My new cheap chineese MPPT charge Controler up in smoke. - Page 1
Forum section: electronics / general

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 18, 2015, 04:51:24 pm
content: well I finally got around to getting a MPPT charge controller, I installed it yesterday and today it went up in smoke.I got it off ebay, search for this if your interested "MPPT Solar Regulator, Solar Charger, Battery Panel Charge Controller,12V/24V/48VDC" item 111436344987 username "domitronic"I got the 40 Amp version and using it on a 12v battery bank with 2 x 37v 175Watt solar panels connected in series as indicated in the description. Strait away I noticed that the 2 x 8 segment display was so bright it was very hard to read, and using my clamp meter it was only giving out 4 to 5 amps, It was a dull morning today so I give it the benefit of the doubt. After about 12pm the sun came out and it started to push out 25 Amps and the fan started to spin and I went into the house. About 4 pm I went into the garden and heard a beeping noise coming from the shed, it was the charge controller, the charging led was off so I thought the breaker might have tripped. The 60amp breaker used as instructed in the manual was still on, I was confused, the next thing smoke started pissing out of the top of the unit. Luckily I had the circuit breakers in circuit and I disconnected the power.I took some pics on what I found. Please let me know what you think.I don't know why any fuses didn't blow, and glad I was in the garden when it decided to blow.After I disconnected it and opened it up the heatsink was still to hot to touch.

author: amyk
author_rank: Super Contributor
timestamp: May 18, 2015, 05:06:01 pm
content: Lelon capacitors... more like lemon crapacitors.Funny how they both vented in the same direction like a pair of ducks.

author: madires
author_rank: Super Contributor
timestamp: May 18, 2015, 05:17:24 pm
content: I_real = I_Chinese / k while k is something in the range of 2 - 3

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 18, 2015, 05:21:25 pm
content: Im wasn't sure if that brand of cap was a good one or not, I assume it some "one hung low" brand as Dave Jones puts it lolThat orange cap is bodged in from the blown caps to the battery + line, and why they got a big resister in a capasitor space I don't know.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 18, 2015, 05:22:41 pm
content: What madires

author: djQUAN
author_rank: Frequent Contributor
timestamp: May 18, 2015, 05:30:36 pm
content: It may be just that the caps could not handle the ripple current. Not sure if it took out anything else.What battery voltage were you using?I'm personally using Epsolar controllers (chinese brand too) but they use name brand components and seem to work well even with an over powered PV array (running 1kW total PV, manual says 540W max on a 12V system).

author: jhufford
author_rank: Contributor
timestamp: May 18, 2015, 05:36:04 pm
content: Any chance the caps are just put in backwards?

author: mtdoc
author_rank: Super Contributor
timestamp: May 18, 2015, 05:37:41 pm
content: There's a reason why quality MPPT controllers are not inexpensive. IMHO, you'll need to pay at least twice that amount for a quality controller that will last.Also - I'm not an EE but I don't think that ripple current is an issue in an MPPT solar charge controller. Where is the ripple coming from?

author: djQUAN
author_rank: Frequent Contributor
timestamp: May 18, 2015, 05:41:20 pm
content: MPPT controllers have a large (depending on current capability) DC-DC converter. Usually they are buck topology. The mcu controls the DC-DC controller to load the PV modules in their maximum power point and keep it there.

author: tom66
author_rank: Super Contributor
timestamp: May 18, 2015, 05:43:48 pm
content: The capacitors used on that model are Lelon LSM. These are general purpose capacitors and the ESR is quite high. The RMS ripple rating is just over 3Arms, the actual ripple will depend on the controller design but if it is just a boost converter (L1 next to large trafo-like device seems to indicate it is) then the output capacitor will experience a large amount of ripple current, it will depend on the duty cycle but typically it will be around 30-100% of the load current. So those capacitors are completely inadequate for this design.D/S for Lelon LSM:http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCIQFjAA&url=http%3A%2F%2Fwww.lelon.com.tw%2Fdown.php%3Ff%3D%2Ffile%2F59.pdf%26n%3DLSM.pdf&ei=iSNaVcKJKomyUdeegbAJ&usg=AFQjCNFe0mU1vQqSbSuDGwz4Zv47JvgNjg&sig2=NvWgccLZrlS6ASKS2m6paw&bvm=bv.93564037,d.d24

