DeepBass9 Posted October 25, 2016 Share Posted October 25, 2016 I have seen a lot of installations with twin charge controllers, inverters etc etc. so I was wondering about what people's thoughts are on redundancy in components. I ahev already had the experience of my Microcare charge controller failing, which was repaired under warranty, but I was still without solar power for a week and had to rely on generator only. I am going to add more panels very soon, but I was thinking instead of sukkelling to match panel characteristics with my current panels, I could instead buy an new array of any type of panels, with their own charge controller and then I have a backup if one of the charge controllers goes down. If they are properly fused, a lighning strike for instance might zap one and not the other (maybe) I may look at buying a cheap second hand inverter if one becomes available as a backup on that side. Batteries? Is there any way to build in some redundancy there? Quote Link to comment Share on other sites More sharing options...
Fritz Posted October 25, 2016 Share Posted October 25, 2016 yeah i would also like to know this. My axpert got its own built in MPPT (60A) and then i buy a stand alone MPPT with its own PV input but both the CC outputs are connected to same battery bank.. Thus you can increase your input PV power in theory. Mark 1 Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted October 25, 2016 Author Share Posted October 25, 2016 I presume if all of the charging parameters are set the same, then there shouldn't be a problem. I am just thiinking of getting another 40 or 60A microcare, connected to its own array. Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted October 25, 2016 Share Posted October 25, 2016 HI DB9 I like the idea of having built in redundancy. Make perfect sense to separate a second array on a separate MPPT. According to the 10-30A Microcare manual the Microcare MPPT cannot be paralleled with another PV array. This is immediately not good news. Fritz - You might as well get a second Axpert and cover your bases. If you are worried about the high quiescent draw you can switch one inverter off and its SCC will continue to operate and charge your batteries. Fritz 1 Quote Link to comment Share on other sites More sharing options...
Mark Posted October 25, 2016 Share Posted October 25, 2016 Hi Chris I am currently running my MC 40A on a small 600w array facing NW. I have set the MC to float at a lower voltage than the Axpert (facing NE @ 1200W) so it doesn't argue. Going well so far! No major issues noticed so far. Extended the charging day a lot now. All the MC sees is the battery voltage so don't expect any issues. Regards Mark DeepBass9 1 Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted October 25, 2016 Share Posted October 25, 2016 4 minutes ago, Mark said: I am currently running my MC 40A on a small 600w array facing NW. I have set the MC to float at a lower voltage than the Axpert (facing NE @ 1200W) so it doesn't argue. That's a clever way of getting around the problem with a 600W array it is unlikely to be able to overcharge your battery bank. Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted October 25, 2016 Author Share Posted October 25, 2016 6 minutes ago, Chris Hobson said: That's a clever way of getting around the problem with a 600W array it is unlikely to be able to overcharge your battery bank. The manual says " The MPPT input cannot be paralleled with another PV array." , but its the output that we want? Best to ask them. Although there is no problem when I charge batteries with generator and solar simultaneously. You can see there is some confusion when the batteries get full, but otherwise no problem. Quote Link to comment Share on other sites More sharing options...
Guest Posted October 25, 2016 Share Posted October 25, 2016 A separate charge controller and array, is seen by the inverter as "battery". Been doing 2 charge controllers on one bank from a long time before I split them. As Mark said, the 2nd controller must just be adjustable to not argue with the main one in the inverter. Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted October 25, 2016 Author Share Posted October 25, 2016 OK, so no problem then! Quote Link to comment Share on other sites More sharing options...
___ Posted October 25, 2016 Share Posted October 25, 2016 40 minutes ago, Chris Hobson said: cannot be paralleled with another PV array. That just means you cannot connect the same PV array to two MPPTs, and that really is common knowledge. You can however connect two MPPTs to the same battery bank (but different PV arrays) and that will work fine. Only issue is when one goes to float before the other. Then one array sits there doing nothing while the the other attempts to finish absorb at half power. Often not a problem, if there is enough power to finish absorb on the other side too, that CC just takes a bit longer to get there but it evens out. It is of course better if they are in agreement, but I know only one MPPT that can do that :-) Quote Link to comment Share on other sites More sharing options...
