Installing a Simrad EP 65R NMEA 2000 Fuel Level Sender/Converter -

Jlawsen

Master Chief Petty Officer
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Apr 22, 2012
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Some of you may be considering installing the EP 65R so that you can use your Lowrance HDS unit's Info screen Fuel Gauge. There's a lot more you can do with this if you also have the fuel flow meter but that's not the subject right now.

If you are like me, you like to have a fall back but the instructions for installing the EP 65R require that you disconnect the analog gauge. When I first read this I said no way, I trust my gas gauge and I don't know if I can trust this new thing or not.

Good news, you can easily put a dual position double throw switch (DPDT) in between the two gages and then switch back and forth.

When you want to run your gauge from the Lowrance you put the switch in the Lowrance position and when you want to read the analog gauge put the switch in the analog position. I labeled mine L and D (Lowrance and Dash).

Even if you fully trust your Lowrance NMEA 2000 gauge, having the dash gauge option is great when you just need a quick read like at a gas station, etc.

FYI I purposely left out the explicit wiring instructions because if you need them you shouldn't be doing this on your own. Any marine electrician can install the switch and the EP 65R in about 1/2 hour.

Please don't PM me for the instructions either, I won't respond.
 

Pez Vela

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Dec 4, 2004
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Re: Installing a Simrad EP 65R NMEA 2000 Fuel Level Sender/Converter -

I trust my digital EP-65R readings, but your comment is interesting. Maybe the switch is not between the gauges, but is downstream from the EP65-R. For lack of details, I will forever be left to guess how my old analog gauge could read the digital data from the EP-65R. Oh well.
 

Jlawsen

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Apr 22, 2012
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Re: Installing a Simrad EP 65R NMEA 2000 Fuel Level Sender/Converter -

The EP-65R just converts the resistance changes in your current float style sender into a NMEA 2000 sentence that is then readable by your Lowrance. Since the sender remains the same you just use the switch to choose if you want to convert it or not. Flip the switch to one position and the EP-65R is connected to the sender. Flip it the other way and the dashboard gauge is connected to the sender.

Just so you know, the output of the EP-65R is not digital, it's analog. They do make a digital fuel level sensor with NMEA 183 output and a interface for that but it's not real popular as a retrofit item on small craft because it often takes more than just a couple of hours to install and calibrate. I experimented with one on another boat and decided against recommending it.
 

Pez Vela

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Dec 4, 2004
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504
Re: Installing a Simrad EP 65R NMEA 2000 Fuel Level Sender/Converter -

Thanks for the explanation. Just as I thought on placement of the switch. Your expertise is appreciated, as I always like to learn as much as I can about NMEA2000 and common sense improvements to my systems.
 

Jlawsen

Master Chief Petty Officer
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Apr 22, 2012
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Re: Installing a Simrad EP 65R NMEA 2000 Fuel Level Sender/Converter -

Thanks. Yes, NMEA 2000 is the protocol and the most common network type is simple peer to peer so there is no routing involved. Everybody is shouting on a peer to peer network and when they're shouting, they're not working so it is relatively slow. Lowrance uses 10mb Etherenet for it's LSS-1 Structure Scan and its Sirus Sattelite WX/Radio reciever. The LSS-1 option comes with a 3 port Ethernet switch. I'd really like to see them expand that but they have to wait for the industry to catch up I guess.
 

dingbat

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Nov 20, 2001
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15,416
Re: Installing a Simrad EP 65R NMEA 2000 Fuel Level Sender/Converter -

.....
 

SteveMcD

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Mar 21, 2011
Messages
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Re: Installing a Simrad EP 65R NMEA 2000 Fuel Level Sender/Converter -

Since the fuel sender varies the current flow, and current remains constant in a series circuit, maybe wiring the gauge and converter in series will allow simultaneous operation without a switch to forget to switch and/or fail.
 

sschefer

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Nov 13, 2008
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Re: Installing a Simrad EP 65R NMEA 2000 Fuel Level Sender/Converter -

Steve, you can't do that because the sender is in series with the gauge. The EP-65 ties into the sender and has it's own 12vdc source in the NMEA 2000 network. Because it's in series, you'd end up with 24vdc and that would blow the EP-65. This is why they tell you to remove the wires from the sender and connect the EP directly to it. You don't need to do that if you understand the circuit but you do have to make sure that the pink and black are only connected to the EP and completely disconnected from the gauge. That's the beauty of the DPDT switch. You can have the best of both worlds.

FYI, I hooked mine up just like JLawsen recommended and it works great. Now, instead of having to fire off the Lowrance at the gas station I just flip the switch and read the dash gauge.

The other way to go about this would be to replace the analog gauge with the Navico NMEA 2000 digital gauge that fits the standard gauge hole. I thought about that but decided it was a lot cheaper to just go with the switch.
 
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