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magnetman

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Everything posted by magnetman

  1. 24v Alternator 55A is £150 (prestolite lucas a127) Couple of cheap lead acid batteries £150. I already have a 50A MPPT which is surplus in winter. In summer the vast majority of the electric is dealt with by solar panels. 50A b2b would be £300. It costs the same. I think the 24v alternator might be better for thermal management as there are fewer amps coming out of it. Which would mean one could eke out more power with less risk of overheating. I expect a good alternator controller solves these problems but how much do they cost?
  2. The Boat domestic system is run by a 12 (13) volt LFP bank. The only 24 volt parts would be the alternator and the small Lead battery bank. This would be routed via the MPPT (might not work) to the LFP battery bank which would be 12/13v. I was proposing repurposing a high current MPPT for winter when their is naff all solar. Making silk purses from sows ears seems quite a wise move to me in a number of different ways.
  3. Cheap and cheerful alternators? Also did you check the operating temperature range of the alternators?
  4. The system I was referring to has dual alternators. The starter would be 12v.
  5. One of those cheap single induction hobs would be good because they have power settings from 300w to 2kw selectable. Maybe more ventilation is needed for these alternators.
  6. If you have a big inverter and heavy load like an immersion heater which the inverter can run you could test the alternator that way. IR thermometer to hand.
  7. Maybe A 24v alternator, 2 LA batteries to make a 24v bank and the MPPT repurposed for winter to charge the LFP batteries via alternator-LA battery-MPPT. In summer the solar does the job and the other alternator is still 12 volts.
  8. 30 amps seems quite a low charge rate. Is it also the point at which Victron B2B hardware gets a lot more expensive? I do idly wonder if my 50A Victron MPPT for the solar panels could be repurposed and used as a B2B in winter if I wanted to charge batteries using the main engine. Sun is predictable due to seasonal changes so there would be a certain point where whipping out the 50A and replacing with a 20A MPPT (observing input voltage) could make some sense. Don't know if it would work and I think perhaps there is a problem with voltage needing to be higher than the battery. Maybe Victron have already thought of that and designed it out of their products. Been here before I seem to recall. 24v alternator is the thing.
  9. It would be fun if a court had to decide what 'drop in' means. They might come to the conclusion it just means two items the same shape. 'Drop in replacement' Not 'drop in alternative'.
  10. 2 fires can be a solution for this. Lots of narrow Boats have two fires.
  11. I seem to recall there are the remains of a miniature railway there for the gasworks.
  12. Have they sold that many ? Warranty claims seem to not include burnt alternators. Also, as I have been saying all along, these things are great for solar panel use. I'm not remotely anti lithium batteries but I do question the drop in status. I guess a lot of these are sold to motorhome owners who are probably just a wee bit conservative and tie up their vans in nice safe camp sites with 6A mains supplies so they can charge their batteries up.
  13. I know what it is supposed to mean but in reality most people can't 'drop' one of these in to replace an existing Lead battery. It won't work. Well I suppose it is possible/probable that more people have shore power than don't but in that situation one would not be looking to maximise battery efficiency anyway. Presumably if it all gets regulated at some stage then terms like 'drop in' won't cut the mustard. They might even turn into 'drop out' when the arrangement is rejected on safety grounds.
  14. Yes but what does 'drop in' actually mean? It appears to be a meaningless term when it comes to batteries. A marketing term made up by someone at some stage. Was it Mr Sterling ?
  15. Drop In is definitely an interesting but of terminology. Obviously this is referring to the size of the battery blocks as provided and it is convenient to supply LFP battery blocks which have the same 'form factor' as normal '110 leisure' type Lead batteries. But... If one were to take the term 'drop in' literally it implies that the battery blocks may be released from a height. In some cases this could be quite handy as getting down into the engine 'ole is arduous. I think the suppliers probably ought to have specs for how high one can drop the battery in from. Is it one metre or two? Perhaps 'drop in' is referring to a casual medical facility.
