CDL

Hi guys, I have a Victron Quattro that is grid connected. Even with the settings correctly configured (ESS), I'm still getting a bit of reverse flow into the grid – about 26 kWh per month on average. Besides the fact that it is technically illegal, the way our municipal meter works, the flow is calculated as being municipal consumption. So we pay for the power that goes back. What is the most suitable and effective way for me to prevent reverse flow? I read about contactors, diodes… And where would I probably best source it online (South Africa)? Any help is much appreciated. Best, CDL

Okay, so I had a look at some of the data again. It seems to happen when the batteries are full. A large load is switched on (let us say for example a draw of -70 A) and you see a sudden drop in the battery voltage at the same time. Say from 54.49 V down to 52.88 V. Then there's a sudden reversal in battery current. Goes from -70 A up to +14 A. Voltage then simultaneously bounces up to say 56.8 V (sometimes as high as 58 V) and then there's a sudden drop almost immediately after that down to 55.5. So it seems to be something along the lines of the charge controller overshooting. This is on my Victron system with the same battery array as my friend is using with his Axpert. So I guess something similar may be happening in that context as well.

H Coulomb, thank you so much for this. I will relay the info.

Thank you so very much Coulomb. These are LifePo4 batteries - but I see on the link you posted that this can occur with both battery types. This is a friend's installation. I see on my own Victron installation, they battery voltage will sometimes throw up a very brief spike on a hot day when something switches on. It looks like a kind of "voltage bounce". And sometimes will go as high as 59.87 V. I think the same batteries combined with the Axpert may also be "bouncing" and causing the inverters to throw up an error.

Hi guys, We have a series of Axpert 5000VA inverters. On a hot day, we have a situation where sometimes something switches on and then the inverters throw up a 03 (high battery voltage) error and the system switches off for about 30 seconds and then back on. Battery importer has been in and checked BMS parameters, et cetera. Problem persists. I suspect possible voltage bounce on the batteries but am not certain. Anyone got any ideas? Thanks in advance.

The MPPTS are rated at a maximum of 70A on the photovoltaic side and 100A on the battery side. There are two of them. The panels are set up East/West (a bit below 5 kW in each direction), which works well in this application because it means we start generating earlier and we keep generating later and we have a more even power generation curve. Mostly, the batteries don't receive more than between 60 and 80 A (in total in respect of both of them together thus 30 and 40 each); a lot of the time it is a bit lower as well. It all depends upon solar conditions and how much is being used by direct consumption within the household. But occasionally it does rise above 80 A and sometimes even to over 100 A (more common in midsummer than this time of year). Absorption on the batteries runs at around 55.6 V and float at around 54.6 V. When the weather is good, the batteries tend to get to absorption around late morning/lunchtime. So they will usually spend an hour or two in float before we start to move into late afternoon/early evening and the power generation drops off. Overnight, with normal usage the batteries tend to drop down to about 52 V. I pretty much only run the heat pump during the day and get the water very hot (11 AM to 3 PM); I don't often need to run it in the early hours of the morning to heated up again but if I do, the batteries usually have enough capacity to handle it and we will go down to around 50 V. Obviously, this is the rough rule of thumb and it is variable from time to time, depending upon who is using what when, et cetera. Most days the household consumes around 30 kWh produced by the solar panels; a little over half of that goes to direct household consumption and the rest goes to recharging the batteries. Provided the weather is good, all of that is generated by the panels. We don't need Eskom at all when the weather is reasonable. Even if it is a little bit overcast, we pretty much get away with what we need from the panels.

About 9.5kw nominal rating of panels - on a good day will push 8.5kw. MPPTs are Victron. Yes re the batteries. One set is 180ah the other 200ah. Actual, not rated.

The system is 48V. The distributor says doubling the charge rate is fine because the capacity is double.

Thank you. Following your advice I spoke to them a few minutes back. They have suggested that I can use 120 amp as the charge current maximum for charging the batteries through all three stages in the normal course of events. They do suggest though that if I want to balance the batteries (if they go out of balance at any point in time) that I should then use 60 A maximum to charge them and then float them for a period of about 24 hours, which should then bring them back into balance. Apparently that this should not be required very often at all.

Thank you very much 20VT – much appreciated. That helps.

Actually, I had to go and look for them after your post above 🙈 (lekker dom) and then went to find them at the distributor's website. See attached. I see the maximum charge rate that is recommended is 65 A. That is for one battery array. Presumably if I have two battery arrays, then presumably I should set the maximum charge rate on the inverter to 130A? Is the logic correct? Revov-LFP200C48VN-C.pdf

Hi guys, I have a Victron Quattro mated to Canadian Solar panels and some second life LifePo4 batteries with their own BMS' supplied with the batteries. The batteries are in two banks of a nominal 180 amp hours each (one bank is in fact about 200 amp hours), connected in parallel. Using the Victron Remote Control interface, DVCC allows one to set a maximum charge current. I am getting conflicting advice as to whether a maximum charge current should be used with these batteries and if so, what that maximum charge current should be. I have been told anything between 120 A and 60 A. Yet reading online, it seems that there is no need to limit the charge current. Is anybody able to provide any sensible input or advice here? Many thanks in advance. The other question that I had is whether it is possible to set the cut off voltage (low-voltage warning) for the battery arrays using the Victron Remote Control interface? I have looked through all the settings, including DVCC and ESS and cannot find anything. I am wondering whether I am looking in the wrong place… If anyone knows where I should be looking, I would appreciate the input. Hope everyone is surviving the lockdown!

Many thanks guys – only logged on today again so didn't see these previously. I have "without batterylife" option, so that factor doesn't apply.

Thank you Plonkster. Your assumption that I am using ESS is correct. I have noted that now that the batteries are at 57% and I have put the grid back on, it is doing exactly as you say. I am not sure why it was not doing this once the batteries got to 47% as the threshold for them is set at 45%. Will keep an eye on it and see what happens. Cheers and many thanks again! 👍

Hi guys, I have a Victron Quattro 10 kVA inverter combined with solar panels and battery array. I have a query as to how I can configure the application of the incoming solar power. I let the system use the batteries down to 45% overnight, even though grid is available (the remaining 45% is "saved" for grid outage situations, the 55% usually being sufficient to carry us through the night). What happens is that in the morning the incoming solar power normally exceeds the AC loads. For example, as I write this, we have incoming photovoltaic of 2 kW and we have AC loads of 474 W. What is happening though is that the system is allocating the full incoming 2 kilowatt to charging the batteries and is drawing the 474 watts of AC load off the grid. This doesn't make sense because a little later in the day we will have excess photovoltaic power; in other words, later in the day the batteries will be fully charged and we will have more incoming photovoltaic power than we have AC loads. In other words, we will have solar power going to waste. It makes more sense to have the incoming solar power in the morning first service the AC loads and then use the balance to charge the batteries. This way we will be able to pretty much service the AC loads through the day and also across the course of the day get the batteries fully charged. I know this because I used to do this with the previous Axpert based system I had. The simple solution – which I am using temporarily – is to simply switch the grid off, which then forces the system to 1st allocate photovoltaic power to the AC loads and the balance to the batteries but this is a bit of dumb way of doing things if the system can be configured differently. If anyone knows how this configuration can be changed and which element of the Remote Console settings need to be altered, I would appreciate your advice and input. Thanks in advance.