Product Description

EGIS XD Flex Single: Programmable ACR / RBS / EP Relay – 500A (w/ Manual Knob)

What the heck is this thing?

Bottom line: It’s really neat EGIS product, you can program it for one of two basic uses:

1. Remote Battery Switch (RBS)
2. Automatic Charging Relay (ACR) & Emergency Parallel (EP) Relay

For the technical types, here’s a complete spec sheet with lots of examples.  For the rest, let’s dive into the two main “modes”.  These are programmable using DIP switches on the back of the unit:

Remote Battery Switch (RBS):

As a Remote Battery Switch the XD Flex Single is basically a very high amp relay (500A continuous, up to 1600A starting).  This would replace a traditional battery switch (big red knob) near your batteries with a small switch like this at the helm or in the console that remotely turns on your batteries:

Why would you want a remote battery switch?

Lots of possible reasons:

1. Maybe your batteries are in a location that is hard to get to (like in a hatch or inside the leaning post).
2. Maybe your battery is a long distance away from where you want to be able to trigger it (ex: in an engine room).
3. Maybe it’s physically difficult for you to turn a physical switch.
4. It’s possible to build a system using XD Flex products that requires almost zero knowledge of the battery system to property run the boat and charge your batteries.
5. Sometimes a boat’s battery switch is in a location (like the console) that gets covered with stuff (ex: life jackets and bean bags).

Set as relay the XD Flex can remotely switch nearly any high amp load.

Automatic Charging Relay (ACR) & Emergency Parallel (EP) Relay:

An Automatic Charging Relay (sometimes called Voltage Sensing Relay, or Battery Isolator) is used on boats to automatically manage which batteries are getting charged by the engine.

Why would you want an Automatic Charging Relay?

Well… we know that your engine’s alternator charges your start battery, but how does your house battery get charged?  Usually this happens by the boater manually switching his physical red battery switch to “BOTH” or “Combine” while the engine is running.  Which parallels the battery allowing the alternator to charge both start and house batteries at once.

The downside is you have to actively mange this on your boat.  Changing between Start, House and Combine throughout the day as you go from running to sandbar to drifting to running to fuel dock, etc.

With an Automatic Charging Relay like our XD Flex Single, this now all happens automatically.  You crank the engine and go… all day… without touching the battery switch again – and the batteries are charged more efficiently and more safely!

The XD Flex senses the voltage of the start battery and knows when it is both:  A) topped off. and B) Charging via the alternator.  And it will keep the house battery isolated until both of those things happen.

Then, when you crank up the engine and the start battery is fully charged, then the ACR will parallel, automatically charging your house battery.

The exact ON and OFF voltage levels can be adjusted by the DIP switches, but default to 13.1Vdc ON, and 12.7Vdc OFF (when used on a 12V system)

What about an Emergency Parallel?

Since this relay is such high current, and features flying wire control leads, it can DOUBLE as an emergency parallel feature while in ACR mode.  Yes – that’s right… our XD Flex can act as both an ACR and emergency combine.  Here’s how and why:

If your start battery does somehow get drained and won’t turn over your engine, then the XD Single set as an ACR will naturally be open (in isolation mode).  But in this case maybe you DO want to parallel your house and start batteries to get that extra burst of power.  Well simply apply 12V to the red “FORCE ON” lead via an external switch, and now the switch parallels the batteries to start your engine.

We recommend a momentary switch for this, near your key switch so you can press and hold, then turn the key… then release to avoid paralleling two batteries with dissimilar charge for very long.

Other Features:

Manual override knob – The yellow knob overrides whatever the flying leads or ACR settings are telling it to do.  Move back to the center, and it’s back on the program.

Works on 12V and 24V nominal systems – Just hook it up, self sensing

Remote status indicator light – one of the flying wire leads is a remote indicator… SUPER nice for ACR’s to know when they are charging, and we can incorporate this into your custom dash panel if desired!

Extremely low parasitic power draw – only 1.3mA!

Extremely high current rating – 500A continuous is unheard of for an ACR

EGIS’s 4 Year Warranty – Bullet-proof construction and unheard of warranty support

Form Factor – Much smaller and more compact form factor than any competing product

Flying Lead Color Code:

• Black – ground
• Red – Force on (+Vdc), Force off (-Vdc)
• Brown – Force on (+Vdc) (use when also using green)
• Yellow – External LED (ground when relay closed)
• Green – Force off (+Vdc) (use when also using brown)

See Also Double, Triples:

So when designing a system with the EGIS XD Flex Series, you’ll often find yourself needing more than one.  For example, if you have a single engine, with two batteries (house and start), and you also wanted an ACR, then you would need three of these XD Series Singles.  Two set to remote switches, and one set as an ACR.

That’s where the Doubles and Triples come in.  They are build into one case, and share lugs, so there are less battery cables, and costs savings over multiple singles.

Note about EGIS Part Numbers:

Since it is programmable, this unit can be programmed to be a number of different EGIS part numbers.  It comes factory configured as a 8710-1300B (an ACR), but can become a 8710-1500B with a change of the DIP Switches.