12v step down module? - Kayak Fishing Adventures on Big Water’s Edge

danjor · 08-13-2013, 04:49 PM

If it was me I would use a PWM controller that way you can adjust the duty cycle to whatever water flow you like. I am currently using the on off timer style controller from OEX but when I get some time I'm planning on setting up a PWM controller to control my bait tank pump since the on off sounds good on paper but it turned out to be annoying to me.

makobob · 08-13-2013, 05:06 PM

Why not do what most of us do. 12v for FF and 6v for bait tank? I got 14 hours on a lifepo4 and it still will run the pump maybe another 6 hours. And it only weighs less than 2 lbs.

iethinker · 08-13-2013, 06:58 PM

Raskal,

The type of device you have suggested will work fine allowing your main dual battery system all to be at 12-volts. This is very convenient for recharging the parallel battery system. Just be sure that the amperage your bilge-pump / bait-pump draws at 7-volts does not exceed the 3A limit of the DC/DC converter. The converter itself will not consume unacceptable excess power and is totally sealed. All of this is of course assuming you wire things correctly. Go for it!

BTW...the resistor suggested by bus_kid will only work if the resistance load of your bait pump is the same as the resistance of the wiper motors of an air-cooled Volkswagen of some vintage.

iethinker

Raskal311 · 08-13-2013, 07:36 PM

My second option is to go Lifepo4.

alanw · 08-13-2013, 08:56 PM

It's only 8 bucks, it won't hurt too bad to try it. Just check the current draw while using it.

Raskal311 · 08-13-2013, 09:24 PM

That's true

PescadorPete · 08-13-2013, 11:57 PM

Here is the answer to your question, based on some science and some assumptions, with the Hobie bait tank pump.

12V battery directly connected uses 16.5 watts of power (and way too much water flow).
12V battery and the resistor uses 6.3 watts of power.
12V battery and the step down module uses 5.6 watts of power.
12V battery and the PWM uses 4.3 watts of power.
6V battery directly connected uses 3.2 watts of power.

Watts is what gets the work done and what the battery needs to supply, so in simple terms, ignoring a few messy details, the 6V battery is the most efficient and will last the longest. That's what I use on my Hobie.

Here is a photo of the elusive PWM. I put it together many years ago for my 12V (non-Hobie) kayak and its still works well.

Enough science for now, my head hurts, lets go

08-13-2013, 05:06 PM	#2
makobob Baitless on Baja Join Date: May 2013 Location: Vista California, Gonzaga, San Quintin, Asuncion, Mag Bay Posts: 4,250	Why not do what most of us do. 12v for FF and 6v for bait tank? I got 14 hours on a lifepo4 and it still will run the pump maybe another 6 hours. And it only weighs less than 2 lbs. __________________ http://www.mako-ville.com Home 760-630-4470 Cell 760-520-2514 YES YOU CAN

08-13-2013, 06:58 PM	#3
iethinker Senior Member Join Date: May 2013 Location: Inland Empire Posts: 370	Verify Amp-Draw But Go For It Raskal, The type of device you have suggested will work fine allowing your main dual battery system all to be at 12-volts. This is very convenient for recharging the parallel battery system. Just be sure that the amperage your bilge-pump / bait-pump draws at 7-volts does not exceed the 3A limit of the DC/DC converter. The converter itself will not consume unacceptable excess power and is totally sealed. All of this is of course assuming you wire things correctly. Go for it! BTW...the resistor suggested by bus_kid will only work if the resistance load of your bait pump is the same as the resistance of the wiper motors of an air-cooled Volkswagen of some vintage. iethinker Last edited by iethinker; 08-13-2013 at 07:05 PM.

08-13-2013, 07:36 PM	#4
Raskal311 Senior Member Join Date: Mar 2011 Location: Santa Ana/Westminster Posts: 1,258	My second option is to go Lifepo4. __________________ Kevin Yellow PA12 Last edited by Raskal311; 08-13-2013 at 08:23 PM.

08-13-2013, 08:56 PM	#5
alanw Made in U.S.A. Join Date: Oct 2012 Location: Dana Point Posts: 1,625	It's only 8 bucks, it won't hurt too bad to try it. Just check the current draw while using it. __________________ Hobie PA 14 ¸.·´¯`·.´¯`·.¸¸.·´¯`·.¸><(((º> Jackson Kraken ¸.·´¯`·.¸.·´¯`·.´¯`·.¸¸.·´¯`·.¸><(((º> Malibu X-Factor ¸.·´¯`·.´¯`·.¸¸.·´¯`·.¸><(((º> Malibu Stealth-12 ¸.·´¯`·.´¯`·.¸¸.·´¯`·.¸><(((º> Its not a spelling B its a fishing B ~yakjoe

08-13-2013, 09:24 PM	#6
Raskal311 Senior Member Join Date: Mar 2011 Location: Santa Ana/Westminster Posts: 1,258	That's true __________________ Kevin Yellow PA12

08-13-2013, 04:49 PM	#1
danjor Senior Member Join Date: Apr 2011 Location: Riverside CA Posts: 673	If it was me I would use a PWM controller that way you can adjust the duty cycle to whatever water flow you like. I am currently using the on off timer style controller from OEX but when I get some time I'm planning on setting up a PWM controller to control my bait tank pump since the on off sounds good on paper but it turned out to be annoying to me.

08-13-2013, 11:57 PM	#7
PescadorPete Senior Member Join Date: Mar 2005 Location: Leucadia, CA Posts: 261	Here is the answer to your question, based on some science and some assumptions, with the Hobie bait tank pump. 12V battery directly connected uses 16.5 watts of power (and way too much water flow). 12V battery and the resistor uses 6.3 watts of power. 12V battery and the step down module uses 5.6 watts of power. 12V battery and the PWM uses 4.3 watts of power. 6V battery directly connected uses 3.2 watts of power. Watts is what gets the work done and what the battery needs to supply, so in simple terms, ignoring a few messy details, the 6V battery is the most efficient and will last the longest. That's what I use on my Hobie. Here is a photo of the elusive PWM. I put it together many years ago for my 12V (non-Hobie) kayak and its still works well. Enough science for now, my head hurts, lets go