Solar Battery Charger

[leeccoll]

Just added this 20 Watt 1.0 Amp DuraVolt solar battery charger to keep batteries topped off when I am not running them, especially in the cold winter months where the boat sits outside and not in use.

Plugs into the dash cigarette lighter charger, and can stow it easily in the cabin when I am out fishing if I want to.

Seemed like it's worth a stab, since I have alot of recent add-ons that might slowly drain the battery charge.

 

[DennisG01]

I like the idea of solar maintainers. Free power is good!

Question... is the cigarette lighter wired direct to the battery? Meaning, when you leave the boat and turn the battery switches off, if the lighter plug turns off, as well, then there's no charging going on.

What things have you added that would draw down the batteries when the battery switches are off? Really, the only things that should be wired direct to a battery would be things like the bilge pump float switches and radio memory.

 

[seasick]

It also seems that you are at sea based on depth and speed. The output of the panel is less than the draw of the plotter.
So what is actually the goal for the solar panel?

 

[leeccoll]

I like the idea of solar maintainers. Free power is good!

Question... is the cigarette lighter wired direct to the battery? Meaning, when you leave the boat and turn the battery switches off, if the lighter plug turns off, as well, then there's no charging going on.

What things have you added that would draw down the batteries when the battery switches are off? Really, the only things that should be wired direct to a battery would be things like the bilge pump float switches and radio memory.

Not wired directly to battery Dennis, but I was told if I leave the battery switch on "BOTH" it would top off the batteries.

Honestly, everything I have installed such as down riggers, instructed to wire directly to batteries. I never had a dead battery except once from old age in the winter, but I want to play my stereo that is a new installment when I am sitting around cleaning things up on the boat, and not have to worry about excessive battery drain.

All my fishing is done by trolling so I might not need it, but the thought of keeping the batteries well charged lured me in

 

[leeccoll]

It also seems that you are at sea based on depth and speed. The output of the panel is less than the draw of the plotter.
So what is actually the goal for the solar panel?

Not sea based, 6,500' mountain lake.

Goal of solar panel is to trickle charge batteries when I am not using the boat. Plenty of sunshine during the year here, I don't have an easy way to charge the batteries during the winter months when the boat sits outside, so this is a guinea pig test for that.

 

[seasick]

Depth on plotter was 98 feet. Speed was almost 2 mph
It looked like you were charging while in motion.

I understand the use as a slow trickle charge. Sorry for my confusion.

 

[leeccoll]

Depth on plotter was 98 feet. Speed was almost 2 mph
It looked like you were charging while in motion.

I understand the use as a slow trickle charge. Sorry for my confusion.

Seasick,

You are correct, I did have it plugged in during that picture, but really intend to just stow it away in the cuddy until I keep the boat outside in dry storage, then I will use it.

You are not confused on that one sir

 

[seasick]

More confused than ever these days

 

[DennisG01]

Honestly, everything I have installed such as down riggers, instructed to wire directly to batteries.

Manufacturers of equipment say that to CYA to ensure clean power. If an owner hooks it up to a bus bar and the equipment isn't working, in many cases, said owner will first accuse the equip manufacturer of supplying a faulty piece. When, in reality, the issue is that the owner hasn't maintained clean power to the bus bar. Best practice would be run equipment off a bus bar installed after the battery switch. "Best" meaning, not "required" - just ideal.

You'd probably be better off if you installed the charger right to the batteries. A direct connection, for any charger, is the better way to go - especially with a small charger. The longer the wires to the batteries and the more connections along the way, less and less power will actually reach the batteries. Using a weatherproof charger and a little quick-disconnect hidden somewhere in the aft area would work well. Just a suggestion!

 

[Sdfish]

I have 2 15 watt solar panels with "battery tender" controllers wired directly to each battery, only plug these in when in my storage. So far it has worked great. I used the same set up on my 17 whaler with 2 batteries for years w/o issue.

 

[leeccoll]

Manufacturers of equipment say that to CYA to ensure clean power. If an owner hooks it up to a bus bar and the equipment isn't working, in many cases, said owner will first accuse the equip manufacturer of supplying a faulty piece. When, in reality, the issue is that the owner hasn't maintained clean power to the bus bar. Best practice would be run equipment off a bus bar installed after the battery switch. "Best" meaning, not "required" - just ideal.

