The one option to really check a battery’s performance is to run it via cost and discharge cycles. You wish to have a look at the voltage at full cost, that the voltage throughout charging and discharging appears to be like as anticipated for the equipped present, and extra. However that testing course of isn’t precisely easy for large battery packs that retailer lots of energy — that energy has to go someplace, in any case. Eric Tischer’s data-logging battery tester has an attention-grabbing resolution: it recycles energy.
You’ve in all probability heard that “power can neither be created nor destroyed,” which is one option to describe the regulation of conservation of power. Realizing that, how do you get the power “out” of a battery? You’ll be able to’t simply destroy it and as an alternative it’s a must to put it someplace. For a big battery, like what you would possibly use for an electrical bicycle or a solar-powered backup system, that finally ends up being lots of power. If you wish to carry out a discharge/cost cycle, you want some option to get that power out and someplace for it to go.
Most battery testers merely flip that power into waste warmth, as a resistor performing as a heater is extremely low-cost. That waste is suitable while you’re speaking a couple of 5V 2000mAh lithium battery for a telephone, however what about one thing like a 48V 10Ah battery for an e-bike? We’re speaking about roughly 500Wh, which might be sufficient to run an electrical area heater for 20 minutes or so. That’s lots of warmth and lots of wasted power! Tischer’s tester recycles all of that energy as an alternative.
The first element of this tester is a SparkFun Factor Plus ESP32 improvement board. Its job is to measure voltage and present, whereas logging these values over time for later evaluation. It takes measurements via an Adafruit INA3221 energy monitor board, which might deal with as much as 26V and three.2A. Tischer needed to measure extra present than that and added a shunt to bump it as much as 100A. An actual-time clock module gives correct time stamps and there may be an SD card module for information logging. Adafruit rotary encoders let the person modify settings, like information recording intervals.
To “recycle” the facility, Tischer makes use of an EcoFlow energy station — the sort of giant battery backup gadget that’s usually marketed as a “photo voltaic generator.” Throughout the cost cycle, the battery tester pulls energy from that. Then, through the discharge cycle, the battery tester makes use of the power coming from the examined battery to recharge the EcoFlow. Then, rinse and repeat!
There’s, after all, all the time a loss every means as a consequence of imperfect effectivity. However that’s definitely higher than losing all of the power and Tischer doesn’t should cope with the sweltering warmth from a battery tester that has change into an area heater.
