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Discussion Starter · #1 ·
Hi all,

I have an Alberg 30 with minimal energy requirements when at shore. I have two 12V batteries (house and starter) and would like to keep them charged with a solar panel. (Editors note: pedestal fees went up to $60/month. Grrr). Just looking for some recommendations for something that I basically place in the cockpit and put away when sailing. I don't have room for permanently mounted at this point.

Thanks for any information.
 

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I use a 20W panel and a Victron 75/10 smart controller to charge a single group 24 AGM battery. It works well. I have recorded about 8 Ah per day replenishment rate.

The controller is mounted in the cabin. I made a bracket with a sleeve that fits over the end of one of my stanchions. I leave the panel connected with a 10 foot cable. When it is time to sail I just remove the panel from the stanchion, and lay it on the cabin cushions, face down to stop the charging.

For your twin batteries, a 50W (~20 Ah per day) panel would be pretty good for the purpose of keeping them topped off. It would still be small enough to make a stanchion mount.

If you are drawing down the batteries, it will take a few sunny days to recharge.
 

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Wauquiez Gladiateur
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its unfortunate that Victron controllers do not have a pure maintenance mode, they try to recharge the battery fully every day. It can bake batteries if the panels are big enough and the sun comes out for a while. Good to have a switch to turn off panels when not in use. self discharge in cool weather with no load is pretty low.
 

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The idea of "trickle charging" is to maintain a fully charged battery. If you are drawing the batteries down at all then you want a little more charging capacity. The idea of taking days to charge a battery up is not a good one. Lead Acid batteries do not like to be kept in a state of partial charge for long periods, and doing so can permanently reduce their capacity. You will want a panel and charge controller that can bulk charge your battery in a reasonably short period of time and then switch to float to maintain it.

If your house and engine batteries are 2 different sizes or types you shouldn't really charge them together on one charging source.

How long do you leave your boat unused? If you are using your boat regularly your engine battery will be fine without a charger. The alternator with replace the charge used for starting fairly quickly so it should be fully charged by the time you get to the dock. If you leave your boat unattended for months at a time you may want to have some kind of battery maintainer.

On my boat the engine battery is not connected to the shore power charger or the solar system. In the winter, when we aren't using the boat as much I go down to the boat every couple of weeks and run the engine. The shore power charger or solar keeps the house bank happy.

Sent from my SM-G981W using Tapatalk
 

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its unfortunate that Victron controllers do not have a pure maintenance mode, they try to recharge the battery fully every day. It can bake batteries if the panels are big enough and the sun comes out for a while. Good to have a switch to turn off panels when not in use. self discharge in cool weather with no load is pretty low.
That's not true. The Victron controllers are fully programmable, and you can set the float voltage to whatever you want. I have mine programmed for 13.4v float as per the battery manufacturer recommendation. Once the battery stops accepting amps it switches to float.

Sent from my SM-G981W using Tapatalk
 

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A 50W panel works for me. Our marina has had power problems off and on for a few years... The 50W will keep the batteries topped off, but if they are down to 50%, it would probably take most of a sunny week to get back to 100%....
 

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Imexus 28 Trailable Powersailer
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That's not true. The Victron controllers are fully programmable, and you can set the float voltage to whatever you want. I have mine programmed for 13.4v float as per the battery manufacturer recommendation. Once the battery stops accepting amps it switches to float.

Sent from my SM-G981W using Tapatalk
Yes you are correct about the more recent Victron chargers which I also have now upgraded to but not the earlier ones I have now replaced which may explain the discrepancy in experience with them. I think the newer ones which allow full monitoring via your phone and manual adjustability are fantastic. 🙂
 

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Discussion Starter · #8 ·
Hey all. Thanks for the replies. I clearly need to learn a little more about batteries. I am going to figure out what batteries I have on board, and then will come back with some follow-up questions I will probably go with a flexible solar panel on top. My diesel engine does a fairly good job of keeping the batteries charged, and when anchored I only need a little bit for my led lights.
 

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I had a 15w solar panel that I bought in 1999. It lasted about 12 years when the connections fell off.
I replaced it with a 100w not flexible cell in the hopes it'll be more durable. Its too big really for my West Wight Potter, but at the moment it rests on the mast on the boat in my back yard.
I have used the Sunsaver-6 charge controller now for 20 years. It seems to be working fine.
A link to Sunsaver-6 Westmarine has the TRAC Battery Monitor I use to check the battery state
Hand Fluid Gadget Finger Communication Device
 

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Chances are your Alberg 30 has 2 flooded lead acid batteries - most likely Group 24, 27 or 31. Typical of older boats. If you are only looking to keep the batteries topped up, then a small panel of 20 to 30 watts and a simple PWM controller will do the job. You can do this for under $100. If you want the ability to bring a discharged battery back, then you will need more capacity - more watts of panels and a better controller.
 
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