Fuse for alarm horn?

[The_Laird]

Ah, second part of the above might indicate an alternator issue; mine’s at about 13.5 volts. And, if I’m only at 1.2 amps without the modules shut down, that doesn’t look like a big drain. What do you think?

[ainarssems]

13.5V at battery is probably OK, it is higher than battery can provide on it's own so alternator is pushing some juice in battery. The voltage will depend on what alternator is supplying, voltage drop in the wiring, charge level of battery and any additional loads like fans or lights. It's hard to say what is acceptable drain while car is still awake. Once everything goes to sleep I would expect drain to be in the 0.05-0.2A range.

[The_Laird]

Well, with the weather being better, I tried the ‘fooling the car that it’s locked’ approach and then left it for about 30 minutes. The test across the negative terminal and cable then read about 1.4 amps on initial connection, but dropped quickly (no more than a few seconds) to 0.4 amps where it stabilised. I put in a new battery and will test it again later today to see if it lost any charge overnight.

[ainarssems]

0.4A is too high. On a 90 Ah battery that would be 225 hours or 9.4 days to completely discharge battery, considering that it's not recommended to discharge lead-acid batteries below 50%, you would need to charge it or drive at least every 4-5 days.