Solar The Solar Panel Thread

Drover

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Hi @Drover , I have a feeling about this, but would be happy to be corrected by other more educated "Tech Heads" on this forum. The following is MY thoughts only, and have not had a chance to confirm with the true gurus on this subject, but I will stick my neck out!!
A battery is really a HUGE capacitor storing electrical current (potential power) just like capacitors in electric motors and other devices. But they are very small in comparison with a storage battery and have only limited capacity (storage) with a plus or minus limit of only 5 to 10%, so they do not accept too much change in voltage or current before being outside design parameters, and/or their electrical potential is utilised. When power (voltage and current) is applied directly to a battery terminal, any changes or variations in voltage/current are quickly absorbed throughout the HUGE CAPACITOR (battery) and would be negligible in the scheme of things when applied by separate wires as input. But by putting both inputs together BEFORE the battery in a single wire input, the different solar controllers are "seeing" the other's voltage/current levels and not the battery's current position which "smoothes" out these variations. More than 100 words, but just my OWN thoughts. Probably more complicated than that, but am happy to be corrected and learn myself.

There you go, not as dumb as first thought, that's what I had in mind though the grey cells just said the battery filters out the noise, the ham operators course I did back in the 70's left something amongst the grey cells.

So if I tap into the van controller is it just plug in to the same input line from the roof panel, pos to pos etc ?? Something says there's a better way, but my mind is distracted.

As you said earlier some post do get refurbished, sometimes a statement is made that we try not to say on this website, compared to others.......I try to stay polite...... @chartrock would get up me otherwise.

@Crusty181 make up your mind, do you want it to look neat and tidy or messy and dodgy looking as if from the factory.

This is the[ distraction so might be weeks before I do anything.

ATTACH]59746[/ATTACH]
 

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Boots in Action

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There you go, not as dumb as first thought, that's what I had in mind though the grey cells just said the battery filters out the noise, the ham operators course I did back in the 70's left something amongst the grey cells.

So if I tap into the van controller is it just plug in to the same input line from the roof panel, pos to pos etc ?? Something says there's a better way, but my mind is distracted.

As you said earlier some post do get refurbished, sometimes a statement is made that we try not to say on this website, compared to others.......I try to stay polite...... @chartrock would get up me otherwise.

@Crusty181 make up your mind, do you want it to look neat and tidy or messy and dodgy looking as if from the factory.

This is the[ distraction so might be weeks before I do anything.

ATTACH]59746[/ATTACH]

You are a card @Drover !! Answers in order:
First paragraph - yes, a battery (or big capacitor) does tend to smooth out the variations of high and low voltages and even out current flow.
Second paragraph: - Correct, just connect into the same solar controller input terminals from roof panels. Pos on Pos and Neg on Neg on INPUT side of controller ie in PARALLEL. Bypass panel controller too. There is a better way, connect in SERIES if you have the right controller, but that is a bit more time consuming.
Third paragraph:- When you put anything in print, you can bet it will come back to haunt you at some time. But then, if you do not stick your neck out, you will never move forward either. Just be prepared to have some smart B.....d tread on your neck. I think I am in the "good books" with @chartrock at the moment. With a bit of care, I should manage to stay there. One of the reasons I like this forum is all members ARE friendly to one another and even though there is a great disparity in knowledge on many subjects, there is always someone there to come forward and offer suggestions and help.
Forth paragraph:- Leave poor @Crusty181 alone!! He is becoming a real Tech Head although he is very modest about it.
Fifth paragraph:- very peaceful scene to sit back and relax, and forget about the rest of the world problems. Even the Pacific Black duck resting on the gravel seems at peace. Take your time at anything you are doing and enjoy.
Enjoy your holiday and travel safely. Lets us know how you are going. The last time if I remember, your diesel heater packed up. Hope you do not have any major hassles you cannot overcome in the field. Cheers
 

Drover

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I think we would get on well in real life, @Boots in Action you remind me of a very good mate of many decades, he is what I would call precise, some might say pedantic, a lot say peculiar, we are like chalk and cheese.....he turns a simple sentence into a thesis as well,.............I think we compliment each other so there's hope for as well...

Yep, I'll sort something out probably at my mates workshop on the Murray, easier to play around........I'm running the portable on the ute and it runs the Engel and all the chargers, easier to get at and the van juices up, a good combination, they seem to be pushing about 7 amp max, batteries are all about 80% in the morning, so not hard to bring back up.

