Alternator for Mazda Miata NB

Completely new items

Maruha’s alternator is made of completely new items.
Not even the link-parts are rebuilt ones.
It has a stable efficiency and we provide it with 1-year guarantee.
You can use it without any worries.
Its capacity is the same as the genuine one’s – 70A.

The price

The new genuine alternator’s price is quite high (around $700). Another option are the rebuilt parts, in other words overhauled second-hand parts but even in this case the price is around $500.

Maruha’s alternator’s price is very reasonable.
We also recommend the simultaneous exchange of the battery.

The alternator is an alternating-current generator. Usually, the alternating current is rectificated by an inner IC regulator.

The IC regulator

When the engine revolution is high even if the generated electric power is more than needed, the IC regulator helps it not to become overcharged.
However, in the case of NB the IC regulator isn’t placed inside but in the PCM (computer).
This is the point where it differs from NA.
This means that the alternator for NB must not be set up in NA vehicles.
If you use it in NA without the regulator, the generated electric power will rise without stopping and the wires and PCM (ECU) will be seriously damaged. For this reason it is very dangerous.

About the battery

Under general driving conditions the alternator manages the generated electric power.
The battery is necessary mainly at the time of cranking when the engine starts and during idling on low rpm.

The alternator’s function is not only operating the car’s electrical components but also charging the battery with the remaining electric power.

Alternator troubles

If the alternator breaks down the generated electricity is not enough and the car just stops.
When the power generation deteriorates the headlights might start to dim, the wiper slows down and the engine’s performance becomes bad. Finally the engine stops and it becomes impossible to temporarily fix it until you get to a service shop. For this reason it is important to understand how big the alternator’s role is.


Maruha Motors Co., Ltd.
Ushizuma 2095-6, Aoi-Ward
421- 2106 Shizuoka city, Shizuoka prefecture
TEL: 0081-54-294-0076
FAX: 0081-54-294-1312