Solar charging

[nicbeer]

Hey

The zook sits and not driven for weeks at a time and have to keep charging the batteries.

thinking about a solar panel on the roof and anderson plug to connect up to the zook. i usually leave it set to only the one battery but if solar connected i leave it on both (manual marine battery switch)

what wattage / controller is best for this (2 x AC Delcor 650cca batteries i belive in there)

i have a BP solar 10w at home at the moment being dormant btw

[stuee]

I'm pretty sure the type of controller you use is dependent on the size of your solar panel.

You shouldn't need more than a 2 amp regulator if your only going to use a 10W panel. You can get that sort of controller from jaycar for under 50 bucks provided your panel is in the right voltage range.

edit*

here's two units to look at

http://www.jaycar.com.au/productView.as ... rm=KEYWORD

http://www.jaycar.com.au/productView.as ... rm=KEYWORD

[nicbeer]

is 10w enough? for constant change or more is recommended.

this is more as a top up device and not to replace it.

those controllers do look ok. going to ebay look also.

found this one that looks the goods for $24
http://secure.oatleyelectronics.com//pr ... e3b0a0356f

also http://solaronline.com.au/cgi/index.cgi ... 1107143926

not bad for parts / pricing.

[stuee]

IMO 10w would be enough for a trickle charge while the car is just sitting about. If your loosing more than that you may have an electrical issue somewhere.

If you've already got a 10w panel you may as well give it a shot and spend $30 bucks on a controller. If it doesn't keep it charged then you've got to worry about purchasing a bigger panel which isn't cheap and makes the $30 outlay for the controller seem insignificant.

[troopy94]

It should be enough as I had a 20watt panel on the roof of the troopy charging twin n70z batteries for several months without a problem jsut pays to keep an eye on the water level in them

[Utemad]

A self contained battery top up solar panel setup like this from Jaycar is $179 for 15 watts. That is only about 1.2 amps on a good day.
http://www.jaycar.com.au/productView.as ... rm=KEYWORD

Just another idea.

I have a CTEK 7000 240v charger. I have it plugged into a power point in the garage and connect it to the 4wd which is parked outside via anderson connectors via a home made anderson connector extension lead. This way I can monitor the charger from inside the garage.

This way the batteries are perfect no matter what the weather is like. Plus I use it on the camper batteries too (camper is in the garage).

Price is comparable to the Jaycar option as the charger was $200 on ebay plus whatever you want to spend on extra wiring.

I use twin 60w panels with a 10amp controller when camping and that setup when new is an awful lot more than $200 for only slightly more output.

[drivesafe]

Hi nicbeer, as long as the total battery capacity is greater than 100 A/H, you don’t need a regulator, the batteries will self regulate and you can trickle charge both batteries at the same time.

Just make sure both batteries are fully charge before you parallel them and then connect the solar panel.

A 10w solar panel is not going to be able to charge the batteries, it will stop the batteries from self discharging, which is what any form of trickle charger is designed to do.

[nicbeer]

Hi nicbeer, as long as the total battery capacity is greater than 100 A/H, you don’t need a regulator, the batteries will self regulate and you can trickle charge both batteries at the same time.

Just make sure both batteries are fully charge before you parallel them and then connect the solar panel.

A 10w solar panel is not going to be able to charge the batteries, it will stop the batteries from self discharging, which is what any form of trickle charger is designed to do.

Cheers,

Yes mainly to be used as a top up, keep them optimum and not to charge them from flat as such, i have the charger for that already.

i grabbed the oatleys circuit anyway. i am going to try get another 10w bp same as mine from a mate as i beleieve he is not using it at all.

we got both for nix ages ago

[chimpboy]

I am finding that I don't drive the Navara sometimes for a couple of weeks, so I am thinking of semi-permanently mounting a solar trickle charger.

Any thoughts on the $30ish ebay ones? They claim about 125mA, which is not much, but my back-of-the-envelope thinking says that a car battery should only discharge itself at 30mA or so anyway. Allowing for limited daylight hours, etc, it still should make the battery last a lot longer than it would otherwise.

The gruntier ones seem to have a pretty massive solar panel which is more effort to fit.

Will the el cheapo be a waste of time and effort?

[drivesafe]

Hi chimpboy, a cheaper and more powerful option is to got to Jaycar and buy one of their 2w 12v solar panels and connect it directly to your battery, no regulator needed and they putout up to 200ma.

These won’t charge a blow battery but they will keep a fully charge battery in good nick.