PS: If I don't have a go at Bruce @Crusty181 he would worry about me.
 

Drover

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Yep @KECL I found it to be a very readable article and while I know what he's talking about on the technical side don't ask me to explain it in other than bush mechanic style..............it filled in many gaps to my solar education without my eyes rolling into the back of my head and is what I've based my system on over time...........I lost the link till today and before it you really needed to check many places to get decent info that didn't bury itself in bench test mire.
 
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Coldspace

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Jan 21, 2018
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Hi guys/girls,

Question on solar,

Our van we bought recently came with 2 near new 130 amp agms, parallel connected with really thick cable which is great . It also has redarc dc-dc /mppt solar 40 amp charger fitted next to them running 6 b&s to Anderson plug at draw bar to take juice from our tug that also has 6 b&s back to battery, so when travelling we get 40-42 amps from my inline power meter which is great quick charge.
On camp we simply plug our 300 watt folding panel ( ebay one but more likely a 250 watt lol) bypassed the crap controller into the redarc Anderson plug and this then puts in 12-13 amps in full sun. We have only done one 5 day free camp recently to test run the new van and because we run large waeco under the awning, plus all the usual power grabs like kids electronics, tv at night we found this just sufficient but last day or so the batts were slowly getting alittle less and less each day. Down to 12.2 on the last day. So I think 4-5 days is max for us ATM with just one panel without venturing into low damage battery territory
So we are planning a near 2 week free camp mid year school hols, I suspect solar generation will be less that time of year so after 5-6 days we will prob be getting too low.
I have 2 options ,
I have another 120 watt folding panel from the old camper trailer days that still works great and puts in 7-8 amps via the redarc on home testing can I add Anderson plugs in parallel connect with our larger panel then into the redarc for more amps?
Both panels are rated similar volts just diff wattages or will the smaller panel drag down the larger one?

Or I just run with the larger panel and at day 4-5 plug car in and crank 40 amps into the batts for 1 hr and maybe have to do this again at day 7 ,9, 12 if the suns not favourable .

I do have a honda gen, but we don't want to take it just for batts if we don't have to I would prefer to boost solar imput into the redarc.

If the diff panels will work togeather nicely, then I might even buy one of those 120 watt solar blankets to store in the van and add Anderson's to it as well so if it's abit cloudy I can crack it out as well and have 3 going to juice things up.
It would be great to see 20-30 amps into the redarc from a couple/few panels if possible. I always have the car/redarc as back up or lug the genny but would prefer the quietness of solar.

Ideas ?
 
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Coldspace

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I just did some googling, looks like we will be fine to connect panels together in parallel with diff wattages as long as the volts are the same they will put out the combined amps. If diff voltages then they will not work.
Ill wire my smaller panel up and do some testing on the weekend .

Anyone got some feedback on the blanket type ones, ??
in looking at the ebay ones for around $300 bucks, I will prob only use it once a year for our annual family free camp.
So don't want to spend much, just want to have it stored easily away in the van and if needed to assist the others get it out..
You know we love our toys...
 

Boots in Action

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I just did some googling, looks like we will be fine to connect panels together in parallel with diff wattages as long as the volts are the same they will put out the combined amps. If diff voltages then they will not work.
Ill wire my smaller panel up and do some testing on the weekend .

Anyone got some feedback on the blanket type ones, ??
in looking at the ebay ones for around $300 bucks, I will prob only use it once a year for our annual family free camp.
So don't want to spend much, just want to have it stored easily away in the van and if needed to assist the others get it out..
You know we love our toys...

Hi @Coldspace , I note that you have an MPPT solar controller for your portable 300w panel and this also does the job of a DC to DC charger for power from your tug to van. Just make sure that the settings for the Red Arc are set to the correct output voltage or battery type. My MPPT controller had a setting for Sealed Battery of only 14.4 volts and as AGMs generally need to get to 14.7 volts to achieve FULL capacity for that type of battery, I changed my setting to Flooded to get the charge voltage a little higher at 14.6 volts. Your sophisticated Red Arc should have these adjustable settings. You have it correct in bypassing the controller on the back of the panel as the MPPT controller is far superior. Another thing is to make sure that the wire from the controller to batteries is as short as possible to avoid voltage loss there. Do you know or does the controller show panel voltage available to the controller?? The Red Arc DC to DC system is primarily to overcome voltage drop from tug to van as voltage from tug alternator is generally NOT high enough to get the batteries to full charge. And AGMs need up to 14.7 volts to achieve FULL charge capacity. See panel below for voltage stats for AGM. If the Red Arc has some sort of output voltage selection, make sure that it is set for the higher voltage. Also, make sure that your AGMs are fully charged with a good SMART charger before you depart on your trips. Don't leave it to the last moment and hope the tug will bring the batteries up to full capacity - it won't. 40 odd amps is just the bulk charge before achieving the max voltage setting, and then there comes the Absorbe phase where the real capacity is stored, before the system goes to Float. Hope this helps.
 

