PWM or MPPT.

[threedogs]

How does that work with panels at 90 to each other
@GQtdauto I see what youre trying to do but do you think it efficient??
@jaysee my 120 folder worked straight out of the box I replaced the reg
with the one back a few posts. Those watt meters are handy to see whats going on.

[GQtdauto]

The small panel is only 20 watt my stuff up , so it's not crucial to the system , was just looking at it and reckon I can get a 200 watt panel up there and then I can flip it up and use it as a sail to save on fuel , just have to learn how to tack across the road .
You're right I have three panels with the camper hooked up each facing a different way when hooked up , just got a quote for an mppt to suit my setup $299 each and I need two so may stick with PWM I think .

[Cuppa]

Cupp that link of the reg. Are you saying to get a folding panel type and replace the reg with this one???

If so I recall someone saying to go for a larger panel in watts. Will the one that I posted the link to earlier work. I would like to use it as is this coming weekend and then change the reg after we return.
It's a 200 watt panel..

Yes, I am suggesting it makes sense to treat the regs on the rear of cheap folding panels as throwaway items.

The answer to would that reg suit a 200w panel is 'it depends'. What it depends on is whether that 200w panel performs as it claims. A 200w panel can in good conditions put out around 12 amps & that reg is only designed to handle 10 amps. I would expect that if the panel provided more than the reg could handle the 'extra' would just be wasted, but not having personal experience with that particular reg I'm unable to give a guarantee that it would not fry it like would happen to many of the cheapies regs. My guess is that it would be ok, but it's just a guess. My suggestion was based on my thoughts that you maybe better with a slightly lower output panel. If you *need* 200w, based upon your assessment of the power requirements you have then I would be suggesting you look for a mid range quality 15amp reg, or bigger if you think you might want to add more panels later.



That said, I would not advise anyone to get that folding panel you linked to. Solar panels are large & fairly heavy items to have to lift in & out of vehicles. From my experience I would suggest that a 120w folding panel (ie 2x 60w) is about the biggest which is practical. 200w folder is a real monster probably weighing around 25kg+ which I 100% guarantee you'll quickly get jack of moving around. (To follow the sun during the day - hourly, & loading in& out of the car...honest! If you need 200w I'd suggest two 100w folders or a 120w folder plus an 80w single. I know you are itching to get sorted, but I'm trying to throw up a bit of caution to save you making what I believe could be a mistake you'll regret....... but of course ya gotta do what ya gotta do. Couldn't you borrow some panels or a gennie for the upcoming trip, & buy your own later in a less rushed manner? If you are passing anywhere near Ballarat I've got a 100w portable folder with reg you can borrow.

Then there is the 'panels aint panels' issue. I have bought panels off various ebay sources & it has taught me that some definitely work much better than others. Some with just a little bit of shadow shut off virtually their entire output, others are far more shade tolerant meaning , for example 10% shading results in maintaining 90% output. I have no idea how the Sunyee work, you might get lucky, you might not. The reason I suggest Low Energy Developments (& Rich Solar panels from 'bit deals') is that they have the well established reputation for quality, & I have personally been happy with both. IMHO they have the best of the cheap panels, & are the best value for money. The rest are a gamble.

[jay see]

Yes, I am suggesting it makes sense to treat the regs on the rear of cheap folding panels as throwaway items.

The answer to would that reg suit a 200w panel is 'it depends'. What it depends on is whether that 200w panel performs as it claims. A 200w panel can in good conditions put out around 12 amps & that reg is only designed to handle 10 amps. I would expect that if the panel provided more than the reg could handle the 'extra' would just be wasted, but not having personal experience with that particular reg I'm unable to give a guarantee that it would not fry it like would happen to many of the cheapies regs. My guess is that it would be ok, but it's just a guess. My suggestion was based on my thoughts that you maybe better with a slightly lower output panel. If you *need* 200w, based upon your assessment of the power requirements you have then I would be suggesting you look for a mid range quality 15amp reg, or bigger if you think you might want to add more panels later.



That said, I would not advise anyone to get that folding panel you linked to. Solar panels are large & fairly heavy items to have to lift in & out of vehicles. From my experience I would suggest that a 120w folding panel (ie 2x 60w) is about the biggest which is practical. 200w folder is a real monster probably weighing around 25kg+ which I 100% guarantee you'll quickly get jack of moving around. (To follow the sun during the day - hourly, & loading in& out of the car...honest! If you need 200w I'd suggest two 100w folders or a 120w folder plus an 80w single. I know you are itching to get sorted, but I'm trying to throw up a bit of caution to save you making what I believe could be a mistake you'll regret....... but of course ya gotta do what ya gotta do. Couldn't you borrow some panels or a gennie for the upcoming trip, & buy your own later in a less rushed manner? If you are passing anywhere near Ballarat I've got a 100w portable folder with reg you can borrow.

Then there is the 'panels aint panels' issue. I have bought panels off various ebay sources & it has taught me that some definitely work much better than others. Some with just a little bit of shadow shut off virtually their entire output, others are far more shade tolerant meaning , for example 10% shading results in maintaining 90% output. I have no idea how the Sunyee work, you might get lucky, you might not. The reason I suggest Low Energy Developments (& Rich Solar panels from 'bit deals') is that they have the well established reputation for quality, & I have personally been happy with both. IMHO they have the best of the cheap panels, & are the best value for money. The rest are a gamble.

Again thanks cuppa for your input.

No rush now as we have pulled the pin on the trip.

Don't need 200watt, well don't think so.
Will take all this onboard and decide.

