Solar Chargers/Conditioners for Gen I Cayman?

[mchan]

Hi all,

Has anyone had any experience with solar chargers/conditioners to keep their batteries topped up and maintained?

As the Cayman's batteries are 80Ah, I think at least a 4W or 6W panel is required, but would like to understand if anyone else has already had any experience with using solar chargers.
Perhaps something like this: Halfords link

Searching through the various forums seems to indicate that there are *some* folk out there using solar chargers but no details about which specific models...

Thanks
Melvin

 

[Buddy]

As most others on here I use a trickle charger off the mains when wanting to boost or maintain the battery during periods of inactivity but see no problem in using a solar panel on the parcel shelf if parked outdoors. It must be better than nothing. And much better than the chap who keeps his car in a lock up with no windows and no power! Ok, he had disconnected his battery and closed the bonnet to make things a little more difficult.[] It will be interesting to hear how your research goes.

 

[glewis]

I bought an ICP Solar DZ 500 Solar Car Battery Charger from Amazon for £69.99 about 3 years ago. I'd just bought my Cayman R and was selling my Boxster S 550 privately, so it was sat on the drive. The charger came with plenty of leads and attachments, including cigar light and bulldog clips and did an acceptable job bearing in mind it was Winter time so shorter days and not so much sun. It kept the battery charged enough to start the Boxster once a week and take it for quick spin.

 

[dpoynton]

My car sits outside all the time and I charge it with a Halfords battery charger/conditioner (£40) once a fortnight, the cycle seems to take about 3.5hrs. I use a standard garden electrical extension cable with this. http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_categoryId_255205_productId_894769_langId_-1?cm_mmc=Google+PLA-_-Bulbs,+Wiper+Blades+&+Batteries-_-Car+Battery+Chargers-_-329075&istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istItemId=aiwrritl&istBid=tzxr&_$$ja=cgid:8475776884|tsid:35522|cid:166296844|lid:52123463814|nw:g|crid:33910835764 The car has always started first time when required. David

 

[tscaptain]

I have one of these http://www.amazon.co.uk/Sunsei-7-75W-Solar-trickle-charger/dp/B001KQ5XBO which I run through a charge controller to optimise the charging. I don't think that particular model is available anymore but I think you need at least 6w for it to be any good. Mine works fine - have it mounted facing south on the end of the garage and just plug it into the cigarette lighter socket. However, I also use a CTEK conditioner from time to time to keep the battery tip top. TBH though I wouldn't bother buying a solar charger again as the cost of it + controller is more than a CTEK and not using the tiny amount of electricity it uses won't save the planet! I originally bought the solar charger as I didn't have power to the garage at the time.

 

[chrisH]

ORIGINAL: mchan Hi all, Has anyone had any experience with solar chargers/conditioners to keep their batteries topped up and maintained? As the Cayman's batteries are 80Ah, I think at least a 4W or 6W panel is required, but would like to understand if anyone else has already had any experience with using solar chargers. Perhaps something like this: [link=http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_927417_langId_-1_categoryId_255205]Halfords link[/link] Searching through the various forums seems to indicate that there are *some* folk out there using solar chargers but no details about which specific models... Thanks Melvin

I bought a Maplins Solar 10w panel charger for under £30 (the 4W did not have enough power to create a change of voltage, so took it back) for charging a Golf's battery that was remote from any mains power source. It did a good job ( it outputs 17v in the sun) and would recommend vs Halfrauds anyway. Never used on my Cayman as its in the garage, can't see any reason why not.

 

[BigAlChesham]

I regularly use a solar charger for my little MG TF which is laid up for 6 months during the winter months and it starts first time. The charger was a cheapo one from Maplin, but I must say it's no use on my 911 and I would think you'd need something fairly substantial for any Porsche. My advice would be to forget it and go for a conventional C-Tek charger.

 

[Buddy]

Someone just passed me a Maplin catalogue and they have 12V Solar Panel chargers of various wattages upto 15W, probably best to make more enquiries there.

 

[Alan_Armstrong]

Having called out the AA last autumn with the flat battery syndrome, I purchased from them (AA) a solar power charger, which comes with the generic 32 pin plug. (Plugs in below the glove box) I just sit the panel on top of the dash board. All for £25, including the mechanic checking that it was providing the necessary charge. With regard to other type chargers, it may be worth checking if any charge is getting through to the battery from the cigar lighter when the ignition is turned off? Cheers Alan

 

[mchan]

Thanks for your responses so far everyone, interesting that there seem to be some varied experiences out there. Must admit i've bought a CTEK unit now, but am still on the lookout for a solar powered unit that I can just "leave on" instead of having to run a socket from the house to the drive for a whole day! Will report back when I've purchased a couple of units to try.... Alan, Is this the one you're talking about - as I had seen an AA branded solar unit on Amazon: [link=http://www.amazon.co.uk/AA-Essentials-Solar-Powered-Battery-Charger/dp/B00AC1LLQY]LINK[/link] Did it work sufficiently in terms of keeping the battery topped up for longer? Concious that the product specs didn't give any indication of the wattage of the unit. From what i've seen documented in the various forums, you need at least 6W to do anything useful for batterys rated ~ 80Ah. Regarding the Cigar Lighter, yes, everything i've seen shows that the cigarette socket can be used to provide power while the key is out of ignition. A lot of owners plug their various mains-powered CTEK trickle chargers through the cigarette socket.