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Crusty181

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Hello @Crusty181 , not a silly question at all!! Connecting two solar controllers to the same battery is like having two cooks in the kitchen . One likes his steak rare and eggs sunny side up and the other one wants his steak burnt black and eggs flattened and dried out. One wants his meal in a hurry and the other is a connoisseur and wants to take his time!! Remember the movie "The Odd Couple"?? Well that is the best example of how to explain what can happen. The greater the difference in solar controllers and settings (made either at the factory and fixed, or user adjustable and different brands), the greater task the controllers have in sorting out charge and voltage requirements and meeting changing load conditions. It may not be particularly evident, but that is what would be happening. I would NOT recommend it under normal circumstances even if it "looks" okay.

DEFINITELY NOT not a good idea to try that with two different types of controllers ie PWM and MPPT. The PWM type drags down the panel voltage to just above battery voltage to charge at what ever the input current is. Any excess voltage from panels above battery voltage is just wasted. In fact, with a Pulse Width Modulation Type, it is really just a switch between the panel and battery, turning on and off as necessary. Whilst charging, it is basically "ON" all the time until charge voltage setting is reached and then it switches "ON " and "OFF" keeping the battery at the set float voltage. But this changes all the time according to load factors which drops the voltage and makes it start charging again to make up what has been taken out and caused voltage to drop. It is a lot more complicated than that too if you want to take in temperature of components and battery. There is a different (best) charge voltage for batteries in all conditions - the hotter the battery and or ambient temp, batteries require a slightly lower charging voltage and in colder times, a slightly higher voltage is optimum. But I digress - sorry!!

An MPPT charger is constantly changing the input current to the battery by converting any excess voltage from the solar panels into extra current (amps). This is IN ADDITION to the current being produced directly by the solar panels. Let's say that the solar panels are producing 10A on their own, but there is 6 volts from panels above the battery voltage which is SENSED by the MPPT controller.( Panel charging voltage to controller is 19V but battery voltage (sensed by controller ) is 13 volts.) The MPPT controller DOES NOT WASTE THIS EXTRA VOLTAGE (like the PWM type does), but converts this excess voltage into additional amps to add to the 10 amps already available from the panels. And this is happening all the time, constantly adjusting current available to charge or carry the load placed on electrical system. The greater the differential between the panel voltage and the battery voltage, the more spare volts are available to be converted to extra amps. So the lower the battery voltage (say only 11.8V (near battery disconnect?) and the higher the input voltage from panels, the more amps you get and the faster your battery/ies are recovered by charging. MPPT stands for MAXIMUM POWER POINT TRACKING and that is exactly what it does!
@Crusty181 , in an earlier post which even @Drover thought was a good idea was to bypass the controller on portable panel with a separate lead and Anderson plug and connect this lead from portable panel in parallel with the existing input line to your MPPT controller. So you end up with two leads hanging off the back of your portable panel - one that goes through the existing panel controller which is still suitable for charging other things, and the new cable from the portable panel (bypassing the controller on the back) which you can easily join into existing system and not lose any of the original properties/uses.

God this has been an epistle!! I hope this covers all the bases and I have not lost too many. Some "Tech Heads" cannot help themselves. Sorry!!
Hey @Boots in Action, in this post you've summarily poo poo'ed the use of a MPPT and PWM controller on the same battery and I made the baseless conclusion that that applied to two MPPT controllers as well. That conclusion curbed my master plan. After reading some important InterGooglyWeb stuff I discovered multiple MPPT controllers is the preferred option when connecting unmatched panels to the same battery, the cost of the additional controllers being the only stumbling block; I have the multiple MPPT controllers so my master plan is now back on track.

