Hi all, I just got a correction from Darren - global charge control is in the Mate3, and therefore works with any FM or MX controller that has the GT mode. It uses the current sense from the FN-DC and the GT mode signal to control the output of the controllers.
Sorry for any confusion Phil On Jul 20, 2012 4:11 PM, "Chris Mason" <cometenergysyst...@gmail.com> wrote: > Phil, > Good explanation of the feature. When did GCC make it into the firmware, > and can the older ones be updated? It sounds like a perfect solution for > some of my installations. > > On Fri, Jul 20, 2012 at 12:34 AM, Phil Undercuffler > <solarp...@gmail.com>wrote: > >> OutBack implemented Global Charge Control in the FM charge controllers >> a while back, based on the input of the good folk at SELF who worked >> to power a number of hospitals and clinics in Haiti after the >> earthquake. In some of those systems, the PV array was based on the >> typical running consumption of the hospital, in the 30 - 100 kW if I >> remember right, and the battery bank was relatively modest. However, >> on the weekends and holidays without the normal AC loads the PV input >> was considerably more than the battery could absorb without >> destructive heating, something like a C2 or C5 rate. >> >> Global Charge Control is implemented using the MATE3, a FN-DC and FM >> charge controllers set to GT mode. You set a high charge current >> limit in the M3, and then it monitors the charge current going to the >> batteries. In normal operating mode the controllers stay in wide open >> mode, harvesting as much power as possible. However if the loads drop >> and the total current from the charging sources begin exceed the >> global charge limit, the system compensates and the controllers back >> off to prevent sending too much current to the batteries. >> >> In today's world of PV modules being cheaper than diesel, we're seeing >> a lot more systems that can use this tool. >> >> Hope this helps, >> >> Phil >> >> >> >> On Thu, Jul 19, 2012 at 7:56 PM, b...@midnitesolar.com >> <b...@midnitesolar.com> wrote: >> > >> > >> > I didn't see that Brian T had the same idea until after I sent that >> email >> > off to Allan... >> > boB >> > >> > >> > >> > >> > >> > On 7/19/2012 7:53 PM, Allan Sindelar wrote: >> > >> > Wrenches, >> > I forwarded Brian's post on to Robin at Midnite, as I thought it was an >> > interesting idea. Below is his response, as well as boB's. >> > Allan >> > >> > Allan Sindelar >> > al...@positiveenergysolar.com >> > NABCEP Certified Photovoltaic Installer >> > NABCEP Certified Technical Sales Professional >> > New Mexico EE98J Journeyman Electrician >> > Founder and Chief Technology Officer >> > Positive Energy, Inc. >> > 3209 Richards Lane (note new address) >> > Santa Fe, New Mexico 87507 >> > 505 424-1112 >> > www.positiveenergysolar.com >> > >> > Allan, It is simpler than what is being suggested. The reason they want >> to >> > limit to 20 amps is because the battery doesn’t need anymore than that. >> The >> > controller will automatically limit the charge current as the battery >> gets >> > full. If a large load is turned on, the controller will try to refill >> the >> > battery up to its capacity. The 80 amps will quickly be reduced because >> the >> > voltage will rise to the point where the charge tapers off. >> > >> > There is nothing else that needs to be done. If the problem is that the >> > battery bank is too small for a big controller, the best answer is to >> get >> > more batteries. A 80 amp charger into a 200 amp hour battery is going to >> > raise the battery voltage so quick, it will not affect the battery at >> all. >> > By the way, discharging a battery at 60 or 80 amps is probably going to >> do >> > damage to a small battery also. We do have an input on the Classic that >> > could probably be programmed to do as requested. That input feature has >> yet >> > to be implemented. I’m sure we will have discussions about this when the >> > time comes to write the input code. Maybe this feature will be designed >> in, >> > but it doesn’t sound like it is a very good feature to spend a bunch of >> time >> > on. After all, the main problem is that the battery bank is just too >> darned >> > small. >> > >> > Bob, Tom and Ryan do you have any comments on the subject? >> > >> > Thanks, >> > >> > Robin >> > >> > >> > >> > One idea I had in mind was to have an option, in software, to limit the >> > current into the battery, >> > when the charging current goes above some set threshold. The controller >> > would have to get its information from >> > the battery monitor over the network. >> > >> > If it is a grid tie system and grid is there and GT inverter is selling, >> > then no problem... The controller >> > can work at its full output. If grid or loads go away, then the CC will >> > know and it can throttle back at >> > that time. >> > >> > We don't have a battery monitor yet, but we will have one. This will >> be one >> > of the settings as well as >> > Re-Bulk based on state of charge, ending amps and those types of things. >> > >> > boB >> > >> > On 7/19/2012 8:34 PM, maver...