12 volt help.

idomeneus5

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i have a vexilar sonar phone depth sounder. it transmits the depth " image screen" via wifi to any suitable tablet and or mobile phone on board. the unit only draws 140ma. The trouble I'm experiencing is that whenever the domestic water pump runs, the power draw turns off the wifi unit. also causes leds to flicker. I've thought of connecting the wifi unit to the seperate 225amp solar battery bank which only runs the dedicated 12v fridge, but i believe the cycling of the fridge on and off will have the same effect. My 12v electric toilet is connected directly to the starter battery. I could move this to the domestic battery and connect the wifi unit to the starter battery. final option is a smaller 12 volt battery say 5amps, solar charged to run the wifi unit. Any other suggestions most welcome, perhaps there is a piece of electronic gadgetry that could inexpensively overcome the problem, cheers Peter
 
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Ammonite

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i have a vexilar sonar phone depth sounder. it transmits the depth " image screen" via wifi to any suitable tablet and or mobile phone on board. the unit only draws 140ma. The trouble I'm experiencing is that whenever the domestic water pump runs, the power draw turns off the wifi unit. also causes leds to flicker. I've thought of connecting the wifi unit to the seperate 225amp solar battery bank which only runs the dedicated 12v fridge, but i believe the cycling of the fridge on and off will have the same effect. My 12v electric toilet is connected directly to the starter battery. I could move this to the domestic battery and connect the wifi unit to the starter battery. final option is a smaller 12 volt battery say 5amps, solar charged to run the wifi unit. Any other suggestions most welcome, perhaps there is a piece of electronic gadgetry that could inexpensively overcome the problem, cheers Peter

First thing I'd do is to check the connections to the pump and wifi etc and also to ensure the cables are adequately sized to prevent the voltage drop you are experiencing. If you really get stuck you can use something like this although you need to be careful where you put it as they do tend to interfer with the VHF. Nothing major but you'll get a back ground hum.
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/401089545945
 

Boathook

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Sounds like some cables aren't big enough for the pump. I had a similar problem years ago and ended up trippling the wire size to get over voltage drop when the pump ran. The other thingis to check connections are they clean and secure.
 

dom

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Sounds like some cables aren't big enough for the pump. I had a similar problem years ago and ended up trippling the wire size to get over voltage drop when the pump ran. The other thingis to check connections are they clean and secure.

Unless I'm missing something, why would the pump's cable size be relevant to any other circuit than the pump?
 

PaulRainbow

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Unless I'm missing something, why would the pump's cable size be relevant to any other circuit than the pump?

More likely to be that the pump shares a common connection to the wifi unit. Could be a cable going to a fuse box or busbar is under rated, when the pump runs it causes a voltage drop across all devices that are connected to it.

For a 150ma device to turn off as a result of voltage drop there is clearly something wrong with the wiring, fitting a DC-DC converter will just be masking the problem.
 

dom

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More likely to be that the pump shares a common connection to the wifi unit. Could be a cable going to a fuse box or busbar is under rated, when the pump runs it causes a voltage drop across all devices that are connected to it.

For a 150ma device to turn off as a result of voltage drop there is clearly something wrong with the wiring, fitting a DC-DC converter will just be masking the problem.

Indeed as the others say, it might be a dodgy connection/inadequate wiring pre-distribution-panel.

Don't agree though that a 150mA device turning off necessarily implies that something is wrong with the wiring. We don't know spec/size/condition of the batt and in any event some electronic equipment can be fussy about power supply. Hence many systems include regulated power supplies as part of at least some electronic circuits.
 

Stemar

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I'd start by measuring the voltage at the WIFI gixmo when the pump's on. If you get a significant voltage drop, follow the circuit back until you find a dodgy connection. A similar issue on Jissel took me right back to the battery terminals & cleaning them sorted it!

If the voltage is OK - 12v or more, I'd wonder about a transient from the pump switching on and try a suppressor either in the pump circuit or the gizmo circuit,
 

lw395

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Possibly the pump is nearly seized and drawing more current than it should?
Possibly the pump is putting spikes on the line upsetting the gizmo rather than it being a volts issue.
Possibly the battery is knackered.
Possibly the gizmo is very badly designed. One could fit longer leads to it and use it as a lead line.
 

PaulRainbow

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Indeed as the others say, it might be a dodgy connection/inadequate wiring pre-distribution-panel.

Don't agree though that a 150mA device turning off necessarily implies that something is wrong with the wiring. We don't know spec/size/condition of the batt and in any event some electronic equipment can be fussy about power supply. Hence many systems include regulated power supplies as part of at least some electronic circuits.

The pump causes the wifi unit to shut down and the LED lights to flicker, that's a clear indication of a problem, that problem needs fixing, not hiding.

There are, as you say, systems that do benefit from regulated supplies, i fit several, for different reasons. Boats have a power system that typically varies from about 12.5V to 14.4/6/8 and some electronics don't like that. Some cheap 12v LEDs get really hot when the charging systems are running at 14.4v or more.
 

PaulRainbow

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Possibly the pump is nearly seized and drawing more current than it should?
Possibly the pump is putting spikes on the line upsetting the gizmo rather than it being a volts issue.
Possibly the battery is knackered.
Possibly the gizmo is very badly designed. One could fit longer leads to it and use it as a lead line.

Why do the LED lights flicker ?
 

PaulRainbow

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I'd start by measuring the voltage at the WIFI gixmo when the pump's on. If you get a significant voltage drop, follow the circuit back until you find a dodgy connection.

:encouragement:

Assuming a good, reasonably charged battery, that should pinpoint a bad connection or identify any undersized wiring.
 

dom

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The pump causes the wifi unit to shut down and the LED lights to flicker, that's a clear indication of a problem, that problem needs fixing, not hiding.

Not wishing to be argumentative, but it could equally be an inadequately specced/ faulty battery, or a faulty pump.

Anyhow, this is starting to drift: a quick once over by the OP of his wiring with a multimeter, retest, if there is still a problem fit a little regulated power supply and he should be good to go ;)
 

PaulRainbow

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Not wishing to be argumentative, but it could equally be an inadequately specced/ faulty battery, or a faulty pump.

Yes, could be any of those.

Anyhow, this is starting to drift: a quick once over by the OP of his wiring with a multimeter, retest, if there is still a problem fit a little regulated power supply and he should be good to go ;)

That would be the way to go.
 

idomeneus5

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problem happens whether I'm at dock on 10amp/12 volt power supply connected to shore power or if I'm off shore. wiring to pump is 15amp tinned cable. in fact all my wiring is the same, the battery less than 18months old. only bad design in gizmo is the led in middle of on/off switch, impossible to see when unit was mounted outside, thanks for replies will visit local jaycar and seek their advice on a puck, and will also do tests as suggested. cheers peter
 
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William_H

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All of the above re bad wiring that is shared by the wifi is correct. However if OP can not identify and fix any bad connections. (don't forget the negative returns) then a simple circuit in the supply to the wifi pos supply may help.
You feed the power to the wifi device through a schotky diode https://www.jaycar.com.au/diode-1n5711-schottky-do35/p/ZR1027 with anode to battery and cathode (with band) to the wifi. That diode will feed power to the wifi with minimul volt drop. (about .4v) Now fir an electrolytic capacitor from the pos on the wifi side of the diode to negative.
https://www.jaycar.com.au/2200uf-16vdc-low-esr-electrolytic-capacitor/p/RE6318
Almost any value of electrolytic capacitor will help over 500ufd. It acts like a small battery to provide the power to the wifi when the supply voltage is low. The diode stops the capacitor trying to feed all the boat. ol'will
 
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