With so much blatantly mislabelled rubbish flowing out of China these days, I did some extensive research. One of the reviewers I found particularly useful is Adam Welch on youtube. He buys cheap charge controllers, puts them through their paces and opens them up for a look inside. I must admit, I bought this one based on this review and though I do have watt meters, I've not bothered to do further testing. https://www.youtube.com/watch?v=1z5r3Yo6fmQ
I have another small system running as a standby charge/backup system on a 4x4 which I have on the property, it's using one of the little EPever landstar 10A PWM contollers, the fully sealed waterproof ones. Which I've been very happy with..
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Hi Xplode, yes the ARKPAK 730P battery box is pretty good in feature terms. According to it's own display, the inverter draws around 8-12w just in standby.. And I definitely switch it off whenever I don't absolutely need some AC power out of it.
Now, to the numbers.. Way back when I started researching all this, I sat down and ran the numbers.. And those note's are long lost. But here's the thing I learned whilst doing that. A: I will use all and any power I can get my hands on. So need is a hard number to determine. And B: Budget is my main limiting factor.
So I abandoned the very sensible approach of working out what I "need" and building the system to supply it.. Leaning instead towards working out what my budget is and just squeezing as much power out of it as I possibly can.... I will then simply adapt my lifestyle to live within my means. My big picture, without going into too much detail is step1 basic 12v system to get me started {done}.. Step 2 Achieve relative comfort with minimal fuel use with a bigger 24v system. Step 3 Develop income streams and build a nice big 48v system to run everything I want. {Hopefully not much more than 18 months away.}
FWIW, with my current setup, if I use the laptop for 3 hours of an evening, then run the CPAP with no humidifier, + a dc fan overnight, I will use approximately 15% of my current 135AH battery which has never been deeply discharged and should be in fair-good condition. If the next day is sunny, After recharging my lights, phone etc. I can usually claw back around 12-13% of those losses, and then every 3 days I will need to fire up the genny to give it a good top up.Leave a comment:
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Funny, With all the info that is within the ad for that charge controller I don't see the Max Voc. limit anywhere. This makes me more than a little suspicious about this being a real MPPT controller. What gives you the feeling this is not a fake? What is the voltage you have coming off your array into the controller? What is the current coming from your array and the current coming from the controller, into your batteries?Leave a comment:
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Since I'm not familiar with this (sounds like combo charge controller + Inverter?) I'll suggest you find out what the Idle losses are on the inverter portion (total lost energy whenever it's on) and see if the inverter portion can be turned off when you don't need it.
A rough guess (if you can get the 225Ah x4 batteries) means you've got about a 5kwh battery bank. Shooting for a daily cycle of 20%DOD you've only got about 1kwh per day of usable power. That should be fairly easy to recover with a handful of 190W panels in a sunny location I think.
Have you worked out what your watt hour needs are? How much does that CPAP machine use? If you haven't done it yet, you need to tally up your devices. Let us knowLeave a comment:
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To Mike and Xplode, I read you loud and clear on the battery thoughts... FWIW, I just can't find anything that resembles affordable FLA 6V deep cycle batteries down under. It's like the whole market has just gone to AGM already and things like Trojan 105's are $350AUD each. I've been hunting for a long time now for any 6V based deep cycle solutions that I can afford and I'm just not finding. Basically it seems like 90% of the Aussie home PV market is grid connect, and most of the offgrid sellers are busily catering to the RV market, selling pairs of 12V AGM batteries.. So that seems to be where the best volume sales price point is here. There are of course off grid 2V banks available, at take out a mortgage prices..
I've got one last lead to follow up, I just called a guy who I've known to buy pallets worth of 2nd hand telco batteries and even some near new banks straight out of the mines. (mines just throw money around, they will build an entire camp, then the dollar value will change and they just cancel that operation and do something else for a while.) I hope to hear back from him today with good news about making a 2nd hand battery purchase which could get me into the 4 or even 8 x 6V 225AH ballpark.
My to do list has finding out if the Upower unit is as configurable as the Tracer series.. I'll be surprised if it isn't. but that will be very handy to know.
To Greta, Hi. My current dinky little setup, powering my slide on camper is an 80W 12v panel, running through a CPT-LA10 controller http://vodasi.com/en/product/CPTLA10.html
One of the very few cheap Chinese controllers that actuall has MPPT beyond the screen printing on it's case lol. And that is feeding a single 12v 135AH AGM in an all in one box (charger, inverter, etc..) Giving me some basic light, a tiny bit of laptop and 300w of pure sine to run my CPAP machine overnight basically.