[chimpboy]

Thanks... like this one? http://jaycar.com.au/productView.asp?ID ... rm=KEYWORD" onclick="window.open(this.href);return false;

Would there be a need for any current flow control or anything, ie can directly connecting it cause battery drain when there is no sunlight? I have a few suitable diodes lying around anyway, but I am not sure if I need to bother...?

[drivesafe]

Hi Chimpboy, most panels come with diodes built-in one way or another.

Those ones your looking at, I use and they work fine for keeping a battery charged and they just don’t have the current capacity to need a regulator, the battery's own internal resistance will keep the maximum voltage below the batteries maximum tolerance.

Not, if you have a dual battery isolator in the set up, you then need to go to a 10W solar panel to generate enough power to keep the battery charged and cater for the power the isolator’s power consumption.

[chimpboy]

No dual battery, it's just the ute for renos/second car. Thanks, I will grab one next time I am near Jaycar.

[tweak'e]

sorry to jump in late.

unless its for a car with a tiny battery, forget anything less than 10watt. those 2 watt solar panels won't even stop a battery from going flat. 10 watt will but won't charge it.
regulator, i would look at a pmw or mppt charger rather than the old on/off type. i'm surprised you can still get the old style ones.
connecting direct to battery you loose quite a bit of power. a 10watt panel gets turned into a 5 watt. thats often due to the panels outputting at 15 volt rather than 12.

[drivesafe]

Hi tweak’s, as chimpboy doesn’t have an isolator, I was going to suggest that chimpboy can save some money and just get a 5w solar panel.

A 5w solar panel will have no trouble maintaining a 100Ah battery and will, given enough time, actually charge one.

[tweak'e]

if hes got the usual navara they typically use 700ah battery (i will have to check whats in mine).
5w panel won't do jack to it.

i had a 10w with pwm regulator that could barely maintain a 650ah in the toyota. (tho that will depend on actual sunlight it gets).

[drivesafe]

Well tweak’s, I’m not getting into an argument here but all the work I’ve done on batteries and solar panels, I have no problems not only maintaining a 100Ah battery with a 5w solar panel and no regulator, but the 5w solar charges, at avery slow rate, but it still charges the battery.

Please note, I posted 100Ah, not CCA. The CCA of a cranking battery has nothing to do with it’s Ah capacity or whether a given size of solar panel will or will not charge the battery.

[tweak'e]

sorry i was thinking cca.
did a quick look up and 100ah probably is a bit bigger than what i've used.

no offense but my experience is different. my 10w didn't charge the battery up. mind you this is battery connected to vehicle, so it depends a bit on what the vehicle is drawing off the battery. with battery disconnected it may be different, however i never tried that.

[drivesafe]

Hi again Tweak’s, as I suggested to chimpboy, if there is a battery isolator in the system, then you need to cater for that.

If you do have an isolator, and it’s one of mine, you need to factor in 24 hours of isolator operation at 275ma per hour.

If it’s something like a Redarc, you need to factor in 600 to 800ma for every hour that the isolator is likely to be on.

With the sort of power an isolator draws, a 10w solar panel is needed, but with no isolator to worry about, as is chimpboy’s situation, a 5w panel will work fine.

[chimpboy]

It's a D21 Navara, not a very big battery although I haven't checked the specific size.

I guess I will find out the answer, but I can't see why a battery would be draining at more than 30mA or so while sitting there. Then again... dunno. Ultimately, a massive solar panel is just not a solution I want, as it costs too much and is too large. If a small one won't do it then I will have to come up with something else altogether... such as driving it more often I guess

[drivesafe]

Hi Chimpboy, I’m testing the use of solar panels for charging some very small batteries ( 7Ah ) but out of curiosity just to see how small I could go in the size of a solar panel and still charge a battery, I put a 60Ah battery ( this is just a bit smaller than the average cranking battery ) and I’m using two 2w solar panels and the battery is charging, furthermore, it’s been overcast here the last two days but the battery is still charging, very slowly.

So as posted, you won’t have any problems MAINTAINING a bigger battery with a 5w panel

When I get some sunny weather I'll try charging the same battery with a single 2w solar panel.

[tweak'e]

Hi again Tweak’s, as I suggested to chimpboy, if there is a battery isolator in the system, then you need to cater for that.

i had no 2nd battery in mine. no radio, no ecu. just the clock. 10w with controller barely maintained it, especially over winter.

that may be the difference here. if your testing only on sunny days, then yes i would say it would charge up a 4x4 battery.
but if its not parked in a good sunlit area, gets shaded during parts of the day etc then theres going to be a lot of time its not charging.

