How to unregulate solar panel

[Symo Advanced Member Find all posts View Profile Close Symo]

Going a bit off topic but not sure I fully understand why a PWM will not do the same, I thought the MPPT advantage is that it finds the optimum voltage for the panel.

Because a PWM is just a swtich which connects the battery to the panel, hence the voltage match (dictated by the battery). An MPPT does not link them directly, and uses smark electronics to perform the conversion of excess volts to Amps. This is why it is mandatory to use MPPT with 24v and up systems.

[Symo Advanced Member Find all posts View Profile Close Symo]

I've just joined this site and found this thread. Can't help but comment. My last car (hate to say it here but it was a Pajero) had an Australian designed and manufactured dual battery system... by Redarc... was sensational.

My current Prado... I had no hesitation in again adding the Redarc battery charging system... Given the need for certainty in battery charging in remote areas, I've researched the competition... and the Redarc product is the gold standard. I'm no auto-electrician and left it to my local man hence missed out on the learning challenges listed above. Since having mine fitted, my Toyota dealership saw it and commented that the Redarc BCDC product has now become the device fitted to Hilux by dealers Australia-wide as an option... hence Toyota recognising the product fully supports my experience.

Just to add to my redarc products... given my positive experience I also now have the towpro brake control unit by redarc... another gold standard product, Aussie designed, manufactured in Australia for our conditions...

Leigh, sorry to be the opposing opinion to yours on these products but my experience has been sensational, has kept me and my family safe and as an end user I couldn't recommend these products more highly.

Safe travels to all.

G

First post, my guess paid article...

[Symo Advanced Member Find all posts View Profile Close Symo]

The supercheap units were on special 20% off last weekend which made them a very good buy.

The only issue might be the setting up, with the Projecta you now get a collapsible rod and three stands. The rod goes through the top of the solar panels and stops them flopping around to much, the stands then prop the top of the panels off the ground to give the correct angle to the sun.

It is a bit fiddly setting them up, the Supercheap version has two rows of panels which will make it interesting as how do you support them at the correct angle, I don't know if the come with a propping arrangement or not, it doesn't appear they do. If not them I'll look at making something similar to the Project system.

My Waeco draws around 2.5A running, with a 50% duty cycle at around 25C, that's
around 30 - 40 amp hours a day, if you get an average of 5 amps out of a 120 watt panel in bright sunshine your doing well, allowing for say 6 hours a day that's 30 amp hours and would just cover what the fridge uses in 24 hours.

Keep in mind you'll only get 120W out of the panel if its in bright sunshine and the panel is around 25C, as soon as you get any haze or the panel starts to heat up which it will do even in 22C conditions the output of the panel starts falling.

I would go with the biggest panel you can afford, I have a 120W blanket, a 150W on the way and a 100W panel, the 370W will just cover the two fridges I run and other equipment when the sun shines brightly! I'll be putting another 200 - 300 watts on the roof of the Vista and hopefully that will cover my needs most of the time without having to run the gen except on a string of cloudy days.

In my setup I have an anderson plug on the back of the car the panels plug into, this goes into an mppt charger in the car. Van similar setup. Saves having to connect and disconnect at the battery, you could do the same either a serperate plug or a piggy back into the trailer connectro if aux in the trailer.

Check your numbers on the waeco, because my 60L uses 5.5A running but only uses 20A a day, right in line with the quoted average of 0.7A/hour.

[pjorek Advanced Member Find all posts View Profile Close pjorek]

Check your numbers on the waeco, because my 60L uses 5.5A running but only uses 20A a day, right in line with the quoted average of 0.7A/hour.

What's the best way to measure this? Easy to measure voltage dropping as the battery is drained but how does a simple person measure Amps getting chewed?

[pjorek Advanced Member Find all posts View Profile Close pjorek]

Yep would be interesting, I do think piggy keeps an eye on suss IP's.

Normally I would only input information I have come across on various fourums if it is applicable to the topic on hand but as we keep getting all these new members going on about how good Redarc equipment is then maybe it is time to tell the other side of the story and start posting up some more posts from some of their unhappy customers

Designed for Australian conditions, a few people travelling north who have issues with the Redarc units overheating under bonnet and not charging their batteries might disagree with that one (do an internet search). You would think by now they would have an external battery temperature sensor that would allow the charger to be placed in a cooler environment while still allow it to sense the correct charge voltage required as do some of their compeditors.

And as for two year warranty, there was a guy on the myswag forum from memory having a camper built with an onboard Redarc BMS. Again from memory they had to change the BMS unit either three or four times before they fianlly got one that worked correctly. He was saying how good the Redarc technical support was working through the issues with the faulty units. Might have been better if they just put some more effort into their quality control. That two year warranty might come in handy in this case, from memory they gave him either a discount off the unit or some gear for all the time involved in getting a unit installed that actually worked correctly, and he was saying what good value for money it turned out to be. He might change his mind about that if the unit fails a few months out of the warranty period!

Yup agree, pretty pricey these redarc units, I opted for a ctek unit instead. 5 years and still going strong (touch wood).

4wd&camping industry has grown significantly in the last 5-10 years, magazines, dvds etc are constantly advertising their products and shoving them down our throats. Even internet forums cannot be independent these days as everyone is afraid of the lawsuit - hard to find an honest opinion between a lemon and a great product.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Check your numbers on the waeco, because my 60L uses 5.5A running but only uses 20A a day, right in line with the quoted average of 0.7A/hour.

Worst case figures running as a freezer in the back of the Prado.

