Convenience. Anyone can buy a drop in this afternoon. You have to import the cells, pay well in advance, possibly sort out import paper work, maybe pick up at the docks (this was the option when we bought our Spade (go and get it).Maybe 'assemble' is a better word than 'build'. The latter conjures up an image of somebody recreating a factory in their shed, when it's more like plugging stuff together.
I knew almost nothing about electronics before going down the DIY route. I can use a multimeter and a spanner, which are the only tools required. You also need to buy an adjustable power supply that works in the 3-4v range.
It's really not rocket science to assemble four cells and a BMS.
Buying drop-ins isn't really saving all that much work. You still need to design the rest of the system, which is where a lot of money and knowledge come in. In most cases there's going to be a lot of new wiring, fuses, changes to other components, etc. None of this stuff goes away just because you bought a 'drop in'. Which is why it's not a very good term.
The BMS disconnecting the lithium battery bank is certainly a real issue that needs to be considered.if Lithium shut off is a real issue - add an extra Lead battery, small, simply for the off chance (and then you do not need to use the engine start battery). The extra solar to keep it charged is minimal.
Jonathan
I'm not sure if it's the point you were making but choice of DIY or drop-in has zero impact on this. Both will shut power off without warning if the BMS trips.One reason for following certain assembly routes is that in the case of an untimely failure and the Lithium circuits switch off (or the Lithium batteries switch off) and this will deny power to Nav, AP etc etc. This is meant to be a serious difference between marine and terrestrial installations.
The class T fuse is there to prevent arcing in case of a very high current short. It's arguable that in small systems it's not really necessary, and ANL or MRBF can be used instead, but it's become the ABYC standard and for larger systems it's definitely what you want to fit.It is already recommended that a 'T' fuse (?) is installed as close to the battery as possible in the positive lead to the Lithium batteries from the alternator
They'll blow for the same reasons a any fuse blows. Are you getting confused between BMS shut off and a fuse blowing?- have not check if my memory is lacking. I wonder how many times these fuses are necessary (ie how often they do what they are meant to do - and blow).
This is pretty much what I have, except I couldn't find a 1-2-off switch.have a 1,2 Both (but remove 'both') switch for the Lead and Lithium batteries to allow temporary power to be established in the critical navigational circuits or any other circuits deemed critical.
That's pretty much standard practice.All yachts will have a Lead battery - as Lithium is not used for engine start. Effectively all Lithium 'powered' yachts are hybrid systems. It seems reasonable that if there is a risk of the Lithium shutting down, the battery management systems cannot be 100% reliable, to use the resources available - plan in advance and use the Lead engine start battery - if there is concern at running the battery flat - run the engine and then sort out the Lithium.
Pretty much what I did. Kept the old lead acid system in place. The batteries live in the engine room so I wasn't going to put my new lithium in there anyway. I have 230w of solar feeding 330Ah of lead acid. Most of my loads run from the lithium, but a handful of cabin lights and charging sockets remain on the lead acid, so I can still get around the boat and use one of the heads- and I can still charge a phone.I vaguely recall that Geem is building a new, or modifying the old, Lead battery bank - but I forget why. For anyone retrofitting a Lithium house bank most of the kit already on the yacht will be perfectly serviceable except the Lead batteries whose failure is promoting the change. Instead of tossing all the old kit - if Lithium shut off is a real issue - add an extra Lead battery, small, simply for the off chance (and then you do not need to use the engine start battery). The extra solar to keep it charged is minimal.
Jonathan
Yes that's true, if you don't want to wait two months you're probably going to need to buy drop in. Not many people stock cells on their ownConvenience. Anyone can buy a drop in this afternoon. You have to import the cells, pay well in advance, possibly sort out import paper work, maybe pick up at the docks (this was the option when we bought our Spade (go and get it).
Its an interesting project but the many who employ a mechanic to service their yacht are not going to do it - they will want it all NOW, or at least soon.
Jonathan
On the assumption that you have a breaker or isolator on your lithium battery, you only need a simple emergency switch to link the engine batteries to the domestic circuit. This is what I have. The emergency switch is in a steel cabinet in the engine room. Open the door, install the key and turn.One reason for following certain assembly routes is that in the case of an untimely failure and the Lithium circuits switch off (or the Lithium batteries switch off) and this will deny power to Nav, AP etc etc. This is meant to be a serious difference between marine and terrestrial installations.
This is introduced as a dooms day scenario - you can always assume someone will introduce a fear factor in threads.
It is already recommended that a 'T' fuse (?) is installed as close to the battery as possible in the positive lead to the Lithium batteries from the alternator - have not check if my memory is lacking. I wonder how many times these fuses are necessary (ie how often they do what they are meant to do - and blow).
