WHITE'S Surfmaster PI Schematics

[ApBerg]

Send you a PM in the next day's.....

TIME Time Time ....were did it go ?

Best regards.

Ap

[silverdog]

could I please have a copy of your pcb as well ? sprint layout is fine

[detectorman]

Hello!

I would like to put a low battery signal circuit in my Surfmaster PI. What is the minimum voltage when the MD works well, but the circuit must have to give a signal before the MD's accumulator discharge?
Somebody can post to me a right circuit?
Thanks and sorry for my bad english.

[Qiaozhi]

Hello!

I would like to put a low battery signal circuit in my Surfmaster PI. What is the minimum voltage when the MD works well, but the circuit must have to give a signal before the MD's accumulator discharge?
Somebody can post to me a right circuit?
Thanks and sorry for my bad english.

Difficult to say by looking at the schematic. There is a linear 5V regulator (78L05) but the transmitter runs directly from the 12V battery. I would suggest connecting the detector to a bench power supply and turning down the voltage until it stops working properly. Then measure the output from the power supply.

[mikebg]

Hello!

I would like to put a low battery signal circuit in my Surfmaster PI. What is the minimum voltage when the MD works well, but the circuit must have to give a signal before the MD's accumulator discharge?

1. If your battery consists of connected in series NiMH or NiCd cells, to prolong their life calculate discharge alert at 1.1V pro cell.
2. If your circuit diagram uses stabilized voltage by 78L05, it stops to regulate when input voltage is below 7V. You can use alert at 7V only if batteries are not rechargeable, and if the test shows that circuit is operable near to 7V.

[detectorman]

Hello Qiaozhi & Mikebg!

Thanks for the fast replies. I will try both!

best regards
detectorman

[kt315]

Hello!

I would like to put a low battery signal circuit in my Surfmaster PI. What is the minimum voltage when the MD works well, but the circuit must have to give a signal before the MD's accumulator discharge?
Somebody can post to me a right circuit?
Thanks and sorry for my bad english.

you can take batt checking schematic of Carl moded Tesoro Bandido. also I put Anker's batt check one to a list. thinking you can use IC like LM3915 or similar one.

[kt315]

..

[mikebg]

Discharge alert for lead-acid battery

To Detectorman.
Addition to my post #20.
LOW BAT alert for discharge of LEAD-ACID batteries.
For design purpose is preferable to calculate minimal discharge voltage 1.8V pro lead-acid cell.
That means if your battery is nominal 6V (3 cells), the alert should be activated if voltage is below 5.4V.
For 12V lead acid battery, the alert threshold is 10.8V.