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 18, 2015, 05:52:50 pm
content: @ djquan, Im using a 12v systerm. Where do i get a Epsolar controller from?@jhufford, i dont think the caps are in backwards, if you look at pic mppt10 you will seethe + sign on the silkscreen and is oppisit to the stripe on the caps.@ mtdoc, you right you get for what you pay for, but i did try to avoid some controllers who say theymppt and been proven that they arnt. I thought the £70 + range should be ok.At the end of the day there no really costly parts in them.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 18, 2015, 05:55:43 pm
content: Well this comes with 2 years warranty, I don't know weather to push for a refund.

author: djQUAN
author_rank: Frequent Contributor
timestamp: May 18, 2015, 05:56:55 pm
content: It may be easy to make an MPPT controller from parts but the important bit is the algorithm that runs the maximum power point tracking. How well it follows the power point and how fast it tracks when conditions change (clouds, shadows on PV cells etc).I got mine from Aliexpress. It is an Epsolar Tracer4215BN controller plus the MT50 remote display. You need the remote display to tweak the controller settings.

author: mtdoc
author_rank: Super Contributor
timestamp: May 18, 2015, 06:05:09 pm
content: Quote from: tom66 on May 18, 2015, 05:43:48 pmThanks for the info. I have a couple of Midnite Solar Classic 150 amp MPPT controllers. These are considered by many to be the "crem de la crem" of MPPT CCs and are designed by Bob and Robin Gudgel (who also designed the Outback FM series of controllers). They only have a few, much smaller, electrolytic caps. I'm not at home to look at values but here's a pic I found.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 18, 2015, 06:22:59 pm
content: I was just looking at this one on ebay 261448754683, I think 30amp charge current is enough for my system.Depends if I can get a refund on this piece of crap.

author: madires
author_rank: Super Contributor
timestamp: May 18, 2015, 06:29:30 pm
content: Quote from: snipersquad100 on May 18, 2015, 05:22:41 pm40 Chinese Amps are about 13 - 20 Amps. This rule applies to cheap stuff and is no "made in China" bashing, just my personal experience.

author: mtdoc
author_rank: Super Contributor
timestamp: May 18, 2015, 06:36:01 pm
content: Quote from: snipersquad100 on May 18, 2015, 06:22:59 pmYes. I have one of those as well (I was a beta tester). It's a very good charge controller.I don't know about that vendor. You can get one for about the same price fromNAWSBTW, Midnite Solar hasan excellent forumwhere you can ask technical questions and get answers sometimes from the designers (Mario in the case of "The Kid")

author: Towger
author_rank: Super Contributor
timestamp: May 18, 2015, 06:43:27 pm
content: You also need to derate Chinese Watts to about 30 percent. Especially when they are LED watts. BTW. Have a look at those car fuses, it is common that they are all stamped out of the same metal sheet and the only difference in the different ratings is the colour of the plastic and number printed on the top.

author: tom66
author_rank: Super Contributor
timestamp: May 18, 2015, 07:02:13 pm
content: Quote from: mtdoc on May 18, 2015, 06:05:09 pmIt's almost certain there will be more - it's kind of necessary for MPPT solar controllers. They're probably buried on the bottom of the board, in the fan air flow to help keep them cool maybe.

author: mtdoc
author_rank: Super Contributor
timestamp: May 18, 2015, 07:15:59 pm
content: Quote from: tom66 on May 18, 2015, 07:02:13 pmMaybe. But there's not a lot of depth behind the board . There is a lot of metal for heat sinking and the FETs are there to be cooled by the fans. You've got me curious now. I may try to do a quick teardown of one of mine when I get home.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 18, 2015, 08:54:37 pm
content: How do you rate the fuses you need for these charge controllers, The manual said to use I 63amp, I used a 60 and it didn't blow.

author: johansen
author_rank: Super Contributor
timestamp: May 18, 2015, 09:45:07 pm
content: It doesn't take that many microfarads to meet reasonable output voltage ripple requirements.I am rather supprised the 100 volt capacitors blew up in OP's mppt converter.If its a buck converter, most of the current ripple is on the input side.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 19, 2015, 08:26:09 am
content: I didn't tell the seller I had opened the unit in case he says I've voided the warranty. However he has got in touch and asked me to open it and have a look if the capacitors have blown. So that tells me it a common fault and he knows about it yet is still happy to take my money knowing it is potentially dangerous and could catch fire.

