Lipo Anyone

Has anyone ever tried using a lipo battery to power a fish finder? Since the voltage requirements on the unit I am getting are 10-17 volts then either a 3S or 4S lipo battery pack should satisfy the voltage requirements. These things are available with over 3 amp hour capacity. The fish finder supposedly draws .25 amps so 3 amp hours or more should give me 12 hours or more of operation. The advantage of these lipos would be the smaller size and weight. Does anyone know a reason these should not be used?

I use them in my R/C models mostly. I have powered my 12v V2 with them to check it out. They are pricy, but last a long time. You can get them up to mega amps, well enough to crank your boat or car.

Battery Packs by Voltage, 11.1v LiPos

Yeah, I have seen them as high as 6 amp hours or more but that is when they get really expensive. But something around 3300 mah or 3.3 amp hours can be had for about $40-$45. I was wondering if anyone had any experience using them with a fish finder or if there was some reason I am not aware of that you should not.

Just a bit of caution here: just because you have a 3 amp battery pack (regardless of battery technology) that does not mean that you will get 12 hours of run time if the device draws 0.25 amps of current. The battery pack voltage will drop as power is used from it, so at some point the device will either shut off or start having problems running due to the decrease in input voltage. Now I haven’t looked at LiPo batteries in several years and they may be able to hold their voltage constant over the majority of their discharge life but I doubt that they would be able to keep the voltage about 10.0 volts for all 12 of those hours. The result should be that you will have less than 12 hours of run time.

The sonar unit doesn’t care where the power comes from, so any power source that provides what it needs to run will work. I have heard of others who have used LiPo batteries but do not remember the pack size or their run times.

I would also opt for the 4s packs if it does not exceed the maximum input voltage for the unit you are going to use this with. That way you know that the unit is getting the power that it needs and there is a greater chance of the voltage staying in the unit’s operating voltage range longer as the packs voltage drops from use.

Greg, thanks for the response. I understand everything you are saying about the electronics aspects of this. I too would have been inclined more towards a 4S battery pack. But even the 3S might work fairly well. The rated voltage on a 3S pack is 11.1 and on a 4S pack is 14.8. But when these battery packs are fully charged they actually test out at about 12.6 and 16.8 respectively. Usually when they are run down to the point where they are ready for recharging they still have close to the rated voltage available. One potential problem that I was concerned about is you can't get away with getting anywhere near fully discharging them or you will kill them.

Both sizes are available in amp hour ratings as high as 6. But they get prohibitively expensive at that capacity at around $85 or $90. But for 3.3 amp hour capacities you can get them at around $45. It is the savings in weight and size over the alternatives that I am interested in.

I wasn't sure if there was anything about them that might preclude their use for powering a fish finder. It seems that most of them are designed for relatively high discharge rates. I didn't know if the slower current draw of a fish finder might cause any difficulties.

Thanks again for your response.

Only thing I would be concerned about using a LiPo in a boat would be getting the battery wet. LiPos and fresh water are not a very good mix. Getting one wet usually ends in a rather exciting fire. :yikes

There are some pros and cons about lipos and water. I use them on my rc boat. No problems. There are some discussions on RC groups about water and lipos. You can have problems with any battery if it gets submerged. I use 7.2v 3300mh in my boat. No problems in 7 years. Batteries still work too.