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      Lowrance Elite 4 CHIRP depth finder     

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SoMpls
distinguished member (129)distinguished memberdistinguished memberdistinguished member
 
04/29/2020 11:30AM  
I'm looking to upgrade to a GPS unit this year so I am selling my current depth finder set up which has been optimized for Canoe fishing. This depth finder has down imaging, CHIRP sonar, many options for viewing down imaging and sonar in a split screen or overlayed. This unit does not have GPS capability.

I have converted the power source to take 10 AA batteries. Includes transducer and mounting clip.

Asking $200 obo, can pick up locally in Minneapolis or will ship, buyer pays actual shipping cost.

Product review - https://fishfinderplanet.com/lowrance-elite-4-chirp-review/
 
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Leo66
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05/04/2020 12:31PM  
What sort of battery life do you get with those 10 AA batteries? I have been looking for something like this... There was one that was used with cell phone, but the more I debated I did not care to go that route. Also, how does the transducer adhere to the Canoe? I know you noted a Mounting clip, but just curious.

Thank you -
Leo66
 
SoMpls
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05/04/2020 01:39PM  
I haven't run a test or paid as much attention as I should on battery life to be honest. I get several days of use with significant usage is the best I can say. I always use energizer lithium AA batteries

The unit specs say it will draw .75 amps per hour, and the 10 AA battery set up should have 7.5 amp hours with alkaline batteries or 28 amp hours with lithium. So that would say you could get 10 hours with alkaline and up to 40 hours with lithium. I think 40 sounds high compared to my experience but I would guess I get 20-30.

I don't actually mount the transducer to the canoe, I place it on top of a zip lock bag full of water and let it shoot through the hull. No issues doing this. I only use the mounting clip on my '14 john boat.

 
mgraber
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05/04/2020 07:50PM  
SoMpls: "I haven't run a test or paid as much attention as I should on battery life to be honest. I get several days of use with significant usage is the best I can say. I always use energizer lithium AA batteries


The unit specs say it will draw .75 amps per hour, and the 10 AA battery set up should have 7.5 amp hours with alkaline batteries or 28 amp hours with lithium. So that would say you could get 10 hours with alkaline and up to 40 hours with lithium. I think 40 sounds high compared to my experience but I would guess I get 20-30.


I don't actually mount the transducer to the canoe, I place it on top of a zip lock bag full of water and let it shoot through the hull. No issues doing this. I only use the mounting clip on my '14 john boat.


"

I'm sorry to break it to you but AA Ultimate lithiums are 3000ma and it does not matter how many you wire in series the ma stay the same. So 10 of them wired in series still have 3000mah of capacity, the only thing you did was increase the voltage. If you wire them in parallel you will increase capacity but the voltage will stay at 1.5-1.8. So you have 3 amp hours of capacity with that set-up. This would give you about 4 hours at .75 amp but most fish finders draw a lot less than published draw which is max draw with light all the way up. I have no idea where you got 7.5 and 28 ah as that would be literally impossible and would be a BIG battery for portability. Someone please correct me if I am wrong.
 
SoMpls
distinguished member (129)distinguished memberdistinguished memberdistinguished member
 
05/05/2020 11:09AM  
mgraber: "SoMpls: "I haven't run a test or paid as much attention as I should on battery life to be honest. I get several days of use with significant usage is the best I can say. I always use energizer lithium AA batteries



The unit specs say it will draw .75 amps per hour, and the 10 AA battery set up should have 7.5 amp hours with alkaline batteries or 28 amp hours with lithium. So that would say you could get 10 hours with alkaline and up to 40 hours with lithium. I think 40 sounds high compared to my experience but I would guess I get 20-30.



I don't actually mount the transducer to the canoe, I place it on top of a zip lock bag full of water and let it shoot through the hull. No issues doing this. I only use the mounting clip on my '14 john boat.



"

I'm sorry to break it to you but AA Ultimate lithiums are 3000ma and it does not matter how many you wire in series the ma stay the same. So 10 of them wired in series still have 3000mah of capacity, the only thing you did was increase the voltage. If you wire them in parallel you will increase capacity but the voltage will stay at 1.5-1.8. So you have 3 amp hours of capacity with that set-up. This would give you about 4 hours at .75 amp but most fish finders draw a lot less than published draw which is max draw with light all the way up. I have no idea where you got 7.5 and 28 ah as that would be literally impossible and would be a BIG battery for portability. Someone please correct me if I am wrong."


I'm sure you're right, my knowledge of electrics is obviously limited.
 
tonyyarusso
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05/05/2020 02:49PM  
mgraber: "Someone please correct me if I am wrong."
Partially wrong, partially correct. First, it's important to note that there is a difference between amps and amp-hours. Amperes are a unit of *instantaneous* current, just one point in time. Amp-hours are a unit of charge, given in the form of current multiplied by time. A battery will have limitations in both senses - a maximum current it is capable of supplying at any moment, and a total amount of charge capacity. The former is important for high-draw devices, and the latter more what we're looking at here. I just pulled up the data sheet for the Energizer Ultimate Lithium AAs, and it lists their maximum discharge rate as 2.5 amps continuous or up to 4 amps for a brief pulse. The useful capacity of batteries meanwhile is actually not entirely fixed, because they have different efficiency levels at different discharge rates, but one of the nice things about the lithium chemistry is that it is a very flat profile, whereas alkalines are much less efficient at high current draws, so if they're a little less with a small load, they're a LOT less with a high load.

Now, the next part is the issue of voltage. The nominal voltage of a AA cell is 1.5 volts. Your depth finder requires a supply of 12 volts. That means you will get a runtime of ZERO hours off one AA, because the unit won't even turn on in the first place. So, to get any functionality at all, you're going to need eight AA cells in series to get up to the 12v needed. Your ten AA cells gives you 15v, which is above the "normal" input, but within the acceptable range of 10v to 17v listed in the manual for that product, and does give you some buffer for voltage drop as they deplete, so that makes some sense (especially with alkalines). When they're giving the "capacity" ratings of the cells, those are given AT the nominal voltage of the cell. When you connect several in series, the voltage across each individual cell remains that nominal voltage, while the voltage across the whole set is the sum of all of them. That means that if one cell can supply 1A of current for 3 hours at 1.5V, then the chain of ten cells can still only supply 1A of current for 3 hours at 15V - but at least at 15V your depth finder will actually function, unlike if you tried to run it on 1.5V. So, yeah, you're definitely not going to be getting 20 or 40 hours while drawing 0.75A.

However, the good news is that it seems like the numbers for this unit often get commingled with specs for larger units, and yes, published specs are often trying to be on the higher side, and it may draws a bit less than that. Googling turned up some anecdotal reports claiming their typical usage is more like only 0.25A. Additionally, at those lower currents the AAs are a little bit more efficient, which means more apparent "capacity" - according to Energizer's graphs, it looks like closer to 3500mAh. Dividing 3.5Ah by 0.25A would give you 14 hours of runtime. Considering that the unit will accept as low as 10v before shutting down and that you started out supplying 15v rather than 12v, you might even push a smidge beyond that, although lithium cells have a very steep dropoff curve once they get to that point. The ten cells in series approach makes sense with alkalines, but probably doesn't buy you a ton with lithium. So, if you wanted to extend the runtime, I'd suggest dropping that down to just the eight, and putting the two left over into your *second* line of eight, with each line being wired in series within itself for 12v each, but then the two lines in parallel with each other, which WILL increase the capacity and get you up around that 28 hour mark with 16 AAs.
 
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