If the 'T' fuse is felt necessary surely it would be equally sensible to have a 1,2 Both (but remove 'both') switch for the Lead and Lithium batteries to allow temporary power to be established in the critical navigational circuits or any other circuits deemed critical. All yachts will have a Lead battery - as Lithium is not used for engine start. Effectively all Lithium 'powered' yachts are hybrid systems. It seems reasonable that if there is a risk of the Lithium shutting down, the battery management systems cannot be 100% reliable, to use the resources available - plan in advance and use the Lead engine start battery - if there is concern at running the battery flat - run the engine and then sort out the Lithium.
I vaguely recall that Geem is building a new, or modifying the old, Lead battery bank - but I forget why. For anyone retrofitting a Lithium house bank most of the kit already on the yacht will be perfectly serviceable except the Lead batteries whose failure is promoting the change. Instead of tossing all the old kit - if Lithium shut off is a real issue - add an extra Lead battery, small, simply for the off chance (and then you do not need to use the engine start battery). The extra solar to keep it charged is minimal.
Jonathan
Noelex,The BMS disconnecting the lithium battery bank is certainly a real issue that needs to be considered.
Combining lead acid batteries with lithium is one common solution to this problem. An advantage of this solution is that it will work with batteries containing a simple internal BMS without any communication.
No lithium system. Our current boat has 600Ahrs @24v of gel batteries.Noelex,
You are a significant contributor to Lithium threads but I don't recall your describing your Lithium system.
That's a serious battery bank (what solar capacity?) - why not Lithium, or was it too early?No lithium system. Our current boat has 600Ahrs @24v of gel batteries.
How do you know where 100% charge is? Are you reading the voltage at cell level? Does your battery have a BMS you can interface and adjust settings?Answering my own question on using the BMS, in a Lithium battery with built in BMS, as a solar controller.
We had not charged our 200amp Lithium Battery to 100%, I thought I had but seem to have been out by 1 or 2 amps when setting the battery monitor. We have also been testing various domestic devices to find out how our 'build' performs (especially as our inverter is only 1500amps). We had been cautious and had been using a 1300 watts air fryer and tried a 1500 watt air fryer only yesterday. The Breadmaker works well (as did the air fryers). The next device is the induction hob - but we don't have one yet.
We should have bought a bigger inverter, lesson learnt
We had the chance to charge the battery fully.
When the battery achieved 100% fully charged - nothing happened. Solar charging amps remained high and the battery Mon displayed the charging amps and the battery at 100% - leaving everything as was the capacity did not increase beyond 100% - which might suggest I had not set the Mon accurately.
But within about 2 minutes the charging amps dropped to 000.1 amp. The only other thing I could check was temperature - and the battery had not warmed up (nor cooled down) - temperature measured by hand (really scientific).
Isolating the charge from the solars, 2 separate cables to 2 x 250 watt folding panels each with an Anderson plug, immediately allowed the Mon to cancel the 000.1 amp and display devices using or taking the stored amps, primarily esky taking 5.5 amps. The 000.1 amp might suggest that battery power was inaccessible. It possibly had isolated itself.
To those that think I'm mad - we do have a solar controller but for some reason it only displays amps being consumed, not amps charging (nor the addition subtraction of the 2). The solar controller has only one connection port, and we have 2 panels (I need to wire up a 'Y' connector) so I'm using 2 separate, spare, Anderson plugs, connected for 'just in case' but not on the solar controller circuit. The amps being produced by the 2 panels, seems, is accurately recorded on the shunt/mon and then reduced when the esky comes on line.
The solar controller charges the battery but only records amps being used. The solar controller only has one input. I can improve the number of devices (solar panels) but cannot alter the display. The cheap as chips battery mon works as it says on the box, reads amps in and out, sums the 2, displays battery state as a little picture, as a % and also as amps remaining. It has a memory function - but I have not had to use it yet. We bought the Mon direct from China, through Aliexpress (and as with much from Aliexpress - no brand name) The off the shelf battery with internal BMS works (though there are no indication on the box how it works, whether volts, amps or when it detects it is full (of amps) - but when the battery is full - it shuts of the input of the solars. It may also shut off access to the battery - I need to check that (the dooms day scenario).
What have I done wrong - what else should I check?
Finally - I'm glad, very glad to be doing this at home and not on a yacht - simply speaking its factorially more convenient. No...we don't have a mast shading the panels, we don't have a yacht swinging at anchor - but we do have mains power and we are not starving through being unable to cook nor needing to take cold showers - because I got it wrong (this is the first electric build I have attempted). As far as I know the terrestrial amps are identical to marine amps - I fail to see the difference. We have yet to test the B2B charging - another exciting aspect.