5w at best is only 500ma charge. real world you might be down to 250-300ma (depending on panel design), thats not including cloudy days, shade etc.

[drivesafe]

Hi Tweak’s my 60Ah battery is just under the size of most cranking batteries, which are around 70 to 90Ah and while this battery was nearly fully charged, with a terminal voltage of 12.72v OPEN CIRCUIT.

In two days, of mostly overcast, with the two 2w solar panels mounted flat against the north facing wall of my shed, they have raised the battery’s terminal voltage to 12.88v

As I posted, I will be interested to see what a single panel can do on a sunny day!

[tweak'e]

if you can, chuck an amp meter on and see what they are outputting.

[drivesafe]

In full sunlight, the 2w solar produce a maximum of 135ma

This is more than enough to stop a battery, in a good state, from self-discharging.

[tweak'e]

depends on whats the vehicle is drawing. it may be more than that.

you have to remember that your not always going to get good sunlight so the amount of charge and the amount of time its charging can be very small. especially over the winter months.
the other factor is also how solar panels are rated. they are not always rated at 12v. a lot of the smaller ones are rated at "max votage" which may be 15-18v. so your 2w panel will only work at max of 1.3 watt.

[DamTriton]

depends on whats the vehicle is drawing. it may be more than that.

you have to remember that your not always going to get good sunlight so the amount of charge and the amount of time its charging can be very small. especially over the winter months.
the other factor is also how solar panels are rated. they are not always rated at 12v. a lot of the smaller ones are rated at "max votage" which may be 15-18v. so your 2w panel will only work at max of 1.3 watt.

OP said it was a Zook. You could probably start it with a couple of AA batteries..........

In short, the 10w system he has available to him will do the job of keeping both batteries fully charged if he switches the battery switch to join them both up. I wouldn't even go to the extent of a regulator as the short circuit/maximum current/power will never be enough to harm the batteries (less than one amp at best). You would only need a 2-5 amp diode in the positive lead to stop the battery discharging through the solar cell at night.

All solar "12v" solar cells have an open circuit voltage of 16-18v, they require a load and to drive.

[drivesafe]

Hi again tweak’s, exactly what DAMKIA posted, and furthermore, you will can use different size panels to do things you normally can’t with a battery charger.

A few months back I realised I had not recharged a Calcium/Calcium ( Ca/Ca ) battery for some time, after I had discharged it during some testing I had done around Christmas time.

After charging the battery, the battery was down to less than 50% of it’s capacity.

The battery was charged using a charger with a boost cycle but the boost cycle was neither high enough ( 15v ) or on long enough.

After a couple of cycles on the battery charger, the battery’s capacity improved very little.

So I connected an 80w solar panel direct to the battery, a 105Ah Ca/Ca Allrounder.

The maximum voltage achieved was 16.15v in the middle of the day. I kept the battery on the 80w solar panel for around 3 day. and then tested the battery again.

I had managed to raise the capacity to a little over 80% of it’s original capacity but even after a few more days on the 80w solar panel, there has been no additional increase in capacity.

I’ve damaged the battery but thanks to the solar panel, the battery is still of some use.

The point of all this is that there is a limit to how high the voltage can get when connecting SMALL solar panels to batteries if you want to use them in a maintenance situation.

In the above case, and I don’t recommend people trying this with a healthy battery ( I had nothing to loose ) the solar panel is an 80w 12v panel with an open circuit voltage of 22v.

Most 12v solar panels have an open circuit voltage of somewhere between 18v to 22v but as DAMKIA pointed out, the battery will regulate the voltage down to a safe level for a small solar panel connected without a regulator.

[drivesafe]

OP said it was a Zook. You could probably start it with a couple of AA batteries..........

Just to get off track but to show how close to reality this is.

There is a guy on a UKD3 forum, who, after arriving back from overseas, finding his D3 had a flat battery and wanting to get home from the airport, he used an 18v rechargeable drill battery and managed to start his D3.

So a couple of AA batteries to start a zook may not be that far from reality ( or not )

[tweak'e]

All solar "12v" solar cells have an open circuit voltage of 16-18v, they require a load and to drive.

not what i meant. they are often RATED differently. cheap/small ones are often rated at open circuit voltage while good ones are rated at load voltage or intended battery voltage. just a catch when buying panels, a 10w and 15w may be the exact same panel.