AVR-Chat

Welcome to my world. It's a bit of an industry separator. In the EV 
industry relays are low current devices and solenoids are used to open and 
close hydraulic valves.

Ø    I’ve encountered that use of “solenoid” as well.  (Does “EV” stand for
Electric Vehicles?  I just bought a Prius.)

The SW500 is probably overkill for you but that's not a bad thing.

Ø    Agreed.

Speaking of which, remember these are open contactors. If you need to 
avoid sparks you may need to enclose them.

Ø    Good point, but probably not necessary for 2 reasons.   First it is at
the other end of the boat from the engine, propane, fuel, etc, but, more
important, the contactor does not make/break the 400 A.  It only has to
carry it.  Thus there should not be any sparks.  Nonetheless, I’ll mention
it when I talk to Teknowledgey.

That leads me to think a DC/DC from your main battery bank might be 
worthwhile. It would keep the thruster battery charged up but the current 
draw would be minimal.

> To charge the thruster battery I  have a marine-grade “Automatic Charge
Relay” (there’s that term again, even though it handles up to 60 A!).   This
automatically connects to the main boat bank whenever that bank is being
charged, and disconnects when not.   The main bank always uses a “smart”
charger, either from shore power (120 VAC source) or the engine.   This is
SOP on boats.  The thruster battery thus automatically gets charged every
time the boat is on shore power or the engine is used, regardless of whether
or not the thruster has been used (the same as the engine start battery).
The Optima batteries hold their charge so well that the battery can go weeks
or even months without being used and not float charged in the interim.  I
use an Optima for the engine start battery.   

> Also, the thruster is only used when the engine is running.   In practice
the engine will have typically been running for many tens of minutes, often
an hour or more, before the thruster is actually used.  Thus the thruster
battery will always get charged immediately before being used in almost all
cases.  (I should add that this is a sailboat, so the engine is not
necessarily on all the time when the boat is underway.)

> I have a third Optima on the boat, a deep cycle one.  This is used for the
source of that 45 A current that I mentioned with the mosfet business.
This gets used on a pretty steady basis and needs to be kept as charged as
possible all the time, whether or not an external charging source is
present.  In this case, I do use a DC/DC arrangement to keep it charged from
the main bank.

To Albright an intermittent duty coil is used on direction contactors and 
is expected to run some thing like 40-60% on with 10's of seconds to 
minutes between direction changes. Continuous can handle more but an 
intermittent coil may well work for you.

The SW500 is a telecom contactor so a 12V coil may take extra lead time. I 
expect it will be available but it might be uncommon.

Ø    Thanks for the tip.  I’m ok with up to a couple of months.

Tek will probably question you on your selection to make sure you are 
making the right choice. They seem quite knowledgeable from my contact 
with them and they don't do much second guessing once it's clear you know 
what you are doing. I've had the same issue with a number of contactor 
manufacturing companies, they don't want to provide specifications they 
want the details of your application so they can pick the contactor for 
you. It's one big reason I like Albright.

> I’ll do as you suggest and talk to Teknowledgy and let them guide my final
decision.

> Steve



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