Is it worth using a solar panel to keep up the charge on lead acid batteries

[stevet]

Hi all

straight from this electrical novice.

Every thing I now do to the boat is based around making it easier to get on the water.

If the weather is right I just want to hitch the trailer to the car and go.

To this end I am running a dual battery system with both batteries lead acid cranking batteries. I gave up running a deep cycle house battery.

I have a 100w solar panel sitting around, and I am seeking advice as to whether it is feasible?, advisable? to hook up the solar panel to the 'house battery' to keep it topped up? if yes , I propose to use an 'Anderson plug' arrangement to allow fast disconnect without touching the battery. If it is a reasonable way to go, should the +ive connection be fused between the panel and the battery?

thanks
Steve

[Corry]

Yeah I do. I've always got a solar panel connected to the boat when it's parked up. I even use it when out on the water. It's a foldable 200w panel, I hang it over the cover when the boat is at home and ocky strap it to the bimini when out and about. Just got to take it down if I'm going to be going at speed when on the water.

[Noelm]

As a general rule, if the battery is OK, and nothing is left on, the battery should maintain adequate charge for quite a long time, if you have to root around with chargers, the battery needs to be replaced, or you need to get out more often.

[NAGG]

I agree with Noel

If you have a good battery with good isolation - there should be no reason to trickle charge your battery .

It's probably better to run your motor every few weeks (30mins) - that will not only top up your batteries but be beneficial for the motor .


Out of curiosity - why did you go away from a deep cycle house battery ?
Did you go with marine batteries or are these 2 x car crankers ?

Chris

[disorderly]

Yeah I do. I've always got a solar panel connected to the boat when it's parked up. I even use it when out on the water. It's a foldable 200w panel, I hang it over the cover when the boat is at home and ocky strap it to the bimini when out and about. Just got to take it down if I'm going to be going at speed when on the water.

Is your boat painted.?.Have you noticed any signs of electrolosis/paint bubbling... ?

I just ask because when discussing sticking a semi-flexible panel to my hardtop with the mechanic, he told me it was the worst thing for a painted tin boat..


Does anyone know how much charge lead acid batteries lose after sitting for any length of time...?

In 20 years I have never had a boat battery go flat enough not to be able to start the motor without having left something on to flatten it..

[NAGG]

Is your boat painted.?.Have you noticed any signs of electrolosis/paint bubbling... ?

I just ask because when discussing sticking a semi-flexible panel to my hardtop with the mechanic, he told me it was the worst thing for a painted tin boat..


Does anyone know how much charge lead acid batteries lose after sitting for any length of time...?

In 20 years I have never had a boat battery go flat enough not to be able to start the motor without having left something on to flatten it..

I've had the VSR flatten the batteries over time .

Lead acid batteries can lose quite a bit of charge over time - depending on temperature you could lose a few percent per week in NQ - Normally you could count on 5% discharge / month at 20 deg C

Chris

[bluefin59]

Ran 2 batteries in my boat for 15 years and never had a problem when I isolated both batteries after a trip but again I was out most weeks or at least once a month , first set of batteries lasted 10 years and I changed them because I felt they had done their time

[stevej]

You have to look up your batteries specs and see what float charge it can handle if day a 100watt panel is too big and will need a charge controller between the panel and battery

are both batteries cranking batteries ?
I see that more of a issue then worrying about them discharging
had boats sit for months and long as the batteries in a box and clean with a isolation switch they will be fine

[Corry]

Yeah, boat is painted, it's a Quinny Top Ender. I've got not issues with electrolysis or anything like that, the boats a 2000 model.
I don't really use the panel to keep the battery charged, I use it to charge the batteries. I've got 3 batteries, one dedicated for cranking, the other two run the fridge and electric motor. I use a VSR between them, so I don't get the option of switching them 'off'. When I return from a day's fishing (nearly every weekend) the 2nd and 3rd batteries need charging from doing their duties, I figure I'm better off using our wonderful FNQ sunshine to charge it while I'm at work for the week so it's ready for the next weekend... and it saves me running a lead out to it for the CTEK.

[stevet]

As a general rule, if the battery is OK, and nothing is left on, the battery should maintain adequate charge for quite a long time, if you have to root around with chargers, the battery needs to be replaced, or you need to get out more often.

Valid points- yes don't get on the water enough and the stereo that needs to be kept connected to keep its presets.

I will still set it up and run bluetooth through the stereo and stuff worrying about keeping the presets