@mavericksolar.com wrote: >> > >> > I say it is waste of time. >> > >> > 1. AGM batteries can take the high current and you are right, the absorb >> > voltage is reached and the absorb current is tapered rather quickly. >> Current >> > generation charge controllers are rather fast at the transitions. I >> have a >> > bunch of data from a system with a PentaMetric that shows the battery >> bank >> > going to absorb voltage at grid tie, during cloud events, but only for >> a few >> > seconds at a time. >> > >> > 2. A properly designed GTBB system should cover the connected loads for >> 24 >> > hours of each sunny day, at a minimum. Keep in mind, off grid systems >> are >> > designed for that, and 3 days + of backup, etc. >> > >> > 3. I would say, based on my experience, the minimum battery bank should >> be >> > 400Ah. I personally try to set it at 600Ah (48V). It is a backup system >> > after all. But the key is the customer's expectations...who are they >> going >> > to call after the lights go out? >> > >> > >> > Thank you, >> > >> > Maverick >> > >> > >> > Maverick Brown >> > BSEET, NABCEP Certified Solar PV Installer ® >> > President & CEO >> > Maverick Solar Enterprises, Inc. >> > Office: 512-919-4493 >> > Cell: 512-460-9825 >> > >> > Sent from my HondaJet! >> > >> > On Jul 19, 2012, at 6:35 PM, Brian Teitelbaum <bteitelb...@aeesolar.com >> > >> > wrote: >> > >> > Drake, >> > >> > >> > >> > I’ve been hounding a couple of the charge controller manufactures about >> this >> > issue, but so far I just haven’t seen a light bulb go off in their >> heads, >> > but I’ll keep trying, and maybe this is a better forum to do it. >> > >> > >> > >> > MPPT controllers can be adjusted to current limit at amperage values >> below >> > their rating, but if you do that, you are also limiting the output of >> the >> > array in general, and the amount of PV power available to run the loads >> > directly from the array (through the inverter). Not the best use of >> > available PV power. >> > >> > >> > >> > Say you have an 80A controller and a 200AH battery. With current >> technology, >> > you have two choices: >> > >> > >> > >> > Let the controller operate at 80A. If you have loads to draw off some >> of the >> > current (or sell to the grid), great, but if not you could be seeing a >> > charge rate of C/2.5, which would be pretty hard on a sealed 200AH >> battery, >> > to say the least. Granted, the battery voltage would rise pretty >> quickly, >> > and the controller would start to taper off, but it would still see high >> > currents especially if the absorption time is set long. Not a happy >> > scenario. >> > >> > >> > >> > Or, you can set the current limiting on the controller to 20A for a C/10 >> > charge rate. But if you had loads drawing 60A, you would be pulling that >> > additional 40A from the battery and not using the array’s full power. >> Also >> > not a happy scenario. >> > >> > >> > >> > What we need is a controller that can read the signal from a shunt at >> the >> > battery, and use that as the basis of current limiting control. >> > >> > >> > >> > For example, if we have an array that can produce 80A of current, but we >> > want to limit the battery to 20A of charge, there would be 60A of >> potential >> > current there to run loads without drawing on the battery. If there are >> no >> > loads running, the controller should current limit at 20A (reading from >> a >> > shunt), but if loads are turned on, the controller should be able to let >> > more current through while still limiting the battery to 20A. When >> loads are >> > shut off, the controller should go back to a 20A limit. >> > >> > >> > >> > This doesn’t all have to happen very quickly as a battery can take a >> heavier >> > charge for a short period of time, but I think that this would be a >> major >> > improvement of controller function. >> > >> > >> > >> > Of course, if you are grid-tied you can sell all the excess power, but >> if >> > the grid goes down, or you are off-grid….? >> > >> > >> > >> > Because of the low cost of PV and the high cost of batteries these >> days, I’m >> > seeing more and more requests for large arrays with smaller batteries. I >> > also think that PV is now cheap enough to allow for oversizing of >> arrays for >> > better battery charging on cloudy days, which can reduce generator run >> > times. We need smarter controllers. >> > >> > >> > >> > What say ye, charge controller gurus? >> > >> > >> > >> > Brian Teitelbaum >> > >> > AEE Solar >> > >> > >> > >> > From: re-wrenches-boun...