What charger size should i use ??.

[collectors]

I am making up a few battery banks to run my RC trains. I am making up two banks of 4 x = 8 3.7V/4.2v 18650 to give me around 14/16v. I will also fit a " 4S 30A 14.8V Li-ion Lithium 18650 Battery BMS"
The only thing i cant find is the charger size i should use. Tried contacting the supplies, but no luck. I was looking at a simple 1amp plugin charger, but not sure what voltage to get. They seem to be anywhere from 5-21v. ??>

 

[JimmyB]

You will need a dedicated Lithium charger, the batteries will inform on their C rating i.e. how fast they can be charged, and at what rate, most are multi voltage for different cell types and quantities, and you will need to set this yourself based on the battery information. A good place to start your lithium learning journey.

BU-402: What Is C-rate?

BU meta description needed...

batteryuniversity.com

 

[dunnyrail]

You will need a ‘Balanced Charger’ for this setup. If you do not get the correct charger you could end up with a nasty surprise when charging.

 

[Cobalt6700]

I did a bit of looking into these when I was going to build my own packs.

Here is the datasheet: https://www.mantech.co.za/datasheets/products/BMS-40A-4S_SGT.pdf

There is a nice little circuit for adding charge status LED's on this eBay sellers site: 4S 40A Li-ion Protection AND Balanced Charge BMS 14.8V/16.8V | eBay


If you have the balanced version of the BMS ( which your picture indicates you do ) you should need a constant voltage / current power supply to charge the battery pack - the BMS should manage balancing for you.

You will need to work out your battery 'full' voltage (should be 4.2V) and your charge current - usually this is 1C - or 1x the Ah capacity.

Voltage - times the number of cells, or 'S'. If you have 4 batteries, then you have 4S, which is a nominal voltage of 14.8V, full voltage of 16.8V. 16.8V would be max voltage for your power supply.

Current - For example if the cells are 2200MAh then you would change at 2.2A or less. For one set of batteries this would be called '1P' ( though usually this is left out of the pack description and the pack would be just '4S' ).
If you are making two banks as you have said - and assuming these are going to be parallel to double the capacity of the battery - the pack would now be known as 4S2P.
In this case, you would take the capacity of one cell and times by 2 to give 4400MAh, or 4.4A. This would now be your max charge current.

 

[PhilP]

So you are building a '4S2P' pack?

Do you really need to parallel up two sets of cells? - How long is your railway? How long do you want to run for? How big a train will you be running?

Personally, I charge at about 0.8C, so for (simple maths) 1000mAh cells at 800mA.
I also connect a balance charging lead, which allows me to 'see' what is going on with the individual cells.

You do not want to stress things, especially if you are creating a 'simple' parallel cell pack (one BMS board). - If you have two cells in parallel, one good cell can mask a problem with the other.
Two 4S packs (each with their own BMS board) adds a little bulk, but could save you trouble in the future.

For a charger, you could do a lot worse than the Imax B6.
Pay a little more, and it should come with a UK (real) mains lead, and a selection of cables.
If you also connect to a balance lead, this charger will show you the voltages of the individual cells, as well.

PhilP

 

[collectors]

You will need a dedicated Lithium charger, the batteries will inform on their C rating i.e. how fast they can be charged, and at what rate, most are multi voltage for different cell types and quantities, and you will need to set this yourself based on the battery information. A good place to start your lithium learning journey.

BU-402: What Is C-rate?

BU meta description needed...

batteryuniversity.com

So you are building a '4S2P' pack?

Do you really need to parallel up two sets of cells? - How long is your railway? How long do you want to run for? How big a train will you be running?

Personally, I charge at about 0.8C, so for (simple maths) 1000mAh cells at 800mA.
I also connect a balance charging lead, which allows me to 'see' what is going on with the individual cells.

You do not want to stress things, especially if you are creating a 'simple' parallel cell pack (one BMS board). - If you have two cells in parallel, one good cell can mask a problem with the other.
Two 4S packs (each with their own BMS board) adds a little bulk, but could save you trouble in the future.

For a charger, you could do a lot worse than the Imax B6.
Pay a little more, and it should come with a UK (real) mains lead, and a selection of cables.
If you also connect to a balance lead, this charger will show you the voltages of the individual cells, as well.

PhilP

Hi, sorry i haven't got back sooner, but wasn't getting any notifications, but i just got a pop up to allow this" So i am hoping all is now ok.
I was hoping to put all the batteries & sound in a wagon behind the train as there is a lot more room & then two leads to the loco, 1 for motor & a second 4 core for things like lights. I was then hoping to build a 4S2P using 18650 batteries & assumed if i fitted a BMS "or 2" i would just need a 1-2amp li-charger via a jack plug to keep it simple. I do have a charger for these battery's "Like bellow" & was hoping the BMS would eliminate my charger for somthing a bit more simple.
Oh, the track is around 72met + times by 2 for twin rail. Still not finished yet, & i thought i will get out there as we got good weather in Norfolk for a few days. But i gave up after an hour. It was cold.
Plan of track on this page.

 

[JimmyB]

Hi, sorry i haven't got back sooner, but wasn't getting any notifications, but i just got a pop up to allow this" So i am hoping all is now ok.
I was hoping to put all the batteries & sound in a wagon behind the train as there is a lot more room & then two leads to the loco, 1 for motor & a second 4 core for things like lights. I was then hoping to build a 4S2P using 18650 batteries & assumed if i fitted a BMS "or 2" i would just need a 1-2amp li-charger via a jack plug to keep it simple. I do have a charger for these battery's "Like bellow" & was hoping the BMS would eliminate my charger for somthing a bit more simple.
Oh, the track is around 72met + times by 2 for twin rail. Still not finished yet, & i thought i will get out there as we got good weather in Norfolk for a few days. But i gave up after an hour. It was cold.
Plan of track on this page.


