The inverter was a glorious device when it was introduced to the Nigerian market. It allowed people to store power from NEPA/PHCN when it was available and released it when the power went out. This worked well for a while and suddenly after years batteries started to die prematurely. What happened to cause the change?
The inverter as sold in Nigeria is a UPS with a large battery. They are designed to be a temporary back up for when power failed and returned not to too long after. (Just like you have with your desk top computers.) They are designed with small simple battery chargers because they were not designed to recharge overly discharged batteries. They also did not have proper low battery cut off for the same reason.
The power situation in Nigeria did not improve, it got worse. The inverter was now being counted on to provide power for longer periods of time. The batteries were now constantly over discharged and the tiny chargers could not charge them fast enough. (lead acid batteries don’t like to be discharged below 50%) Constant deep discharge and a poor charging regime causes sulfation. Sulfation is the build up of sulfates on the battery plates and on the positive and negative terminals of the battery. The build up reduces the flow of electricity from the positive and negative plates. Sulfation reduces the capacity of the battery. Your battery that once lasted 8 to 10 hours is now dead after 1 hour. Very severe sulfation can cause shorting of the plates and in extreme case bulging of the battery case.
How do you prevent premature death?
- Buy good quality batteries. They resist sulphation better.
- Avoid deep discharges. Your 24 V system should not be discharged below 24 V. Fastest way to kill them is by over discharging them
- Fully charge your batteries every day with a smart charger. They don’t like to be partially charged. A smart battery charger has three stages. Bulk, Absorption and Float phase. This helps the plates shed sulphates.
- If your finances allow get a good quality inverter. Adding solar power with a good charge controller is another way to get your battery properly charged while saving on fuel.
Try these steps and your batteries will last for as long as they were projected to last.