can I change from 12v to 9v on a depth finder?

[skeeter115]

What do I have to do to go from a 12 volt battery to a 9 volt depth finder?

 

[180shabah]

Re: can I change from 12v to 9v on a depth finder?

Use a transformer.

 

[Ned L]

Re: can I change from 12v to 9v on a depth finder?

Voltage dropping resistor

 

[Silvertip]

Re: can I change from 12v to 9v on a depth finder?

Sorry 180shabah -- but a DC transformer hasn't been invented yet.
If we were talking AC power that would be an acceptable solution.

 

[180shabah]

Re: can I change from 12v to 9v on a depth finder?

Sorry 180shabah -- but a DC transformer hasn't been invented yet.
If we were talking AC power that would be an acceptable solution.

OOPS!!!

 

[Moody Blue]

Re: can I change from 12v to 9v on a depth finder?

Why? I would have thought than virtually everything out there intended for either marine use or automotive would be 12V.

 

[Nandy]

Re: can I change from 12v to 9v on a depth finder?

Why? I would have thought than virtually everything out there intended for either marine use or automotive would be 12V.

That was my thought too....
skeeter115, a bit more information about the hardware might allow for a better answer. A voltage regulator will only be an answer if it can handle the current needed by the load and it is a bit inefficient, but might be your only option.

Good luck!

 

[Silvertip]

Re: can I change from 12v to 9v on a depth finder?

This is probably a battery operated unit (not hard wired) and he wants to hard wire it into the boats electrical system . It's a very appropriate request. There are lots of 1.5, 3.0, 4.5, 6.0 7.5 and 9.0 volt devices out there that would be nice to operate from 12 volts DC. Those DC-DC converters are not easy to find. AC to DC is as easy as visiting any electronic shop for a converter that plugs into a standard 115 volt ac wall outlet. It can be set for any of the voltages shown above. Note that each increment is 1.5 volts which is the voltage of a single cell. What could be done in this case is to buy a 25 buck low current 12 volt inverter (cigarette light socket style). Plug the converter into the inverter and you can then select whatever voltage you want to power the DC appliance that does not run on 12 volts. It's a 35 buck conversion process but fairly efficient so battery drain is not significant.

 

[TerryMSU]

Re: can I change from 12v to 9v on a depth finder?

Four posibilities.

1. Check the instruction manual. It MAY tolerate a "12 volt" system. If it looks like it will, contact the manufacturer and verify first. "12 volt" batteries can run as high as about 14 volts under certain conditions (such as charging).

2. Get someone with a little electronic experience to build you a solid state regulator. If this runs off a single 9 volt battery, this is likely a piece of cake.

3. Again, given the allowable supply voltage range, it may be possible to put 4 or 5 couple of diodes in series to lower the voltage to 9 volts. Each diode will drop about 0.7 volts. The cathode end of each diode (the bar on the diode) should be toward the load (fishfinder) and away from the batteries. Measure the voltage.

A series dropping resistor will behave similarly to the diodes, but the drop is not constant but varies directly with the current draw. It will NOT be constant, and is not what I would recomend.

4. As a last option, Silvertip's idea will work, but I have seen battery eliminators for 9 volts (and other voltages) that plug into a cirgarette lighter.


Good luck,
TerryMSU