NiMH vs LiPo batteries

Most hobby-grade models now run on LiPo, but plenty of ready-to-run cars still come with a NiMH pack in the box, and older models from the 2000s were built around them. So which should you use, and is switching worth it?

The short comparison

Why LiPo feels faster

A NiMH pack starts strong straight off the charger, then its voltage slowly falls during the run, so the model gets gradually slower. A LiPo holds a much flatter voltage until it is nearly empty. The result is that a car or plane on LiPo feels just as quick at the end of the run as at the start, and it carries less weight doing it.

That's also the trap. Because a LiPo doesn't fade, you get very little warning before it is flat. Without a low-voltage cut-off in the speed controller, you can run it below the safe minimum and ruin it.

Where NiMH still makes sense

• Children's models. NiMH packs survive knocks, being left flat and careless charging far better.
• Older brushed cars. Older brushed motors and speed controllers were designed around NiMH, and many have no LiPo cut-off.
• Receiver packs for nitro cars and older planes.
• Occasional use. If a model sits for months between runs, NiMH asks less of you.

Can you use a LiPo instead of NiMH?

Often yes, but check these five things first:

1. Speed controller support. The ESC must say it supports LiPo and have a low-voltage cut-off, either set by jumper, switch or programming. Check the manual. If it doesn't have one, don't use LiPo with it. Our guide to ESCs and brushless motors explains cut-off settings.
2. Voltage match. A 2S LiPo replaces a 6 or 7-cell NiMH. A 3S LiPo is a big step up and needs electronics rated for it.
3. Connector. Older cars often use Tamiya plugs; LiPos usually come with XT60, Deans or EC3. Fit the same connector on everything rather than relying on adapters.
4. Physical fit. Hard-case 2S packs are a standard size for 1/10 cars, but older chassis can be tight. Measure first.
5. Charger. You need a balance charger with a LiPo program. See our best LiPo chargers.

Charging differences

NiMH chargers stop when they detect a small voltage drop at the end of charge (called delta-peak). LiPo chargers use a constant-current, constant-voltage method and balance each cell. The two are not interchangeable, and a NiMH-only charger must never be used on a LiPo. Most modern hobby chargers do both, but you choose the right program each time. The full routine is in LiPo battery safety.

Cost over time

NiMH packs are cheaper to buy and tolerate more neglect. LiPos cost more and need a better charger, but they give more performance per pound and per gram. If you run a model every weekend, LiPo is worth it. If it's a child's car used twice a year, NiMH is the sensible, lower-risk choice.

By type of model

• Cars: LiPo is standard for hobby-grade; NiMH is common in ready-to-run boxes and kids' cars. If you're weighing up motors as well, see brushed vs brushless RC cars.
• Planes: almost entirely LiPo, because weight matters so much.
• Helicopters: LiPo throughout, from 1S micros to 12S 700 class.

To understand the numbers on a LiPo label before you buy, read LiPo batteries explained. Everything else battery-related is on the Electronics hub.