When we get it right we can take the whole build and re-build on a yacht. It will work 'out of the box' the trial and error will have been completed.
Jonathan
In answer to most of your questions:How do you know where 100% charge is? Are you reading the voltage at cell level? Does your battery have a BMS you can interface and adjust settings?
Is your cheap as chips battery monitor set up for lithium? What value for Peukerts are you using? What about charge efficiency factor? Is this taken care of with a generic lifepo4 setting?
Thr BMS will likely ignore the 100% charged figure and will simply keep accepting charge until there is a HVE (high voltage event). The BMS then shuts down to protect the highest cell from over charge.
I know you are not using this on a yacht so shutting down the battery is no big deal, but since we are on a boating website I would point out thst this is very bad practise.
In my opinion, drop in batteries with a BMS that isn't fully interactive via Bluetooth has no place on a boat. SOC of the battery bank is best monitored with something designed for the job. A Victron Smart shunt does an excellent job. Way more accurate than the built in SOC monitors within a BMS. The voltage can be calibrated to accurately reflect battery voltage.
What is the current handling capacity of your BMS in each battery?
Jonathan, your thinking is way off here. The BMS disconnected on a HVE. They do not disconnect on full charge. They are not a charge controller. The BMS is there as a mechanism to stop you destroying the cells. It is your last ditch attempt to save the cells when something goes wrong with your charging system or you over discharge.In answer to most of your questions:
No.
The BMS is not adjustable, there is no ability to monitor the BMS. I think this is common for many Lithium Batteries with a built in BMS
The cheap of chips Monitor/shunt is specifically for Lithium.
I don't know if the BMS in the battery shuts the charging down when a high voltage is detected or if the battery shuts down when the battery is detected as being full. I can monitor voltage - maybe I need to almost fully charge, or fully charge and then monitor. Either my operator input of 'full' is very accurate or the voltage shot up when the battery was full (and my setting is accurate) but the battery shut down within a couple of minutes, literally - not 5 or 10m but 2 minutes (though this might be coincidental), of the Monitor detecting my 'full' input. The monitor, or rather shunt, is rated at 200 amps, 250 amps max. Our single battery is 200 amps (but that is insufficient).
My take is slightly different.
Historically we would monitor our Lead batteries almost constantly - we were living on the boat and battery state was critical, because we needed the power and we ensured we did not over charge (and have the annoyance of an engine running wasting diesel). We are quite familiar with shutting down the engines at 90% capacity as that last 10% takes an age to input. We had an original Xantrex battery mon and shunt, though the device was built by the company that Xantrex bought about 15/20 years ago (but I forget its name). This was 25 years ago. The technology is hardly new. The new Mon displays the self same data - except the SOC is displayed more usefully in 1% increments (though how accurate this is - don't know).
I see no reason why we would not do something similar with Lithium based on a large solar display and simply disconnect the solar when a charge of, say, 90% had been achieved and/or reduce the number of solars being used to, almost, balance the power needed to run the the systems on the boat, fridge, freezer, AP etc. We are very used to monitoring equipment on a yacht, testing oil, check water flow in engines, checking the batteries etc etc - its part of the facts of life - which we accept.
I think this is what Alan S is doing on a canal boat.
Its only Noelex that mentions this is not for a yacht - but that is a bit of imaginative fiction on Noelex part he just wants to needle me - it brings out the child in him,
The intention is to instal the system in a new cat - unless someone can define why there is a significant difference between a good yacht build and a new terrestrial build that is for a yacht. We are finding out what works and does not work so that we get it right - first time.
In the fullness of time we will take on board - comment. We are currently testing.
Being a realist I don't see uptake of Lithium being very rapid if the Lithium batteries have to be owner built. Looking at Lithium threads and Lithium 'users' you are few and far between on this forum and can be counted on the fingers of 2 hands. Yet Lithium is now common place (in terrestrial applications) in cars, it has undoubted advantages but even Noelex who has a spanking new custom built yacht is not using Lithium. Or to put it another way - I see off the shelf Lithium batteries being the common route and most owners will not have a clue (with no disrespect) and will accept what the local sparky says. We are not willing to test the sparky, we are doing it ourselves, and relying on the few here for correction.
In the fullness of time we will have a decent solar controller - but should it fail - we know what the fall back is. Charge to 95% etc. I think we might be able to better tune the 'charge to 95%' - maybe automate it. Again time will tell.
I am immensely grateful for access to the resource the few of you command - and share.
Jonathan
Jonathan, I think you have missed the point. Like Kelpie, we have the same Vango Sizzle Double currently priced at £109 on Amazon UK. Its designed for camping because that is were Vango see their main customer base, they are a camping firm.
