Solar Panels ?

[T_Dot]

SOLARFLAT 15:

- 15 watts maximum output

- Amorphous solar cells for low light

- Great for charging 12 volt batteries

LINK:

- http://www.basspro.com/servlet/catalog.TextId?hvarTextId=73589&hvarTarget=search&cmCat=SearchResults

i have a alumacraft 1436 jon boat, and will be carrying 3+ batteries since i will be upgrading to a larger trolling motor. i will also need to power a fish finder and some lights if i want to fish at night.

now if i take a long trip, and fish day and night... how fast or slow will this charge my batteries while i run?

with all the weight and people i dont think i can carry anymore batteries. though i like the idea of charging a few batteries while im out there in the sun. this will also aid if i go out to remote locations where there are no power outlets.

please advise

thanks

EDIT:

to avoid further confusion... i always charge my batteries before going on an outting. what i basically want the panels to do is to provide some power and recharge my batteries while im out on the water.

the question is, how much would these things charge my batteries on a 6 - 8 hour trip?

what do you all think about these:

LINK:

- http://www.brunton.com/product.php?id=256

[Team_Dougherty]

A long time. That solar panel is designed to keep a fully charged battery charged. At 15w in full sunlight it will produce about 1 amp of current. If you have a 105 amp hour battery that is 75% discharged it would take 25-30 hours to bring the battery up to full charge. That is in full sun. On cloudy days it will produce less, at night none.

[Team_Dougherty]

If you want to charge your batteries in remote locations use one of these.

http://www.hondapowerequipment.com/ModelDetail.asp?ModelName=eu2000i

The 12v circuit can put out 8 amps. Or, you can power an on board charger using the 120v outlet.

http://www.basspro.com/servlet/catalog.TextId?hvarTextId=74190&hvarDept=200&hvarClassCode=3&hvarSubCode=4&hvarTarget=browse&cmid=PP_P0_2&cmCat=CROSSSELL

with the that combo you can keep your batteries topped off all day and night, as long as you have fuel.

Those hondas are very quit you can run it with out most people knowing.

[HPBB]

They are not ment to be used for a fast charge, and they only charge 12volt setups, not 24 or 36 set ups. they are good on boat that sit out . We use them on our pontoon boats. We don't have power down to our dock so the onboard chargers can't be used. they sit all week long on the docks and the solar chargers keep the batteries up. Since we have been using them, about 2 years. we have seen far less jump starts after the boats have sat. If your boat is going to be home or somewhere you can plug it in , an onboard charger can not be beat. If you have 3 batteries, BPSs sell a nice 15amp 3 bank charger for around $150, less when on sale. It can be hooked up anywhere and it can charge 1, 2 or 3 batteries in any 12, 12-24, 24, or 36 volt setups. Just plug it in when you get home and forget about it till your off again.

[chitwnbass]

They do produce larger solar panels that put out 7-10 amps but thier definitley more expensive. Your at about the same price of a generator and charger with these larger units.  Generator might be the way to go in your case since you'll probably be charging at night.  Solar is a opton but probably not as portable as a generator also.

[Way2slow]

You can use solar panels on 24 and 36 volts setups, you just have use one solar panel per battery, ie if you have a 24 volt system, you would need two solar panels with one hooked to each battery.  As mentioned they are stickly for maintaining the charge after the battery has been fully charged.

[T_Dot]

A long time. That solar panel is designed to keep a fully charged battery charged. At 15w in full sunlight it will produce about 1 amp of current. If you have a 105 amp hour battery that is 75% discharged it would take 25-30 hours to bring the battery up to full charge. That is in full sun. On cloudy days it will produce less, at night none.

so if the math is right, i would need about 7 of these to produce about 7 amps of current.

how many amps would i roughly need to charge a battery that is 50%?

thanks

[T_Dot]

If you want to charge your batteries in remote locations use one of these.

http://www.hondapowerequipment.com/ModelDetail.asp?ModelName=eu2000i

The 12v circuit can put out 8 amps. Or, you can power an on board charger using the 120v outlet.

http://www.basspro.com/servlet/catalog.TextId?hvarTextId=74190&hvarDept=200&hvarClassCode=3&hvarSubCode=4&hvarTarget=browse&cmid=PP_P0_2&cmCat=CROSSSELL

with the that combo you can keep your batteries topped off all day and night, as long as you have fuel.

Those hondas are very quit you can run it with out most people knowing.

thanks for the tips

im trying to keep the generator as my last option.

[T_Dot]

They are not ment to be used for a fast charge, and they only charge 12volt setups, not 24 or 36 set ups. they are good on boat that sit out . We use them on our pontoon boats. We don't have power down to our dock so the onboard chargers can't be used. they sit all week long on the docks and the solar chargers keep the batteries up. Since we have been using them, about 2 years. we have seen far less jump starts after the boats have sat. If your boat is going to be home or somewhere you can plug it in , an onboard charger can not be beat. If you have 3 batteries, BPSs sell a nice 15amp 3 bank charger for around $150, less when on sale. It can be hooked up anywhere and it can charge 1, 2 or 3 batteries in any 12, 12-24, 24, or 36 volt setups. Just plug it in when you get home and forget about it till your off again.

sorry for the confusion...

i should have rephrased it.  what i meant to say, is that i would like have somewhat of a charge going on while im out on the water, rather than going home with barely any juice.

on that note, how much would it charge my battery on a 6 - 8 hour trip.  mind you, it will still charge my batteries while i leave my boat docked.