[1980Fletch Lurker Find all posts View Profile Close 1980Fletch]

Fitted many Redarc bcdc chargers in our workshop, and have had none fail. I had a client that had 2 Ctek dc-dc chargers fail and opted for the Redarc dc-dc charger. She hasn't been back since. Hence why I trust and use only Redarc when it comes dual battery installations. Yes the Ctek was a cheaper option, but it let her down twice.

[Fred63 Advanced Member Find all posts View Profile Close Fred63]

What's the best way to measure this? Easy to measure voltage dropping as the battery is drained but how does a simple person measure Amps getting chewed?

There are quite a lot of ways to measure what is being consumed by the fridge.

Google 12v amp hour meter have seen them on ebay for around $40
Have not used one of them so not sure how accurate
As far as accuracy goes.
When i set my system up i measured the Amp hours in worst case and added 25%
I used a high end data logger / scope meter to test mine.
Set the fridge to lowest temp left it in the caravan in the middle of summer, measured temps in the caravan over 37 deg
Not a bad stress test

Forgot to add i am using the Redarc product.
Works great for my application. 2.5 years never missed a beat installed under bonnet.

[snewby Junior Member Find all posts View Profile Close snewby]

I run a Ctek not for any involved electrical reasons... but simply because I preferred the "bolt" on connections and no need for an extra relay for the solar pannels. It works great!
ps. the controller on my pannels is bypassed, direct to the solar input. (I get a bit more charge that way)

[pjorek Advanced Member Find all posts View Profile Close pjorek]

Fitted many Redarc bcdc chargers in our workshop, and have had none fail. I had a client that had 2 Ctek dc-dc chargers fail and opted for the Redarc dc-dc charger. She hasn't been back since. Hence why I trust and use only Redarc when it comes dual battery installations. Yes the Ctek was a cheaper option, but it let her down twice.

I don't receive any $$ from CTek unlike you do from Redarc and I've had my unit for 6 years now under the bonnet - no worries at all. I went with Ctek as Redarc was 2 x the price back in those days.

Similarly went to get a quote on a 80W blanket solar panels supplied by ARB (unregulated). Projecta 80W can be bought for $450 regulated, on the other hand I have a 72W Redarc unit - $1,100. I think the days of charging premium because it's a known and "well regarded" brand are over. I know where I'd rather spend my money.

[1980Fletch Lurker Find all posts View Profile Close 1980Fletch]

Hi pjorek,

Last time I checked, I and MY business buy all our accessories from very reputable suppliers. I can assure you, that MYSELF and my business don't receive $$ as you implied. I was only expressing my opinion, and experience within the auto electrical field with other 4wd enthusiast's. You are entitled to fit what ever you want to suit your budget and needs. I also use the Projecta 120w regulated solar panel, and by pass the reg to run through the Redarc BCDC1225.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Have just got round to testing the Supercheap 150W folding solar panel/blanket,
good news is the panel produces its rated output ok.

Bad news is the regulator, at least the supplied with my unit is not the best in the world to say the least.

I found as soon as the solar panel was plugged into the regulator the high voltage light would come on, I intially though this was due to not having the battery connected but found same issue with a battery connected. The instructions state that if the overcharge light comes on then disconnect the charger and on the front label it states over voltage 15V +- .5V from memory.

I found during bench testing that the low voltage light came on at 10.7V and disconnected the load, it turned of with a battery voltage of 12.2V or higher but when it turned off the high volts light came on.

I inspected the printed circuit board and found the high volts led to be designated "charging" on the board. I also found during testing that once the battery was deemed fully charged the light labelled "solar" turned off. It would seem the instructions are not right, the solar light comes on when the panels are connected and the charger charging, the high volts comes on when the low volts goes out and the solar turns off when the battery goes to float, well actually there doesn't appear to be a "float".

As for the regulators performance, the unit I tested leaves a lot to be desired, it charged the battery to around 15.2V then appeared to turn off, when the voltage dropped somewhat it turned back on and repeated the cycle. I would not use this regualtor on any of my batteries!

The panel works very well with my mppt charger, OC voltage is around 22V, mppt settles around the 17.5V mark which would indicate the max power voltage would be around that and the panel easily pumped 10A into the battery at 13.5V on a slightly overcast day with the ambient around 25C. I had the blanket proped up on a few cane poles and the angle would not have been optimum to say the least.

Overall it was fairly good value for money but you'll need to junk the regulator and buy a decent unit, in my case the regulator is onboard the car and van so I don't need the supplied unit.

Another strange aspect is there is an inline fuse to protect things but it is installed between the panel and the regulator, I thought this odd but having a quick close look it appears the wiring for each panel comes out in thin wire that connects to the heavier power cable, this is strange as it feels like there is thick wire running through the material to connect each panel, so not sure how rhe panels are actually wired internally but it seems the manufacturer feels they need to be protected by a fuse. There is no fuse on the battery side of things!

The panel itself should work well with any good regulator.

I sent Suprcheap an email asking for them to check with the supplier how the regualtor should function but have not received any response.

[Symo Advanced Member Find all posts View Profile Close Symo]

I fixed up my solar today:

I wasn't happy with the 2-3Amps coming form the panels, being cheap ebay ones they had low volts too, only around 16.5v generated. So I wired them in series and they are making 30-34v. Then I bought a MPPT charge controller from Victron (reviews show it to be the fastest MPPT tracker) and the results are excellent.

I am now getting peaks over 7.8Amps from the same panels and the 120A AGM stayed full all day running the 60L waeco, at sunset it was on 12.9v at rest. While the fridge was off I noticed it was flaiting the battery which is good, the instant the fridge started the controller pumped the same Amps into the battery (around 5.5Amps), then the instant the fridge shut off, back to bulk for a few minutes while the volts came up and back to float.

Highly recommended to go 24v setup with MPPT instead of 12v and PWM.