I think this subject has come up before by my question is has anybody had success with them?.
Many Thanks Sir Roger
Many Thanks Sir Roger
Solar Powered Battery Charger.
- Thread starter SirRogerFFS
- Start date
Hello Roger,
I don't personally use a solar charger, but a number of people on the forum do. They tend to use 60W or more Solar panels , and a charge regulator to prevent excess charge and to stop the panels discharging the battery when there is in suffcieint light.
Several report being able to stay away for extended period with no EHU, and simpley relying the panes to top up the battery. I think reasonable care has to be excersised to prevent excess use of 12V power, such as turning lights and fans off when not needed, and limiting the watching of TV.
I don't personally use a solar charger, but a number of people on the forum do. They tend to use 60W or more Solar panels , and a charge regulator to prevent excess charge and to stop the panels discharging the battery when there is in suffcieint light.
Several report being able to stay away for extended period with no EHU, and simpley relying the panes to top up the battery. I think reasonable care has to be excersised to prevent excess use of 12V power, such as turning lights and fans off when not needed, and limiting the watching of TV.
PROF John L.
Thank you for your reply, the reason I ask is I bought one from Maplins for a good honest tenner and thought its only a tenner and found after 3 days the tracker called me to say battery low .
Now this could possibly help others I dont know , what I did was moved my £10 Solar Panel and stuck it to the Hekki Sun Roof and plugged it into ciggy lighter etc, but also changed my battery to a 12 volt car battery ,I have been back to storage several times and the battery is still on 12 Volts and my trusty 110 amp sits at home in the warm still holding at nearly 13 volts.
I now feel my hard earned tenner was well spent.
I hope sharing this info will help others in some way.
Sir Roger
Thank you for your reply, the reason I ask is I bought one from Maplins for a good honest tenner and thought its only a tenner and found after 3 days the tracker called me to say battery low .
Now this could possibly help others I dont know , what I did was moved my £10 Solar Panel and stuck it to the Hekki Sun Roof and plugged it into ciggy lighter etc, but also changed my battery to a 12 volt car battery ,I have been back to storage several times and the battery is still on 12 Volts and my trusty 110 amp sits at home in the warm still holding at nearly 13 volts.
I now feel my hard earned tenner was well spent.
I hope sharing this info will help others in some way.
Sir Roger
The solar chargers that you can buy for £10-15 produce less than 100 milli amps. Most alarm systems etc draw about 30-50mA, so it'll just about be enough to cover any parasitic drain while the 'van is lying idle. If you intend to use a solar charger while camping without ehu this type will be a lost cause, taking something in the order of 100 hours sunlight to recover the power used watching tv for a couple of hours. But if it keeps your battery from going flat in storage or whatever then for a tenner you've scored.
Mcghee Thanks for your reply,just to clarify yes the caravan is in storage, so as you say Ive scored your input is appreciated.
As i have already said its just that I have to put a car battery on but at the end of the day I guess I am saving the life of my 110 amp battery.
Regards Sir Roger
As i have already said its just that I have to put a car battery on but at the end of the day I guess I am saving the life of my 110 amp battery.
Regards Sir Roger
Your leisure battery couldn't have been fully charged if it was low after 3 days? What kind of charger was it charged on, and does it work fully? Had the battery stood for a good while before being fitted to the 'van? Don't misunderstand me, I'm not here to criticise your methods, but there's no reason a car battery should perform better, in fact if anything it should be slightly worse. Which would lead me to believe your leisure battery was almost flat to begin with.
If it was fully charged the tracker would need to draw a constant 1.5 amps to flatten it in three days, unless there is another current draw at work.
Just out of interest, what size car battery did you fit? I would be surprised if the reserve capacity was anything like 110 amps. I have a 110amp reserve battery in my ML which is monstrous and certainly wouldn't fit in my 'vans battery box.
As I say SirRoger I'm not trying to criticise but I wonder if you may have a problem which you've missed.
If it was fully charged the tracker would need to draw a constant 1.5 amps to flatten it in three days, unless there is another current draw at work.
Just out of interest, what size car battery did you fit? I would be surprised if the reserve capacity was anything like 110 amps. I have a 110amp reserve battery in my ML which is monstrous and certainly wouldn't fit in my 'vans battery box.
