That 100A guideline is a WAG ballpark, but as stated de-rating will allow empirical testing as a stage 2
project.
C-rate is a proportion of bank capacity. Say yours at 12V is 400A, then .3C is 120A.
To optimize for longevity, make that an "occasional when needed fast charge" rate, and stick to 80-100A normally.
But on truly critical occasions say under 3% of cycles, a 160A rate won't cost much off the back end.
So for 24V, cut the above Amp rates in half, same watts, same belt issues.
The heat issue is a qualified yes, 24V is a bit cooler, but IMO usually not needed at such
low power rates. Other possibilities, not mutually exclusive but in order of my preference
fitting an alt that is inherently designed to output near its rated capacity 24x7 - or oversized so you'll only rarely even draw over 50% of its max
moving the
electronics away from the alt body
improving airflow in the compartment and specifically over to / away from the alt
The added cost and complexity of going 24V for a
small boat with small power draws, though not huge just seems unnecessary to me, personally.
If you do end up using point-of-load buck converters, they can be found very cheaply in the sub-300W range, just carry plenty of spares. Or you need to rely on a pricey say
Victron unit and run a 12V distribution
network as well as the 24V backbone. yech.
Why are you even talking about DC-DC charging? Best to charge direct at the bank-native voltage, only convert for loads. If you're converting to a 24V alt, I would have thought everything
engine related like cranking goes that way too?
But again, don't think the conversion's called for in the first place.
Quote:
Originally Posted by rgleason
I wonder what the difference in the cost of the alternator wiring would be between 12v & 24v?
|
Supposed savings in wire gauge amortized over time will be infinitesimal, it's a once-off and bulletproof.
The "cost" factor you need more focus on is simplicity, reducing the number of gadgets that make the System as a whole less reliable, need to carry spares, more difficult troubleshooting at the **least** convenient times.
Even paying more to achieve KISS is worth it, happily here it's probably cheaper.
How about this step-wise approach?
Never mind about the bank selection for now, just set that issue aside.
Yes do your location/space carpentry mods for maximum flexibility, but not locking you into a **specific** battery size.
Big spending decision fork - invest in higher amp alt output first, or solar? Personal choice, but be sure to physically mock up your panel placement to be able to accurately judge your maximum Wattage and see its impact on aesthetics & windage.
Get all the other infrastructure in place, able to properly care for and use whatever type of chemistry you choose in the future.
But take that "which bank?" choice out of the picture for now, you're juggling too many simultaneous decision trees, focus on the charging infrastructure and loads distribution, systems monitoring etc first, pick one subsystem at a time, design and select the components to
work well with "whatever chemistry", actually put it in place, and then move on to the next area
Stick to cheapest lead for meantime until you're happily working with all the rest, average daily
income consistently above the average outgo, have a good idea how many bad-weather buffer days you want if by now shooting for "almost free always quiet mostly-solar".
Of course in the meantime continuing to
research trustworthy domestic sourcing at reasonable pricing if you decide LFP.
And giving Bruce plenty of advance notice for your FFs if your model's back-ordered.
And of course gives you more time to save those pennies in advance so it doesn't hurt as much, that cheapest lead may
work fine for quite a few years given the white-glove care it's getting 8-)
Linear Mode
Recent Discussions