Solar or conventional charger

[alumrock]

Does anyone have an opinion on solar charger versus a smart battery charger?
I replaced the batteries (wet style) on two years ago; they are now dead and I think it is because of the old original charger. I now need to replace the batteries and get a new charger. Would like to consider getting a solar charger, free to run and initial cost is probably the same. Can I use one of these instead of a smart charger?

 

[Bill1565]

Different things.

Smart regulators" charge batteries in 4 different ways, High amperage moderate voltage, Moderate both, low amperage, voltage over 12.6(fully charged number for 12 v batts. and finally on demand or on a monthly cycle, overcharging to drive accumulated lead sulfate on the battery plates back into pure lead and sulfuric acid, renewing the battery.

Solar chargers put out up to 7 or 8 amps for a few hours in the middle of the day, Wind mills can put out up to 20 or 30 in a storm, but don't start producing electricity till 6-10 knots of breeze. 110 v chargers can put out up to 20 or 30amps for as long as you are plugged in. Alternators on inboards produce 50 to 100 amps or more. All can be "Smart regulated". Live aboards and long term cruisers typically have 3 or even all four of these.

If you don't use much electricty and only use your boat some weekends, and can find a spot that is not shaded, perhaps a single solar panel will do you, but it needs to be "regulated". Solar panels can produce 17 volts or better. This is too much voltage on a long term basis.

Old style ferrite core chargers were very, very, heavy, put out constant 13 ish volts, amps were controlled by the state of the battery. as the battery approached 12.6, the rate of charge (amps) went way, way down. overcharging to remove accumulated sulfates was not possible. Battery life was shorter.

 

[Steve Dion]

I could not agree more. High quality multi chemistry battery charger (I would recommend a Xantrex XC unit). If you think you need solar after that it would be an add on. You will have a much larger investment in solar than you will with a good battery charger to keep your batteries in tip top shape.

The Xantrex XC unit will allow you to have multiple battery chemistries in different banks. You could have flooded house keeping batteries and a Optima for a starting battery if you want.

It is also a good time to think about changing your battery types too. You may want to look into AGM batteries. They tend to be less expensive in the long run but it depends on what your wallet can stand.

 

[Bill Roosa]

things that kill batteries

There are three things that kill batteries effectively; deeply discharging them, not charging them fully once in a while and over charging them. The deeply discharge is something no battery charger item can fix. That is in your court to either reduce the AH out between charges or increase the frequency of charging or buying more AH so you can go longer, discharge less (% of battery capacity wise) or a combination. Overcharging and not fully charging batteries can be prevented with smart charging regulators AND a charging source that has enough oomph to do so.
With all that said; a good battery charger is the first thing you should buy to get and keep your batteries maintained. An alternator with ~25% of your battery AH capacity is the next thing. Stu has shown data that you can probably get by with even less and just a little more run time on the engine, solar and wind can't really compete with an alternator BUT they work without the engine and work every day for long periods of time. they need an additional regulator also except a solar panel that is ~1% current output of your battery AH (100 AH bat bank would be ok with a 1 amp panel with out a regulator). hydro can provid a lot of AH but you have to be moving.
As was said before, most cruisers have all the above for the various situations they get into. For weekend sailors a bigger battery bank and good AC charger are all you need.

 

[Benny]

A solar system is not a substitute for an inboard smart charger if you have access to shorepower on a regular basis. A solar system could be the best alternative for a boat on a mooring or complement a charging system for a boat that spends frequent days at anchor in sunny areas. Verify what constitutes your sailing style and do your homework and familiarize yourself with the pros and cons of any system. An inboard battery charger when plugged in may provide a steady output but a solar panel will not work at night, barely on a cloudy day and may be inadequate at certain sun angles during the day. Another factor to check might be the length of the anticipated working life of each system.

 

[JoeWhite]

I use a 12VDC charger that is made to charge the batteries of a home burglar alarm system. They measure about 2" by 3" and all they need is a 2 AC Amp transformer. Its output is adjustable. I set it to 13.5 VDC. I can leave it charging for a long time without damage to the batteries. I etimate that it puts out 1.5 AMPS. My batteries are about 5 years old and going strong.

 

[jtm]

On my H28.5 I have tried this - one 5W solar panel is mounted on my winter companion board (plywood primed and painted- a lexan cover box floating on spacers allow for heat dissapation). The lead runs under my cockpit seat to the bilgepump /house battery- a second 5W hangs under my V berth haych(yes not optimally angled in winter) and it makes a somewhat longer run (via forward cigarette lighter socket) to the house battery. I know I'm losing some voltage in that run length. I have a nanopulser mounted by the battery whichperioically blasts the sulfation off the plates. Compared to prior years were I have to swat battery about mid winter, I just checked my voltage on the battery this week and I'm at 13.2 at the panel. So while not perfect, it seems to be doing well. I have a 1.5W panel which I can still add in the galley window but had waited to see how the system keeps itself.

I should add some controller but I think I am just below overcharging as is. This summer I plan to install a prosport 12 (2bank) charger- but I don't like the electrolysis leak potential of leaving this on 24/7.

Thoughts of others are welcome.