My 2 x 250w new glass roof panels have arrived (with bypass diodes), along with my new Victron portable MPPT controller. My plan is to mount the new 250w glass panels on the van, to the Epever. Ill leave the current roof 150w in place but disconnected from the Epever. The Victron will be the controller for my 2 x blanket panels, the panels I have been using till now via a PWM for the Engel in the car. I have a Anderson under the van chassis on the off side direct to the van batteries to power external pumps, and with the Victron in hand I can now plug the blanket panels into that Anderson to assist the Epever fed roof panels if required.

Ill cable the 150w roof panel to an Anderson on the vans drawbar, which I can connect to the car via the Victron to run the Engel which will save me jerking about with the blankets most of the time. The blankets will become top up panels for the van, or shade busters if cant escape the shade over the vans roof panels

The Victron sounds like it will be everyones friends and getting connected all over the place.

Does this all sound like fun

www.altestore.com have some great info and field testing videos of all manner of solar panel stuff. Practical demos of shading, connections and equip etc is very easy to understand and follow. Search Youtube "altE"
 

Drover

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I have found out on this trip that it appeared that my 2 PWM controllers looked like they were in conflict they have since shown that when the battery is charged up one will go to float while the other goes off but until then both will charge away happily, which is pretty good as the roof panel doesn't do much before 9 or after 3 and the portable will still shunt heaps, so thats shot down one theory.....now my portable is ambidextrous in regards to controller use so can still be used on my ute......................as for other tech data on how much when, I cant be stuffed, it all works well heaps of power so good enough.

and I'm most interested in the high temperature performance curve of the controllers shown in http://12voltblog.com.au/a-guide-to-using-solar-panels-and-regulators/ I know my portable gets burn fingers hot so hate to know what the roof unit gets up to and yes it does have heaps of clearance around 50mm at least.
 

Coldspace

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Jan 21, 2018
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Yes good chart on agm batteries crusty, thanks for that .
The redarc is a good piece of gear, lucky mine van came with it and it's all wired up in 6 bs cable to the draw bar so plenty thick . I have a 5 mtr 6 bs lead to connect and keep the panels out in the sun if we are near a tree.

I have order more Anderson plugs from flea bay today, genuine ones and will wire up both my panels in a parallel connection to see if I can get 17-20 amps on a good day imput via the redarc.

Does anyone have any reports on these 120 blankets put out by kings ect at around $290 ATM ?

I'm looking at getting one mainly to keep stashed in the vans rear compartment but can get it out if need be when the days might be abit patchy to add into the mini solar farm to crank up some more amps.

I'd only be using this once maybe twice a year, do they perform like they claim.

Cheers
 
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Crusty181

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Yes good chart on agm batteries crusty, thanks for that .
The redarc is a good piece of gear, lucky mine van came with it and it's all wired up in 6 bs cable to the draw bar so plenty thick . I have a 5 mtr 6 bs lead to connect and keep the panels out in the sun if we are near a tree.

I have order more Anderson plugs from flea bay today, genuine ones and will wire up both my panels in a parallel connection to see if I can get 17-20 amps on a good day imput via the redarc.

Does anyone have any reports on these 120 blankets put out by kings ect at around $290 ATM ?

I'm looking at getting one mainly to keep stashed in the vans rear compartment but can get it out if need be when the days might be abit patchy to add into the mini solar farm to crank up some more amps.

I'd only be using this once maybe twice a year, do they perform like they claim.

Cheers
I tested my 150w Super Cheap blanket today actually. I had it lying flat on the ground out the back of the factory, hot'ish day and cloud free skies. It was oooozing out 7amps, which I thought was pretty reasonable considering the heat, its a blanket and it was lying flat.
 

Boots in Action

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Mar 13, 2017
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Ferny Grove, Queensland
Yes good chart on agm batteries crusty, thanks for that .
The redarc is a good piece of gear, lucky mine van came with it and it's all wired up in 6 bs cable to the draw bar so plenty thick . I have a 5 mtr 6 bs lead to connect and keep the panels out in the sun if we are near a tree.

I have order more Anderson plugs from flea bay today, genuine ones and will wire up both my panels in a parallel connection to see if I can get 17-20 amps on a good day imput via the redarc.

Does anyone have any reports on these 120 blankets put out by kings ect at around $290 ATM ?

