VHF/AIS Power Consumption

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Slipperman

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I have just fitted a Raymarine combined VHF/AIS unit which seems to integrate nicely with my Raymarine chart plotter. Reading the manual for the new kit, I note that the current consumption is quoted as 600mA at Standby, but 2A when receiving. Whilst the receiving of VHF radio traffic is obviously intermittent, am I right in thinking that receiving AIS signals will be more or less continuous - and thus that I should not switch on AIS reception until I really need it to conserve battery power?
 
Slipperman said:
I have just fitted a Raymarine combined VHF/AIS unit which seems to integrate nicely with my Raymarine chart plotter. Reading the manual for the new kit, I note that the current consumption is quoted as 600mA at Standby, but 2A when receiving. Whilst the receiving of VHF radio traffic is obviously intermittent, am I right in thinking that receiving AIS signals will be more or less continuous - and thus that I should not switch on AIS reception until I really need it to conserve battery power?
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The currents you're quoting are basically related to the VHF radio; the AIS receiver will use very little current so can safely be left on. As a comparison, the Raymarine AIS350 receiver uses less than 2W (about 150mA).
 
My Garmin VHF/AIS uses .5a. It makes no noticeable difference if i turn the AIS on or off, neither does it make a noticeable difference when the VHF receives a transmission.
 
jac said:
The speaker though must use a reasonable amount of power?
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Mine doesn't have a separate speaker, as such, it's in the handset. The .5a i quoted was with one handset connected, not sure if the second handset will make a significant difference, if i remember i'll try it again in the morning with 2 handsets.
 
The current consumption quoted is probably about right. The higher current consumption when receiving relates to the audio power going to the speaker. ie max audio power when most of us use quite low audio power so as said not much increase with receiving a voice. ie forget it. Even with 2 seakers/handset not much increase. olewill
 
Slipperman said:
current consumption is quoted as 600mA at Standby, but 2A when receiving
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Without a bit more detail that statement is meaningless as a radio receiver is receiving all the time even if it is just carrier signal. Your assumption that AIS is continuous is correct.

My own radio technical sheet gives 450mA in receive mode and 5A on transmit, if I add my separate AIS that reports power usage of 210mA.
 
Well I don't have any more detail - that's why I was asking! But am encouraged to hear that it is the VHF loudspeaker which will use up most power, not AIS reception. Thanks to all.
 
Slipperman said:
Well I don't have any more detail - that's why I was asking! But am encouraged to hear that it is the VHF loudspeaker which will use up most power, not AIS reception. Thanks to all.
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That isn't what i found. Mine used .5 amp just being on. That's just sitting there, no VHF transmission coming in, but AIS obviously being received. If i switched the AIS off, no difference. If an incoming transmission was received, no difference.

Power draw was measured using a Vicron battery monitor (amps to two decimal places) with everything but the VHF turned off.
 
Looking here : http://www.raymarine.co.uk/view/?id=221

Raymarine quote the same Current Consumption for all of their VHF sets, the basic model, the one with built in GPS and the one with AIS.

IMO, this is bollox. A more reasonable set of figures for the OP's set would be 600ma at standby**, 2a low power transmit and 6a high power transmit. To suggest that the power draw will jump from 600ma to 2a when a call is received is (IMO) nonsense.

**Standby for the OP means the set is on, receiving AIS, but not transmitting. For a basic set it would be a lower figure, as there would be no AIS receive.
 
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Just tried mine with and without the deck speaker on and it's hard to see a difference. There obviously must be a slight difference, but it's so small it's hard to spot with the battery monitor.

I also checked figures for some Garmin VHF sets, with and without AIS. These figures support my opinion that the Raymarine figures are bollox.

Roger has just posted that the SH SH GX2200 VHF / AIS / GPS uses 1w at low power transmit. According to the Raymarine figures their VHF uses double that just to receive
 
PaulRainbow said:
Just tried mine with and without the deck speaker on and it's hard to see a difference. There obviously must be a slight difference, but it's so small it's hard to spot with the battery monitor.

I also checked figures for some Garmin VHF sets, with and without AIS. These figures support my opinion that the Raymarine figures are bollox.

Roger has just posted that the SH SH GX2200 VHF / AIS / GPS uses 1w at low power transmit. According to the Raymarine figures their VHF uses double that just to receive
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Using the figures from SH the input power consumption when transmitting at 25W is 60W and when transmitting at 1W its about 12W

The power on standby will be about 6.6 W so could be about right.
 
Rogershaw said:
Using the figures from SH the input power consumption when transmitting at 25W is 60W and when transmitting at 1W its about 12W

The power on standby will be about 6.6 W so could be about right.
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Yes, i think they look about right, as do the Garmin figures. Raymarine seem to have thrown any old figures in, i can't see how the most basic set uses the exact same power as the top of the range VHF/AIS/GPS.
 
I have been fiddling with this only this week, battery monitors are great entertainment.

Different set up though; an Icom gps VHF linked to a Vesper 850 transponder.
Monitor only measures to one decimal place.

The set up draws 0.4A even as the VHF receives. I can get it up to 0.5 if I wind either screen backlight up to the max. Here is a surprise to me; it does not change with the AIS tx on or off.
 
doug748 said:
I have been fiddling with this only this week, battery monitors are great entertainment.

Different set up though; an Icom gps VHF linked to a Vesper 850 transponder.
Monitor only measures to one decimal place.

The set up draws 0.4A even as the VHF receives. I can get it up to 0.5 if I wind either screen backlight up to the max. Here is a surprise to me; it does not change with the AIS tx on or off.
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ISTR there are 2,000 odd timeslots per minute, so it is only transmitting for a fraction of a second.
Say 15W for the transmitter, would average as around 7mW or 0.5mA at 12V.
The receive consumption sounds a bit heavy to me.
Even bearing in mind that AIS will be receiving on two channels and doing some data processing.
I guess it's the data processing, as a handheld VHF on receive uses very little.
 
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