INSTALLATION GUIDE — UPDATED SEPTEMBER 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 September 2026, and Eskom has gone more than 470 days without implementing it. 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 current failure pattern is evident in the mid-2026 forum threads we reviewed.
Cons: Smaller installed base in SA — fewer owners means less data on long-term reliability. Limited SA support network compared to Hubble and Pylontech.
⚠ Reported: individual 2022–2023 threads describe a B3 failing after about two years with the warranty claim rejected, and a B4874 that showed full charge but collapsed under load. These are isolated owner reports, not a pattern we can confirm — but read our notes on SoC problems and warranty scope before buying.
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 — the main argument for the price premium.
Cons: Significantly more expensive than Hubble or Dyness. Lower cycle life spec than some competitors at similar price points.
⚠ Reported: a thread from around 2023 describes a Lite Home 20/16 giving intermittent sudden SoC drops from new, and another a unit returned for diagnostics with a faulty BMS and most cells affected. Individual reports only — note the warranty-scope questions in our SoC and warranty section.
Verdict: The premium choice, mainly for local support and accountability. 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 | Isolated 2022–23 threads (failure, warranty) | Promising but less proven |
| Freedom Won | R22 000–R30 000 | Excellent (SA mfr) | Isolated 2023 threads (SoC drop, BMS) | Premium; verify warranty scope |
* 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).
A common question: can I add one more battery in a few years to get more backup time? Sometimes, but only within the manufacturer's rules. Most battery manuals explicitly prohibit mixing batteries from different manufacturers, different types or models, or putting old and new units together in one bank — the Dyness B3 manual (file version 20231114-V2-EN) states this in its safety precautions, and other brands publish their own conditions. Units of different age or condition can behave differently under charge and discharge, and the bank's BMS is designed around the units it was specified for.
Before buying a second unit, get written confirmation from the battery supplier — not from a salesperson — that your exact combination is approved: same model, compatible firmware or BMS version, and the maximum number of units that may be paralleled. The SunSynk SUN-BATT-5.32 manual, for example, allows a maximum of eight units in parallel and requires all parallel power cables to be the same length, with master and slave IDs assigned automatically. Check your own model's parallel limit rather than assuming you can keep adding.
Then confirm the rest of the system can carry the bigger bank: your inverter's charge and discharge current limits, the rating of the DC protection and cabling, and how the warranty applies once the units share one bank. Ask for that in writing before you pay. If your existing battery is already several years old, price a replacement bank against adding one new unit to the old one, and size the bank for the loads you actually need to cover — see our panels versus battery upgrade comparison and the solar FAQ.
If your app says 100% and the lights die 20 minutes later, the reading is usually the problem — not the stored energy. In a lithium (LiFePO₄) home battery the state-of-charge (SoC) figure in your inverter app is an estimate the battery's BMS calculates from voltage and current. It can drift away from the energy actually available.
This is a recognised class of problem in South Africa, and it is not limited to one brand. Across PowerForum owner threads dating from 2022, the same symptom types recur:
Evidence level: multiple independent owner threads describing a similar symptom type across different brands — a pattern, not a confirmed defect. Some threads are undated and outcomes differ case by case. Treat them as questions to put to your installer, not as a verdict on any brand.
Warranty claims are decided on evidence, and the owners whose claims were questioned most often had no record of the failure behaviour.
A PowerForum thread on Hubble AM-5 warranty, DoD and SoH notes that the advertised 10-year warranty applies to the battery cells, not the BMS, circuits or sensors. A separate thread reports a Dyness B3 that failed after about two years and two months with the warranty claim rejected, on a bank the owner described as lightly used. Another reports a Freedom Won pack returned for diagnostics with a faulty BMS and most cells affected.
Those are individual owner reports, not a statement about how every warranty claim is handled. What they do show is why the scope and conditions of your warranty belong on the quote, in writing, before you pay — including who decides a claim, what void it, and who pays return freight.
LiFePO₄ home batteries store a large amount of energy. Cell balancing, BMS replacement and internal inspection are work for the manufacturer or a qualified installer. If you see bulging, swelling, heat or an unusual smell, isolate the system as described in the battery manual and call a professional — do not keep cycling it.
Working through an installer problem rather than a battery problem? Our installer red flags checklist covers the quote, registration and CoC points that matter. Deciding where the next rand goes? Compare panels versus battery. For cabling specifically, the CAN bus pinout guide explains the most common comms trap, and the solar FAQ answers the rest.
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.
Log evidence before you change settings: export a week of SoC and load history, note exactly when the load dropped and what was running, and write down any inverter error code. Then ask your installer to (1) confirm the BMS communication is live rather than voltage-estimated, (2) read individual cell voltages and reported SoH, and (3) verify the programmed charge voltage and discharge cut-off against your battery's datasheet. A full charge → discharge → recharge cycle is the usual first fix for calibration drift, but a sudden, repeatable drop usually points to cell imbalance or a comms fault and needs a technician. Work through the six-point checklist above.
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.