I'm looking at getting one mainly to keep stashed in the vans rear compartment but can get it out if need be when the days might be abit patchy to add into the mini solar farm to crank up some more amps.

I'd only be using this once maybe twice a year, do they perform like they claim.

Cheers

Hi @Coldspace, just to give you some idea to compare what sort of generation is possible with your panel/s and Red Arc MPPT controller. I have two portable folding panels of 200w and 180w. I have mine connected in SERIES to the one controller to make the most of panel voltage available to the MPPT controller, especially if weather is cloudy or dim. I also have a 120ah battery in van and an "auxiliary" battery of 75ah which I connect in parallel - both AGMs. The max working voltage of each solar panel is very close - about 18.5v even though of different types. I have replaced the diodes in the back of the panels with Schottky 15A 60V type as they have a lot less forward voltage drop than the ones in the panels originally . Cost $2.39 for 5 on Ebay. Needed 8 as there are two on each fold of both panels (2 folds per panel needs 4 and 2 different panels).
When battery voltage was low recently and skies had been cloudy and/or misty for long periods (days!!) , there was a short period of bright but cool sunshine - 21C. My MPPT display indicted 21.4A going into batteries with a current load in van of 4.1A. Voltage available from panels to controller was nearly 32V. Battery voltage before charging was around 12.3V. This amount of current continued for about 5 minutes before dropping to 19.1V for a while and then to 17.8A for quite some time. After chasing the sun just before lunch, I was able to position panels for the afternoon session. Before 3.00pm, the MPPT controller had FULLY charged both batteries and had moved into "Float" mode. According to controller daily record, a total of 58ah was generated and put into batteries that day. So do not be put off by what some people think about the value of MPPT controllers, despite what a recent link said. IMHO, there is more value in purchasing a good MPPT controller instead of another solar panel. Good and proper MPPT controllers are available for around $160.00 (mine cost $140.00 about 12 months ago) whilst a reasonable solar panel of 200w is still dearer. And one has to find some place/s to fit it on van or carry it somewhere too.

@Bellbirdweb recently fitted an Epever MPPT controller and has his panels (200w each?? I think) in parallel and recently was generating 19A, (and not optimum conditions either!) when before with his PWM controller, the best he could achieve was only 12A. Although having his panels on the roof of van and having losses due to heat, that output is considerably better than what he had before. To each his own in this field!! But I am very, very satisfied!!
Note: connecting dissimilar panels in parallel will average out panel voltage, but amps are added together. Connecting two dissimilar panels in Series increases the voltage , but amps out is restricted to output of the lowest panel. But the MPPT controller uses that extra voltage to generate more current, and there is less voltage loss in the leads to the panels (higher voltage - 18v or so against up to 36V or more).
 

Crusty181

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Feb 7, 2010
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Mentone, VIC
Hey @Boots in Action, in this post you've summarily poo poo'ed the use of a MPPT and PWM controller on the same battery and I made the baseless conclusion that that applied to two MPPT controllers as well. That conclusion curbed my master plan. After reading some important InterGooglyWeb stuff I discovered multiple MPPT controllers is the preferred option when connecting unmatched panels to the same battery, the cost of the additional controllers being the only stumbling block; I have the multiple MPPT controllers so my master plan is now back on track.

My 2 x 250w new glass roof panels have arrived (with bypass diodes), along with my new Victron portable MPPT controller. My plan is to mount the new 250w glass panels on the van, to the Epever. Ill leave the current roof 150w in place but disconnected from the Epever. The Victron will be the controller for my 2 x blanket panels, the panels I have been using till now via a PWM for the Engel in the car. I have a Anderson under the van chassis on the off side direct to the van batteries to power external pumps, and with the Victron in hand I can now plug the blanket panels into that Anderson to assist the Epever fed roof panels if required.

Ill cable the 150w roof panel to an Anderson on the vans drawbar, which I can connect to the car via the Victron to run the Engel which will save me jerking about with the blankets most of the time. The blankets will become top up panels for the van, or shade busters if cant escape the shade over the vans roof panels

The Victron sounds like it will be everyones friends and getting connected all over the place.

Does this all sound like fun

www.altestore.com have some great info and field testing videos of all manner of solar panel stuff. Practical demos of shading, connections and equip etc is very easy to understand and follow. Search Youtube "altE"
Mixed day on many fronts yesterday. The new "250w " roof panels arrived yesterday, and the Victron the day before. Exciting times.