author: amyk
author_rank: Super Contributor
timestamp: May 19, 2015, 02:16:20 pm
content: Quote from: snipersquad100 on May 19, 2015, 08:26:09 amVenting caps will make a mess but I haven't seen any catch fire before.

author: mtdoc
author_rank: Super Contributor
timestamp: May 19, 2015, 07:11:31 pm
content: Below is a picture inside my Midnite Solar "Kid" charge controller - a real 30 amp MPPT controller. 2 short fat 1000uF caps.Also - sure enough as tom66 pointed out there is some large caps (at least 1) on the Midnite Classic 150 amp controller. I have a 3rd one sitting around awaiting a future install so I opened it up. Full removal of the main board would be too much trouble but a peak in from the top does reveal at least one short fat cap (2000uF I think).Still not sure I understand where the large ripple comes from requiring these large filter caps. I guess I need to do some reading and learning about buck converters..

author: Seekonk
author_rank: Super Contributor
timestamp: May 19, 2015, 07:52:03 pm
content: What exactly are 37V panels? Is that open circuit voltage? You could have had well more than 100V on those capacitors.

author: tom66
author_rank: Super Contributor
timestamp: May 19, 2015, 08:26:00 pm
content: Ah - if they are buck converters then the ripple is the other way around. The input cap suffers the worst ripple, whereas the output cap suffers relatively little, the ripple being determined by the inductor ripple current plus any applicable transient load changes etc.See:http://electronicdesign.com/site-files/electronicdesign.com/files/archive/electronicdesign.com/content/content/63629/63629-fig4.jpgas a good illustrator of the ripple currentsIf the frequency is high enough, then ceramic or film caps can handle the majority of the ripple current. Lower frequencies will require electrolytics with their associated lifetime issues. The elcaps also help to absorb some of the lower frequency components like load steps on the output which can cause oscillation with pure ceramic designs (very high Q)I'm not a fan of the JH high voltage caps having seen quite a few fail on Samsung PSUs, on the high voltage side.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 20, 2015, 08:18:02 am
content: @Seekonk, Sorry the vmpp voltage is 35.4v and the open circuit voltage is 43.6v and I had two in series as stated in the ebay item description as being the min amount they recommend for this unit. I was getting 82v open circuit when I connected them.Even thou if that's what they recommend to use and 100v is rated to be the max pv voltage for the system, im sure those caps (if they are the ones the connected to the pv input net) should be at least 160volt rated.

author: tom66
author_rank: Super Contributor
timestamp: May 20, 2015, 11:12:51 am
content: As I said, it won't be over-voltage that's killing them but the excessive ripple current thru the caps. This assumes the Lelon datasheet is being completely truthful about those figures (which, I doubt...)

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 20, 2015, 11:37:59 am
content: I think ill get a refund and get a Midnight solar kid.

author: Kibi
author_rank: Unknown
timestamp: May 20, 2015, 02:54:05 pm
content: +1 for Midnite kit.My Classic 150 has been running for over two years now.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 21, 2015, 07:35:14 pm
content: I don't know how much they pay in China to send stuff to the UK but for me to return this 2.5KG tracked parcel with insurance of £100 to China will cost me £70.60. I only paid £99 for it.

author: tom66
author_rank: Super Contributor
timestamp: May 21, 2015, 07:58:01 pm
content: If you complain about this to eBay, they may simply force the seller to refund you - eBay are extremely biased towards the buyer's side, although there are exceptions, this is generally something you can use in your favour.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 21, 2015, 08:02:04 pm
content: Thanks Tom

author: Seekonk
author_rank: Super Contributor
timestamp: May 21, 2015, 09:46:57 pm
content: I imagine you could possibly get a third of that back selling it on ebay. I have been trolling for a while for one that is blown up. There are plenty of people that could fix this for next to nothing. If they weren't trying to shave every third if a cent off everything they make, the designs wouldn't be that bad. I wouldn't run any of these without an external capacitor bank.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 22, 2015, 05:41:36 pm
content: @Seekonk, I would try to fix it myself but as it only lasted a day and the display is so bright you cant read it, ive lost all faith in the unit.Out of interest what size of cap bank would you use? and would that be in parallel with the two caps that have gone.

