Boosted XR Battery Charging Info

Boosted XR Battery is made up of 26 LG HG2 Cells. In a 13S2P config. The LG HG2 has the following specs:

• Capacity = 3ah or 3000mah
• Charge methods: 1.5A @ 4.2V or 4A @ 4.2V
• Charge time @ 4A = 85mins, 1.5A = 165mins
• Nominal Voltage = 3.6V

I did some quick maths to figure out how long my battery should last.

The battery pack is technically 267WH. But it's limited for safety to 199WH. On Pro or Hyper mode I get about 6 miles of range.

• Roughly 33.3wh per mile
• 1 Battery cycle = 200wh = 6 miles (sort of)

A lithium battery life cycle is considered over when it's capacity has dimished to 80% of original capacity. Even if it has more life to give, thats the official guide. I'm sure the chance of RLOD error gets higher as capacity drops.

If we look at the cycle life charts in the data sheet for the HG2 we see some interesting things.

Here are the 10A and 15A cycle life charts. A (or amps) is how much power is being used during the discharge. The Boosted Stealth has a max power rating of 2100W. Which is roughly 22.43 amps for the Boosted XR battery.

The higher your speed mode the more amps you can push through the motors. As you're not constantly flying around at top speed in Hyper mode I'd guess the average discharge rate would be somewhere around 15A (maybe less). The charts show theres not much difference in cycle life between 15A and 10A. And we can get 400 cycles before dipping below 2400mah or 80% capacity.

400 cycles works out as 2400 miles. Which is quite reasonable I think. Things change when we look at the 20A discharge chart however.

The cycle life at 20A is WAY worse. It only takes 200 cycles at this discharge before reaching 80%. Bad bad bad. 150 cycles is only 1200 miles. That's 50% less than at 15A. Half!

So how does this make me feel? I like going fast but I also like having my Boosted Stealth. I literally go everywhere on it. To work. To the shops. The cinema. So here's what the charts are saying if you haven't gotten it yet.

Higher Speed modes = Battery Dies Faster.

So I've decided that my new speed mode is 4 (or Pro). This is 22mph on the Boosted Stealth. It's plenty fun at that speed. And it could mean nearly doubling the battery life. I can't say for sure but it will definitely last longer.

Fast Charging

What's interesting about those life cycle charts is that the cells are being charged at their max speed of 4 amps. And because we have 2 cells in parallel in our XR battery their max charge rate is 8 amps!

The Boosted Charger is only 2 amps. And is painfully slow. I've been using a 2.8 amps charger for months now which is about 30mins faster than the original. I was a bit scared at first but so far it's been a dream.

And I've just ordered a 5amp charger. 5 amps is much higher than 2. A far scarier amount of amps. But 5 amps is only 62.5% of the max rate which sounds quite conservative to me.

The battery I've been fast charging is on firmware 2.5.1 (aka the good one). My other board is on 2.1.7 and I'm nervous to fast charge that. I've had many 2.1.7 batteries RLOD on me.

Conclusion

My boosted stealth I ride around everyday is nearly on 2000 miles on the odometer. And that's what got me thinking about all this.

The numbers in this post are likely worst case scenario. Because they all calculated with the 199wh capacity when the batteries are actually 267wh.

Also don't be too scared to fast charge!