How do I charge a 4S 18650 battery pack?

[Ratdoux]

I've been trying to find out the answer to this but there's not much information around so I hope you guys can shed some light

 

[marcexec]

Welcome to the forum mate.
We do have a nice Wiki, best start there: https://endless-sphere.com/w/index.php/Charging_Lithium_ion_batteries

 

[kdog]

Can't you just buy a 4s Li-ion charger and stick it on?
any further details?

 

[Ratdoux]

Welcome to the forum mate.
We do have a nice Wiki, best start there: https://endless-sphere.com/w/index.php/Charging_Lithium_ion_batteries

I did have a look but I didn't find what i was looking for

 

[Ratdoux]

Can't you just buy a 4s Li-ion charger and stick it on?
any further details?

It's for a portable speaker, looking to have the batteries sealed inside the speaker box with an external power supply to charge them

 

[marcexec]

Welcome to the forum mate.
We do have a nice Wiki, best start there: https://endless-sphere.com/w/index.php/Charging_Lithium_ion_batteries

I did have a look but I didn't find what i was looking for

Well, it would help to have some more details. Bulk or balance? What chemistry/cell type? Overall pack design, does it have a BMS?
Please don't leave us guessing.
In case you missed it, balance chargers are discussed here (as linked in the Wiki page), they would be a good start if you don't have much experience.

 

[Ratdoux]

Welcome to the forum mate.
We do have a nice Wiki, best start there: https://endless-sphere.com/w/index.php/Charging_Lithium_ion_batteries

I did have a look but I didn't find what i was looking for

Well, it would help to have some more details. Bulk or balance? What chemistry/cell type? Overall pack design, does it have a BMS?
Please don't leave us guessing.
In case you missed it, balance chargers are discussed here (as linked in the Wiki page), they would be a good start if you don't have much experience.

They're Li-ion 18650 batteries, panasonic ncr18650b with a rated 3400mah, the final pack will have 8 batteries, with 2 packs of 4S in parallel, so 4S with 6800mah capacity. They already have a protection chip inside but I was thinking of sticking a BMS on them nonetheless

 

[Ratdoux]

Do I just charge them by running a 16.8v current <1.7A thru the 4s pack?

 

[DVDRW]

Imax B6 RC charger Or compact and cooler SC-608

 

[Ykick]

RC Charger -or- 4S BMS (some very cheap) and bulk charge with a DC power supply which outputs 16.8V or so.... IMO RC Charger is way more useful for all sorts of battery needs,

 

[dogman dan]

Imax b6 would be one of the better ways to do it. But to use the balance function, you'd need to have an external 5 pin jst plug attached to the pack, a balance plug.

A 4s bms would not require the external plug. so that may be the best way to do it.

 

[Ykick]

I’ve used these as charge only protection -

http://www.ebay.com/itm/New-Cool-BMS-Protection-PCB-Board-for-4-packs-18650-Li-ion-lithium-Battery-Cell-/201434924156?hash=item2ee675047c

These look pretty useful to me if you need 20A - http://www.ebay.com/itm/20A-BMS-Protection-PCB-Board-for-4-packs-18650-Li-ion-lithium-Battery-Cell-4S-/252673441308?hash=item3ad482be1c

 

[Ratdoux]

Thank you all for your replies, i love you all <3

So I will probably go with a 4s BMS and a 16.8V supply.

But before that I just realised that I could charge them in parallel but discharge them in series, this would be relatively simpler for me as it just needs some more brain power to figure out but I was wondering if there's already some time of product like this out there that does the same function..


EDIT: so the way the switch works is that when it's in parallel, the series connection is disconnected but when it's in series, it disconnects the opposite parallel connection (opposite to the series one),

 

[Ratdoux]

I’ve used these as charge only protection -

http://www.ebay.com/itm/New-Cool-BMS-Protection-PCB-Board-for-4-packs-18650-Li-ion-lithium-Battery-Cell-/201434924156?hash=item2ee675047c

These look pretty useful to me if you need 20A - http://www.ebay.com/itm/20A-BMS-Protection-PCB-Board-for-4-packs-18650-Li-ion-lithium-Battery-Cell-4S-/252673441308?hash=item3ad482be1c

So basically I'd charge the batteries through the BMS? Sorry for the newb questions hehe

 

[Ykick]

I’ve used these as charge only protection -

http://www.ebay.com/itm/New-Cool-BMS-Protection-PCB-Board-for-4-packs-18650-Li-ion-lithium-Battery-Cell-/201434924156?hash=item2ee675047c

These look pretty useful to me if you need 20A - http://www.ebay.com/itm/20A-BMS-Protection-PCB-Board-for-4-packs-18650-Li-ion-lithium-Battery-Cell-4S-/252673441308?hash=item3ad482be1c

So basically I'd charge the batteries through the BMS? Sorry for the newb questions hehe

That's one way if you need to put more than the maximum current through them. I'd think the 20A BMS would be more than 4S1P 18650 pack would ever need? But I've never used that particular BMS before. I have been using 3-4qty of the 5A BMS for charge only on my 12-16S RC Lipo packs with good results.

 

[Ratdoux]

I’ve used these as charge only protection -

http://www.ebay.com/itm/New-Cool-BMS-Protection-PCB-Board-for-4-packs-18650-Li-ion-lithium-Battery-Cell-/201434924156?hash=item2ee675047c

These look pretty useful to me if you need 20A - http://www.ebay.com/itm/20A-BMS-Protection-PCB-Board-for-4-packs-18650-Li-ion-lithium-Battery-Cell-4S-/252673441308?hash=item3ad482be1c

So basically I'd charge the batteries through the BMS? Sorry for the newb questions hehe

That's one way if you need to put more than the maximum current through them. I'd think the 20A BMS would be more than 4S1P 18650 pack would ever need? But I've never used that particular BMS before. I have been using 3-4qty of the 5A BMS for charge only on my 12-16S RC Lipo packs with good results.

welp the final pack would be 4S2P totaling to a final 16.8v at 6.4amps so probably the 20A bms will do, thank you very much!