ONYX Voltage Sag
Don’t play games with voltage sag over 15 volts-it’s a losing battle. If your aftermarket battery has a sketchy rep, is close to retirement, or has been living the rough life, don’t try to squeeze extra rides out of it just to save a few bucks or for convenience. It’s not worth cooking your setup.
For a fully charged battery reading 83+ volts, in temps between 60°F and 90°F, and with capacities from 40Ah to 60Ah, here’s a quick voltage sag vibe check.
| Volts | Good | Poor | Risky | High Risk |
|---|---|---|---|---|
| 3v | ✅ | |||
| 5v | ✅ | |||
| 8v | ✅ | |||
| 10v | ✅ | |||
| 10v+ | ✅ | |||
| 15v | ✅ | |||
| 15v+ | ✅ |
Some battery builders try to mask poor-performing cells by stuffing them into large packs over 45Ah. But size doesn’t fix quality-two batteries with the same capacity can feel like night and day depending on the cell quality and specs. You really have to own both a good and bad pack to understand the difference.
Low-quality, poorly spec’d batteries have higher internal resistance, which creates more heat and leads to major voltage sag-often over 10V. I’ve seen riders misinterpret high power output readouts as strong performance, when it was actually just resistance causing misleading spikes.
When you’re thinking about voltage sag, think internal resistance. The more heat your battery generates under load, the more power you’re losing to resistance.
If your battery is sagging over 15V from full charge, it’s time to either replace it or tune your setup for lower power. Major sag that drops your voltage from full to nearly empty in a short pull is a big red flag.
Also, don’t trust temperature readings from thermal probes if your battery is sagging above 15V-hot spots can form that probes won’t catch. And if your battery regularly sags 10V or more, keep temps under 122°F (50°C) to avoid long-term damage.