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Tom and Bex

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About Tom and Bex

  • Birthday 10/31/1975

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  • Occupation
    Emergency Care Assistant
  • Boat Name
    Diesel & Dust
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  1. I think the time and research involved in the design stage is worth it in the end. I certainly spent a long time reading up and researching the different options before deciding the route I went down. Pleased I did as now they're installed they just sit there and work! Occasionally glance at the BMV to see if I need to charge or not. Definitely less monitoring and much easier to look after than lead acid. Getting very good results from solar at the moment, much better than expected based on last years performance. Might need to keep eye on charging and voltages as solar input increases to check I've got the optimum settings for the solar controller. Once set up they really are fit and forget though. As I mentioned previously, we charge to 100% to synchronise the BMV every 4-6 weeks or so, generally to coincide with a cruise to pump out. We find generally the BMV remains fairly accurate now we've tweaked the settings though. It's interesting to see the data from other installs, particularly how much the charge rate affects SOC as various voltage points are reached during charging. One of our alternators has developed a fault and consequently the batteries are now at much higher SOC by the time 14.0v is reached, although it is obviously taking a lot longer. Max charge at present is 65-70a compared to 100a with both alternators working well. We tend to leave everything switched on when leaving the boat now, it doesn't matter if they sit for a week or more at partial SOC. I figure the low voltage cut out on the fridge will stop the batteries getting excessively drained, and solar (even in winter) will keep up with minor power usage (WiFi router etc). I notice peterboat and me just enjoy using the batteries now they've been installed for a while, enjoying their benefits and superiority over lead acid, and basically ignore them! Hopefully MP and Dr Bob will have the same benefits when their installs settle in and any teething problems are sorted out. It's been interesting reading the different routes that have people have taken to hopefully get the same end result. I think the 4 installs on this thread have taken 4 quite different routes, so will be interesting to follow how these different methods compare and hold up over time.
  2. No problem at all. It is very quiet though.
  3. I think voltage settings very much depend on charge rate. Charging a 480ah bank with a 30A charger then not really surprising you are getting to higher state of charge at lower voltage. We charge our 320ah bank at 90-100A+ and that gets them to 80% charged by the time the voltage climbs to 14v. The cells certainly stay very well balanced up to the very end stages of charging to 100% when they can start to drift if pushed too hard. Don't know if this would occur if only charging at 13 8v or not, suspect it would if charging was continued. By only charging at 30a you're missing out on one of the big advantages of lithium and that is their ability to accept high charge rates - up to 240A with your setup! Agree about learning the correct voltage settings to use with experience. We had to vary ours a few times from my initial settings to get the best compromise between looking after the cells and avoiding false alarms. If only cycling them from 20-80% then from what I've read they should be good for 10000 cycles plus! I guess only (a very long!) time will tell how likely it is to get close to that figure. We do take ours to 100% every few weeks though to sync the BMV, but so far it seems to be staying in sync remarkably well. That's where I do like MP's setup with his arduino based BMS as I think he said it keeps track of any drift and self corrects.
  4. I still think charging to 13.8v and then terminating charge may not get them very well charged, but that depends on charge rate. I feel charge to 14.0v then cut charging will work better, at least on our setup it seems to work well - if we stop charging at 14.0v that's approx 80%. That might be the case initially! However having had ours installed since September, I rarely think about them now. Just run engine when convenient and I feel like it for an hour or 2 every now and then, and occasionally glance at BMV to see what percentage they are at. If looking a bit low after couple loads of laundry, soup maker etc, might run engine a bit longer. Now we've got used to them they seem to be performing very consistently, and if they're getting towards 20% (not often now) then it's time to charge for a bit longer. Far less care and monitoring than the old lead acid batteries! The other improvement noticed is the fact our lights don't dim or flicker at all when flushing toilet, running waking machine, starting Eberspacher etc like they used to.
  5. Looks like it's going well for both of you. Yes the cells do behave slightly differently from each other, don't know if brand new cells would be the same or not? Current does drop reasonably quickly at the end of charge with voltage at 14v. 3.5v per cell is easily enough to charge to 100%. It's surprising just how quickly a cell's voltage can rise at the end of charge, although those figures do look quite well balanced to me. As to one cell's voltage dropping slightly, that's not unexpected - the rising voltage on one cell has to come from somewhere if charging at constant voltage. It demonstrates clearly how having a high voltage disconnect must be done on cell level, and just relying on pack level would allow an individual cell to climb too high. Just a word of warning about using lithium settings on charge sources - these are generally set to much too high a voltage. I presume they are only suitable for the propriety ready made packs from the likes of Victron with their own built in BMS, not for charging bare cells directly. I would advise manual balancing if any more is required. Don't rely on the balancing function on the monitor - these small devices are designed for monitoring and balancing small rc models, not huge capacity leisure banks!