[T_Dot]

They do produce larger solar panels that put out 7-10 amps but thier definitley more expensive. Your at about the same price of a generator and charger with these larger units. Generator might be the way to go in your case since you'll probably be charging at night. Solar is a opton but probably not as portable as a generator also.

where can i find some of these larger solar panels?

thanks

[T_Dot]

You can use solar panels on 24 and 36 volts setups, you just have use one solar panel per battery, ie if you have a 24 volt system, you would need two solar panels with one hooked to each battery. As mentioned they are stickly for maintaining the charge after the battery has been fully charged.

thanks for the tips

i might pickup 3 - 4 panels

[Team_Dougherty]

so if the math is right, i would need about 7 of these to produce about 7 amps of current.

how many amps would i roughly need to charge a battery that is 50%?

thanks

Your math is correct.

The amount of amps you will need to charge a battery that is 50% charged depends on the size of the battery and how fast you want to charge it.

For example:

a 105 AH battery 50% charged needs 52.5 AH put into it to it to be fully charged. So to charge it in an hour you will need to put 52.5 amps into it. A 7 amps it will take 7.5 hours to charge it. If you can put 10 amps into it you can charge it in 5.25 hours.

Do you get the relationship of battery power? Batteries are rated in AMP Hours Or AH. That is the amount of power they can hold. The two most common ones are 75AH or 105AH. If you draw a 10 amp load from a 105 AH battery it will provide approx 10.5 hours of power. If you draw 5 amps from it, it will provide 21 hours of power. these number are approximate and can change with the amount of current.

Now to charge the battery it is the same but backwards. If you draw 10 amp from that 105 amp hour battery for 5 hours you used 50 amp hours. the battery is about 50% charged. If you use a 10 amp charger it will take 5 hours to charge it to full. If you have a 5 amp charger it will take twice as long, or 10 hours.

You did not mention in your original post how big your electric motor is. Lets assume it is 30 Pounds of thrust.  A general rule of thumb is 1 amp of power draw per pound of thrust. So, If you run your motor for 30 minutes to your favorite spot.  you just used 15 AH from your battery. That solar panel puts out one amp so it would take 15 hours to recharge that battery after just a 1/2 hour run. Now, add lights and  electronics you will see how futile it will be to use solar panels to charge the battery or batteries.

Hope this helps

[T_Dot]

so if the math is right, i would need about 7 of these to produce about 7 amps of current.

how many amps would i roughly need to charge a battery that is 50%?

thanks

Your math is correct.

The amount of amps you will need to charge a battery that is 50% charged depends on the size of the battery and how fast you want to charge it.

For example:

a 105 AH battery 50% charged needs 52.5 AH put into it to it to be fully charged. So to charge it in an hour you will need to put 52.5 amps into it. A 7 amps it will take 7.5 hours to charge it. If you can put 10 amps into it you can charge it in 5.25 hours.

Do you get the relationship of battery power? Batteries are rated in AMP Hours Or AH. That is the amount of power they can hold. The two most common ones are 75AH or 105AH. If you draw a 10 amp load from a 105 AH battery it will provide approx 10.5 hours of power. If you draw 5 amps from it, it will provide 21 hours of power. these number are approximate and can change with the amount of current.

Now to charge the battery it is the same but backwards. If you draw 10 amp from that 105 amp hour battery for 5 hours you used 50 amp hours. the battery is about 50% charged. If you use a 10 amp charger it will take 5 hours to charge it to full. If you have a 5 amp charger it will take twice as long, or 10 hours.

You did not mention in your original post how big your electric motor is. Lets assume it is 30 Pounds of thrust. A general rule of thumb is 1 amp of power draw per pound of thrust. So, If you run your motor for 30 minutes to your favorite spot. you just used 15 AH from your battery. That solar panel puts out one amp so it would take 15 hours to recharge that battery after just a 1/2 hour run. Now, add lights and electronics you will see how futile it will be to use solar panels to charge the battery or batteries.

Hope this helps

yup i understand, im pretty good with math, i just dont know all the short form words when it comes to batteries.  now that you have mentioned what they mean, i understand everything better.

currently i have 2 30# trust TMs.  i will be upgrading to a 36 volt TM system.

thanks again

on the flip side of things, is there a down side when you charge and use your batteries at the same time?

[Team_Dougherty]

on the flip side of things, is there a down side when you charge and use your batteries at the same time?

Nope. You do it all the time in your car.

[Way2slow]

One thing that math does not account for. A 105 Ah battery is rated at that on a 20 hour draw down rate. Meaning it's only a 105 Ah battery if it only has about 5 amps being pulled off it. When you start drawing 30 amps off that battery it becomes about a 75 Ah battery instead of a 105 Ah battery so you can't figure at a 30 amp draw your going to get 3 1/2 hours run time, it's going to be more like 2 1/4 hours.

Look at the Trojan SCS225, it's rated at 130 Ah on a 20 hour rate but only 105 on a 5 hour rate. http://www.trojanbattery.com/Products/ProductSpec.aspx?Name=SCS225 Look what happens to the RC when increased for 25 amps to 75 amps.  The more the amp draw, the less the battery can stand it.

[gtbehary]

I have a small solar panel that I was going to use to charge a small garden tractor battery for my depth finder on my canoe.  Should this work?

[Team_Dougherty]

I have a small solar panel that I was going to use to charge a small garden tractor battery for my depth finder on my canoe. Should this work?

It should. But like that example above, It will take time. I would only use a small solar panel as a way to keep a fully charged battery charged. You need a bigger unit, 10 amps or more, to make a good charger. The amount of sunlight available to charge a battery is limited.