As I say SirRoger I'm not trying to criticise but I wonder if you may have a problem which you've missed.
As an afterthought, have you had your leisure battery load tested? It may well seem to charge ok, and will quite possibly hold up at 12.7 or so volts when standing idle. But it may be dropping voltage when its loaded, and therefore discharging quickly.
I have a tiny solar panel which puts out only one third of an amp, but this is enough to keep my battery up over winter, with nothing switched on. We don't have an alarm though.
Thank you all for your replies each one constructive and appreciated.Mysterious as it is ,both batteries charged on the same charger and tested with a meter before going to caravan ,its only a small 12 volt batttery but as I say its seems to do the job quite well,and me not being that clever was thinking my 10 quid solar panel couldnt handle the 110amp battery.
Sir Roger
Sir Roger
Hello Roger,
When you posted you did not indicate your need was for a storage site, I assumed you were looking for a means of keeping your battery live whilst on holiday without an EHU.
With the new found information, then a smaller panel may well suit your needs.
Just as a postage stamp calculation, assuming teh batteries natural discharge rate and a the alarm panel uses 50mA of power continuously, then that is the equivalent of 1.2Ah per day. Bearing in mind that Solar panels only give their rated output when they directly face the sun and at other times their out put will be substantially less, so assuming a fixed position for the panel its effective power delivery is will be restricted to about 30% of the daylight hours.
In the depth of winter we only have 6 hours of day light so the panels needs to be able to deliver 1.2Ah of power in roughly 2 hours to be able to keep your battery fully recharged over winter
That equates to a rated capacity for the panel of 12W.
But other factors need to be considered such as, the sun in winter is less strong than in summer, During autumn and winter the panel may be obscured by leaves and snow, and of course all year round there will be dust and other debris which whilst not thick will reduce the effectiveness of a panel.
For more or less guaranteed security of supply you may need to consider an 18 to 24W panel.
When you posted you did not indicate your need was for a storage site, I assumed you were looking for a means of keeping your battery live whilst on holiday without an EHU.
With the new found information, then a smaller panel may well suit your needs.
Just as a postage stamp calculation, assuming teh batteries natural discharge rate and a the alarm panel uses 50mA of power continuously, then that is the equivalent of 1.2Ah per day. Bearing in mind that Solar panels only give their rated output when they directly face the sun and at other times their out put will be substantially less, so assuming a fixed position for the panel its effective power delivery is will be restricted to about 30% of the daylight hours.
In the depth of winter we only have 6 hours of day light so the panels needs to be able to deliver 1.2Ah of power in roughly 2 hours to be able to keep your battery fully recharged over winter
That equates to a rated capacity for the panel of 12W.
But other factors need to be considered such as, the sun in winter is less strong than in summer, During autumn and winter the panel may be obscured by leaves and snow, and of course all year round there will be dust and other debris which whilst not thick will reduce the effectiveness of a panel.
For more or less guaranteed security of supply you may need to consider an 18 to 24W panel.
If you want to know for sure what the constant drain on your battery is disconnnect the negative connection and connect an ammeter in series between the negative battery lead and the battery post. A decent digital multimeter will tell you exactly how many milliamps are being drawn while the 'van is standing idle.
As the Prof says, to compensate for a 50mA draw over 24 hours a 1.2w solar panel would need 12 hours daylight Which at this time of year isn't likely.
Theoretically a 110amp battery should take 45 days to drop to 12.1volts at a 50mA discharge rate (I'm guessing your tracker will alert you at 12.1volts, it maybe 11.5volts, I don't know). At this time of year when the ambient temp is about 20 deg lower than is ideal for a battery it could discharge to 12.1volts in about half that time. But to discharge in three days somethings not right.
As the Prof says, to compensate for a 50mA draw over 24 hours a 1.2w solar panel would need 12 hours daylight Which at this time of year isn't likely.
Theoretically a 110amp battery should take 45 days to drop to 12.1volts at a 50mA discharge rate (I'm guessing your tracker will alert you at 12.1volts, it maybe 11.5volts, I don't know). At this time of year when the ambient temp is about 20 deg lower than is ideal for a battery it could discharge to 12.1volts in about half that time. But to discharge in three days somethings not right.
just had the new towsure catalogue arrive today and inside it gives you a guide on solar panels and which ones you will need depending on how you use your van
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