Batteries

[paintboy]

Hello, been on and off a year trying to build battery packs. I don't intend to burn my shed down so just experimental with cheap batteries.
I ve a b6 cloned charger which seems to work.
My immediate problem is l ve made a simple 2s battery with balance leads and it discharged and charged ok.
I made a 6s and it turns itself off after few minutes.
I disconnected a cell so had a 5s and just charged without balance leads( l don't have BMS), and it worked fine.
I only know a little, but it's looking like my charger doesn't like 6s? Any ideas.
Ps, l have plenty of questions!

 

[cyclebuddy]

The pack voltage you set determines the number of cells (the S value). When you press start, the B6 gives you an R value - the number of cells it "reads"/thinks you have. The two need to match. If they don't, you may have a poor cell connection somewhere.

I had a cloned B6 but it packed up. My current one is a B6 original with the built-in power supply. It's a few years old now so may differ from yours.

 

[Nealh]

You are best to use a BMS with top end balance then you don't need to use fancy balance chargers which there are a lot of clones that are a bit iffy at the best.
Use a generic charger for the correct voltage and let the BMS do the work.
So if you venture into large voltage series opt for the safer route.

Even with my 6s -15s multi chemistry charger it has the feed connection and balance connection and will not charge without balance connected. Buy a decent charger and forget about the cheap clones.

My choice is a SKYRC dual channel charger, one has to select the cell value correctly and also with my charger if it detects a bad cell/group will give an audible alarm and message and will not charge.

 

[cyclebuddy]

My choice is a SKYRC dual channel charger, one has to select the cell value correctly and also with my charger if it detects a bad cell/group will give an audible alarm and message and will not charge

The B6 is THE original SKYRC charger product. It's because it was so good, versatile, and thus successful that it has been cloned. I'd say it's fine for what the OP is trying to do... with the caviat that there are clones and clones.

The B6 is multi-chemistry, has up to 6-cell lithium balancing connections, the user does need to select the correct cell group to match what the charger reads too, and it too won't charge if there's a bad cell group. It has thermal sensing and an audible alarm/error messaging too.

There's a YT video that examines the differences between an original SKYRC B6 product and a clone: IIRC the main internal difference is the tolerance of the balancing resistors, the clone having wider tolerances... meaning the balancing is sort of okay but less exact.

IMHO an original SKYRC B6 charger is perfectly fine for what the OP is currently trying to do... a B6 clone is likely okay, but as it's been manufactured to undercut the original on cost one never really knows what compromises have been made.

 

[paintboy]

I didn't realize but it said on top line confirmation 5s and 6s so not a match. I checked the connections again so either it doesn't recognize a 6s or something faulty. Could be anything l m doing wrong . What is a recommended charger if l try and build a battery with a BMS? I like a challenge but l think I'll give up and buy a battery complete

 

[paintboy]

I think l ve found the charger

You are best to use a BMS with top end balance then you don't need to use fancy balance chargers which there are a lot of clones that are a bit iffy at the best.
Use a generic charger for the correct voltage and let the BMS do the work.
So if you venture into large voltage series opt for the safer route.

Even with my 6s -15s multi chemistry charger it has the feed connection and balance connection and will not charge without balance connected. Buy a decent charger and forget about the cheap clones.

My choice is a SKYRC dual channel charger, one has to select the cell value correctly and also with my charger if it detects a bad cell/group will give an audible alarm and message and will not charge.

Hi, think l ve looked up this charger correctly. So what type of connector does a battery need to fit this? All good research!

 

[Nealh]

Unless one is using lipo chemistry one is better just using a generic 10-20 quid charger for lion cells.
Pointless building batteries and a charger that will do up to 6s unless you have a need for it. With ebikes common voltages are 7s/24v, 10s/36v & 13s/48v so if building a battery opt for the voltage you are going to use and include the appropriate BMS in the build, once done just buy a charger to supply the correct voltage.

 

[Nealh]

My skyrc d100 comes with 2 x xt60 plug for the main discharge and 2 x small jst balance board for various balance wires up to 6s. I use it as I have a need to use 3s lipos for other 12v devices I use.

 

[paintboy]

My skyrc d100 comes with 2 x xt60 plug for the main discharge and 2 x small jst balance board for various balance wires up to 6s. I use it as I have a need to use 3s lipos for other 12v devices I use.

