I would want a voltmeter and a wattmeter. Neither is expensive.
In the USA, one national chain store gives these voltmeters away if you buy something else. They're good enough to see if your mains AC is live or if your battery has a charge. I have about four of them.
https://www.ebay.com/itm/DT830B-LCD-Digital-Voltmeter-Ammeter-Volt-AC-DC-Tester-Meter-Ohmmeter-Multimeter/302704532897?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3Dd5cc64a3ee86452e9d92412874d4f0ac%26pid%3D100005%26rk%3D2%26rkt%3D12%26sd%3D273412462586%26itm%3D302704532897&_trksid=p2047675.c100005.m1851
This is what I use when I need accuracy in a voltmeter.
https://www.ebay.com/itm/Craftsman-Digital-Multimeter-Volt-AC-DC-Tester-Meter-Voltmeter-Ohmeter-34-82141/201571138059?hash=item2eee937a0b:g:vvcAAOSwSTpbzdAE:rk:3
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I use this wattmeter. It's not accurate as far as watt-hours. The volts are uncalibrated, but is reproducible for amps and amp-hours (aH). Also unreliable. I've had two fail. It's only 10 dollars.
https://www.ebay.com/itm/Digital-LCD-RC-High-Precision-Watt-Meter-Power-Volt-Amp-DC-Analyzer-60V-130A/292658364532?epid=13021904940&hash=item4423cc4074:g:3gsAAOSwatRbXBon:rk:10
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In India, you can probably find similar items.