Jonathanpaul
Well-Known Member
I have a 45ah leisure battery for service and a cigar lighter on my switch panel Would anyone know of a plug in item for the cigar lighter with a gauge to show amp been used per hour. Or has someone ever made one?
Amp gauge
- Thread starter Jonathanpaul
- Start date
Phoenix of Hamble
Well-Known Member
You need something in series with the main battery to measure amps... the cigarette socket can only measure volts.....
NASA do a neat little unit that drops in series using a big resistor and then measures consumption and charge....
NASA do a neat little unit that drops in series using a big resistor and then measures consumption and charge....
fluffc
Well-Known Member
An Amp-hour meter would have to go between the battery and the first positive (or negative) terminal: You can't plug them into a cigar lighter and get a reading.
You can, however, get voltage based gauges which you -could- plug into the cigar lighter socket, but it wouldn't give a proper reading due to voltage drop caused by equipment being turned on.
You can, however, get voltage based gauges which you -could- plug into the cigar lighter socket, but it wouldn't give a proper reading due to voltage drop caused by equipment being turned on.
davel
Well-Known Member
Can't be done I'm afraid. You'll need to insert an ammeter in series with your battery to read the current draw. Your cigar lighter is just one outlet amongst many. It's a bit like trying to guage how much water is being drawn from the water mains by looking at the bathroom tap.
fluffc
Well-Known Member
Is that a double or a triple lakesailor?
VicS
Well-Known Member
To measure any current consumption the current has to flow through the meter. Or it has to flow though a shunt to which a sensitive meter is connected (in parallel), or you have to use some form of clamp on meter that clamps around the wire carrying the current and senses the strenth of the magnetic field around the wire.
About all you can connect to the cigar lighter socket is a voltmeter which will give you an indication of the state of charge of the battery, 12.7 volts fully charged 12.2 volts half chaged 11.7 volts effectively dead flat and correct charging about 14 volts
There are plug in devices that give these indications with a series of colouted LEDS (light emitting diodes)
I have seen one in, I think, the Force 4 catalogue for about £17 pounds but I have just bought one from Kleeneze for £10. That's the firm who periodically leave a catalogue of cleaning products etc on your doorstep. Forum user sbc has a similar device that attaches with leads and clips. I have no serious need for the device I bought as I have several digital voltmeters but I bought it any way. It seems to do what it should.
I suggest that you will benefit from a basic book on boat electrics or from the notes HERE
If you want to spend seious money then there are some power consumption meters on the market but they will require permanent installation by a "competant person"
About all you can connect to the cigar lighter socket is a voltmeter which will give you an indication of the state of charge of the battery, 12.7 volts fully charged 12.2 volts half chaged 11.7 volts effectively dead flat and correct charging about 14 volts
There are plug in devices that give these indications with a series of colouted LEDS (light emitting diodes)
I have seen one in, I think, the Force 4 catalogue for about £17 pounds but I have just bought one from Kleeneze for £10. That's the firm who periodically leave a catalogue of cleaning products etc on your doorstep. Forum user sbc has a similar device that attaches with leads and clips. I have no serious need for the device I bought as I have several digital voltmeters but I bought it any way. It seems to do what it should.
I suggest that you will benefit from a basic book on boat electrics or from the notes HERE
If you want to spend seious money then there are some power consumption meters on the market but they will require permanent installation by a "competant person"
Jonathanpaul
Well-Known Member
Hi thanks will have to put in a gauge. NASA or something
Jonathan.
Jonathan.
VicS
Well-Known Member
[ QUOTE ]
Is that a double or a triple lakesailor
[/ QUOTE ] My post makes it a quadruple lakesailor but I did say more than any one else and i am the slowest typist on the forum.
Is that a double or a triple lakesailor
[/ QUOTE ] My post makes it a quadruple lakesailor but I did say more than any one else and i am the slowest typist on the forum.
halcyon
Well-Known Member
Better off buying more batteries, before investing in a monitoring system. A 45 ah battery is very small for anything but a 1 amp or 2 load, if it's that low then NASA and similar would not be worth the outlay.