author: VK3DRB
author_rank: Super Contributor
timestamp: May 24, 2015, 09:13:09 am
content: It is likely the caps were faulty, or underrated, and the sweatshop that built the device did not bother testing it. I have seen this sort of thing with my own eyes in a factory in Tianjin - "build" and ship (no test), as well as shameless fraud ("Made in USA" printed on copied Alan Bradley PLC's).Better to buy German made solar equipment. Speak to any experienced and honest solar company and they will tell you the Germans make the best inverters, MPPT's, and regulators.At the end of the day,YOU GET WHAT YOU PAY FOR. This is the same now as it was 40 years ago.MPPT = Mao's Proles Plagiarize Technology

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 24, 2015, 10:06:12 am
content: I totally agree with you.

author: wagon
author_rank: Frequent Contributor
timestamp: May 24, 2015, 12:05:14 pm
content: Have a look atwww.lumiax.comI have some smaller regulators from them, they seem to be excellent quality for the money. In fact, I've have one running outside in the weather for over a year now, no troubles at all.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 24, 2015, 07:44:07 pm
content: I had a reply from another seller who sells this type of charge controller. I asked them if their products use the Lenon brand caps as his auctions say they use top brand parts. This was his reply.Dear pcb-electronicsdotcodotuk,Thank you for your patience and reply. The capacitors we use are the lelon brand. However in fact the lelon brand doesn't mean the poor quality. And you can check on its website. And many 40a controllers have been sold to all over the world, none of our customers report this issue like the unit burnt up. Maybe there are some other problems in the pv system. Anyway as you have bought another one, if you wanna one more, our products could be considered.Best Regards,

author: mtdoc
author_rank: Super Contributor
timestamp: May 25, 2015, 05:12:31 am
content: Quote from: VK3DRB on May 24, 2015, 09:13:09 amWell, yes and no. If you're talking grid tie inverters then yes, SMA is top of the line (along with Fronius). But other than that, at least here in North America, German products have little market share and are not necessarily considered the best. For off grid and grid interactive (aka grid tie with battery back up) inverters Outback, Magnum and Xantrex (now Schnieder Electric) have been considered the best for some time. The lineage of these companies came out of the legendary Trace inverters and Bob and Robin Gudgel who went on to found Outback (and then Midnite Solar). Xantrex tooks some hits to their reputation when they where sold to Schnieder Electric and later renamed due to some recalls and reputation for poor customer service. Outback Power equipment was recently acquired by a large company and has offshored most of their manufacturing with as of yet unknown consequences.Outback in particular has a large international market share and make specific inverters for those markets.. The only European company with any appreciable off grid market share in North America is Victron Energy -but they are Dutch I believe and mostly sell to the Marine off shore cruising crowd.As far as charge controllers, Steca is the only German company with any market share in North America that I am aware of and that is only small share for their small PWM controllers that do have a good reputations. Their MPPT controllers are not sold much or at all here that I am aware of. Outback, Xantrex, and Morningstar all have very good reputations for their CCs, but Midnite Solar (which was founded by the Gudgel brothers who previously designed the first widespread used high amp MPPT controller the Outback MX60) has now become one of if not the best designer and builder of MPPT controllers - worldwide.

author: Seekonk
author_rank: Super Contributor
timestamp: May 25, 2015, 08:06:30 am
content: Some do not share that opinion of SMA.http://www.fieldlines.com/index.php/topic,148681.msg1033244/topicseen.html#msg1033244

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 29, 2015, 10:44:31 am
content: Well that's the controller sent back to China, they found that Ipostparcels would do it for £30 odd quid.Anyway if got a midnite solar kid on order, cant wait.I was wondering what's the best way to connect the two 175watt 37v solar panels, in series or parallel on a 12v system.

author: Kibi
author_rank: Unknown
timestamp: May 29, 2015, 04:05:06 pm
content: If shading will not be a problem at any time of day then you could go with the two panels in series. I have heard though that greater voltage differential between the PV side and the battery side is less efficient and more heat will consequently be dissipated, it makes sense in the linear world, but a good MPPT charger, like The Kid, should mitigate this issue.I run my four 250W panels (also about 37V) in parallel due to partial shading issues during the course of the day. Each panel is fused.I have a build log of my currently running system if you are interested:https://www.eevblog.com/forum/projects/solar-powered-workshop-take-two/msg224744/#msg224744

author: djQUAN
author_rank: Frequent Contributor
timestamp: May 29, 2015, 04:27:21 pm
content: Less efficiency of the MPPT controller is not much of an issue when you get some of that back with less loss on the PV cables.Series connection = higher voltage, less current so lower I2R losses. It may not make much of a difference though if your cable runs are short and wires are thick.I'm running ten 100W panels in 5S2P config to an MPPT controller and 12V system. (520W limit on a 40A controller? pfft haha still working fine with lots of low light output). PV cabling is a single pair of #12 wire about 37ft long.I'd post pics about my system but it isn't as nice as Kibi's so....

