Solar Charging

[Duncs]

As I am on a swing mooring I am looking for a cheap solar charger that can be used just to keep the batteries topped during the week, so that when we go down to the boat on a Friday evening I am not at risk further depleting the battery bank (2 x 75Ah) that have been merely self discharging since the last visit.
I have been considering one of the cheap ones sold for auto batteries but wondered if the output would be so low as to make little difference.
Has anyone any experience?



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[oldharry]

If the cheap ones do anything at all - and not all of them do because the output is just too low - they will at best stop the self-discharge process. Panels powerful enough to re-charge the batteries are more expensive and larger, but top up the batteries quite well enough to allow them to recover during the week.

If you do try one of the cheap ones check there is a diode or other non-return device so that it does not actually discharge your battery during hours of darkness. Unfortunately cheaper diodes cause a voltage drop which can further reduce their viability!

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by oldharry on 05/02/2004 12:20 (server time).</FONT></P>

 

[VicS]

I have a 5watt panel feeding a 48 AHr battery in just the way you are asking about. It easily keeps the battery topped up and I rate it as one of the more useful bits of kit that I have bought.

I bought it quite a number of years ago from one of the major mail order chandleries (sadly no longer with us) for about £100. I think prices are a little lower now and possibly performances a little better. It is permanently mounted and the space available limited the choice of panels. Mine is fitted on the sloping cabin front but it's a flatter angle than that of a Centaur.

If possible I would consider fitting two small panels, one for each battery, rather than one larger one for both. If you want to charge both from one panel you will need two diodes (one is needed anyway) in order to keep the batteries isolated from each other but that still won't avoid the scenario of one failed battery taking all the available output from the panel leaving you with one flat battery and the other not charged as you expected. Two separate panels will overcome that.

Voltage drop across the diodes is not an issue because the no load voltage from the panel is quite high and more than compensates for it. Also small panels do not require a regulator.

I believe that the panels sold for keeping a car battery topped up are intended to be placed on top of the dash board and may not, therefore, be sufficiently weatherproof to be used on deck. No problem if one had a wheel house, of course.
While they may have an adequate output to keep a fairly new car sized battery topped up (if they don't they are not fit for the purpose for which they are sold) they probably won't do 150 Ahr especially as the self discharge rate increases as the batteries approach the end of their useful lives.

These litte panels are so cheap, though, why not give one a try anyway. If it's no good then you can always use it to keep the car battery topped up while you are away sailing. If you try one do let us know the results.

What ever you do be sure to incorporate a fuse or fuses as close to the batter(ies)
as possible.

When I first fitted my panel I just used small crocodile clips to connect it to the battery but I have now made terminal posts by screwing short lengths of 2BA brass studding (screws with their heads cut off), and a couple of nuts and washers, into the battery posts and fitting spade terminals on the panel leads.

<hr width=100% size=1><font color=purple>Ne te confundant illegitimi.</font color=purple>

 

[Redscouser]

There some very reasonable priced ones on Ebay.co.uk
I email the guy and he was very helpful


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[Guest]

Yep .... I have 2 auto-trickle solar jobs and they do a grand job ....
24.99 each....... even included the socket and croc clips converter cable.

<hr width=100% size=1>Nigel ...
So WHAT does the EU really stand for ????/forums/images/icons/cool.gif

 

[Guest]

Trickle charge panels

These litte panels are so cheap, though, why not give one a <<try anyway. If it's no good then you can always use it to keep the car battery topped up while you are away sailing. If you try one do let us know the results.>>

I have 2 and they work well - wind, rain and shine they sit outside without problem, OK the packing said on dash - but I've left them for long period and no probs.

AND they are on large capacity 120 a/hr batts.



<hr width=100% size=1>Nigel ...
So WHAT does the EU really stand for ????/forums/images/icons/cool.gif

 

[VicS]

Re: Trickle charge panels

Thanks for those comments. Sounds like they were a good investment. I'm not sure that they were around when I bought my panel.

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