Old cars. Old Wiring. This Innova "Battery and Charging System Monitor" saved my butt again.
Almost every time I start my 1987 Vanagon I plug in this voltmeter, and watch the voltage drop as I start the car. It goes right into the cigarette lighter plug. I watch to make sure the battery doesn't drop below a healthy level while starting. 10.5 is about as low as it should read.
Earlier this week, returning to my bus with a bag full of groceries, I put in the meter and turned the key. The meter ready 12.7v. That is healthy. Turning the key didn't drop the voltage at all, and there was no sound coming from my starter. The fuel pump, tho, I could hear.
I tightened up all the contacts on the starter, checked a few things up at the dashboard (there is a ridiculous "do not start" switch in the automatic transmission's shift-lever box) and magically the current would drop to 12.4 and the starter made a little click. Clearly there was juice in the battery, but it wasn't getting to the starter.
Corrosion and old wires were the culprit. Some clipping and solder later, now the car starts up great.
I keep this fine tool in each of my cars. I keep a real multitester under the seat of my motorcycle.
Salt air is a real pain in the ass.
INNOVA 3721 Battery and Charging System Monitor Read the rest
Yes, I really do "need" a 12V USB charging adaptor with a built-in voltmeter.
Driving my VW camper van around, I frequently swap the USB charger with a voltmeter. I'm always curious about how much current my alternator is putting out, and if my house batteries are charging up. I also worry that my kid may plug into the wrong 12V outlets and drain the starting battery. This charger lets me know what is going on as I charge. I NEED TO KNOW!
There are a few chargers with voltmeters, I picked this one as it has both 2.4A and 1A charging, the swivel lets me angle it so I can read it while driving, and the display is super easy to read/understand. When the engine is running the voltmeter tells you what current it sees at your 12V port, with the engine off it's reading the charge from the battery.
Thanks to help from our readers, I successfully put together and sized my house battery, solar panel and portable fridge to allow me uninterrupted cold storage, regardless how long I stay out. This voltmeter helps me manage the system. I'll write up a post what I ended up going with soon.
HAWEEL Rapid LED Dual USB Car Charger Adapter(5V/3.4A output) with LCD Screen Display via Amazon Read the rest