Incorrect information on Motion Boom Plus

Soundcore promises us a 13400 mAh battery, but the SAR report says that a 2S2P battery with 7.2 V and 6400 mAh is installed.

The main drivers are not 30 watts, but 25 watts with 4 ohms
and the tweeters are 15 watts with 8 ohms, not 10 watts.

How can that be, that they advertise with wrong values? Is that even allowed?

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I have been hearing and reading about this too. Seems fishy to me but i don’t have the technical knowledge to verify it.

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We need a proper teardown to know for sure.

Already without looking at the insides we know from the charging times do not match 13400mA 7.2V. Excluding the trickle-charger overhead, 13.4Ah x7.2V = 96Wh , and at 5V 3A 15W would take a minimum of 6.4hr. Including trickle-charge overhead (from 85% charges slower) to make an estimated 8.7 hours (my best guess).

If this is true, of the speaker has half the battery capacity stated, that would fully explain the impossible charging times.

It was discussed here:

The cell within is indeed:




For Soundcore to not be in error it is possible there are quantity 2 of these 7.2V 6400mAh cells within. A full teardown is needed to be sure. Ask the video owner above to look at the batteries, if one blue pack or two?

So either the recharge times are wrong or the actual installed battery is less than stated. At this point I cannot know for sure which, just something being said by Soundcore is incorrect or misleading.

Not much into the speakers but did like that one. If wrong battery then bad advertising on Soundcore

Not advertising. If you look at their FAQ and their manual they don’t align. Something is wrong and the error, whatever it is, is spread throughout the documentation.

The simplest, but not necessarily true, error is the 13400mAh is actually 6400mAh because that doesn’t need an implicit quantity 2 and the recharge times to be wrong.

Don’t even get me started “what I would do” why they have 7.2V cells and a 5V input when it should really be an IQ2 or IQ3 input to do 9V.

I asked customerservice about this and it’s now been 48hrs without them answering the question.
The customerservice of soundcore is very slow in general, but i guess this time they are just ignoring me.


Thanks for the update. It may just be them trying to figure it out for themselves.

A screwdriver and a camera would clear this up quickly. I did look at the cell’s dimensions and I see from the video you linked to the cells are under the PCB, who’s dimensions are on the Japanese sites, but if they placed two lengthways propped on their narrow side you probably could fit two cells.

So I can’t tell from what is available.

Update, I don’t like mysteries, things not adding up so here’s a strawman analysis from public information.

Here is the battery pack 2inr19/66-2, I invite someone else to do searches and see if they find similar.

Replacement Battery+Tool For JBL Xtreme 2 Speaker XTREME2BLKAM 2INR19 66-2  Repai | eBay

See it has one connector? Not two you cannot daisy-chain them (that I can see)

The Boom+ is like this - with the battery underside of the PCB (so could be two hidden there, there’s enough space for sure)

The side above of the PCB from above

and importantly from underneath side

Do you see what I see? There’s 1 connector for the battery


which goes to this off the battery


As such it is physically impossible for two such 6400mAh 7.2V cells to be connected. Or there has to be something else going on, say one of the batteries it’s plug removed and the wires placed into the connector of the other to be in parallel.

It does appear just from searching publically available information the specs of 13400mAh 7.2V is not capable of being true.

If I’m wrong, please do show how? A teardown and a photo would help figure it out.

This aligns also with the maths of power and charge times 5.5hr recharge times can at most in perfect situation with no headroom for trickle-charge 5V x 3A x 5.5h = 82.5Wh. 13.4Ah x 7.2V = 96.5Wh. So it is physically impossible to get that recharge time with the quoted 5V 3A to a quoted 13.4A 7.2V cell setup.

Happy to be corrected and challenged, it’s all laid bare above.

Thanks for the detailed info.
Just to make sure i am not the topic starter.

So you are saying there can only be one 6400mAh battery in the boom plus.

But how can it be that the speaker does last for 20plus hours on normal volume?
I mean if it would be double that great. But should it not be less if there is only one 6400mAh battery.

I have contacted customerservice again about this to explain what’s true about this.

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It is a mystery.

Basic math (assuming perfect everything) 48Wh (7.2V x 13.4Ah) to last 20 hours is 2.4Watts meaning the speaker is loud at 3% of the drivers capability.

There is a lot of air inside the case, that helps it sound loud.

It is a mystery, a reply from Soundcore would help. Thanks for emailing them as a customer owning the product.

Hope they reply and you can share their reply.

Extrapolation from the Motion Boom.

It gave 40 hours in benchmark with this


So in roughly half the volume it got double the battery life out of 36Wh.

So, again, it is believable to think there is a Soundcore error here. Waiting for their reply.

To my knowledge, it looks like this.
You have a 2S2P battery without a balancer board in the battery pack.
Therefore you also have a connector with 5 pins. The balancer electronics are on the motherboard.
The battery connector has 2 plus pins and 2 minus pins. One pin is for the balancer

There are probably 4 x Sinowatt SW18650-34MP 3250mAh cells. They can deliver 19.5A in parallel at peak discharge, that’s why they have 2 plus and 2 minus pins. That’s a good way to get to the 46.08 Wh.

When charging the 2S2P battery with a balancer, the charge current is reduced to about 80% of the charge to protect the cells. This increases the charging time.
The maximum charging voltage of the battery is 8.4 V.
At 15 W, this corresponds to a charging current of 1.78 A. The charging time is therefore 4.4 hours. If you consider that the balancer reduces the charging current to 80%, you get 5 to 5.5 hours of charging time.

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True but that means its not 7.2V 13400mAh, it’s 7.2V 6400mAh and 5.5h is believable for 7.2V 6400mAh.

Exactly that simply cannot be 13400mAh.
I think they simply added up 4 x 3250 mAh and rounded up to 13,400mAh, for whatever reason.

With the Motion Boom, they also just added 2 x 4,900mAh and rounded up to 10,000mAh.

That is so wrong.

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I asked customerservice and i got this answer:

‘After I checked, the charging time and battery life are correct, and then the speaker contains a 2s2p battery pack and it includes 4 batteries. In total, it is 3350mAhx4=13400mAh battery.’


So the 2s part which doubles voltage but doesn’t double current they ignore and give a 1s4p answer.

Utter electrical nonsense.

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Lol, so they are talking bs?
I mean it doesn’t really matter to me because the battery lasts long enough for me.
Not sure what to make of all this.


Energy is Watt-hours, made up of Volts x Watthours.

When you place cells in series you add their voltage, not their current, when in parallel you add their current not their voltage.

From their 4 cells they could make 4s1p 14.4V 3350mAh, or 2s2p 7.2V 7200mAh , or 1s4p 3.6V 13400mAh.

It is actually a 2s2p 7.2V 7200mAh but they gave a 1s4p answer.

At least we know.

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It’s all so ridiculous. :pensive:

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Well at least we got to the bottom of it and know what’s the truth. There are 4 3.6V 3200mAh cells, with 46.1Wh within the Boom+

The Motion Boom has 2 4900mAh cells, 36.26Wh

So two Motion Boom has 57% more battery stored energy than one Motion Boom Plus.

You’d expect that to show in like-total-volume battery tests.

I am puzzled why they didn’t put in 26650 instead of 18650 cells in, would have cost a couple of $ more.

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Seems like a lot of companies have the PR people writing this stuff up instead to the Engineers.