14-08-2026
Time-of-Day (TOD) tariffs charge a higher rate for electricity consumed during defined peak hours. A hybrid inverter with TOD bypass detects the peak window and automatically shifts the load onto the battery, so you stop importing at the expensive rate without touching a switch. Most hybrid inverters need a manual mode change or an external controller to do the same thing.
What is a TOD tariff?
A Time-of-Day tariff means the price of a unit of electricity depends on when you consume it. Instead of one flat rate, the day is split into windows - typically a lower-priced solar window, a normal window, and a higher-priced peak window. Applicability, peak-window timings and rates are set state by state by the respective electricity regulatory commission, so the only reliable source for your own site is the tariff order that applies to your connection and consumer category. Check it before you size anything.
Why TOD matters if you have solar
Solar generates during the day. Peak tariff windows commonly fall in the evening, after generation has dropped. So a solar system without storage often produces its cheapest power when electricity is already cheap, and imports at the highest rate exactly when it is most expensive.
Storage fixes the timing problem, but only if something tells the system when to use it.
What is TOD bypass?
TOD bypass is the inverter doing that automatically. On selected Devsol hybrid inverter models, when the TOD peak window begins, the system automatically shifts the load to battery. Grid import during the peak window stops, and normal operation resumes when the window ends.
| Approach | How the switch happens | Reliability |
|---|---|---|
| Manual mode change | User changes inverter mode twice a day | Depends on the user remembering |
| External timer or controller | Additional hardware, separately configured | Extra cost and an extra failure point |
| TOD bypass, built in | Inverter switches on the window automatically | No user action, no extra hardware |
How to set up TOD bypass
- Confirm the TOD windows that apply to your connection from your DISCOM tariff order.
- Size the battery bank to carry your peak-window load for the full window duration.
- Set the reserve state of charge so a portion of the battery is always held back for outage backup, separate from daily TOD cycling.
- Set the low-voltage cut-off to protect battery life.
- Enable TOD bypass on the inverter and enter the window timings.
All of these settings are user-programmable on Devsol hybrid inverters. Selected models are supplied with a touch-screen display, which makes on-site configuration faster.
Sizing the battery for TOD
The battery does not need to carry your whole day. It needs to carry the peak window, plus whatever reserve you want kept for outages.
Peak-window load (kW) x window duration (hours) = usable energy needed (kWh). Add your outage reserve on top of that number, not inside it.
This is why programmable reserve state of charge matters. Without it, a battery sized for TOD cycling will routinely be empty when an unplanned outage arrives.
Which Devsol models support TOD bypass?
TOD bypass is available on selected models. Ask for the current model list before ordering, and confirm it in writing on the quotation.
Across the range: models from 2 kW to 5 kW run on a 24 V battery bank and support battery-free operation; models from 6 kW to 15 kW run on a 48 V battery bank and can be paralleled, including single-phase to three-phase configuration. Any brand of lithium (LiFePO4) or lead-acid battery can be connected, with programmable low-voltage cut-off and a reserve state-of-charge held back for backup.
See also: best hybrid inverter in India and on-grid vs off-grid vs hybrid.
Frequently asked questions
What is TOD bypass in a solar inverter?
It is an automatic function that shifts the load from grid to battery when the Time-of-Day peak tariff window begins, so no electricity is imported at the peak rate.
Do all hybrid inverters handle TOD tariffs?
No. Most need a manual mode change or an external controller. TOD bypass as a built-in automatic function is available on selected Devsol hybrid inverter models.
How big should the battery be for TOD?
Size it to carry the peak-window load for the full window duration, then add your outage reserve on top, and set a reserve state of charge so the two do not overlap.
Can I use TOD bypass with lead-acid batteries?
Yes. Devsol hybrid inverters work with lead-acid as well as any brand of lithium (LiFePO4) battery, though cycling economics differ between the two.