One fir the electrical bods
One fir the electrical bods
Author
Discussion

silverfoxcc

Original Poster:

8,078 posts

166 months

Thursday 3rd April 2025
quotequote all
Have a 12v Halfords charger. what volttage would i expect to see on a tester when i connect the two outlet wires....

TIA

200Plus Club

12,800 posts

299 months

Thursday 3rd April 2025
quotequote all
If you mean across the battery terminals it will start at about 12.9v and then creep up probably to about 13.8v - 14.4v depending upon the charger and battery type
When you remove the charger the battery terminals will show above 13v initially then drop back to perhaps 12.6v-12.8v ideally if its nearly fully charged.

spikeyhead

19,512 posts

218 months

Thursday 3rd April 2025
quotequote all
What are you connecting the wires to?

OldGermanHeaps

4,861 posts

199 months

Thursday 3rd April 2025
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Most new ones? Nothing until it senses a battery connected

GreenV8S

30,996 posts

305 months

Thursday 3rd April 2025
quotequote all
What sort of tester, connected how?

If you connect the two outlet wires to each other, that isn't going to show anything useful.

Zad

12,934 posts

257 months

Sunday 6th April 2025
quotequote all
If it is an electronic "smart" charger, then they often refuse to start charging unless they detect a certain minimum voltage on the battery. This means that on a REALLY flat battery they will refuse to charge. The way around this is to briefly put a battery booster pack on and fool the charger into thinking it has 12V in the battery.