog standard lead acid' when I got it. The AGMs are only three years old and should have another seven to ten in them. Upgrading to lithium would be a complete waste of beer tokens at the moment.
The power management system is Victron allowing me to keep a close eye on what is going on.
Sandy
Well-known member
Have you seen the price of a Watt and Sea unit?
geem
Well-known member
My 20 year old Duogen is still going but I certainly won't be buying a new one. Crazy price when you compare to the cost of solar. I think for the price of a new Duogen I could install new lithium and solar!
Sandy
Well-known member
I looked in detail at them. Ideal for sailing at high latitudes in winter.
Tranona
Well-known member
Agree with your thinking. The zealots often emphasise properties of their favoured products rather than whether they add value in specific circumstances. In this case they forget that people have been cruising successfully with LA based systems for years and there is really no need to change unless you want to something different that is not viable with LA or your LA needs replacing and you can use the properties of lithium to reduce the size and possibly cost of your energy storage. While the first reason has been worth pursuing for some for 4 or 5 years, it is only in the last 1-2 years that availability of product and reduction in cost has made lithium worth considering as replacement. No doubt in 7 years time when your bank needs replacing the choice will be obvious.I understand you can fill the batteries faster and will have an extra 30% of usable power, but how often do need to fill the batteries faster or run it down to 20% - I understand that's good working limit.
Looking at the numbers – 240 Ah against my 195 Ah usable amp hours.
I sized the bank before I added solar so that I can run with everything at 'full chat' for 24 hours before any need to recharge. To date the longest passage has been six weeks with a mix of engine and occasional marina charging. The next time I head off on a long adventure I won't need to plug into into a marina.
On your last point, the boat had 'bog standard lead acid' when I got it. The AGMs are only three years old and should have another seven to ten in them. Upgrading to lithium would be a complete waste of beer tokens at the moment.
The power management system is Victron allowing me to keep a close eye on what is going on.
lustyd
Well-known member
I’m not a zealot I may just have different requirements. We were on board for two months with AGMs and our 200W didn’t keep up with house loads so we had to run the engine to top them up. The Lithium has changed that and the same 200W now keeps up with house loads. I’m not imagining it, I measured it and lived with it.
PaulRainbow
Well-known member
I lived aboard my last boat full time with 200w of solar and a bank of T105s. In the Summer, they kept up with my consumption, but used gas for cooking.
geem
Well-known member
..........
The alternator rotor is not balanced. They go through alternator bearings for fun. Eclectic are in denial about having a problem. I asked them if they had uprated the alternator bearings in the later versions and they said not. If I get time whilst I am home over the winter, I will see about getting the rotor balanced.
I haven't decided if I will refit it for the East to West trip back across the pond next year. For the power it develops, I am coming to the opinion that its more trouble than its worth, now its so old that it requires even more regular maintenance. I found out I could add my crappy Renogy panels to the upturned dinghy on the foredeck so we will see how we get on with solar only on the trip up to Bermuda.
I have to say, I much prefer the water mode for charging but it's ability to collect discarded fishing nets and destroy itself in the process is not so good.
I doubt we will be able to run it in water mode here because of the sargassum weed in the water stopping it every 5 mins
I don't think the Duogen air mode is robust enough. Certainly not on my mk1 version. The blades are not balanced. It can't take strong gusty conditions without wearing parts rapidly.
The alternator rotor is not balanced. They go through alternator bearings for fun. Eclectic are in denial about having a problem. I asked them if they had uprated the alternator bearings in the later versions and they said not. If I get time whilst I am home over the winter, I will see about getting the rotor balanced.
I haven't decided if I will refit it for the East to West trip back across the pond next year. For the power it develops, I am coming to the opinion that its more trouble than its worth, now its so old that it requires even more regular maintenance. I found out I could add my crappy Renogy panels to the upturned dinghy on the foredeck so we will see how we get on with solar only on the trip up to Bermuda.
