superdiy

Hi Jay, Some things I struggled to get hold of when I did my installation (and I have not spotted it in the store yet ) are: Panel mounting hardware DC disconnects / breakers for PV (high voltage) and battery (high current low voltage) PV Fuse holders and fuses DIN / DB mount battery fuse holders and fuses MC4 connectors / splitters / branch connectors / PV combiner boxes Then things like crimp-on lugs for the battery cables and crimping tools for those as well as heat-shrink tubing (red and black) to finish off the ends of the crimped battery cables. Thanks

Spanner in the works.

OK, yes, I'm with you. But as you've said, you need the grid and therefor your solution will not work in off grid installations.

I think we are talking about the same thing here. 1st infini's load connection connected to 2nd infini's grid connection - 2nd infini's load connection connected to the load. Or do you have another idea? I'm referring to the 3KW infinis which only have GRID and LOAD connectors, I'm not sure if you are perhaps referring to the 5KW infinis and if they maybe have more connectors?

I hear you, it all depends exactly how they do the "backing off". Since the grid and load waveforms are synced, it might work, even if the "backing off" is slow.

I've thought about the following idea a while ago - not to parallel the outputs of the 3KW infinis, but rather to cascade them. Since the infini can easily handle twice its rated capacity (and more) while grid power is available I think you might be able to cascade 2 (or more) infinis. First infini: GRID connection either connected to grid or not, depending on grid availability, may be configured to "feedback to grid" or not, PV array connected, battery bank connected. Second infini: GRID connection connected to first infini's LOAD connectors, "feedback to grid" must be DISABLED, load connected to LOAD connectors, PV array connected, battery bank connected. Note: PV arrays and battery banks of 2 infinis NOT IN ANY WAY SHARED or electrically connected. First infini will be able to supply up to 3KW, depending on PV, battery and configuration. Second infini will also be able to supply up to 3KW (again depending on PV, battery and configuration), but furthermore it will also "see" the first infini as the "grid" and add the 3KW from the first infini and be able to supply a load of up to 6KW. Technically you should be able to cascade more infinis in the same way, without having any electrical connection between any battery bank or PV array and with having the "feedback to grid" option DISABLED on all downstream infinis.

My Fluke and BMV are within 0.01V of each other and I calibrated my inverter to as close as possible to that. I've not hooked up my DS scope yet, basically bought it about 4 years ago and only used it once since - it is permanently stored in the vault. But multimeters, inverters as well as oscilloscopes need to be calibrated and not only once, but at certain intervals, sometimes more than once a year depending on the level of accuracy you need. Best way to test voltage is without any current flowing or with as little as possible, because depending on the resistance in the circuit and the amount of current flowing, you will get voltage drops - batteries must definitely not be charging or discharging while you do your measurements - on 25mm2 cables the current drawn by the BMV should not make that much of a difference, but even then, try to measure where the BMV measures or as close as possible to those points - that would be on the battery side of the shunt (for negative) and the point where the lead from the battery positive enters the shunt PC board (positive).

Very true, so who's gonna be the first? Is there anyone on the forum with a LiFePO 4 bank?

Dis 20 jaar @ 30% SOC elke dag! Very impressive.

Ek wil net seker maak jy verstaan reg: 7000 cycles @ 70% DOD - dis is 30% SOC, nie 70% SOC nie! 3600 cycles @ 100% DOD - Dit is 0% SOC! Dit is ongeveer 10 jaar @ 0% SOC elke dag! Dit is baie "impressive"!

Prices look good, especially the Can USB @ R1.00

Second section - Page 1: The Solution: battery balancing The Battery Balancer equalizes the state of charge of two series connected 12V batteries, or of several parallel strings of series connected batteries.