  16. I have never run a main engine while moored in 30 yars of living on Boats. Always had a generator for charging when not moving. I disagree with using the main engine for this but when the Boat is moving taking advantage of the power available seems wise. More than half of that 30 yars was without shorepower although I admit one of the Boats has had the umbillical for a while. I hate it. and from beginning of April to coincide with the anniversary both Boats will again be off grid and free to roam. Yaay!
  17. Oh maybe not then. Perhaps an inverter running off the AGM bank charged by the 175A Iskra alrernator powering a lithium specific charger. At the end of the day the issue is with inappropriate rotating electrics so perhaps this is where things need to change. I sometimes wonder about a permanent magnet alternator with a magnetic clutch. The best one would be running from the propshaft then you could pull some real power off it.
  18. Maybe a job for a travelpower instead of the second alternator and a mains powered lithium battery charger. The standard 12v alternator seems to be the weak link. If it was done via a travelpower then the main domestic battery could be 48v with converters for small 12v consumers. I wouldn't be surprised if a lot of consumers on modern craft are mains powered via inverters. 48v is nice.
  19. Something similar happens with ships The Lifebatteries geyser is already doing this. The webshite looks pretty amateur so I don't know if it is a genuine player but he thinks it works.
  20. Yes. When I was doing my BTEC in marine engineering in 1995/6 the same college was doing the Boat Safety certification scheme. I missed a trick there. I did two yars full time and these buggers were only doing two weeks !! anyway there were random people and I bet if you had asked them none of them would have known what a gripe is or even a forefoot. Terrible really and I have always made an extra effort to ensure the BSS examiner is a keen Boat owner.
  21. One of my Boats was passed with a disconnected pile of random lithium batteries enough to blow a hole in the riverbed if I accidentally get the connections wrong. I used to have a car which whizzed around on roads with loads of other cars and even bikes and pedestrians and believe it or not it had a thin metal container with a load of undiluted petrol in it ! major hazard yet it was for some unknown reason allowed.
  22. In the case of 'Lifebatteries' the "10 year warranty" is in fact not a 10 year warranty it is a warranty based on number of cycles and assumptions. " This Limited Warranty does not cover a Product that has reached its normal end of life due to usage which may occur prior to the Warranty Period. A battery can deliver only a fixed amount of Energy over its life which will occur over different periods of time depending on the application. For example, cycling the battery more than 2 times daily, may cause the normal end of life to occur before the end of the Warranty Period. The Manufacturer reserves the right to deny a warranty claim...." This Limitwarrantyed Warranty does nohttps://www.lifebatteries.co.uk/blank-page-2t cover a Product that has reached its normal end of life due to usage which may occur prior to the Warranty Period. A battery can deliver only a fixed amount of Energy over its life which will occur over different periods of time depending on the application. For example, cycling the battery more than 2 times daily, may cause the normal end of life to occur before the end of the Warranty Period. The Manufacturer reserves the right to deny a warranty claim So have the LFP in the cabin and just disconnect when the BS inspection is carried out. The BS is only a snapshot on the day. Would they be concerned if you have ebike batteries in the Boat? or batteries for the electric canoe ? Things can change afterwards. Good reason to have a Lead battery connected to the engine and alternator. Keeps it all straightforward. There is no lithium bank.
  23. There is that. One would hope that in an arrangement where "This has to be a manual intervention with monitoring so would not suit everyone. " as noted in a previous post the individual carrying out the procedure would be aware of the elf of the batteries. I did mention previously this is not a fit and forget system and would need manual intervention and monitoring. I guess it is rather unusual for people to have a close relationship with their batteries.
  24. You only find out what happens if you try it. are you saying if you connected a charged nominal 13.2v LFP 100Ah battery to a discharged 100Ah LA at lets say 12v the LFP would try to discharge into the LA at 100A? How do you know this if you have not tried it? Are you basing this on theoretical calculations of internal resistance?
  25. Have you actually tried it? I know there is the theory that there will be a terribly large discharge from the lithium battery and sparks and melted wires but have you actually done it and found out what happens? I have. It doesn't go crazy and make sparks or burn anything. Maybe it would with an enormous battery bank but I am not advocating for tonnes of lithium batteries.
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