[threedogs]

@jaysee you've probably heard this before but add up the amps on everything
you take camping. That will determine what size panel you'll require.
More than welcome to try my 120 watt folder before you decide what you want.
My mate has a 160 watt folder but thats a big unit to muscle around chasing
the sun.

[Throbbinhood]

There's a handy excel spreadsheet on the myswag forum that helps calculate expected amp usage for various things (fridges/lights etc), then you plugin your batteries/panel sizing etc and will give you estimate usage rates, how many days you'll get out of x etc. Its good kit.

[Cuppa]

There's a handy excel spreadsheet on the myswag forum that helps calculate expected amp usage for various things (fridges/lights etc), then you plugin your batteries/panel sizing etc and will give you estimate usage rates, how many days you'll get out of x etc. Its good kit.

Sounds useful. Knowing your power requirements is the important first step, often missed.

However 'how many days' as a balance between usage, battery capacity & charging source capacity only becomes useful if 'pattern of usage' is included in picture. Eg. solar & battery requirements for weekend camping trips after which you can go home & plug in to a 240v mains charger will be very different than if you want to camp longer periods. (Once over 3 or 4 days you are into 'indefinite usage' territory). On caravan & motorhome forums this frequently causes argument because those doing so often fail to take usage patterns into account. ie. if prepared to go to a caravan park & plug into power every 3 nights or so, the solar/battery capacity is far less. Similarly if using in car charging the time spent driving daily (or not) can make a big difference to how much solar/battery capacity is required. For many weekend campers the decision is to *extend* the time spent at camp, (accepting that even with solar charging the charge level of the battery will reduce a bit each day until getting back to 240v).

I suggest that before ever considering how much solar/battery capacity is needed the following questions need to be answered.
1. What is the max time I want to camp for with only solar charging?
2. What will be my max power requirements ( check the power requirements of each appliance when running, average time in use each day).

Once those two questions are answered - the constraints of storage space & weight restrictions will very possibly introduce compromises eg. Could we switch the fridge off after a couple of days, use less lights etc etc

Just as an example my personal choices : I wanted to be able to rely on solar & in car charging indefinitely as we intend to travel long term without reliance on caravan parks. I also want to be able to camp for weeks at a time without needing to drive to recharge. Those two choices meant I needed a system capable of bringing the batteries back to full charge via solar every 24 hours, with as big a 'buffer' to cope with poor solar input as possible (possibilities determined by available space & weight). As long as I get moderate sun I have sufficient panels to cover my power usage & bring the batteries back to full daily. If I don't get sufficient sun, I estimate we have the ability to stay put for at least 10 days before we have to think about either limiting our appliance use or driving to charge the batteries. Having recently been put on a CPAP machine means I now have more critical appliance use, which may reduce our buffer a bit, but thems the breaks. Many full time travellers are happy enough with a buffer of 3 days & are prepared to plug into 240v at a caravan park if they need to. We expect to be travelling in country where this is not an option (& don't want to carry a gennie).

Soooo..... I hope that rather than telling anyone what they should or should not have, that I am demonstrating that everyone's needs are different depending upon the choices they make about usage patterns. Many get hung up on amps, watts, amp hours etc but that is relatively easy once requirements are determined. The harder part is knowing what your intended usage pattern will be & everyone has this issue, but once you get your head around this the rest falls into place (including what compromises are necessary). Experience makes it easier of course, but for most it's a chicken & egg dilemma. Many push ahead making arbitrary decisions about what they believe their needs will be, most commonly on the basis of cost and/or 'my mate said X watts of panels & Y amp hours of battery' suits him, so thats what I'll get, basically 'cos it's easier than working out personal usage patterns. This *may* yield a good result if lucky, but commonly results in disappointment when requirements exceed capacity & the user gets frustrated 'chasing their tail' with batteries which get over-discharged, or just decide to live with a system which provides for less than was desired.

[Throbbinhood]

The spreadsheet is an indication only (like anything we say here, really). If the clouds are black for three weeks on end, you'll struggle with a 95L engle, lights everywhere, for more than a few days. It's a handy indication when making solar purchases etc, to give you a rough idea and it accounts for summer/winter length of days.

For me, I have a 250w panel plus 180ah on board. Plus the ability to hook up the aux on the car, or just run the car for a quick juice up if need be. We stayed for two weeks over summer, plenty of overcast days, running 50L fridge at 1c, led lights on from 7pm-11pm and some on low all night (have a bub so it's easier leaving them on to see him at night). Plus phone chargers and whatever else. Never had an issue with that. Didn't need to use the electric blankets, if I did I'd like another 250w panel to juice them up during the day (when I do snow trips for instance), but I'll see how the current 250w copes (theoretically the fridge will draw fewer amps as the ambient temp will be much the same as internal fridge temp anyway).

[GQtdauto]

Possibly the best and easiest to understand explanation I've seen Cuppa , some of us do push the risk of having a warm beer and replace expensive batteries all for the sake of a buck or two and I will admit I'm probably in that category.
Midday here in northeast vic thought I would test the diffence between having the roof panel flat and angled up at the sun , I get just over a third of a volt difference which for a small system would be significant but a system like yours not so much.

[sooty_10]

This is the solar controller I run. I didn't get it from this seller so shop around.


I also have a Bluetooth dongle for it so I can check it out on my phone.



Gives me 30day history with total times in each charge mode. Voltages customisable through the app for the different modes too.



I have a 160W folding panel on the roof and car doesn't move often these days. Fridge is on permanent with it.

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