The Air Flow Meter
In a hybrid vehicle the single most important sensor is the Air Flow Meter. We cannot overstress how important this sensor is.
In the Generation 1 Prius 54 Kwh of power is provided by the internal combustion engine. If the
air flow meter is not working at 100% this full amount of power is never available. In a standard vehicle with 90 - 110 Kwh power you will not notice much difference, however in a hybrid the loss in power is compensated by the electric motor. This drains the HEV battery and usually leaves the HEV battery undercharged, leading to early battery failure.
A new HEV battery can handle this adequately but a reconditioned HEV battery with reduced capacity would struggle We have put in a perfectly good HEV battery is a vehicle with a faulty air flow meter and noticed the battery going down to yellow very quickly.
The next most important component of a hybrid vehicle is the HEV battery. Assuming that all cells are working the battery always gives the full voltage and current to the electric motor. However how long it can maintain this depends on the state of the battery.
So the difference between a reconditioned HEV battery and a new HEV battery is the duration that the battery can maintain full power to the electric motor. As long as it can provide this power the battery will not out the triangle error.
However because the ICE motor charges the HEV battery the ICE motor is the more important component in this power chain. Keeping the ICE engine working at peak efficiency will keep the HEV battery healthy as well.
How to maintain the ICE motor.
Fortunately there is not really much to do to keep the ICE working at 100%.
1. The Air Flow Meter - If there is lack of power on acceleration clean or change
2. The Spark plugs - Change every 10,000 kms
3) Change motor oil when dirty.
4) Top up coolants in both reservoir
Loss in compression in the engine is a normal feature in standard vehicles. However in the hybrid vehicle even after clocking uo 150,000 Kms there is no appreciable loss in compression. This is because the engine does not run all the time and it works at much lower RPM. ( Notice that the motor oil is seldom black, and there is usually no oily deposits on the spark plugs. )