need to know how to drop the load for a test

[Razco53]

We are needing to test a Classic 150 so the batteries drop off when a certain voltage is reached (low). The system runs a 24vdc RWIS set up.  I am needing some instructions since I am ignorant to how this works. I do know that AUX 1 in diversion mode will be set up, but I am not sure how the relay will work with in the system or how the install works.  Please forgive me as I am new to this Solar Set up.

Thanks

[Westbranch]

Is this a safety shut down to protect the batteries or ? 

What type, make and capacity battery is being used ?

What other euipment is involved?

more later...

[mike90045]

Didn't Chernobyl meltdown start as a "test" ?

A "charge controller" does not drop Load.  The Load must be programmed to disconnect a your desired voltage. 

[Razco53]

The test is to find out how long the system will run on battery power only. The customer would like it to run for a certain amount of days.  We need to have the power stop drawing from the batteries when they get to a certain level as not to "kill" them.
The system has a double battery / solar array each having it's own Classic 150.  Batteries are 2v gel 1250 ah each 12 in series for each system.
So I need to know the proper relay to use, how it needs to be wired in etc. 

Thanks

[Westbranch]

What type, make and capacity battery is being used ?

What other equipment is involved?

more later...

[zoneblue]

If you want to implement a load disconnect, you should do this at the load, not at the batteries. This has been extensively discussed here previously, (try a google search on this site).

Basically, your choices are;
- the inverters aux disable
- inverter AC side relay or SSR
- inverter DC side relay or SSR

The latter is the last resort, and if you go this route these remote trip breakers are probably the go:
http://midnitesolar.com/productPhoto.php?product_ID=578&productCatName=Breakers&productCat_ID=16&sortOrder=3&act=p

If you use a relay, make SURE that it is a adequately specified to handle the current and arcing. If you use an SSR make sure you buy a name brand quality unit  such as Crydom.

However, in normal practice you should try not to rely on LVD, as its likely to overstress the battery by taking it too low SOCs too frequently. For a one off emergency its fine, but as you can see its not trivial to implement.

[Razco53]

Haze HZY21250  2 Banks with 12 ea. 2) CL150's
3660W Solar array. 12 Canadian Solar CS6X-310P PANELS

[Westbranch]

found this page and google translate from Russian,

Capacity:  (Ah) 1250
Rated voltage: 2 volts
Form Factor: Lead-acid with gel electrolyte (GEL VRLA)
Purpose: Stationary
Life time: More than 12 years

RWIS = A Road Weather Information System

that bank has a usable capacity of 1250Ah @ 24v  with a DoD of 50%.  or 30,000Watts
Going below 50% gets you into the zone that is difficult to recover a battery from.

What is the total power demand @ 24V  for the cameras and the telecommunications devices in watts or AH ?