INSTALLATION GUIDE — UPDATED JULY 2026
Already have solar panels but no battery? You are not alone. Here is how to add battery backup to an existing grid-tied solar system — inverter compatibility, outage-resilience sizing, costs, battery brand gotchas, and exactly what to ask your installer.
National load-shedding was not active in July 2026. Local outages and load reduction can still interrupt supply, and future grid conditions can change. If you installed solar-only, your panels normally shut down when the grid fails unless the system includes suitable backup equipment. A compatible battery can keep selected essentials such as lights, WiFi, a television and a fridge running during an outage.
Read our current load-shedding reality check and preparedness guide.
Yes, in most cases. If you already have a hybrid inverter or an inverter with a battery port, adding a battery is straightforward. If you have a string inverter (grid-tied only, no battery support), it is still possible but more involved.
There are three common scenarios:
Best case. Hybrid inverters have built-in battery terminals and BMS communication. Adding a battery is plug-and-play — your installer connects the battery, configures charge/discharge settings, and you are done. Most SA homes with hybrid inverters installed in the last 3 years fall into this category.
Some string inverters (notably Victron, Fronius, and some SMA models) support AC-coupled battery retrofits. An additional inverter-charger is installed alongside your existing system, and the battery connects through it. More expensive than Scenario 1 (adds R10 000–R15 000 for the extra hardware) but still cost-effective compared to a full system replacement.
If your inverter is a simple grid-tied string inverter (common in pre-2022 installations), you cannot simply connect a battery to it. Options: (a) Replace the inverter with a hybrid model — R14 000–R24 000 for the inverter alone, (b) Add an AC-coupled battery system with its own inverter-charger, (c) Install a separate off-grid inverter and battery that charges from the grid (independent of your solar system).
Look at your inverter's label or manual. You need to find:
If you are unsure, take a photo of the inverter label and send it to a PV GreenCard installer for confirmation. Most will check for free as part of a quote.
Size a battery around the essential loads you want to run and the outage duration you want to cover. The scenarios below are planning examples, not a statement that any load-shedding stage is currently active:
| Planning scenario | What you want to run | Indicative battery | Approximate runtime |
|---|---|---|---|
| Short outage | Lights, WiFi, TV, laptop, fridge | 3.6–5.1 kWh | About 4–6 hours* |
| Extended outage | Lights, WiFi, TV, laptop, fridge, security cameras | 5.1–10.2 kWh | About 6–10 hours* |
| Extended outage + comfort | Above + occasional microwave, kettle and small appliances | 10.2–15.4 kWh | About 8–12 hours* |
*Illustrative runtime only. Actual runtime depends on usable battery capacity, inverter losses, battery condition and the appliances running.
One battery is usually not enough for geysers, stoves or pool pumps. Those loads require careful design, load scheduling or a substantially larger system. A 5.1 kWh battery can cover modest essential loads, but an installer should calculate runtime from your measured consumption rather than promise a fixed duration.
Prices as of July 2026 (excluding installation labour, which is typically R1 500–R3 000):
| Battery capacity | Price range (battery only) | Popular models |
|---|---|---|
| 3.6 kWh | R12 000–R16 000 | Pylontech US2000C, Hubble S100 |
| 5.1 kWh | R16 000–R22 000 | Hubble AM-2, Pylontech US3000C, Dyness B3 |
| 10.2 kWh | R32 000–R44 000 | Two 5.1 kWh units in parallel |
| 15.4 kWh | R48 000–R66 000 | Three 5.1 kWh units or larger format |
If your inverter needs replacing because it does not support batteries, add R14 000–R24 000 for a hybrid inverter. If your inverter is AC-coupling compatible (Scenario 2), add R10 000–R15 000 for an additional inverter-charger.
Based on PowerForum discussions and installer feedback, here is what real owners have experienced with the main battery brands sold in South Africa.
Price: R16 000–R22 000 for 5.1 kWh
Pros: Competitive pricing, good availability, CAN/RS485 compatible with SunSynk, Deye, and most hybrid inverters
Cons: Multiple PowerForum users (April–May 2026) reported battery housing bulging on older v1.5 BMS units. Hubble's BMS requests 53.8V from the inverter, but support has denied warranty claims at anything above 53.6V.
⚠ What to do: Ask your installer to confirm the exact charge voltage they will program. Get it in writing on the quote.
Price: R18 000–R25 000 for 3.5 kWh (US3000C)
Pros: Long track record, broad compatibility, well-documented CAN bus protocol
Cons: Smaller usable capacity per unit than Hubble at similar price. Warranty disputes over swollen batteries have been reported. The BMS allows cell voltages up to 3.9V, which some argue reduces LiFePO₄ longevity.
⚠ Cable gotcha: Pylontech uses a specific CAN bus pinout that only uses pins 4 and 5. Off-the-shelf network cables with all 8 pins wired often cause communication failures. See our SunSynk vs Deye cable pinout guide for details.
Price: R15 000–R20 000 for 5.1 kWh
Pros: Generally well-reviewed, good compatibility with SunSynk and Deye. No major failure pattern reported on SA forums as of July 2026.
