Help me modify a 2S 18650 battery pack.

Batteries and Chargers Rechargeable Batteries
1

I recently bought a bluetooth speaker, the Bang & Olufsen beolit 15; very expensive but it sounds amazing.

After a couple weeks playing with it I was not pleased with the short battery life: less than 3 hours in high volume. So I opened it and to my disappointment, an 7.2V 2200mAh 2S 18650 battery pack. That’s some anemic capacity for such a powerful speaker.

At first sight it seems like an easy swap however there are 5 cables coming from the pack, even if 3 are for balance charging I don’t know what the other 2 are for. There is a rectangular pcb alongside the second battery, I didn’t take the shrink wrap apart to look. And the pack says 7.2 instead of 7.4V, not sure if that’s normal for Li-ion?

This speaker has a very large compartment in the back to store the AC power cord, I want to put 4x Sanyo NCR18650BL in there, and 2 more in the original battery bay for a 2S3P configuration, any help is appreciated!

2

At any rate you will need to reuse the existing electronics. The batteries are probably spot welded together with tabs. You will have to disassemble the assembly and if they are all indeed 18650 batteries, solder in your replacements. Leave the circuit board alone with the output wires attached to it. Basically your going to just replace the batteries and leave the rest of the circuit alone. Be sure to install the new batteries according to their previous arrangement.

3

One maybe a temp sensor. Charge the batteries up and check the voltage to work out what cells they are.

4

Are the two blacks ground?

Seems like it could be two blacks ground, two separate charge wires(red, yellow) and one monitoring wire(white). Really hard to tell by that picture.

This website mentions a battery pack with 5 wires. However B&O is known to always do things differently.

5

I think the easiest way to find out how its connected to cut open the original battery.
and you probably can use the existing pcb and protection electronics. just put 2 cells parallel on each of the cells of the original pack.

6

hi

im french i have a same problem

have you a news ?

7

Hi there cote_de_boeuf, hope you’re still around…

I ended up using 4x Samsung 2600mAh in 2S2P configuration in 18650 battery holders from fasttech and battery tabs from ebay, with a 3-pin balancing plug for quick disconnect and change battery packs when necessary. The original balance board is inside. I can tell you the runtime is at least 3 times longer than before and I made 2 of these packs for quick swap, very happy with this mod.

The speaker charges the battery at a rate of 800mA so instead of taking 3 hours to fully charge now it will take about 7.

8

i use 2 keeppower 5400mha 26650 :slight_smile:

9

hi my friend
I do not understand your connection , can you explain

10

…hi there!!

Any chance to get the wiring from above??

THX!!

11

Hi, sorry but I can’t exactly remember which cable was what, But they were 5, so most probably:

Red: Bat+
Black: Bat-
Yellow: goes between the two batteries for balancing
Blue and white: just the temperature sensor, leave them on the board, stick the board on the batteries.

I used 4x 18650, Two pairs in parallel and then in series.

When you dissasemble the pack you will see, just use the exact same wiring but with different batteries.

12

…ah!!!

thanks!! i’ll give it a try!!!

13

Hi Guys,

Any updates on these two battery modifications? Any issues?

Thanks

14

Can the same mod be applied to the newer Beolit 17, i can understand that the cable room is no longer there, but is there still room inside the speaker for some batteries?? :smiley: Have a nice day :smiley: