GPS Power Drain?

Stoo · 13 November 2006, 02:05

I have recently installed a Lowrance LCX-25C plotter. It appears to be a bit of a power hog. When I am diving for extended periods, something is draining the batteries and, since only the plotter is new, I am assuming it is the source of the problem.

Beyond that, Lowrance has suggested that the antenna (LGC 2000) which is separately powered, might continue to draw power even when the unit is turned off. Their suggestion is to put the antenna on a separate switch, or turn the batteries off when I am not under way!

Has anyone else had any issues like this, and if so, what did you do about it?

Thanks!

codprawn · 13 November 2006, 02:45

Electronic equipment like this only draws a small amount of power. My Raymarine draws 10w for the plotter and 1.5w for the gps unit. In total this is only about 1 amp. fishfinders use more - typically about 30w or 3amps. VHF sets use a fair bit when transmitting.

With just the gps/charplotter running you should have about 50hrs running on a big battery. I suspect either a short or else a knackered battery. Maybe a few cells playing up - still shows a good voltage but falls down on load.

Stoo · 13 November 2006, 10:56

Quote:

Originally Posted by codprawn

With just the gps/charplotter running you should have about 50hrs running on a big battery. I suspect either a short or else a knackered battery. Maybe a few cells playing up - still shows a good voltage but falls down on load.

That's pretty much what I thought as well. I suspect that one battery isn't great and I will replace it any way... It's easier than hunting fora fault that probably doesn't exist!

Texel Tom · 13 November 2006, 20:10

The LGC2000 antenna does indeed continue to draw power when the LCX is switched off as it forms of an expandable NMEA2000 network (LowranceNET).The LCX purely acts as a host to supply independant power to the network which could include fuel management, speed and temp devices plus outboard interface connectivity.

It's recommended that this is switched independantly via a switch panel or such like.

TT

codprawn · 13 November 2006, 20:29

Yes but 1.5w is not a lot!!!

Texel Tom · 13 November 2006, 20:44

You're right - just thought it would be helpful to know for periods of non-use.

Stoo · 13 November 2006, 23:41

Quote:

Originally Posted by Texel Tom

You're right - just thought it would be helpful to know for periods of non-use.

Initially, I was having problems after perhaps 2-3 hours... the duration of a dive, lunch and a cocktail.... I presume that if this is causing problems, then I must have an ailing battery.

I am no electrical expert, but if the draw from the antenna is in fact about 1.5 w, how long would this take to drain a healthy battery?

What I find odd is that Lowrance had included a special bulletin (on hot-pink paper no less...) with their instruction manual reminding us that the antenna needed to be powered separately, but that wiring to the same power supply as the LCX was fine. The only mention of a separate switch was in reference to salt water use to reduce corrosion. (I use this exclusively in fresh water...)

I had a Globalmap system before this and it seems odd that this "improvement" results in dead batteries!

Biggles · 14 November 2006, 00:37

Its a fact of life modern batteries usually just totally fail without warning. Then you can get a jump start or recharge them and get some life out of them but generally they are then dead.
Thats your warning.
Any problems. get the battery out of the boat and drag it down to local battery shop. They will check it and tell you if its knackered.
If not you need to look elsewhere.

codprawn · 14 November 2006, 02:20

Quote:

Originally Posted by Stoo

Initially, I was having problems after perhaps 2-3 hours... the duration of a dive, lunch and a cocktail.... I presume that if this is causing problems, then I must have an ailing battery.

I am no electrical expert, but if the draw from the antenna is in fact about 1.5 w, how long would this take to drain a healthy battery?

It would take about 900 hours to drain a 120amp battery. The battery has it's own discharge rate of about 4% so the battery will lose more charge than that by itself.

it amazes me that with all the modern technology battery technology isn't much different from the early 1900s!!!

Stoo · 14 November 2006, 02:28

Thanks guys... You have pretty much confirmed what I thought. Sadly, I am about to pack the boat away for the season, so I won't replace the battery until spring at this point....

I did manage to kill the batteries ealier this season when I left the VHF on for two weeks when I was away! As you point out, once they are deaad, they never really recover...!