I connected the panels individually to the new Victron controller with a very mixed results. The Victron was impressive with its bluetooth phone App connection .... the panels themselves not so impressive. Yesterday was warm in Melb, with magnificent clear blue sunny skies. At 1pm, well within the solar collection sweet spot I tested the 250w panels on my truck's battery which was feeding a 150psi tyre pump. I started with the panel standing up ,then flat , then the magical 37, then everywhere in between, the best I could get out of each 250w (individually) was 8.4amps ... I got 7amps from the 150w on the van currently being flat, probably dusty and bird pooped and thru a PWM.

Preliminary results from the fridge bucket experiment are also disappointing ... the fridge buckets may soon become just buckets

One bright light on the otherwise underwelming day was when I tested my cheap and nasty 150w Super Cheap blanket panel which I had low expectations for. Thrown flat on the lumpy ground next to the 250w panel .... 7amps straight up. Woo hoo. I did some testing shading various areas of the panels with staggering results. Bit of a David and Goliath thing, with a little bit of shade knocking the bejesus out of the panels capacity to generate power.
 
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Drover

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So do not be put off by what some people think about the value of MPPT controllers


Uncalled for dig Booties, I have nothing against MPPT controllers but they aren't worth throwing away a top line PWM controller and that link laid out the facts quite well I thought..................replacing some of the cheap rubbish PWM and MPPT controllers that come with most portable panels of course with a quality MPPT unit would be the way to go.
 
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Coldspace

Member
Jan 21, 2018
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Shailer park
I tested my 150w Super Cheap blanket today actually. I had it lying flat on the ground out the back of the factory, hot'ish day and cloud free skies. It was oooozing out 7amps, which I thought was pretty reasonable considering the heat, its a blanket and it was lying flat.

That's very acceptable considering they are flat too.
 

Coldspace

Member
Jan 21, 2018
31
55
18
Shailer park
Hi @Coldspace, just to give you some idea to compare what sort of generation is possible with your panel/s and Red Arc MPPT controller. I have two portable folding panels of 200w and 180w. I have mine connected in SERIES to the one controller to make the most of panel voltage available to the MPPT controller, especially if weather is cloudy or dim. I also have a 120ah battery in van and an "auxiliary" battery of 75ah which I connect in parallel - both AGMs. The max working voltage of each solar panel is very close - about 18.5v even though of different types. I have replaced the diodes in the back of the panels with Schottky 15A 60V type as they have a lot less forward voltage drop than the ones in the panels originally . Cost $2.39 for 5 on Ebay. Needed 8 as there are two on each fold of both panels (2 folds per panel needs 4 and 2 different panels).
When battery voltage was low recently and skies had been cloudy and/or misty for long periods (days!!) , there was a short period of bright but cool sunshine - 21C. My MPPT display indicted 21.4A going into batteries with a current load in van of 4.1A. Voltage available from panels to controller was nearly 32V. Battery voltage before charging was around 12.3V. This amount of current continued for about 5 minutes before dropping to 19.1V for a while and then to 17.8A for quite some time. After chasing the sun just before lunch, I was able to position panels for the afternoon session. Before 3.00pm, the MPPT controller had FULLY charged both batteries and had moved into "Float" mode. According to controller daily record, a total of 58ah was generated and put into batteries that day. So do not be put off by what some people think about the value of MPPT controllers, despite what a recent link said. IMHO, there is more value in purchasing a good MPPT controller instead of another solar panel. Good and proper MPPT controllers are available for around $160.00 (mine cost $140.00 about 12 months ago) whilst a reasonable solar panel of 200w is still dearer. And one has to find some place/s to fit it on van or carry it somewhere too.

@Bellbirdweb recently fitted an Epever MPPT controller and has his panels (200w each?? I think) in parallel and recently was generating 19A, (and not optimum conditions either!) when before with his PWM controller, the best he could achieve was only 12A. Although having his panels on the roof of van and having losses due to heat, that output is considerably better than what he had before. To each his own in this field!! But I am very, very satisfied!!
Note: connecting dissimilar panels in parallel will average out panel voltage, but amps are added together. Connecting two dissimilar panels in Series increases the voltage , but amps out is restricted to output of the lowest panel. But the MPPT controller uses that extra voltage to generate more current, and there is less voltage loss in the leads to the panels (higher voltage - 18v or so against up to 36V or more).

