gooseberry

I have a property I'm going to rent out and then probably live in myself after a few years. I have installed 3.6kWp of panels there and I want to offset my capital layout by having the tenant use a prepaid submeter (see Recharger.co.za) to pay for their usage. In simple terms, I then get the difference between the municipal meter reading and the total electricity used. This is all very simple to do with a grid tied setup, or with a hybrid that's running without a battery. I do lean towards getting a hybrid because of the flexibility it provides. If the tenant wants a loadshedding/backup solution I can add a battery. I could even set it up for self-consumption at night and pay back the battery over time. The issue then becomes where do I put my submeter? As soon as I add a battery, if the meter is on the grid side it will flow in reverse when the grid charges the battery or powers the backup loads. If I put it on the backup loads, all the non-essential load usage is not metered. If I were to switch the non-essential loads to the Aux port (Sunsynk) can the submeter measure two conductors at the same time? Will a clamp work if you put it around both? The alternative is to go grid tied and then add a UPS inverter. This will make self-consumption tricky though (for that you want to be sure you're using excess PV to charge the batteries) so you won't get the full benefit. When I move in myself and remove the submeter I will curse it and wish I just had a hybrid. Which option would you go with?

Makes sense now!

Ok so this is lame. Someone showed me a screenshot from their Goodwe ES which blends PV and grid for over 9kW, even though itself can generate only 4.6kW. They've done up to 13kW no problem (on the non-essentials loads). Are you saying the 5kW Sunsynk can't do this?

Wait. So the Sunsynk can't deliver more than 35A for grid and solar combined? So if you have some large loads you need to make sure some are not connected to the inverter at all, not even on Non Essential, in case they're all on at the same time? If the inverter shuts down if the 35A is exceeded, will I be without power completely? Does the same apply with string inverters? I see the 4.6kW Solis 4G has a Max Output Current of 21A? I always thought that larger loads would just be supplemented by the grid, but if my load was 25A what would happen? Would I lose power?

@recre8can you confirm your issue has been fixed? I'm busy deciding between the Deye and the Sunsynk, would you still go for the Sunsynk over the Deye despite the R3k difference? And can you please tell me what current clamps/wifi modules/earth bonding relays you had to get extra?

Awesome, so looks like the Sunsynk is back in the game. I may just go for that then seeing as there are so many of them out there. That Solis uses normal 48V batteries and are compatible with Pylontech, Dyness, BYD, Freedom Won etc.

Also following with interest. The current clipping issue is why I'm considering th Solis RHI hybrid instead.

I'm deciding between the same but leaning towards the Solis RHI-6K 48ES-5G hybrid. The reason is the 9.9A limit on the 5kw Sunsynk per MPPT which is below that of the larger panels. Another option has popped up and that is the Sofar HYD 6000 ES. And then, a bit more expensive the Goodwe and the larger Sunsynk. Seems there are a lot of choices at the moment. I'm leaning towards the Solis RHI though, Solis just looks legit and has a large international footprint.

The MPPT seems to be designed for 2 60 cell panels in series. They go up to about 340W each, which will be fine, your MPPT will just limit the output power to 600W.

Thanks! I think I'll just go with the manual switch for now. And perhaps at first only connect to the Solis for getting signoff then add the switch and connection to the Axpert. The Solis won't power the geyser alone as is but I can probably replace the element with a 2kW one, otherwise just it will just pull a bit from the grid too.

I can't. The batteries are all in series already. 4x 6V 200ah batteries

yes

No, they are 6V batteries.

I only have a 200ah 24V lead acid bank at the moment. I'm not aware of any 24V Hybrid inverters and don't want to buy more lead acid.

I would need a new inverter and battery (R45k) vs < R10k for this solution

Haha no that's just the negative... it's been a while since drawing circuits. Perhaps instead of doing something so fancy I can just use 2 of these https://thepowerstore.co.za/products/k-n-dual-string-dc-switch-disconnector-25a-220v-11a-460v-per-string and switch manually. Would just need to make sure that you switch both off before switching over.

I want to be able to power non-essential loads like the geyser from the Solis. I think my Axpert and batteries are too small to do AC coupling safely and I doubt the Axpert supports frequency shifting.

No they're about R17k nowadays. Also consider the HOSELECT 24V battery if the Pylontech is too expensive. You may need a BMV/ICC though to determine state of charge. 900W of panels should be enough.

I'm planning on getting a Solis 4G single string grid tied inverter (Probably the 2kW model) and 6x345W JA Solar 60-cell panels. I plan on wiring the panels 3S2P but connect the two strings in series before going into the Solis. I’ll use my current Axpert 3kVA MKS Plus as a backup/off-grid inverter. If Eskom fails I plan to disconnect the PV from the Solis and wire them in parallel to the MPPT on my Axpert to keep the batteries charged. When the grid comes back, I just switch the PV back to the Solis. Can this work? See the attached diagram. I'm thinking of using Solid State Relays as the switches (something like this) and control it possibly using the ICC Raspberry Pi , which should be able to detect a grid presence on the AC in of the inverter. I'm under Stellenbosch municipality but getting power directly from Eskom, if that has any bearing on the COC/SSEG registration. Any thoughts?

By the way, is this your trolley? I see they specify deep cycle batteries only but it's interesting that they said you can use LifePO4. Do you have any information on the LifePO4 battery they offer? Asking, because I know someone with the same trolley whose batteries may be damaged. Someone put the unit on its side on the back of a bakkie and the batteries shorted. 🙈 https://ecodepot.co.za/products/smart-power-sps-1000-battery-backup-power-supply-with-solar-connector-1000w-batteries-not-included-1

+1 for bluenova, also a good option

Hi Racer It's likely you have a 24V system (2 12V batteries in series) while the US2000 is a 48V bank. You can look at https://lithiumbatteriessa.co.za/collections/frontpage/products/24v-120ah-3kwh-lifepo4-wall-mount-solar-ups-battery?variant=35354510950567 either get that or buy the cells and BMS listed separately and build it into your trolley. Just check if you can adjust the charging voltages to what Bain recommends on your system.

Is the inverter also broken? Can't you take the batteries out and replace with a DIY lithium pack?

I'm looking for a 150-200l low pressure evacuated tube thermosiphoning solar geyser with no electrical element in the Overstrand region. This is to be used in an off-grid setting to reduce usage of the gas geyser. We plan to manually open and close a valve feeding it depending on the weather. There are some suppliers online but all seem to be based up north and I'd like to avoid large shipping costs. Any in the Western Cape or alternatively, which of these would you recommend? https://shop.thesunpays.co.za/products/low-pressure-150l-solar-geyser-with-water-level-control-2year-guarantee https://solarbackup.co.za/product/solar-geyser/ http://www.sosolar.co.za/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=137&virtuemart_category_id=18&Itemid=623

You don't want to be running off only PV with no batteries or grid to "smooth" out the output. Not even sure if it's possible with the VMIII. Any passing clouds or shadows could interrupt your power and having this happen constantly won't be good for the inverter or the loads. Off-grid == batteries. What makes more sense to me is leaving the swimming pool, geyser, borehole etc on grid and going off-grid (with battery backup) for your normal household loads. That is if hybrid or grid tied isn't an option. Not sure I understand the reasons why not, as long as you don't feed back why can't you keep your prepaid meter?