Yes l ve just read up on this charger. I do have uses for it so it wouldn't be a waste of money. What l don't understand is how a basic charger works with a battery with BMS which has been recommended. Can you still plug the balance leads in?
Getting confused here

 

[matthewslack]

Yes l ve just read up on this charger. I do have uses for it so it wouldn't be a waste of money. What l don't understand is how a basic charger works with a battery with BMS which has been recommended. Can you still plug the balance leads in?
Getting confused here

The basic charger does not handle balancing, so does not need the balance leads. It is just a source of the correct fully charged voltage. The BMS does the balancing. But the voltage needs to be right, not roughly right.

So for 10S Lithium Ion it needs to be 41.7V. Then if the BMS is doing its job, it is not possible to overcharge.

 

[paintboy]

The basic charger does not handle balancing, so does not need the balance leads. It is just a source of the correct fully charged voltage. The BMS does the balancing. But the voltage needs to be right, not roughly right.

So for 10S Lithium Ion it needs to be 41.7V. Then if the BMS is doing its job, it is not possible to overch

 

[paintboy]

Forgive my lack of knowledge. So a lipo would have a BMS, with the leads on show. So surely they would be plugged into a charger?

 

[Nealh]

lipo's don't generically use a BMS unless the one add's one as I have done so to two 10s packs I made up. They all have a main discharge plug and a set of balance leads for a balance charger or to plug in to a parallel balance board.
You have to clearly state what you are trying to achieve and the battery chemistries involved.

 

[paintboy]

Ok l see. I assume lipos have a BMS so didn't know why they had balance leads hanging out. Why don't they when you're told to be careful with them.

 

[cyclebuddy]

I didn't realize but it said on top line confirmation 5s and 6s so not a match.

Then that is your problem - something isn't connected properly. If ultimately you're trying to build a battery for an e-bike, Neal's advice is the way to go - an external BMS and a standard £20 42v charger. The SKYRC B6 can't handle 10s.

 

[Nealh]

lipos are mainly the domain of the RC community so they fats charge them on site and a BMS adds unnecessary weight for them. Lipos were used by early ebike users as they were very cheap and one could cobble then together with knowledge of how to do so, but for the average user they just aren't worth the aggro and the extra time needed to keep checking them for balance. The 18650 lion cell soon came in to being and they proved a much safer bet and started to give pretty much as good or if not better results.

I eventually got fed up using lipo on my bikes having to keep disconnecting the Series connection to parallel charge them, eventually I decided with my best four graphene lipos to hack the discharge wiring to a permanent soldered series connection and also do the same with the sense wire connectors and hacked them to the 10s balance connector on a BMS which I glued and heat shrunk on. All I do now is allow a generic 42v charge to charge and balance them.

My lipo conversion thread with BMS.
Adding a bms to lipo 10s. | Pedelecs - Electric Bike Community

 

[matthewslack]

Ok l see. I assume lipos have a BMS so didn't know why they had balance leads hanging out. Why don't they when you're told to be careful with them.

Some of the differences come from different historical uses of different battery types and the constraints: lipo is much used in the radio controlled flight world where weight is critical, so you don't want to carry a BMS on the aircraft. So it is separate from the battery. But that is a smallish scale hobby market.

Ebikes are a massive consumer market in which a lithium ion battery without integral BMS is unthinkable from a safety point of view.

Overcharging lithium ion cells is a guaranteed fire or explosion, so charging with no BMS is unwise.

 

[paintboy]

lipos are mainly the domain of the RC community so they fats charge them on site and a BMS adds unnecessary weight for them. Lipos were used by early ebike users as they were very cheap and one could cobble then together with knowledge of how to do so, but for the average user they just aren't worth the aggro and the extra time needed to keep checking them for balance. The 18650 lion cell soon came in to being and they proved a much safer bet and started to give pretty much as good or if not better results.

I eventually got fed up using lipo on my bikes having to keep disconnecting the Series connection to parallel charge them, eventually I decided with my best four graphene lipos to hack the discharge wiring to a permanent soldered series connection and also do the same with the sense wire connectors and hacked them to the 10s balance connector on a BMS which I glued and heat shrunk on. All I do now is allow a generic 42v charge to charge and balance them.

My lipo conversion thread with BMS.
Adding a bms to lipo 10s. | Pedelecs - Electric Bike Community

Thanks for the advice. You've lost me on the last section. I know the fundamentals of it all. I ve just discharged a simple 5s on my clone b6 and that seems ok. Doesn't want to know when charging though. So my cheap batteries are crap or something wrong with charger. Think that's made me go for what's been recommended

 

[soundwave]

it wont balance charge unless the balance cable is also connected.

 

[paintboy]

Thanks for the confusion. Balance leads to what? I ve been told a BMS will protect the battery and get a cheap charger