Brian
Brian
VicS
Well-Known Member
[ QUOTE ]
I have seen one in, I think, the Force 4 catalogue for about £17 pounds but I have just bought one from Kleeneze for £10
[/ QUOTE ] Sorry that was total nonsense. I was getting muddled up with something else I had seen at Force 4
and the one I bought from Kleeneze was only £2.99
I have seen one in, I think, the Force 4 catalogue for about £17 pounds but I have just bought one from Kleeneze for £10
[/ QUOTE ] Sorry that was total nonsense. I was getting muddled up with something else I had seen at Force 4
and the one I bought from Kleeneze was only £2.99
VicS
Well-Known Member
[ QUOTE ]
A 45 ah battery is very small for anything but a 1 amp or 2 load,
[/ QUOTE ] Quite adequate though for a small boat with modest electrical reqirements. I have a 45ah leisure battery in a small boat. It powers Autopilot, cabin lights, nav lights occassionally, VHF R/T and one or two other odds and ends.
I gets a bit of recharging from the outboard but is chiefly recharged from a 5watt solar panel. It is also light enough to take home easily if ever necessary. .
A 45 ah battery is very small for anything but a 1 amp or 2 load,
[/ QUOTE ] Quite adequate though for a small boat with modest electrical reqirements. I have a 45ah leisure battery in a small boat. It powers Autopilot, cabin lights, nav lights occassionally, VHF R/T and one or two other odds and ends.
I gets a bit of recharging from the outboard but is chiefly recharged from a 5watt solar panel. It is also light enough to take home easily if ever necessary. .
halcyon
Well-Known Member
As I think I said 1 or 2 amps, modest requirement, see no point spending money on amp hour monitoring, far better a solar panel.
Brian
Brian
William_H
Well-Known Member
Your best approach is to buy a digital multimeter with a decent amp scale. !0 or 20 amp max range.
You disconnect the battery positive and insert the 2 leads into the gap and then proceed to turn each item of equipment on to find its amp usage. This amount will not vary very much just a little less on a flat battery. remember the nubers and remove the meter and resore the circuit.
Now there is a trap with digital multimneters in that the resistance inserted in the circuit to produce a meter reading can affect the actual current in the circuit. So a digital mm inserted in the +ve line may inset a .1 ohm resistance which at 20 amps current will reduce the voltage to the services by .2 volt so reducing the current. or the current will be higher when the meter is removed. Although usually you can ignore this effect. Just use a high current range with low actual current.
Moving coil analogue meters don't need as much resistance so are better in this regard.. if you are interested you can get a moving coil analogue meter and mount in the switch panel and make and fit or buy your own shunt which will give a always available current reading. PM me good luck olewill
You disconnect the battery positive and insert the 2 leads into the gap and then proceed to turn each item of equipment on to find its amp usage. This amount will not vary very much just a little less on a flat battery. remember the nubers and remove the meter and resore the circuit.
Now there is a trap with digital multimneters in that the resistance inserted in the circuit to produce a meter reading can affect the actual current in the circuit. So a digital mm inserted in the +ve line may inset a .1 ohm resistance which at 20 amps current will reduce the voltage to the services by .2 volt so reducing the current. or the current will be higher when the meter is removed. Although usually you can ignore this effect. Just use a high current range with low actual current.
Moving coil analogue meters don't need as much resistance so are better in this regard.. if you are interested you can get a moving coil analogue meter and mount in the switch panel and make and fit or buy your own shunt which will give a always available current reading. PM me good luck olewill
castaway
Well-Known Member
I wanted a quick and easy monitor for my charging and batteries and ended up making a spare set of leads for my £5:00 Maplin multimeter, with a fag lighter end on it.
Now I just plug it in when when I want to check the charge or volts.
Bit untechnical I'm afraid but it works well and took about 10mins to make with a couple of bullit connectors and an old fag lighter connection.
Regds Nick
Now I just plug it in when when I want to check the charge or volts.
Bit untechnical I'm afraid but it works well and took about 10mins to make with a couple of bullit connectors and an old fag lighter connection.
Regds Nick
VicS
Well-Known Member
[ QUOTE ]
So a digital mm inserted in the +ve line may inset a .1 ohm resistance which at 20 amps current will reduce the voltage to the services by .2 volt
[/ QUOTE ] Go to the bottom of the class Will. 0.1 ohms X 20 amps = 2.0 volts
A 2 volt drop will have a serious effect on the light output from for example a nav light! You would not want to ignore that.
Plenty analogue meters to choose from. A car type will do. I've got one ex Ford from the late 1960s in which the (insulated) wire is just passed through a loop on the back and it works on the magnetic field just like a clamp-on does. Ideal for someone with little know how with electrics.