However, The Sizzle Double has one major advantage over many of the other induction hobs and that is the width. Many European yachts have 450mm wide cookers and therefore the manufacturers have built the galley to accommodate this size. Add a bit for gimbals and you end up with a space about 480mm. Few other double induction hobs on the market will fit in this space and be gimbaled, apart from the Vango, hence why folk are fitting them to yachts, as we did. Retaining the gimbaling was important to us, others may feel its not necessary for their sailing.
The one question that we are often asked is about the 800w power level per heating element and is this enough when many induction hobs are rated for 1500 - 3000w. The answer is yes as Noelex has pointed out. In practise with our first Sterling 1500W single induction hob, we were always turning it down or it just burns food. For example, once brought up to boiling, rice or pasta will quite happily simmer at 200-400w with a lid on the pan. Our go to heat settings for bacon or eggs is 600 - 800w. Since a kettle is a foreign object in the USA, they boil water on stoves, so perhaps a higher wattage hob is useful there, but back in the civilised world with 240v electric, we just use a kettle.
Do we have any regrets going for the smaller Vango? no its a perfect fit for us. With a 2kW inverter we can run both elements at the same time. Or use one and the remoska / sandwich toastie widget (great for a quick snack on passage). Even the kettle or slow cooker and one Vango element. In the past two years we haven't needed for anything else. We do have the basic Ninja Air Fryer (1500w) as well which we occasionally use if chips are needed. Chips aside a Remoska (580w) is a more versatile cooking implement in our opinion. Indeed we bought a second one for use at home, we think they are that good. Cakes, fish and joints of meat are cooked just superbly.
You commented on our cooking stats a month ago, in particular the daily average of 0.9kWh. Yes on a large yacht with oodles of solar and battery capacity, you can run big Victron inverters and therefore just about any domestic appliance. For a smaller yacht choosing appliances carefully can also be very successful without high price tag items and wondering were its all going to fit.
Pete
Pete
Yes, because new ones are chrome plated or something, whilst the old ones are stainless steel. So an hour with a brillo pad and they cleaned up lovely.@Pete7 that looks really smart. Did you strip an old cooker for the gimbles and pan retainer things?
It might work in the short term, but not the long term. Cheap shunts that are not programmable will start to run out of sync. Even BMS SOC readings very quickly show the wrong state of charge. It is possible to have several lithium batteries in parallel and they all show different states of charge at BMS level.Geem,
I've taken on board your 2 posts, particularly Post 52 - in which I read your passion. Normally you are not passionate (or not on posts).
Thank you also for chapter and verse, full of detail, in post 54. All duly noted.
I don't mind critical comment especially when it is supported with options.
We were out today and the simple solution, part of what I suggested yesterday, was to disconnect the solars.
The worry is hundreds of these and similar batteries, maybe thousands, have been sold in Australia and certainly thousands across Europe. Lithium is heavily promoted and the batteries are all similar, internal BMS. The owners will not be sharing how they use them and will not enjoy the attentive support from you and your like, Pete7, Kelpie et al. Lithium fires enjoy high media coverage here (bad news sells) but reports are limited to recharging of small devices, bikes, scooters or the occasional car. No reports of fires on boats, (and for Noelex, none on caravans and motorhomes) - but maybe its too soon.
Going back to our shut down, it was too coincidental that the battery shut down because the battery was fully charged. Your interpretation of an HVE seems very much more likely. I don't commonly and attentively monitor volts the emphasis has been amps and SOC. However it seems that monitoring voltage is not going to be very effective anyway. I now know that a HVE will occur, effectively, as soon as the current setting on battery state reaches 100%. One thing I can do is change the state of full charge to its charge at 85%, so 85% then becomes the new 100%. Its easy to change 85% to become the new 100%. I appreciate this does not meet your advice - but your advice will take some time to enact. Its not automatic but I can easily calculate when 85% SOC will occur so, anticipate new full charge, the new 100% and shut off the solar at that point. This give me a 30 amp buffer before a potential HVE. With the best sun we are currently reaping 25 amps - so again with the best sun I have a 1 hour window - and phones have underused timers
Jonathan
Enough with the petty insults.it brings out the child in him,
Jonathan
This is new and 700w for £72 able to run off a 1000w inverter. Add a Renogy PSW inverter or Sterling 1000w from their clearance range and for £200 you are in business. Probably be able to run it off a couple of lead acids.I do see the the smaller Vango unit as being a very neat niche for yachts as many people have inverters but simply too small for domestic induction.
I had thought to put a 'toe in the water' for the Aldi unit but have been discouraged by the criticism of pulsing. 2,000 Watts is a big unit and would need a big, expensive, inverter (ours is cheap and only 1,500W). There are more people using induction on a yacht than I had envisaged.