I'm not so sure about that. If you quickly google the topic, you will find many references which warns against/discourages "equalize" charges for gel and AGM batteries. http://shop.pkys.com/Battery-Equalization_ep_44.html Equalizing AGM and other sealed batteries is a bit more tricky. The bubbling electrolyte results in some loss; electrolyte vapor exits the vent caps. However because there is no way to replace the lost electrolyte it is obvious that a different strategy is required. I couldn't find any manufacturer that recommended equalizing Gel batteries. These batteries are highly sensitive to over-charge and equalizing is not going to work for them. However although I did find a manufacturer that definitely did not recommend equalizing their AGM batteries (Trojan) I did find at least one manufacturer (Lifeline) that did recommend equalizing their AGM batteries. Lifeline use the term "Conditioning". They say this should only be done when the battery is showing loss of performance due to having spent extended time in a partial or low state of charge, or that don't often get charged above 90% (Cruisers that never come to the dock please take note!) Lifeline AGM instructions: To apply a conditioning charge, first go through the normal charge cycle to bring the battery to full charge. The conditioning charge should then be applied by charging for 8 hours. At 77°F (25°C), the conditioning voltage should be set at 2.58 VPC (15.5 volts for a 12 volt battery). The conditioning voltage at other temperatures is shown in Table 5-2. By using the temperature compensated conditioning voltage, batteries that are not in controlled temperature environments may be conditioned without bringing them to room temperature. If temperature compensation is not available, it is best to bring the battery as close to room temperature as possible before applying the conditioning charge. http://www.mkbattery.com/content_container.php?page=downloads-and-technical-reference-faq Q: How often should I equalize my MK GEL Batteries? A: MK GEL Batteries never need to be equalized. Here is why: ... http://www.sailnet.com/forums/island-packet/18498-equalizing-agm-batteries.html http://www.trojanbattery.com/tech-support/battery-maintenance/ Equalizing FLOODED BATTERIES ONLY... http://all-about-lead-acid-batteries.capnfatz.com/all-about-lead-acid-batteries/lead-acid-battery-charging/equalizing-charge/ Applying an Equalizing to VRLA batteries. Balancing AGM or Gel batteries with an overcharge is not something a lot of battery manufacturers recommend. This is partly due to the fact that you cannot check the specific gravity of the electrolyte. Further, the nature of the equalization is one where some electrolyte will likely be boiled off. Being sealed batteries, it is impossible to refill the electrolyte with distilled water. While this could be a point of concern about AGM and Gel batteries, it is important to note that the manufacturing deviations between cells (that cause imbalance) are not as great in the VRLA as they are the serviceable flooded lead acid battery. That said, people can and do apply equalizing charges to AGM and Gel batteries. People doing such a thing are either ignorant or have developed a pretty good “feel” for performing this maintenance step.

No, don't set it to 48V. 48V or 12V per battery is in your case a SOC of 50% under no load condition. (The exact voltages differs slightly between battery brands and types etc.) If the inverter needs to supply a load and current is drawn from the batteries the voltage might drop to way below 48V while the SOC might still be much more than 50%. The higher the current drawn from the batteries, the lower the voltage reading will be - that is determined by the internal resistance of the batteries. Once you remove the load from the inverter the battery voltage will rise and stabilize at a higher value, depending on the SOC at that moment. As discussed many times before on this forum and others, the Voltronic inverters use battery voltage to determine the SOC of the battery bank and that is unfortunately not the best method and is very inaccurate. A more accurate method to determine the SOC of the battery bank is to make use of a proper battery monitor and that is why so many people on this forum refer to the Victron battery monitors e.g. the BMV702. To get back to the low DC cut-off voltage, do not change it to 48V, because your inverter will trip under load while the SOC of the battery bank is still fine, rather leave it on 42 V and invest in a proper battery monitor and use the battery monitor to control the load or inverter at a specific SOC. If you feel very uncomfortable with 42V, set it to 44V then, but it might still cut out unnecessarily.

That is a very good price! Just sad that it is orange and not green.

That is standard on all GTIs, it is a required safety feature called anti-islanding. For that very reason I decided to rather go for the hybrid inverter, which would still supply the load and charge the battery bank when the grid fails.

I can't help you with the LDPR or FDGL commands, but QGPMP is "The current max grid output power inquiry" command.

Wow, that is an impressive and very neat installation!

If it was used as a UPS system - not daily cycling.

I assume you meant you'll change the fuses to 12A per set of panels?

I was also a bit uncertain when I read his post, but then I googled and got many hits for 8mm2 solar cable overseas, not sure if he actually have some of it or if he thinks it is 8mm2. The popular sizes in SA are 4mm2 and 6mm2.

I stand corrected.

Keep in mind that the LED globe has a terrible power factor and as @plonkster said, it might draw anything up to about 15VA. Now running that from the GRID is fine, because you pay for 3W, not for 15VA, but if the inverter needs to invert DC to AC and have to drive the 3W lamp, it will actually draw 15W from the DC side. (losses / efficiency ignored). Rather use a pure resistive load when you want to do these tests, e.g. a filament type globe of known wattage. A small one in a sewing machine might be in the region of 15-20W.

That thing will cook everyone close by. Best would be to install it no closer than 1km to the closest human being.

You've posted some text yesterday, I assume from the terminal emulator screen, which included (NAKss and then I told you that that is the inverter's response to tell you that it did not understand the command sent to it - that means that the comms to the inverter is working.