GTom

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About GTom

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  1. GTom

    Lead crystal batteries?

    That's very interesting and a bit difficult to believe, simplest, cheapest = best? How much heeling do these flooded cells tolerate? Lead crystal is costs about 30% more than an equivalent AGM/gel.
  2. GTom

    Lead crystal batteries?

    Correct, but those are not practical products for the everyday yachtie. Quality gels rarely go above 600 cycles - still no concern if you sail only <100days a year.
  3. GTom

    Lead crystal batteries?

    Right, I go with a full cockpit tent.
  4. GTom

    Lead crystal batteries?

    That's why you decorate your bimini with a 310Wp, 220EUR cost solar panel.
  5. GTom

    Lead crystal batteries?

    That would be really interesting although not at LiFeYPO4 prices. Also 2V/500Ah units are a pain, I don't intend to buy 500Ah capacity for a 30' boat.
  6. GTom

    Lead crystal batteries?

    Haven't done the maths but probably a single 250Wp panel on your bimini could top up that 15% you need as "slow charge".
  7. GTom

    Lead crystal batteries?

    Agree with that! The effective costs are very similar, the actual use/abuse will decide your final budget. Replacement cycle/service life is also very usage dependent, heard about well kept quality gel units running after 8-9years... Right, that's where a solar panel comes in the picture.
  8. GTom

    Lead crystal batteries?

    No, it is NOT, that's what I am trying to explain... On a boat you DON'T deplete your bank to let's say <30% SOC. Not just at night, you need VHF, Chart plotter at broad daylight too. And if you don't, what is the advantage of LFP at a ~3x price? If you understand what the Peukert effect is, then you know how much of an issue is in case of 0.05C load.
  9. GTom

    Lead crystal batteries?

    You'll have more to worry about than your wallet if you're left without lights, radar and even chart plotter in a busy channel at night. 20% means how much reserve if your engine fails, 2 hours?
  10. GTom

    Lead crystal batteries?

    SOC=0% IS the safety concern because you can't run your instruments, vhf, lights. Being close to it means risk.
  11. GTom

    Lead crystal batteries?

    Are there any reliable controller options for a Rutland 1200 windgen+solar? Did any big cruise ships change to lithium? They are profit driven businesses, if really lithium is the way, they should have moved in that direction I suppose. As for price: yes, LiFePO is pricey, the only sane pricing I saw were the Winston WB-LP12V90AH, costs 480$+VAT. That amount of money buys you 250Ah worth of quality gel. I doubt that the lithium option is more than 2.6x better in realistic conditions. One argument for Lithium is that lead is plagued by Peukert's law. Indeed it is, but that begs the question: how many hours of reserve you want in a passage making or any off-the grid boat? Do you really want to minimize your bank that it can be depleted in <5hours? (discharge current >0.2C) Do you really want to risk getting close to 0% SOC (=no lights/instruments, etc) as a routine? Because as I understood, these are the situations where lithium shows its teeth. No problem for a commuter car, but crosses many safety and sanity guidelines for off-the grid cruising.
  12. GTom

    Lead crystal batteries?

    That's my impression to and leaning towards quality VRLA's at a more realistic price point. LiFeYPO4 is interesting but charging lithium is a pain and they don't live longer than 10 years either.
  13. GTom

    Lead crystal batteries?

    Apparently nobody heard about them... Short summary after doing the homework: cycle life at 60% DoD, 25°C: ~2200cycles (Sonnenschein claims for their quality gel batteries around 800Cycles), Peukert's law still applies, and the coefficient is in the same range as AGM's. Claimed service life around 12 years at 25°C, more at lower temperatures. Datasheet. And a tech review - latter disputes the longer service life. If every bits are true, the deeper cycles, longer life might worth the additional ~30% cost.
  14. Thank you for the feedback! I have an alternative boat choice that needs a new engine (price is correspondingly lower) - it seems then, Solé/marinized Mitshu is absolutely a viable option! In case I do the engine upgrade I considered Bukh (DV36), but that seems a bit pricey for the task...
  15. Anyone upgraded to lead crystal batteries? I can't find relible 3rd party comparison to AGM, only marketing claims.