Yes, I had an Epever 20 amp mppt in my old expanda and it was great with my 120 panel, on good sun it was getting upto 8 amps.
My new to me van the redarc will give me best of both worlds, I seen 42 amps on the meter so great for topping up if we get into low territory. One thing I like is if in national park where no generators are allowed I could still have the car idle for 1 hr to top up but prefer more solar power especially with my power hungry family lol...
I will wire up my 300 watt , ( flea bay special )actually it's more like 220 - 240 watt from the amps I've seen compared to side by side tests with my 120 panel with parallel connection as the redarcs max voltage is 32 and see if the 2 can get me upto 20 amps in good conditions.

We have 2000 watt pure inverter inverter wired up under the lounge with really really thick 2 b&s wire across the 2 130 batts and I run a lead from a secondary outside weatherproof socket dedicated to the inverter back to the inlet side of the van so at unpowered sites we still have 230v at the sockets throughout the van , this runs the microwave, toaster in morning etc for quick easy breakfast. Microwave puts a lot of load on the batts, but what I do is start the car, redarc puts in 42 amps which helps the batts stay above 12.5 v for the quick 2-5 mins needed for the microwave. Or when on the road we can do a quick microwave hot lunch etc. I love the setup that came with the van plus my added touches with the inverter etc.

I wired in an RVD/rcd combo for added safety when using the inverter throughout the van.

I also can run electric blankets on the beds as my wife and daughter feel the cold in winter and the blankets are great at prewarming the beds for 1-2 hours before bedtime and first up in the morning. They draw approx 4 Amps each so might use 30 odd amps each day in cold weather.
We had a diesel heater in the last expanda for 10 years which was great but I will be getting the new Truma eco heat system soon when time allows for winter camps.

I might get a cheap kings solar blanket to store in van for cloudy type days so the 3 might still get 12 odd amps in cloud cover. I'll report my findings in the coming weeks.($279 ATM)

Gotta love our toys, :)
 
Last edited:

Boots in Action

Well-Known Member
Mar 13, 2017
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Ferny Grove, Queensland
Yes, I had an Epever 20 amp mppt in my old expanda and it was great with my 120 panel, on good sun it was getting upto 8 amps.
My new to me van the redarc will give me best of both worlds, I seen 42 amps on the meter so great for topping up if we get into low territory. One thing I like is if in national park where no generators are allowed I could still have the car idle for 1 hr to top up but prefer more solar power especially with my power hungry family lol...
I will wire up my 300 watt , ( flea bay special )actually it's more like 220 - 240 watt from the amps I've seen compared to side by side tests with my 120 panel with parallel connection as the redarcs max voltage is 32 and see if the 2 can get me upto 20 amps in good conditions.

We have 2000 watt pure inverter inverter wired up under the lounge with really really thick 2 b&s wire across the 2 130 batts and I run a lead from a secondary outside weatherproof socket dedicated to the inverter back to the inlet side of the van so at unpowered sites we still have 230v at the sockets throughout the van , this runs the microwave, toaster in morning etc for quick easy breakfast. Microwave puts a lot of load on the batts, but what I do is start the car, redarc puts in 42 amps which helps the batts stay above 12.5 v for the quick 2-5 mins needed for the microwave. Or when on the road we can do a quick microwave hot lunch etc. I love the setup that came with the van plus my added touches with the inverter etc.

I wired in an RVD/rcd combo for added safety when using the inverter throughout the van.

I also can run electric blankets on the beds as my wife and daughter feel the cold in winter and the blankets are great at prewarming the beds for 1-2 hours before bedtime and first up in the morning. They draw approx 4 Amps each so might use 30 odd amps each day in cold weather.
We had a diesel heater in the last expanda for 10 years which was great but I will be getting the new Truma eco heat system soon when time allows for winter camps.

I might get a cheap kings solar blanket to store in van for cloudy type days so the 3 might still get 12 odd amps in cloud cover. I'll report my findings in the coming weeks.($279 ATM)

Gotta love our toys, :)

My apologies @Coldspace . You appear to be all over it with all the luxury (for me anyway) items you are running with your set up. Great gear the Red Arc as I have done some research on that piece of equipment. Guess that you will have to watch your input verses output to maintain all that energy hungry gear, but with proper care, you should get by. Good luck!! I am envious of what you have, but still happy with my lot.