Cons: Smaller installed base in SA — fewer owners means less data on long-term reliability. Limited SA support network compared to Hubble and Pylontech.
Verdict: Promising but less proven. Check that your local installer has experience with Dyness commissioning.
Price: R22 000–R30 000 for 5.1 kWh (premium tier)
Pros: SA-manufactured. Strong local support in Cape Town and Johannesburg. Good warranty reputation.
Cons: Significantly more expensive than Hubble or Dyness. Lower cycle life spec than some competitors at similar price points.
Verdict: The premium choice. If local support matters most and budget allows, Freedom Won is a safe bet. The price premium is 30–40% over equivalent Hubble/Pylontech packs.
| Brand | 5.1 kWh price | SA support | Forum complaints | Our take |
|---|---|---|---|---|
| Hubble AM-2 | R16 000–R22 000 | Good (national) | Bulging reports, warranty voltage disputes | Good value but verify charge voltage |
| Pylontech | R18 000–R25 000* | Good (national) | Swelling reports, 3.9V BMS concern | Proven but smaller capacity per unit |
| Dyness | R15 000–R20 000 | Limited | Not yet documented | Promising but less data |
| Freedom Won | R22 000–R30 000 | Excellent (SA mfr) | Minimal | Premium choice, strong support |
* Pylontech US3000C is 3.5 kWh, not 5.1 kWh. Two units in parallel = 7.0 kWh for R36 000–R50 000.
Adding a battery to an existing hybrid inverter system takes 2–4 hours for a professional installer. The steps:
After installation: Do a full discharge/recharge cycle within the first week to calibrate the BMS. Most installers recommend doing this every 3 months.
This is the #1 problem reported on PowerForum when adding a battery. If the cable does not have the correct pinout (pins 4 and 5 only for CAN), your inverter and battery will not communicate, and the inverter will not charge or discharge the battery properly. Read our complete cable pinout guide for the full details.
LiFePO₄ batteries perform best between 15°C and 35°C. In a garage that reaches 40°C+ in a Johannesburg summer, battery lifespan drops significantly. If your inverter and battery are in a hot garage, consider:
Adding a battery to an existing registered system may require updating your SSEG registration with your municipality. This is because your system now has storage and potentially changed export behaviour. Ask your installer whether your municipality (City Power, CoCT, Tshwane, Ekurhuleni, etc.) requires notification. Operating with an outdated SSEG registration can technically invalidate your insurance for solar-related claims.
If your inverter was installed 2–3 years ago, its firmware may not have the battery profile for newer models. For example, some early-2024 SunSynk firmware versions do not have a Hubble AM-2 preset. The solution is a firmware update, which typically requires an installer visit (R1 500–R3 000 callout fee). Check with your installer before buying the battery.
Adding a battery means you now have two major investments to track. Local monitoring via SolarAssistant or Home Assistant (R1 500–R3 000 for a Raspberry Pi setup) gives you real-time battery SoC, charge/discharge history, and alerts if something is wrong. It also works during cloud outages (remember the 17 June 2026 Deye Cloud outage).
Not automatically. The inverter and battery must speak the same BMS protocol. SunSynk and Deye use CAN bus. Most lithium batteries (Hubble, Pylontech, Dyness, Freedom Won) support CAN, but the specific voltage and charge parameters need to match. Your installer must configure the inverter's battery profile to match the battery's BMS requirements. Getting the charge voltage wrong by 0.2V can cause warranty disputes — especially with Hubble.
There is no universal minimum. Start with the watts used by your essential circuits and the number of hours you want to cover. A 5.1 kWh battery can support modest essential loads, while heavier or longer use may justify 10.2 kWh or more. Ask the installer for a written runtime calculation that includes usable capacity and inverter losses.
Three options: (1) Replace the inverter with a hybrid — most expensive but cleanest solution. (2) Add an AC-coupled battery with its own inverter-charger — works with any grid-tie inverter but costs R10 000–R15 000 extra for the additional hardware. (3) Install a separate off-grid inverter and battery that charges from the grid — independent of your solar panels, your solar continues exporting to the grid while the battery runs your essentials. Option 2 or 3 is usually better value than replacing an otherwise functional grid-tie inverter.
Yes — potentially. If you currently export excess solar to the grid, adding a battery may reduce exports because excess energy charges the battery first. Compare your current import tariff, export credit, battery efficiency and expected cycle life before deciding; tariff values vary by municipality and change over time.
Labour is typically R1 500–R3 000 for a straightforward hybrid inverter + battery connection (2–4 hours work). If a firmware update is needed or the installation requires new cabling/breakers, add R500–R1 500. If the inverter needs replacing, budget R14 000–R24 000 for the inverter alone plus R3 000–R6 000 for installation labour.
Technically, yes — any modification to an electrical installation requires an updated Certificate of Compliance under SANS 10142-1. In practice, some municipalities (City Power) do not require re-registration for a battery-only addition if the inverter stays the same. Others (City of Cape Town) do. Ask your installer to check your municipality's current rules and issue an updated CoC.
Get matched with PV GreenCard-accredited installers who can check your inverter, recommend the right battery, and handle the installation — including all paperwork and SSEG updates.