  6. Happy to comment on ideas you come up with either here or via pm. We live off grid and have to say I think the lithiums offer us a better return on investment than solar (although both together are excellent combo for off grid liveaboard). Saved a fortune in diesel over this winter, down from average of 4hrs per day to average of about an hour. I'd hardly call myself any sort of expert! Just trying to share the knowledge I've gained over the past year or so of my research and experience. If installed correctly with the correct settings etc, they should be maintenance free - just use them and charge them as and when you want with no real worries about how they're treated - that's certainly how we use ours. There's no way my wife would put up with constant monitoring and looking after batteries - she just wants to use them! Quite agree they are not for everybody, not yet anyway. I don't think they are as fragile as some seem to think. I seem to remember @peterboat has taken his quite low with no I'll effects. I would like to think our system has been designed to be idiot proof. The BMS will protect from over discharge if we ignore the monitor and alarms, and over discharge would be just as likely with lead acid. All our charging sources are set not to overcharge, and again, the BMS would protect the cells if the chargers developed a fault. I think if properly installed and set up they are at least as safe as lead acid, if not safer, and less likely to be damaged. I agree it does require some basic knowledge and careful system design to achieve this though, and if you don't feel confident then you have the option of the £6k Victron system! I've been roped into doing repairs for a couple of our neighbours recently. It's much more difficult and time consuming when faced with fault finding an unfamiliar boat, with no wiring diagram and seemingly illogical wiring colours that change half way along the loom! Both boats had a broken wire in the engine to control panel loom (along with several other faults). Same here! It's amazing the difference it makes having the wiring diagram in your head! Really should get some of it onto paper at some point though - no doubt in a few years I'll start forgetting bits of it. Tom
  7. Yes, my cells were not as well balanced as the supplier suggested they might be. It's certainly interesting just how quickly and how high the voltage can rise on an unbalanced cell, yet still easily remain within max overall voltage. Mine are still not quite as perfectly balanced as I might like, but perfectly ok to use, and haven't varied in use. Need to keep a close eye on cell voltages during initial charge though as when hitting the knee it can rise surprisingly quickly! I balanced mine initially by connecting cells in parallel, and charging until voltage was around 3.6v. I probably should have taken them a little higher, as a couple needed a further top up after installation. Both the initially parallel charge, and subsequent individual top up was performed manually using a standard sterling 12v charger, but with voltages very closely monitored - as discussed towards the end off this article in method 2: charging and balancing cells on board. Definitely worth spending the extra time to get the balancie correct, particularly if you don't have active balancing as part of the BMS. This stage requires patience and concentration if doing it manually, and can't be rushed!
  8. For those that haven't seen it the pictures don't do it justice. It really is the most ugly and impractical boat I've seen on the canals. Far worse than the pictures show! Added to the fact the quality of finish on the outside looks like something a 5 year old would be ashamed of. Can't see it being worth £7.5k, £75k for that is utter madness!
  9. Yes, couldn't get it to work at all at first, but after a couple email exchanges he noticed the mistake! I ran out of time to trace the other fault so went with the commercial option in the end. Sure it was to do with my circuit building though🙂 Yes, that's the one I went for in the end.
  10. This! The less user intervention required the better. Yes, although you may have to reverse the relay operation in the BMV. See my earlier reply for control options, although if only wanting disconnect, MP might come up with simpler circuit. Can't see this being a big problem. Lithiums would only be at 13.5v or so, so not sure how much current would actually flow. Certainly won't damage the lithiums. One issue I can see with your diagram is the BMV (1) is wired to monitor the total system. This will work well for seeing voltage and amps in the whole system, but will be virtually impossible to set up for meaningful SOC readings due to the completely different characteristics of the two banks. As already stated, LiFePo4 is a very safe technology, and unlike the lithium batteries found on mobile devices, are not likely to spontaneously burst into flames if overcharged! The worst that might happen is they might swell a bit, and if significantly overcharged, might vent some electrolyte. LA batteries have their own safety issues, and pose a possible explosion risk if overcharged and the hydrogen gets ignited. As to bss, the usual battery precautions and requirements apply. With lithiums it's important to protect the terminals by using insulated cover or other means. They generally have more exposed terminals, and more delicate wiring (monitoring, bms etc). They can produce many times more current than LA's in event of short circuit (e.g. dropped tools etc), and for longer! I'm sure I read somewhere (although can't remember where!) that at least one cell manufacturer recommended a max cell size of 200ah for marine use as larger cells were more at risk of structural failure due to vibration. The BEP switch needs a switched -ve. input -ve = switch on, input open = switch off. I think the problem may come from the fact the BMV has relay contacts that are NO unless in alarm state, whereas the Aus BMS has solid state relays that are NC unless fault detected.
