Motive

Enoki bought a battery holder for 1A ammeter power supply as shown in Photo1.

Photo1 Ammeter power supply

But the actual one was poor.

Summary

Checking the battery holder drawing, Enoki found that the design diameter was too little to hold AA battery.

Takachi SN3-4

Takachi enclosure is popular in Japan.

No circular tolerance
SN3-4 contains 4 AA batteries. But one has to put 2 outside batteries at first. Otherwise one cannot put them too tight.

Electrode eccentricity
The positive electrode center is eccentric from battery positive electrode.

Drawing
Takachi publishes the battery holder drawing^[1].

Method

Enoki downloaded the DXF file and cheked it by JWCAD.

Allowable battery diameter

Result

The drawing battery diameter design is too little 13.3 mm as shown in Figure1.

Because the actual battery diameter was 14.3 mm by vernier caliper.

Conclusion

Enoki thinks that the battery holder electrode cannot contact for a long continuous time. If the ammeter display doesn't work normal, one may reload the batteries.

Why Takachi did approve the poor battery holder?

Ref

[1] https://www.takachi-el.co.jp/products/SN_MP_BH