On a good day, I claw back about as much energy as I used the night before.. And on a cloudy day I fire up the genny and pour money into it. My plan, once the bigger system is in play, is to install the 12v system onto a little truck I have for farm duties. Just as a maintainance system/backup.Leave a comment:
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The critical voltage level is the Open circuit voltage, namely the elevated voltage panels will produce on cold cleat mornings. If you live in a cold part of the world and your string open circuit voltage is already close to the limit you need to find the coldest expected temperatures and factor them with the temp coefficient of the panels.Leave a comment:
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Arrgh... I'm having a mind blown moment.. So, just to be sure I'm understanding correctly. I need to obey the voltage limit, but there appears to be significant flexibility on the wattage/amperage of my array, over and above the rated power???? I can't believe in everything I've already read, I never saw that before. Thanks.
FWIW, I'm sure the Upower all in 1 series will have one of the Tracer mppt unit integrated. I'm going to try to confirm that today.
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I agree with Mike about the golf cart batteries. That is, unless you already have the AGM batteries. If you've already got them, then I'd say use them for now and replace them with larger capacity units when you can save up.
I'm not familiar with the epever units you posted about, but I've become quite familiar with the TracerAN series. They let you configure the max charging currents to match your batteries, so you could over panel and over size your charge controller in an attempt to line up with the better batteries you can hopefully afford soon.
Those panels seem like a good batch to you, and you've got more than you need. Post up what the watt hour requirements of your loads are and maybe we can try to help you out with an overall configuration.Leave a comment:
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You have a nice batch of panels that can do a lot !
I'd strongly suggest considering starting with a batch (four) of 6v 200ah Golf Cart batteries. That would give you 24V @ 200ah of storage, which will run lights and laptops for a long time
The learning curve for a "new to solar" can be steep and those pricey AGM batteries are easy to kill while you are learning the ropes.Leave a comment:
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The EP line has this chart on how much you can over panel their controllers. Not exactly your controllers but as the chart shows, rated charge power vs. Max PV input. MPPT controllers process the incoming power differently than PWM controllers and their amp rating is referring to their output charging amperage. Basically they can be over paneled.
EP max panel power chart.jpgLeave a comment:
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Entry level system for a small cabin
Hi everyone, First post here and I'll start by saying thanks for this forum, what an awesome source of knowledge and experience. I've been devouring sticky posts whenever I get near the internet. But I'm still not 100% on a few things and I've just run out of time to understand everything. So I need to make some purchases and I hope someone can look over my plan and advise accordingly.
Location is rural Australia where everything costs a living fortune. but sunlight abounds.. Situation is offgrid remote cabin. Utterly minimal budget with no hope of improvement any time soon. I've saved and scrounged what I can and hope to achieve enough power to comfortably enjoy lights, run a cpap machine overnight, recharge a phone and power a laptop for as many hours per day as possible.. say 4-5hrs would be ample.
I have scrounged some second hand panels for a good price, they were first installed in 2016, so should have some good life left to give me.
P_20190217_154832.jpg
I have 11 good panels to work with.
Based on my budgetary limitations, I'm looking at a 24v system consisting of a pair of 12v 135AH AGM batteries. I would like to be getting some nice 6v Titans, but it's not an option.
And I'm looking at an all in one MPPT charge controller/inverter from EPever which seems to be one of the more highly regarded products coming out of China.
Based on the reading I've already done here, I know this system leaves much to be desired. But I just need to take the next step up from the little 12v system I'm struggling to get by with right now. The things I'm stuck on are:
The EPever Upower UP3000-M3322 and UP3000-M6322 are basically the same inverter and the same AC charger, but the 2nd one has a bigger capacity MPPT PV controller.
The 33 has Max.PV open circuit voltage 100V①（at min. operating environment temperature）92V②（25℃）.Max.PV input Power 780W and Max.PV charging current or 30A
The 63 has Max.PV open circuit voltage 150V①（at min. operating environment temperature）138V②（25℃）.Max.PV input Power 1500 and Max.PV charging current or 60A for about $200AUD more than the 33.
So as I understand it, with my battery's having a max charging amperage of 33.75A, I will never be able to use the 60A charging of the bigger unit. However, am I correct in thinking that there is value in being able to have more panels hooked up to the system for those cloudy days/weeks and winter months? And should I be concerned about overcharging? {I really don't think so, but my mind is so full of info, I'm starting to 2nd guess what I think I know}
I believe my options are 4 panels, 2Px2S on the UP3000-M3322 or 6 panels 3Px2S on the UP3000-M6322
And since I'm here asking noobie questions, is there any scope for me to save up and add another pair of batteries in parallel soon after... Say a month after initial install. (knowing that matching batteries would be more ideal.) I think I read something on here about never putting 12v AGM batts in parallel.. But I'm not sure why.
Anyway folks.. I would appreciate any thoughts on this matter... I fear if I just keep reading, my brain will explode before I can navigate all the options and considerations lol.
Cheers,
Bryce AKA Fireside.
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