The Projecta 12V Smart Battery Gauge BM320 gives you straight numbers on what your 12V house battery is doing from 6.0–17.0 V. You see amps flowing up to 320 A plus time to full or empty so you can plan fridge loads and lights without guessing. The screen shows capacity from 5–320 Ah so it suits everything from a small starter battery to a bigger caravan bank. The gauge pulls only 1.5 mA at 12V so it will not chew through charge while the rig sits in the shed. The 1.5 m lead and compact face make it tidy to mount in a panel near your main switch gear. It works with wet AGM gel and calcium batteries inside that 5–320 Ah range which covers most Aussie touring setups. Built‑in reverse polarity and 17 V over‑voltage protection help the kit handle day‑to‑day bumps and wiring mistakes.

• Projecta BM320 12V smart battery gauge for monitoring house batteries
• Operates on 12V systems with 6.0–17.0V input range
• Measures current up to 320A for high‑draw setups
• Supports battery capacities from 5Ah to 320Ah
• Compatible with wet AGM gel and calcium batteries
• Full colour LCD shows volts amps and remaining Ah
• Displays time remaining to full or empty plus charge status
• Shows ambient temperature plus time and date
• Reports battery state of health as Ideal Good Fair or Poor
• Protection includes 6V minimum voltage and 17V over‑voltage with reverse polarity safeguard

Q: Will this gauge work with AGM and gel batteries in the same 12V setup?

Yes it supports both AGM and gel types on a 12V system. The BM320 is specified for wet AGM gel and calcium batteries within the 5–320Ah range so mixed fleets are fine if they share that voltage. The key is that the connected bank stays within the 5–320Ah window. The monitor then reads and displays capacity and current for that combined bank.

Q: How much power does the 12V Smart Battery Gauge draw from my battery when the vehicle is parked?

The gauge draws 1.5mA at 12V. This very low standby current means it has minimal impact on larger touring banks in the 100–320Ah range during storage. Over long periods you should still consider a maintenance charger or solar input. The low draw simply helps reduce unnecessary parasitic load on the system.

Q: What information does the display actually show while I am camping?

The screen shows voltage current and remaining capacity in amp hours. It also displays time remaining to full or empty plus charge or discharge status. Ambient temperature along with time and date appear for extra context. Battery state of health is reported as Ideal Good Fair or Poor so you know when capacity has dropped.

Q: Is there any protection if I accidentally wire the gauge back to front?

Yes the BM320 includes reverse polarity protection. The internal electronics are set up to handle incorrect connection at the input terminals within the specified limits. It also has input over‑voltage protection rated to 17V. These protections help safeguard the gauge and the rest of the 12V system from simple wiring mistakes.

The Projecta BM320 12V Smart Battery Gauge suits 12V battery systems with capacities between 5 Ah and 320 Ah. The gauge supports wet AGM gel and calcium batteries in camper trailers caravans and other 12V setups. Installation requires connection to the battery via the supplied terminal block and Molex 4‑pin snap‑fit connectors. The unit must be wired within its 6.0–17.0 V input range and within the specified 320 A maximum current monitoring rating.