@lists.re-wrenches.org >> > [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake >> > Sent: Thursday, July 19, 2012 2:21 PM >> > To: RE-wrenches >> > Subject: [RE-wrenches] Small battery bank vs too large array >> > >> > >> > >> > Hello Wrenches, >> > >> > Where can I get a device that will measure current through a shunt and >> > create a signal to trigger a relay? >> > >> > We want to be able to use a 2 kW array with four, 200 AH sealed >> batteries on >> > an Outback system. 2 kW of PV would be too much amperage for the >> batteries. >> > The idea is to open relays to disengage strings in conditions of high >> > current to the batteries. >> > >> > The reason for this is to create backup systems where power will be >> > abundantly available when the sun shines. The system will normally >> connect >> > to the grid, except during outages. In normal charging conditions the >> power >> > will go straight to the grid. When the grid is down, power will be >> > available for loads and battery charging, but batteries will be >> protected >> > from overcharge? >> > >> > Any suggestions on ways to accomplish this are welcome! >> > >> > Thanks >> > >> > Drake >> > >> > >> > Drake Chamberlin >> > Athens Electric LLC >> > OH License 44810 >> > CO License 3773 >> > NABCEP Certified Solar PV Installer >> > 740-448-7328 >> > http://athens-electric.com/ >> > >> > _______________________________________________ >> > List sponsored by Home Power magazine >> > >> > List Address: RE-wrenches@lists.re-wrenches.org >> > >> > Options & settings: >> > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> > >> > List-Archive: >> > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> > >> > List rules & etiquette: >> > www.re-wrenches.org/etiquette.htm >> > >> > Check out participant bios: >> > www.members.re-wrenches.org >> > >> > >> > >> > _______________________________________________ >> > List sponsored by Home Power magazine >> > >> > List Address: RE-wrenches@lists.re-wrenches.org >> > >> > Options & settings: >> > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> > >> > List-Archive: >> > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> > >> > List rules & etiquette: >> > www.re-wrenches.org/etiquette.htm >> > >> > Check out participant bios: >> > www.members.re-wrenches.org >> > >> > >> > >> > >> > >> > _______________________________________________ >> > List sponsored by Home Power magazine >> > >> > List Address: RE-wrenches@lists.re-wrenches.org >> > >> > Options & settings: >> > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> > >> > List-Archive: >> > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> > >> > List rules & etiquette: >> > www.re-wrenches.org/etiquette.htm >> > >> > Check out participant bios: >> > www.members.re-wrenches.org >> > >> > >> > >> > >> > _______________________________________________ >> > List sponsored by Home Power magazine >> > >> > List Address: RE-wrenches@lists.re-wrenches.org >> > >> > Options & settings: >> > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> > >> > List-Archive: >> > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> > >> > List rules & etiquette: >> > www.re-wrenches.org/etiquette.htm >> > >> > Check out participant bios: >> > www.members.re-wrenches.org >> > >> > >> _______________________________________________ >> List sponsored by Home Power magazine >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Options & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out participant bios: >> www.members.re-wrenches.org >> >> > > > -- > Chris Mason > President, Comet Systems Ltd > www.cometenergysystems.com > Cell: 264.235.5670 > Skype: netconcepts > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Options & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > > >
_______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