So a digital mm inserted in the +ve line may inset a .1 ohm resistance which at 20 amps current will reduce the voltage to the services by .2 volt
[/ QUOTE ] Go to the bottom of the class Will. 0.1 ohms X 20 amps = 2.0 volts
A 2 volt drop will have a serious effect on the light output from for example a nav light! You would not want to ignore that.
Plenty analogue meters to choose from. A car type will do. I've got one ex Ford from the late 1960s in which the (insulated) wire is just passed through a loop on the back and it works on the magnetic field just like a clamp-on does. Ideal for someone with little know how with electrics.
William_H
Well-Known Member
yes you are right Vic I was rushing again. The .1 ohm should have read .01 ohm. The bottom line is that virtually all chaep DMM have a 200 millivot anlague to digital converter. ie full scale will always drop 200 millivolts with full reading. 100mv at half reading 20 mv at 10% full reading. So my point is DMM can affect the circuit you are measuring current in. olewill
G
Guest
Guest
[ QUOTE ]
............ Forum user sbc has a similar device that attaches with leads and clips. I have no serious need for the device I bought as I have several digital voltmeters but I bought it any way. It seems to do what it should.........
[/ QUOTE ]
I do indeed have a device ... as many others ... it was 9.99 at Halfords ... Maplins and other places do them for about half that price now .... It was bought as a cheap stop-gap diagnostic item ... that proved worth every penny. It diagnosed my duff alternator and also shows battery state.
Draper Battery / Alternator tester
I'm seriously thinking to permamently wire mine in with a press to make switch for each battery or a rotary momentary switch that allows me to check either battery. At the price ... above link is 6.99 .... got to be worth a look !
............ Forum user sbc has a similar device that attaches with leads and clips. I have no serious need for the device I bought as I have several digital voltmeters but I bought it any way. It seems to do what it should.........
[/ QUOTE ]
I do indeed have a device ... as many others ... it was 9.99 at Halfords ... Maplins and other places do them for about half that price now .... It was bought as a cheap stop-gap diagnostic item ... that proved worth every penny. It diagnosed my duff alternator and also shows battery state.
Draper Battery / Alternator tester
I'm seriously thinking to permamently wire mine in with a press to make switch for each battery or a rotary momentary switch that allows me to check either battery. At the price ... above link is 6.99 .... got to be worth a look !
VicS
Well-Known Member
[ QUOTE ]
I'm seriously thinking to permamently wire mine in
[/ QUOTE ] I think that would be well worth doing. The trouble with the thing I bought is maintaining good connection in the cigar lighter socket although the phone charger seems to do so OK. But at only 2.99 it was still a good buy.
I'm seriously thinking to permamently wire mine in
[/ QUOTE ] I think that would be well worth doing. The trouble with the thing I bought is maintaining good connection in the cigar lighter socket although the phone charger seems to do so OK. But at only 2.99 it was still a good buy.
G
Guest
Guest
[ QUOTE ]
[ QUOTE ]
I'm seriously thinking to permamently wire mine in
[/ QUOTE ] I think that would be well worth doing. The trouble with the thing I bought is maintaining good connection in the cigar lighter socket although the phone charger seems to do so OK. But at only 2.99 it was still a good buy.
[/ QUOTE ]
At 2.99 a throw ..... cutting of the cigar lighter plug and wiring in is even better news than my higher priced jobbie !!
Another idea I have ... I have a couple of the rotary switched analogue meters ... small ones about palm sized. One is duff on the rotary part but meter works fine. Idea is to do away with the rotary switch part ... solder leads to the volts 0-20 range contacts ... mount in a panel and have similar press to make contact switch to check actual battery voltage ... or a 1-o-2 switch so I can check either battery ...
[ QUOTE ]
I'm seriously thinking to permamently wire mine in
[/ QUOTE ] I think that would be well worth doing. The trouble with the thing I bought is maintaining good connection in the cigar lighter socket although the phone charger seems to do so OK. But at only 2.99 it was still a good buy.
[/ QUOTE ]
At 2.99 a throw ..... cutting of the cigar lighter plug and wiring in is even better news than my higher priced jobbie !!
Another idea I have ... I have a couple of the rotary switched analogue meters ... small ones about palm sized. One is duff on the rotary part but meter works fine. Idea is to do away with the rotary switch part ... solder leads to the volts 0-20 range contacts ... mount in a panel and have similar press to make contact switch to check actual battery voltage ... or a 1-o-2 switch so I can check either battery ...