Beesource Beekeeping Forums banner

1 - 14 of 14 Posts

·
Premium Member
Joined
·
3,097 Posts
Discussion Starter · #1 ·
Hey anglers and sparkies,
So I'm getting a fishfinder for the 'yak, and have some head-scratchers. I'm working out how much battery capacity I'll need. Humminbird support tells me that the two models I'm considering (Piranhamax 170 and 160) draw the same amperage, 100 milliamps (mA), which I take to mean .1 amps per hour. They use the same transceiver. However the 170 runs 1600 watts and the 160 runs 800 on the same 12V supply. How could they possibly have the same draw?

And part II, for fishing 'yak nerds only: I might also run my night light off this same power supply (as opposed to a battery-powered flashlight conversion dealie). Anyone use or recommend a 12V DC LED white 360 lamp I could PVC up into a night-time running light?
 

·
Registered
Joined
·
1,493 Posts
Hey Brew Cat,

For the night lights check into Bass Pro Shops or Cabelas or other marine store and get the battery operated clamp-on "running" lights. You should be able to rig them on your Yak.

I imagine you will be fishing mostly shallow water anyhow, less than 50' deep? You could get away with the 160 and use it for mostly structure and bottom contours. The more wattage the deeper it will accurately tell the tale under water. I used to run the Cuda in my little aluminum boat, mostly used it as a depth finder (when it worked) but it was a heck of a liar when it came to finding fish like kokanee!!LOL

As for drawing power, I would think the more wattage draw of the 170 would draw more power to run as well, even though they dont draw much off a battery anyhow.

I run a Lowrance X-125 in my fishing boat and like it, although when I fished with my buddy for sturgeon last week I seen his Hummingbird with GPS and color graph................LOVED it!!!LOL
 

·
Super Moderator
Joined
·
11,121 Posts
However the 170 runs 1600 watts and the 160 runs 800 on the same 12V supply. How could they possibly have the same draw?
You are mis-interpreting the specs.
http://store.humminbird.com/products/307381/PiranhaMAX_170
To start with they are talking about "peak to peak". That is much different than RMS (a form of averaging). But real "power" output can never be more than power input - energy cannot be created, only transformed. If they are accurate that each device uses 100 milliamps, which is .1 amps, then at 12 volts input, power usage is 12*.1 = 1.2 watts. This kind of math is represented as (watts = volts * current) and applies to any electrical device. The claimed output power of 200 watts / 1600 watts is more "marketing speak" than any real power input / output.

For reference, a portable heater that plugs into a wall socket (110 volts), on "high heat" is generally about 1600 watts. That would be 110 volts * 15 amps = 1650 watts. If a fish finder drew that kind of power, your battery would die quite quickly. 1600 watts at 12 volts is 133 amps!, and would require cables similar to those going to a vehicle starter motor.

Here is their page that shows current draw for all Humminbird products:
http://www.humminbird.com/Faq.aspx?TaxonomyId=94A2903
 

·
Premium Member
Joined
·
3,097 Posts
Discussion Starter · #4 ·
I guess I could have done that math :rolleyes:. Why then do they (indeed why CAN they) call whatever the transceiver is putting out "watts"? I guess more to the point, what's the difference between the 160 and the 170 if the literal wattage (and hence power) is actually identical, when they call one double the other in whatever magic pseudo-watt measure they're using?
 

·
Super Moderator
Joined
·
11,121 Posts
I don't have any knowledge of these two specific devices, but even though the input power is the same, the output may not be the same. Consider two 60 watt light bulbs. They each consume 60 watts, but they may put out differing ratios of heat vs light.

Its possible that the more expensive fishfinder uses a more efficient (but more expensive) technology to get better performance from the same input power. Or it could be that the marketing department decided they needed products at different price points and simply rewrote the published specs to make them look/seem different. Detroit automakers were masters at that game.
 

·
Registered
Joined
·
85 Posts
I have a 8 AH battery , gel cell. And a really cheap charger. I can get several trips out of it. I did try a group of D cells. That was a one trip thing.

Red Fish rule!

O ya a 12 foot red fish kayak here.
 

·
Premium Member
Joined
·
3,097 Posts
Discussion Starter · #7 · (Edited)
Followup: Anyone know how to calculate how many amp-hours would be in an 8-pack of 1.5V AA batteries (the poor-man's 12V)?

(edit) got some info from Energizer: their NiMH rechargeables have 2300 mAh. Times 8 = 18,400 or... 18.4 amp-hours? And yes of course I wouldn't realize that full potential with voltage drops/temperature/etc... but is the math sound?

Seems like a screamin' deal: with a hundred potential recharges, that should run a sonar (and heck, a couple LEDs) for a good long trip :applause: right?
 

·
Registered
Joined
·
151 Posts
would be 2.3 amp hours, you dont gain any amp hours by hooking batteries in series they have to be hooked in parallel to increase your amp hours but you need them in series to get 12 volts.
maybe a small 12 volt lead acid battery you find for alarms or even spot lights may be the way to go if you want more time buy 2 and hook parallel should be able to charge them up with most chargers on low.
http://www.amazon.com/gp/product/B0...&pf_rd_t=101&pf_rd_p=470938631&pf_rd_i=507846
 

·
Premium Member
Joined
·
3,097 Posts
Discussion Starter · #9 ·
Hm.. right! Knew I should ask here :), thanks. Also noting that the rechargeables only push 1.2V each, leaving me a bit short on 12V. I think the Humminbird can roll with it though... more planning!
 

·
Registered
Joined
·
151 Posts
you probably wont be happy with the run time, but you could push the voltage up to 14 pretty easily by using 11 or 12 batteries at 1.2 wich would be normal voltage for sonar to run at with charging system in use, with engine running on a boat, voltage to sonar is usually higher than 12 and around 14 volts.
 
1 - 14 of 14 Posts
Top