 

[Buddy]

Alan, Interesting to hear some positive news on your charger, some have said that we need 6W for an 80AH Battery but the ones I've seen from the AA are significantly less and the mains trickle chargers are generally running about 3.8A max, do you find it good at maintaining the charge? The lighter socket is rated for charging and is powered through a 10A fuse, permanently live although I know that mine with some plugs needs to have them rotated to make a good contact. Other sockets are on a lower rated fuse. Melvin, We look forward to hearing whatever you find regarding these chargers, some have no power where they park such as in lock ups or on the road. I had a call recently from one member who had decided to save his battery while away on holiday so disconnected it and when he came home found that he had actually locked the car with the bonnet shut! Richard came up with the method to open the boot for him but as the chap didn't feel practical enough he called Autofarm out who opened the bonnet and checked the ECU etc, reconnected the battery and relieved him of £365 after first requesting £465 so at least they did let him off £100. Others may not have done so.[&o] Of course if parked in a lock up it would need to have either a skylight or a window. Following a short chat with a colleague who deals with battery charging issues in the car industry, batteries generally charge at around 13.4V and this is in order to overcome the standing voltage of the battery at 12V. If we regard the system as 12V then 2.5W is equivalent to 180mA and so not a lot but it may be sufficient to allow the battery to hold it's own, it won't aid a flat battery to get going any time soon! On the other hand a mains powered trickle charger will run at 2A and in many cases 3.8 - 5A and even at this rate it will take an 80Ah battery such time as the charger at it's max rate around 20 hours to fully recover, thankfully they rarely get that low before demonstrating that they are not able to rise to the occasion. One of the good things about the modern trickle charger is that it is "intelligent" and so charges while monitoring the state of battery charge usually without risk of damage. ( I use the word "usually" because well, things can go wrong but that is if there is a defect in the battery such as in an aged item, the charger developes a fault or in the operation ).

 

[Buddy]

And for a simple way as Alan suggests to check the lighter socket is ok for charging, switch off the ignition, remove the key, press the lighter and if it pops up it's ok, it means that it has power with the ignition off so the battery circuit is open. ( It will charge ).

 

[mchan]

Hi all, Thought i'd do a quick reply back for those that are interested. I've been using the CTEK XS 5.0T which is a nifty piece of kit to charge off the mains while I research solar panels, and has been useful as I haven't had any real sun in my part of the UK for the past few weeks! I've been continually looking around and as a summary, I have come to the next few conclusions (feel free to point out if i'm wrong!!): 1) As previously queried by others - the Cayman will definitely charge from cigarette lighter socket as this is "always live" and is linked to a 10A or 15A fuse (Kevan's other post [link=http://www.porscheclubgbforum.com/tm.asp?m=721338]here [/link]helped!) 2) Mains-powered trickle chargers (such as the CTEKs) generally output 3.8-5A max and will charge a flat battery in approx 20 hrs or an 80% full battery in about 3 hrs. 3) Solar panel needs to be at least 6W to output enough mA to keep a 80-120 mA battery topped up; in our climate there will never be enough sunlight to charge a "dead" battery back up (not in any useful time at least) 4) Many solar panels do not come with charge regulators; a charge regulator is required to limit the rate at which electric current is added to or drawn from the battery - specifically preventing overcharging and also draining the battery back to power the solar panel circuitry. So a charge regulator really is a good idea. I've found the following 13W solar "briefcase" panel at Maplins for £63.99 which seems to tick all the boxes: [link=http://www.maplin.co.uk/p/13w-solar-briefcase-n00cx]link[/link] - comes with 4A charge regulator - outputs max 2A through cigarette adaptor, 4A directly to battery - 17.5V / 743mA peak power though this clearly will be reached on very few occasions - fits the back parcel shelf of the Cayman I will look to purchase tomorrow and report back.... Cheers Melvin

 

[mchan]

Hi all, It's taken a while to compile some useful data. It's not completely conclusive yet as the scientist in me needs a few more runs of data capture to normalise out the base case and the drain with/without the solar panels, mostly because I haven't had many instances where I've not driven the car for a period of consecutive days so the chances to capture relevant data have been reduced. But so far the solar panel looks like it's helping. [] As my "base case" I charged the battery to “Full” using the CTEK charger (a CTEK MXS 5.0T) , then left it alone and captured voltage using a simple cigarette-lighter voltmeter. …Yes I know it’s not the most accurate device to use, however I’ve used the same device in every test so hopefully that means any margin of error is maintained! [8|] Without solar panels (base case) - 12.4v dropped to 11.7v within 4 days With solar panels - 12.4v to 11.8v within 8 days Weather was similar in both cases – approx. 20 degrees, mixture of cloudy/direct sunlight. As I said, need to attempt this a few more times but the signs are encouraging. Hopefully this helps anyone who was thinking about getting a solar charger but wasn’t sure whether it would give the right results. It seems to have halved the battery drain so I would recommend if you think you won't drive the car for a few weeks at a time, and it isn't a possibility to keep the car plugged into a mains-powered trickle charger all the time (due to parking location etc) PS - The Solar charger I used was bought from Maplin, it’s a 13W solar "briefcase" panel (model N00CX) “which came with a 4A charge regulator: [link=http://www.maplin.co.uk/p/13w-solar-briefcase-n00cx]LINK[/link] Cheers