You'd probably be better off if you installed the charger right to the batteries. A direct connection, for any charger, is the better way to go - especially with a small charger. The longer the wires to the batteries and the more connections along the way, less and less power will actually reach the batteries. Using a weatherproof charger and a little quick-disconnect hidden somewhere in the aft area would work well. Just a suggestion!

I agree, I just haven't had a chance to. I need to order an extension for the terminal connectors as well. Thanks for the tip Dennis!

 

[leeccoll]

I have 2 15 watt solar panels with "battery tender" controllers wired directly to each battery, only plug these in when in my storage. So far it has worked great. I used the same set up on my 17 whaler with 2 batteries for years w/o issue.

That's encouraging, we all like to be juiced

 

[seasick]

Manufacturers of equipment say that to CYA to ensure clean power. If an owner hooks it up to a bus bar and the equipment isn't working, in many cases, said owner will first accuse the equip manufacturer of supplying a faulty piece. When, in reality, the issue is that the owner hasn't maintained clean power to the bus bar. Best practice would be run equipment off a bus bar installed after the battery switch. "Best" meaning, not "required" - just ideal.

You'd probably be better off if you installed the charger right to the batteries. A direct connection, for any charger, is the better way to go - especially with a small charger. The longer the wires to the batteries and the more connections along the way, less and less power will actually reach the batteries. Using a weatherproof charger and a little quick-disconnect hidden somewhere in the aft area would work well. Just a suggestion!

Having to leave the battery switch on for the batteries to charge adds some risk. Some are electrical and some are potential user errors such as leaving the VHF radio on or a light and coming back to fine a dead battery.
The idea of have a 12V receptacle handy to plug in the solar panel is attractive in this particular situation. So one option is to either install at the helm a new separate outlet that connects directly to the battery or option 2, run a new wire from the battery to the existing outlet. The feed must be fused near the battery. A 3 amp fuse is plenty.
With this arrangement you can turn off your batteries and still be able to plug in the panel for a trickle charge. I wouldn't worry about voltage drop especially since you will be charging at an amp max.
If you want to get fancy, you could also install a wire to each battery (with fuses) and add a selector switch at the helm to allow you to select which battery is connected to the solar panel

 

[dogdoc]

When do I need a charge controller and why?
The safest way to figure out if you need a charge controller is to take Battery Amp Hour Capacity and divide this by the Solar Panel max. power amp rating. If the quotient is above 200, you don't need a controller. If the number is less than 200 than you need a controller.
For example if you have a 100 amp hour battery and a 10 watt panel, you take 100 and divide it by .6 (600mA) and you get 166.6. Since this is less than 200 you need a charge controller. If you have a five-watt panel in the above example you take 100 divided by .3 (300mA) and you come up with 333.3. Since this is larger than 200 you do not need a charge controller. However you still need a blocking diode, to prevent the battery from discharging to the panel at night. So as a general rule of thumb you don't need a charge controller unless you have more than five watts of solar for every 100-amp hours of battery capacity.

I always put a charge controller in the mix and wire directly to the batteries with a fuse when setting up a maintainer system. While your current arrangement might keep you from getting a dead battery, it will probably not give you the maximum battery lifespan possible.

 

[Sdfish]

These are the panels I used, 10W not 15.

ECO-WORTHY 10W 12V Portable Waterproof PV Polycrystalline Solar Panel System kit W/Battery Charge Controller & 30 A Battery Clips Adapter

I did not use the controller it came with.


This was the controller I installed for each panel and battery. It may be overkill, but I don't worry about batteries.

 

[dogdoc]

Have used the above battery tender for about 3 years to maintain starting battery on portable generator. Only addition was a small digital volt meter to monitor system a little easier

 

[Seafarer_Bob]

I'm planning to do this and done some research but open to feedback if anyone disagrees. I'm told anything more than 10 watts you'll want a charge controller so you don't over charge and damage your battery. You could probably connect the charge controller to the common posts inside the battery switch or get a dual battery bank controller and run it straight to each battery. You don't want to leave your battery switch on.