Mark Posted October 25, 2016 Share Posted October 25, 2016 My mc stays off until the battery voltage drops as the sun moves past the first string and then feeds in as needed until to starts taking over.I have also set the bulk lower as well. The axpert falls over if I try and equalise with the mc. Obvious really as 60v equalise is to high for the axpert. I knew that going with the change.Sent from my SM-G800F using Tapatalk Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted October 25, 2016 Share Posted October 25, 2016 46 minutes ago, plonkster said: That just means you cannot connect the same PV array to two MPPTs Hi PLonky I differ with you on this. The word "another" would indicate more than one array. Multiple MPPTs should not be a problem but this seems to be perculiar to Microcare. Why there should be this restriction I cannot understand. I have never operated with a Microcare there appears to be no mechanism to limit charging rate. So a 20A Microcare is a 20A charger and cannot be asked to charge at 10A. Quote Link to comment Share on other sites More sharing options...
___ Posted October 25, 2016 Share Posted October 25, 2016 1 minute ago, Chris Hobson said: So a 20A Microcare is a 20A charger and cannot be asked to charge at 10A. Not true. You can set a limit lower than the max of the device. (Used to have a MC in my system). Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted October 25, 2016 Share Posted October 25, 2016 23 minutes ago, plonkster said: Not true. You can set a limit lower than the max of the device. OK must admit it did not make sense not to be able to modify charging rate. Impressed by its <1W consumption. Quote Link to comment Share on other sites More sharing options...
Mark Posted October 25, 2016 Share Posted October 25, 2016 28 minutes ago, Chris Hobson said: Hi PLonky I differ with you on this. The word "another" would indicate more than one array. Multiple MPPTs should not be a problem but this seems to be perculiar to Microcare. Why there should be this restriction I cannot understand. I have never operated with a Microcare there appears to be no mechanism to limit charging rate. So a 20A Microcare is a 20A charger and cannot be asked to charge at 10A. You set the max charging rate as a % of size of MPPT. I have set it to 50% of 40A ie: 20A for my battery bank of 200aH. Quote Link to comment Share on other sites More sharing options...
___ Posted October 25, 2016 Share Posted October 25, 2016 12 minutes ago, Chris Hobson said: OK must admit it did not make sense not to be able to modify charging rate. Impressed by its <1W consumption. Around 60mA when I measured it. Some of it is an estimate, the isolated boost stage they use to drive the mosfet was broken when I poked around inside so I had to guess how much it might use. This was with the backlight on. At 24V it comes in around 1.5W. It uses an SMPS to drive the internal stuff, so I expect that figure to stay more or less constant as the voltage goes up. Quote Link to comment Share on other sites More sharing options...
___ Posted October 25, 2016 Share Posted October 25, 2016 13 minutes ago, TinkerBoy said: So it all comes down to the 9's 3 nines is sufficient for solar I'd think :-) That's around 8 hours in a year :-) Quote Link to comment Share on other sites More sharing options...
Guest Posted October 25, 2016 Share Posted October 25, 2016 2 hours ago, plonkster said: I know only one MPPT that can do that :-) Not true. I know of two, one is the priceless blue, the other the Morningstar range - they where the 1st to say you can use 2 controllers on the same bank, seeing theirs can be programmed to each person unique needs, and if you set your MS on the exact same settings, no need for a cable at all. So I tried the MPPT and the MS PWM on the same bank. Set the MPPT to the exact same settings as the MS PWM. Early mornings and late afternoons the MPPT did better, added value, whilst the PWM with the larger array on, powered the load during the day with the MPPT in float. NOTE: I just played a bit to see what will happen, as the parts where there. Would not suggest anyone mix MPPT and PWM controllers. Quote Link to comment Share on other sites More sharing options...
___ Posted October 25, 2016 Share Posted October 25, 2016 1 minute ago, The Terrible Triplett said: Not true. Of course it's true! Or it was true when I wrote it, in fact it was objectively true (refer to our other conversation :-) ). I did KNOW only one. Now I know two :-) Quote Link to comment Share on other sites More sharing options...
Guest Posted October 25, 2016 Share Posted October 25, 2016 1 minute ago, plonkster said: Of course it's true! Or it was true when I wrote it, in fact it was objectively true (refer to our other conversation :-) ). I did KNOW only one. Now I know two :-) I fell off my chair laughing! Damn that was sharp. Quote Link to comment Share on other sites More sharing options...
Chris Hobson Posted October 25, 2016 Share Posted October 25, 2016 46 minutes ago, The Terrible Triplett said: I fell off my chair laughing! Damn that was sharp. +1 Quote Link to comment Share on other sites More sharing options...
SilverNodashi Posted November 1, 2016 Share Posted November 1, 2016 The Microcare LED MPPT's can also be "stacked" together, as long as the float and bulk charge settings are the same. Quote Link to comment Share on other sites More sharing options...
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