Lithium Polymer (LiPo) batteries are presently the standard power source for most hobby-grade RC vehicles. These batteries have seen steady improvement since they were first introduced to the hobby around the turn of this century. Most of that progress has been related to increasing their fast discharge and charge capabilities. During the last year or so, we have seen the emergence of LiPo cells that evolved in a slightly different direction. High-Voltage LiPo batteries (LiHV) look and perform much like contemporary LiPo cells, but have a tad more voltage.
More voltage fed your electric motor equals more RPMs. That will give your RC toy a zippy performance boost, right? Well, maybe. There is more to consider than just voltage. I recently tested a LiHV battery to determine whether these types of cells are an overall advantage for me.
What is LiHV?
Standard LiPo batteries have 4.2 volts per cell when fully-charged. LiHV cells go up to 4.35 volts. That extra .15 volts may not seem like much, but it could make a significant difference in some applications. Most RC vehicles use two or more cells in series. So the extra voltage of a LiHV battery is multiplied by the number of cells.
A regular LiPo is considered discharged when it drops to 3.2 volts per cell under load. This usually equates to about 3.7 volts at rest. LiHV cells have the same bottom end values. So, LiHV cells operate over a slightly broader voltage range than standard LiPo variants.
There are numerous LiHV options available on the market. From what I can tell, most of these batteries are very similar in size, weight, price, and discharge capabilities to their normal-voltage contemporaries. Yes, there are some differences. But I think most of those deltas would be insignificant to the average hobbyist.
Hyperion provided two similar batteries for testing, one LiPo and one LiHV. The LiPo is their G5 3-cell (12.6 volts) 850mAh unit that is rated for 70C maximum discharge (59.5 amps). On the LiHV side is a G7 3-cell (13.05 volts) 900mAh battery rated for 60C discharge (54 amps). Before getting into my results from using these batteries, we should cover a few things to think about regarding LiHV cells.