Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[bigsnag]

Anyone have insight or experience using solar panels to charge / top up batteries ?  Thanks.

[DanL]

What sort of battery usage do you anticipate? Top up is certainly possible, charging is not so practical as solar panels dont really output that much current relative to marine battery capacity unless you spend a load of money for huge surface area. Gas generator will be much more effective on a per dollar basis.

Buy the largest panel(s) you are willing to pay for and carry around. Based on the panels output rating in amps  you can roughly calculate how long it will take to charge say, 10%/50%/whatever of your battery. A group 24 marine battery might have ~100 Amp-hr capacity so you'll quickly see how much solar power you need to charge at any appreciable rate. Panel ratings are in absolutely ideal conditions so the actual output will be much lower too.

[bigsnag]

Hi Dan L,
I was looking at a Noma Flex solar panel 15 watts $79.99 on sale at Cdn Tire to use primarily for topping up purposes. I wasn't going to use a solar controller for topping up as the panel in actual use will put out less than 15 watts. It has a built in diode to prevent energy back flow damage to the panel.

I was looking for comments/ tips from use in the field with these things. Just using a depth sounder and a 46lb. thrust electric motor.

Thanks


 

[Noahs Arc]

Honestly, I'd just spend the money you're willing to spend on the solar panels, and buy another deep cycle battery.

I have 2 batteries and they last me a full week fishing during trout season.
Just using a 30lb thrust and no fish finder though.

[canso]

A 15watt solar panel will charge 1.25 amps, if clouds are present it drops dramatically.

If you drain your 100ah battery by 10%, leaving you with 90% battery power (short troll on an electric motor) it will take 8-10hrs to get back to 100%.

For solar panels I would suggest something in the 150-250watt size but now your talking 3'X4'+sizes

[DanL]

In fact the model the OP refers apparently outputs 0.76 amps in ideal conditions, which probably means placed at the equator for the 1 hour the sun is directly overhead. The math would dictate you might be able to recharge maybe 5% of a typical marine battery with a whole days charging, and likely not even that.

Are you planning to mount it on your boat to charge during the day? If so that panel might be able to keep up with the usage of your fish finder which probably draws up to a few hundred milliamps depending on model. Trolling motor, not so much, they simply draw too much current to recharge with a small panel.

I admit I have no field experience in actual usage cases. I researched it earlier this year and decided I wasnt prepared to invest the money nor space to get a system that could recharge a battery at any useful rate. In my very humble opinion if you are going to go down this road maybe consider two batteries where one can be left at camp charging on a larger panel (say 100 watts) all day while the other is being used.

[Knife]

 I have 2 of the 40wt. Can. Tire solar panels and I think they help. I leave one connected to the tent trailer battery and the other to charge the battery for the trolling motor. The charge rate can't compare to a gas generator,but solar panels sure are quiet.
 Our last fishing trip was 8 days and both deep cycle batteries lasted with the solar panels topping them up. Before using the panels, they would never last that long. My portable fish finder battery ran out on the 5th. morning, and after an afternoon of being connected to a panel, lasted the rest of the trip.
 

[troutbreath]

I use a 40 watt to charge two 12 volt batteries on my water pump system at the cabin. I then use one of those batteries for my trolling motor. I use to use a 5 watt panel for the smaller 12 volt batteries (motorcycle size). I would charge a few of them to use on the electric motor.

The main thing with them is to charge during peak sunlight hours. So instead of being out fishing and trolling for skin cancer in the middle of the afternoon, your charging your battery.

I have three 100 watt ones to power up the cabin and they can charge up my two 12 volt deep cycles remarkably quick. My cheapo phoney foreign charge controller says 4 amps when charging. I use all the power tools I use to run on the generator on the solar system now. I intend to get another deep cycle for my electric trolling motor and charging it on that system instead of using the batteries from my water pump system. I also intend to get a real MPPT charge controller from the USA. Still experimenting.

[Birkenhead]

New guy here but long time user of solar for both camping and fishing. For my trailer and electric boat motor batteries (group 27 size) I currently use a 100 watt Renogy solar panel. As another person here mentioned, using solar to charge your battery during the mid day sun is idea.

During this time of year and at fishing lakes such as Tunkwa where the terrain is wide open (meaning no trees to block the sun) with good sun from about 6:00 am to 8:00 pm, this same panel will also easily keep my 2 trailer batteries topped up during the day and ready for overnight use as my fridge is run off an inverter from the batteries.

On cloudy or rainy days, I use a Champion 2000 watt inverter generator along with a 12 amp charger to help keep all batteries topped up. Depending on discharge rate and how long I use the trailer and trolling motor batteries, the generator may need to run for 1-2 hours during the morning and again during the evening. These inverter generators are very quiet and if placed slightly away from your camp area, they can be barely heard. As these generators barely use any gas, they are cheap to run for a few days. Typically the generator burns about a gallon very 2 days, depending on actual run time and load.

For my fish finder, I use a separate 7AH, sealed lead acid battery as I also use a 6hp gas motor for my 12 foot lake boat and do not always need to lug a big deep cycle battery just to power the fish finder. This 7AH battery will easily last a weekend of powering the fish finder but since I have the capability, I charge it every day.

As for battery discharge, having a hand held voltmeter or wired in voltmeter is essential to keeping an eye on battery voltage. If you run the batteries down too far, you risk permanent damage and or severely risk shortening the battery life. The below image is a good guideline on battery discharge.

[doja]

Is that chart for deep cycle battery's?

[Birkenhead]

Is that chart for deep cycle battery's?

Yes it is.

Forgot to add last night. This website has some great info on batteries, wiring etc. Though it is more geared to the RV crowd, it is still very applicable to boating fisherman.

The 12 volt side of life

[Noahs Arc]

I always thought deep cycles were designed to be drained but that chart says in the comments section it affects the lifespan of the battery?

[banx]

I always thought deep cycles were designed to be drained but that chart says in the comments section it affects the lifespan of the battery?

I think, and I could definitely be wrong, but ya, a deep cycle can be drained and recharged frequently.

I think its just what you consider drained..... for instance, using the 'battery meter' on my minn kota whern it says 25% left its not really 25% of the remaining battery. possibly 25% left of safe usage i suppose..  I have quite a few class 31's. and when it shows 25% remaining on the minn kota, they get swapped out. when I check them on a voltmeter they are never below 12.15 volts. even If i forget to charge them when I get back, they never dip below the 12.15 volt threshold.

[doja]

I always thought deep cycles were designed to be drained but that chart says in the comments section it affects the lifespan of the battery?

More tolerance...  But not designed too and life is affected.  Nicad are,  lithium no....  They all have their own preference.



Every kind of batter I have last a long time as I keep in its preferred operation state.

[bigsnag]

Thanks to all you guys for you comments. My line of thinking here was to avoid lugging a second battery and a charger , where I have power , during a 5-7 day fishing trip.
 I do plan and have room to bring a panel aboard  during the fishing day so it will be topping up as I fish. I can monitor battery discharge with a meter.

Now I have to be patient and grab a solar panel on a good end of season clearance price.