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 30, 2015, 06:17:12 pm
content: Thanks Kibi and djQUANI'm just experimenting at the moment, my two panels are on my shed roof with no shading issues.Well apart from the clouds that cover the UK 90% of the year. The charge controller is in side theshed so very short run. The cables are just normal pv cable, not sure of the gauge.I like your combiner box Kibi, That be my next thing i need to look at. I just got a couple of40amp circuit breakers on mine.djQUAN love to see your system. Please post pics.

author: mtdoc
author_rank: Super Contributor
timestamp: May 31, 2015, 08:07:35 am
content: Here's a longish video showing showing production and testing of Midnite Solar products. No crazy Australian bloke narrating, just good engineering porn and insight into production and testing of a quality MPPT controller.Pick n place porn starting about the 10 min mark.Skip to the 28 min mark to see the Kid MPPT controller production line and testing.Interesting to see all the old, cheap Rigol scopes being used. Even an Atten scope. Apparently these aren't just toys and actually are used to produce real products...Also starting at the 58 minute mark starts a cool sequence on their design and testing of the wind turbine and controller they're producing for the military.

author: djQUAN
author_rank: Frequent Contributor
timestamp: May 31, 2015, 12:48:32 pm
content: Quote from: snipersquad100 on May 30, 2015, 06:17:12 pmI have some pics of them here:http://quan-diy.com/projects/apower/alternativep.htmI currently run my entire workshop 100% off grid, run an extension cable to the garage when I'm doing more messy stuff (cutting wood, belt sanders etc). The whole house has a separate 12V wiring for off grid lighting. We rarely use 240V mains lights these days. We also run two washing machines and a spin dryer 100% off grid too.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: May 31, 2015, 08:01:07 pm
content: Thanks mtdoc, I will watch that video now.djQUAN nice set up, I will pop back now and again to see your progress.

author: Kibi
author_rank: Unknown
timestamp: May 31, 2015, 08:41:54 pm
content: Thanks mtdoc, that was entertaining. Before watching it, I wondered if Midnite Cat was going to make an appearance.djQuan, that's a cool system. Thanks for sharing.

author: djQUAN
author_rank: Frequent Contributor
timestamp: June 01, 2015, 02:14:56 pm
content: Thanks for the comments... Here's something I made a couple weeks back. Portable power source also charged by a small folding 40W PV array. I mainly use it to power a 12V electric fan in my bedroom just so it gets used daily. I do take it out though when I need a portable power supply.http://quan-diy.com/projects/apower/powerbank.htm

author: johansen
author_rank: Super Contributor
timestamp: June 02, 2015, 04:33:43 pm
content: I spoke with Bob Gudgel 3 months ago at a hamfest in Tacoma.He is interested in finding a true 6 or 8 channel scope, not some combination of 2 good channels, 2 not so high bandwidth channels and 4 logic channels...we talked a bit about cheap digital scopes, I tried to explain to him the biggest thing I miss is the Tek 475 split triggering as shown here:btw, i have a blown up 475 if anyone needs parts.and there is a whole lot more data on that screen than 8 bits...

author: snipersquad100
author_rank: Frequent Contributor
timestamp: June 03, 2015, 06:55:00 pm
content: Hi guys, I just bought another 235watt 37v panel. After I bought I was wondering how much wattage the solar kid can handle.The ebay listing don't say. Would two x 175watt panels and a 235watt be to much?

author: mtdoc
author_rank: Super Contributor
timestamp: June 03, 2015, 07:11:21 pm
content: Quote from: snipersquad100 on June 03, 2015, 06:55:00 pmThe voltage will not be an issue. See specsHEREIt can take up to 150V input.The problem will be the output amps. You have a 12V battery bank, correct? With 585 watts of PV you could easily produce over 40A output on a sunny day if in Bulk charge mode - but the Kid will only put out 30A max. Best to go to at least a 24V battery bank with that much PV - or go to a bigger controller like the Midnite Classic (but more expensive!).BTW - how do you plan to combine those panels? If all three will be in series the Imp's need to be close (within 10% or so). If in parallel, the Vmp's need to be close.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: June 03, 2015, 07:26:46 pm
content: ThanksI think I'll use the new panel on my old pwm controller and just use the 2 x 175's on the midnite kid.Still not sure witch is best series or parallel.Would I need blocking diodes if I use 2 controllers n one bank?

