Originally Posted by karkauai
Gotcha. Thanks for clarification.
The previous owner of my 2016 boat is picking up a new Emil 50 right now, he's going to sail it back to Oz.
He said to me about Lithium:
3rd party installations of lithium have resulted in a number of fires with boat wiring not up to scratch which is why insurance companies are giving them a wide berth. Even on my new boat with lithium factory installed there is an insurance excess of 50% of the value of the boat should the cause of the incident be related to lithium.
The new boat an AMEL 50, has lithium, a genset and 1.5kw of solar. I though about the hydro generator but because the boat has a swim platform it would have to be permanently in the water. Not wanting the constant drag on performance I left it out. Yes all sails are furling and electric – bliss (if it doesn’t break!).
So even in a 2 million Aussie dollar boat, the owner has to pay 50% more insurance excess on damage to the boat due to lithium consequences, and that is obviously a factory install.
I asked the owner because my boat is designed to be lightweight and hence lithium would suit it better. Lithium also affords fast charging
, if one has the capacity to charge quickly and safely, which gets complex if you want the alternator
to directly charge the lithium batteries. Hence typically external regulators, continued charging
of the lead acid starter battery, a BMS, etc. But it seems the safest way to charge is with a DC-DC, and those have charging bottlenecks that can effect the advantages of charging lithium, which can be charged quickly if the alternator can be prevented from overheating
. Also with more charge going through, the wiring
has to be heavier. Plus if charging stops before the alternator stops, the alternator burns out due to no where for its charge to go. So alternators also need to charge a lead acid at the same time as a fail safe for a BMS stopping the charge while the alternator still generates. Cooling
of the alternator is also an issue, because if they run at high capacity, they get very hot and the boat is unlikely to have extra cooling
capacity for the alternator to be running at several times its expected output. The fast charging capability of lithium also means it is riskier as it can dissipate its energy much quicker, which is another danger
. And who knows - that may compromise the earthing capacity of a boat. I don't understand the earth side of boats properly, and all boats are different as well in that regard, so I am told, and it seems, the people telling me don't understand either!
Hence the complexity of lithium.
I am exploring ensuring my system is "balanced" - and my main usage will be auto pilot, followed by the fridge.
I reckon for me a water
powered generator and less batteries would do the job better ... the problem with lots of batteries is that once run down, you are even worse off than with less batteries! One has to achieve some balance it seems to me!
I am also checking out lead acid "carbon" batteries, which insurance companies don't specify in their tick check boxes. They are more efficient and are supposed to last longer (less sulphation due to carbon on one of the poles). Also less weight. But less known ...
let us know what you did!