  11. A lot of new posts since I last looked! If I miss anything anyone wanted a specific reply to give me a nudge. You need to take charger profiles labelled as LiFePo4 with a pinch of salt. Most have way to high voltages. I think this is because they are designed to interface with a proprietary system with built in bms. Alternatively they just want you to keep replacing their expensive batteries on a regular basis🙂 Ideally you need equipment with fully customisable voltage settings for charging LiFePo4. I use the Tracer MPPT with display. This has customisable settings for voltage and absorption time etc. Just remember if charging from solar (or any other source), to disable temperature compensation (some solar controllers and other charge sources still have this even if no external temp sensor fitted). I don't think temperature is as big an issue as some make it out to be. Providing you are not pushing at the very extreme limit of charging, it is highly unlikely they will even get warm let alone hot. If on the boat in freezing temps then unlikely the batteries will be at or below freezing, and if away unlikely they will receive much if any charge in freezing conditions - it would have to be a prolonged freezing spell to get much below freezing inside the boat. By doing this you lose one of the big advantages of lithiums which is fast charging from the alternator. What about a voltage sensitive switch as linked to earlier, set to disconnect from alternator at 14.0v? Also may be worth having a switch to manually disconnect solar if lithiums are fairly well charged and you're leaving the boat for a while. The BMV just has a standard relay that closes in alarm state (can be set to open if you change settings but uses more power). The Aus unit has solid state relays built in (one for high and one for low voltage) that from memory are closed in normal operation but open in fault conditions. These can be wired together to give one output. BEP 701 motorised switch just needs a permanent -ve, and a switched -ve to turn on and off. When switch wire is connected to -ve switch turns on, and when disconnected switch turns off. This is slightly more tricky! I've used one of these for high voltage disconnect (charge bus). There is a circuit here but having tried to build it, I was only able to get one output working correctly (probably made an error somewhere). In the end went for the simpler but more expensive option - the Rec BMS bistable relay driver, available here and here. Was surprised not to be able to find anything else commercially.
  12. That's why I mentioned the change to lithiums in my post🙂 Last winter we used mix of genny and engine (although engine much more convenient). This year with our lithium install we've only used the engine, and yes, with lithiums, an hour engine running will put 90ah back in!
  13. Living off grid and having done both, I sort of agree with mrsmelly. Our last boat was a trad with noisy aircooled lister, and although it would give good output from the alternator just above tickover, we tended to run the genny for power due to noise. Our current boat has a more modern Izuzu engine, with sound insulaton and hospital silencer. You really struggle to hear the engine at all from the front of the boat. Last year we did a mix of engine and genny running, but there's no doubt the engine wins for convenience as well as giving a tank of hot water. This year with our lithium batteries, we've not run the genny at all. Why would we spend 3 hrs with the genny putting 30A into our batteries when we could run the main engine for an hour putting 90A in and get a tank of hot water as well. A quick note on genny's though, get the best you can afford! If you can't run to a Honda then I go with Kipor. We started off with a cheap Impax one from Screwfix, but having replaced it twice during its 1 year warranty, when the third one packed up we went for a Kipor. Our neighbour went for a Clarke one, the 1st he sent straight back as leaked fuel, the second was replaced after a couple month as no output, the 3rd is still running, but only had it a month or so! The Kipor IG1000 we have is a bit under powered really for liveaboard use, but is still working fine after 2.5 years (used for 2 winters but not used at all this year).
  14. I would say experience Birmingham and some of the BCN. I think Birmingham at night is a must see by canal, and the BCN as a whole offers a huge variety, from city centre, semi derelict industrial areas, to the surprisingly rural feeling around the northern BCN. Cruising under the elevated section of the M5 or under spaghetti junction is quite interesting. Personally I could easily spend a week just on the BCN! But you could include Birmingham as a part of a ring, say the Stourport ring which includes the river Severn, and gives choice of Droitwich or Worcester. Alternatively the black country ring or Warwickshire ring include quite a variety including central Birmingham.
  15. I can see how it might damage blacking, particularly if sending sheets of ice skimming across the surface. However I would say the damage would be minimal, and not something to complain about. If you were that precious about blacking then don't moor online, simple. Alternatively if you must moor online then hang ice boards down along the waterline. Would look a bit over the top for a steel narrow boat though. I don't think moored boats have any right at all to complain about ice breaking along a navigable canal regardless of how thick it is. Certainly our neighbours never make any comment to us about it when we go ice breaking to the water point.
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