author: mtdoc
author_rank: Super Contributor
timestamp: June 03, 2015, 08:10:24 pm
content: Quote from: snipersquad100 on June 03, 2015, 07:26:46 pmPutting your panels in series would reduce voltage drop and allow smaller wire size. On the other hand controller may be slightly less efficient due to need to buck voltage down further. The decision depends partly on how far panels are from the controller - i.e. how much voltage drop comes into play. Wire from panels to controller should be sized to keep voltage drop less than 2-3%.No need for blocking diodes.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: June 03, 2015, 08:14:06 pm
content: Thanks mtdoc.I'll parallel them then as it very short distance.

author: djQUAN
author_rank: Frequent Contributor
timestamp: June 04, 2015, 12:09:35 pm
content: One other advantage I see when reducing the voltage difference between PV Vmp and battery voltage is that the MPPT charge controllers spend less time "scanning" the entire PV voltage range to find the Vmp of the array.A smaller voltage difference means the controller needs to sweep only a small voltage range to find it. It depends on the charge controller though. Outback controllers sweep only a percentage of the VOC of the PV array (50-90% IIRC) but my Epsolar controller always sweeps the entire range from battery voltage to the PV VOC.

author: Seekonk
author_rank: Super Contributor
timestamp: June 04, 2015, 01:03:42 pm
content: Scanning does waste some energy, but it doesn't work like that. The losses would be very minimal. Monitoring panel temperature is a very effective way to track solar. IR losses can be dialed in. Conventional MPPT controllers are like your engines controller. When everything is OK it is very effective. When a fuel injector malfunctions it throws all the rest of them off. Fifteen years from now the single conventional MPPT controller used in large systems will be known as Panel Killers!

author: djQUAN
author_rank: Frequent Contributor
timestamp: June 04, 2015, 04:16:34 pm
content: I wasn't talking about the method on how it is scanned... It was about how long it would take to sweep the entire range of the panel voltage.If it was taking more time to sweep the entire range, then that is less time for the PV to run at its maximum power point which is energy not harvested and used by the loads.

author: mtdoc
author_rank: Super Contributor
timestamp: June 04, 2015, 04:29:39 pm
content: FWIW, not all MPPT scanning algorithms are the same. In fact the Midnite controllers let you choose between a few different algorithms - some optimized for solar, hydro, wind, etc. They have regular firmware updates that sometimes includes changes to these.It's not easy to do a carefully controlled comparison but Midnite claims that their controllers outperform others based on testing done by APRS world:http://www.midnitesolar.com/pdfs/performanceComparison.pdf

author: Seekonk
author_rank: Super Contributor
timestamp: June 04, 2015, 09:56:05 pm
content: I had been doing a test for a month with a 100W 12V panel boosting it up 35V to heat water with one of those cheap ebay 150W boost converters. I was taking it apart this morning and noticed the 35V output cap had blown apart. I was running it at the max voltage, but had several external capacitors in parallel so it wasn't a ripple current problem. Evidently the posted voltage is a real maximum. Much like the surge voltage that used to be listed on capacitors. Really blew up, still haven't found the case for it.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: June 07, 2015, 03:40:08 pm
content: My midnite kid has been delayed as I have been stung with a £60 Import duty (Ouch)Any why I have put my new 235 watt solar panel on my shed roof but as I'm waiting for the charge controller to comeid thought id connect it strait to the battery bank. My PWM controller is busy charging the bank but when I connect the new panel to the batteries the pwm turns off the charge, I think its seeing more voltage on the batteries and disconnecting the Charge.I was wondering if there was a way around this.

author: mtdoc
author_rank: Super Contributor
timestamp: June 07, 2015, 04:13:02 pm
content: Can you configure you battery bank for 24V?. What's the Vmp of your 235 W panel?

author: snipersquad100
author_rank: Frequent Contributor
timestamp: June 07, 2015, 05:08:08 pm
content: VMP is 30.3vI cant set it up as 24v system cos my inverter is 12v.

author: mtdoc
author_rank: Super Contributor
timestamp: June 07, 2015, 09:01:15 pm
content: 30 volts will boil your 12V battery bank.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: June 07, 2015, 11:04:34 pm
content: So best wait till the new charge controller comes then lol.