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

silverfoxcc

Original Poster:

8,115 posts

168 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

12,961 posts

301 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

19,709 posts

220 months

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

OldGermanHeaps

4,959 posts

201 months

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

GreenV8S

30,999 posts

307 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

12,946 posts

259 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.