Marine
What house battery suits my boat?
Sealed AGM or lead-carbon is the usual choice replacing old flooded banks - one boatie swapped four 6V 225Ah flooded batteries for a sealed AGM 12V bank. We size 2-4 large NOMAD E2 ULTRA and NOMAD C2 CARBON for house duty.
Can I charge the boat bank from a big alternator and a shore charger?
Yes, but mind the charge rate - a large alternator plus, say, a 130A shore charger can push a bank hard, so the battery accept rate and charger supply need to match. We spec these components to be compatible with each other which gives enhanced longevity.
Do your inverters suit marine use?
Yes - the NOMAD NPS range is designed for mobile, marine and fixed installs, which is why they're used by multiple defence arms. Mount them firmly and ventilate well .
What standard governs boat electrics in NZ?
AS/NZS 3004.2 (the 2014 edition incl. Amendment 1, for boats up to 50m) applies to recreational boat installations; for ships 24 metres or less overall, Maritime NZ rules require the electrical system to comply with the applicable parts of it. Critically, RCDs installed for personal protection must be Type A with a residual operating current of 30mA or less.
Do I need a marine electrical warrant?
Yes - marinas can't legally supply shore power to a vessel without a current Vessel EWOF, renewed every four years, to the marine standard. It's the marine equivalent of the RV EWOF.
Can I run a 12V circuit off my 24V boat bank?
Yes - a 24V→12V converter creates a stable 12V circuit; customers use these in boats, trucks and motorhomes routinely. Your converter must be of sufficient size to power your maximum load including surging.
What about a bow thruster or windlass?
Those are big momentary loads - a 12V windlass can pull ~85A running and ~140A surge, so they need very heavy, short cable runs to avoid voltage drop. The key here is to size the cable to the surge, not the average.
How do I stop galvanic corrosion with shore power?
Use the correct galvanic isolation and bonding per the marine standard; get it inspected as part of the vessel EWOF. This is safety-critical, not optional.
Best way to keep the bank charged on a mooring?
Solar with an MPPT keeps a boat battery bank topped between trips; add a shore charger for when you're berthed and have mains supply available. Lead-carbon batteries cope well with the partial state of charge use a moored boat imposes.
Is a dual-purpose start/house battery ok on a small boat?
For a small runabout, an upsized dual-purpose AGM with high cranking amps works; on anything larger or anything you sleep aboard, separate the start and house battery banks.