I have to say, I much prefer the water mode for charging but it's ability to collect discarded fishing nets and destroy itself in the process is not so good.
I doubt we will be able to run it in water mode here because of the sargassum weed in the water stopping it every 5 mins
Tranona
Well-known member
That is your experience and in contrast Sandy was saying his current setup is perfectly adequate for his use and sees no benefit FOR HIM in changing. The different properties are not in question. Look back at the last sentence in your post#22. You say can't see any alternative but there clearly is because the vast majority of boats do not have lithium and seem to get along quite nicely.
If I recall rightly your batteries were knackered so you decisions on replacement will be different from somebody in 2024 who sees 7 years life in their current batteries.
Neeves
Well-known member
WattnSea are magic - but costly (as said) and are only useful if the water or the yacht move ie anchor where there is strong tidal flow or make reasonable passages.
WnS are not much use if you are sitting in an ideal tropical anchorage (which is the location of many liveaboards).
The best investment for renewable energy is solar - limited by ones ability to instal a decent display.
Jonathan
Sea Change
Active member
20% is a very conservative limit. In practise you can use 100% of the capacity and the lithium batteries will still outlive any lead acid chemistry, by a long way.
How much are AGMs? I'm paying about £120/kwh for lithium. For lead acid to be cheaper (assuming 50% usable capacity) you'd need to be paying less than £80 for a 110Ah battery.Looking at the numbers – 240 Ah against my 195 Ah usable amp hours.
I sized the bank before I added solar so that I can run with everything at 'full chat' for 24 hours before any need to recharge. To date the longest passage has been six weeks with a mix of engine and occasional marina charging. The next time I head off on a long adventure I won't need to plug into into a marina.
On your last point, the boat had 'bog standard lead acid' when I got it. The AGMs are only three years old and should have another seven to ten in them. Upgrading to lithium would be a complete waste of beer tokens at the moment.
The power management system is Victron allowing me to keep a close eye on what is going on.
Neeves
Well-known member
I am reminded of a recurring thought
- the Duogen offers two mechanisms to produce electricity. Its a clever idea, though as Geem mentions, not too well engineered. WattnSea recognising the impressive electricity product of a hydro generator and are a power source of choice for ocean racers. When we used a LVM wind gen in hydro mode, a sort of trailing log, it produced impressive levels of electrical power (from memory 8 amps at 8 knots) - but was a faff to convert from wind mode to hydro mode (and we did not have Sargasso issues).
Are there opportunity to make a combined electric outboard/hydro generator?
Jonathan
lustyd
Well-known member
If you’re going to misinterpret what I said then I can understand your confusion.
vas
Well-known member
last time I checked, Sailing Uma was doing just that, check them out on youtube.
Lovely couple, during covid (iirc) removed diesel engine and leg on their small yacht and replaced with el. motor/leg combo that produces current when sailing. Mated with some lifepo4 banks and a massive solar panel they've travelled up to Norway iirc.
V.
Sea Change
Active member
Some of the Torqueedo (or it may possibly the ePropulsion) outboards have a regen facility. It's been discussed on here; one concern raised was that you'd have to mount it pretty low down on the back of a yacht to actually work, which would then risk swamping the whole thing in following seas, or even just with your own stern wave.
With solar panels down to £65 for 400w+ it's pretty hard to justify any other form of generating electricity these days, unless you just don't have the space for them.
Sandy
Well-known member
How frequently do you run the batteries down to zero?
Where is the 'real world data' that backs up the technology claim that it will outlive any other form of battery, has anybody run lithium for 15 years?
I've seen a lot of claims about lithium, but have seen little real world data. By 'real world' I mean large numbers of data points over many years and environments.
At least with this forum we can start exploring the real world data.
Sea Change
Active member
I've never actually gone down to 0%, it's not necessary and would reduce the lifespan of the batteries. From memory I think 12% might be the lowest I've personally gone, and a friend dropped to 6%.
Rod Collins is the guru for lithium, he's been running a battery for about 14yrs with almost no noticeable degradation.