View attachment 322610

The slots at the bottom are for balance charging, and the BMS should manage this for you, it is often recommended that a balanced charge is carried out occasionally.

 

[GAP]

These are popular down in Aust

SKYRC Genuine iMAX B6AC V2 Lipo Battery Balance RC Charger LiFe LiHV N

SKYRC iMAX B6AC V2 is the ultimate RC hobby intelligent multifunction charger which can charge and discharge for Li-ion /Polymer batteries, Ni-MH/Cd batteries, even Pb batteries. It's all-powerful at an extremely well known model to enthusiasts in the RC and model hobby industry. SKYRC iMax B6AC...

www.hobbyinn.co.uk

I use one of these; actually have 4

Amazon.co.uk:Customer reviews: Accucel 6 TURNIGY 50W 6A BALANCER CHARGER LiPo LiFe LiHV NiMh Nicad Heli Cars RC

Find helpful customer reviews and review ratings for Accucel 6 TURNIGY 50W 6A BALANCER CHARGER LiPo LiFe LiHV NiMh Nicad Heli Cars RC at Amazon.com. Read honest and unbiased product reviews from our users.

www.amazon.co.uk

This is how I made my battery packs.

Making 18650 Lithium Ion Battery Packs

After the failure of my third model store bought LiPo battery in my Bachmann Shay and Consolidation ("Connie")I decide that I would make my ...

ringbalin-light-railway.blogspot.com

I charge my Li-ion batteries at 1/3C C= capacity eg 10AH capacity charge at 3A.

I use a 12V power supply made from an ATX computer PSU for my chargers.

 

[collectors]

I did a bit of looking into these when I was going to build my own packs.

Here is the datasheet: https://www.mantech.co.za/datasheets/products/BMS-40A-4S_SGT.pdf

There is a nice little circuit for adding charge status LED's on this eBay sellers site: 4S 40A Li-ion Protection AND Balanced Charge BMS 14.8V/16.8V | eBay


If you have the balanced version of the BMS ( which your picture indicates you do ) you should need a constant voltage / current power supply to charge the battery pack - the BMS should manage balancing for you.

You will need to work out your battery 'full' voltage (should be 4.2V) and your charge current - usually this is 1C - or 1x the Ah capacity.

Voltage - times the number of cells, or 'S'. If you have 4 batteries, then you have 4S, which is a nominal voltage of 14.8V, full voltage of 16.8V. 16.8V would be max voltage for your power supply.

Current - For example if the cells are 2200MAh then you would change at 2.2A or less. For one set of batteries this would be called '1P' ( though usually this is left out of the pack description and the pack would be just '4S' ).
If you are making two banks as you have said - and assuming these are going to be parallel to double the capacity of the battery - the pack would now be known as 4S2P.
In this case, you would take the capacity of one cell and times by 2 to give 4400MAh, or 4.4A. This would now be your max charge current.

Hi, thanks for the info. With these BMS boards & paticaly the one in your data sheet seem to have a very narrow charge voltage. This one is : 16.8 ~ 18.1V & not very common charger size. Have you ever tried a 12v charger & had any luck with all charging up, as a single battery is only 3.7 to 4.2v.
OK, it may take a little longer, but was a thought.

 

[JimmyB]

Hi, thanks for the info. With these BMS boards & paticaly the one in your data sheet seem to have a very narrow charge voltage. This one is : 16.8 ~ 18.1V & not very common charger size. Have you ever tried a 12v charger & had any luck with all charging up, as a single battery is only 3.7 to 4.2v.
OK, it may take a little longer, but was a thought.

I would only use a charger dedicated to charging lithium batteries for lithium batteries, you have seen all the reports of bikes and scooters going up in flames, your single cell can go the same way if miss-treated, which includes not charging it correctly.

 

[dunnyrail]

I would only use a charger dedicated to charging lithium batteries for lithium batteries, you have seen all the reports of bikes and scooters going up in flames, your single cell can go the same way if miss-treated, which includes not charging it correctly.

Well said Jimmy strengthening my warning in Post #3.

 

[GAP]

I charge mine inside a charging bag, sitting on a stand that has a top of ceramic tiles and is on a concrete floor in an open area.

 

[dunnyrail]

I charge mine inside a charging bag, sitting on a stand that has a top of ceramic tiles and is on a concrete floor in an open area.

Sound policy, that with a proper charger will maintain safety. The vid linked below shows the possible out what could occur.

Luckily that guy and dog could escape the room, imagine if that battery had been charging in a closed room with the dog snoozing on the settee.

 

[JimmyB]

Lithium fires on the news again last night and this morning, often is seems from not using certified matched components.

 

[collectors]

Must admit, i got rid of 2 mobile phones a few months back as i new there would be personal info on them, so i took them into the garden & took a club hammer to the 1st one & forgot about the battery. On the 1st hit there was smoke & about a second later it traveled about ten feet across the ground like a jet. There is a lot of power in these little battery's. "Yes i took the battery out the 2nd phone.

 

[dunnyrail]

Lithium fires on the news again last night and this morning, often is seems from not using certified matched components.

To say nothing of them catching fire in bin lorries when disposed if in ignorance, disposable vapes should never have been called thus. But what you would call them in probably open for debate, to my mind spawn if the devil.

 

[Rhinochugger]

Must admit, i got rid of 2 mobile phones a few months back as i new there would be personal info on them, so i took them into the garden & took a club hammer to the 1st one & forgot about the battery. On the 1st hit there was smoke & about a second later it traveled about ten feet across the ground like a jet. There is a lot of power in these little battery's. "Yes i took the battery out the 2nd phone.

Easier to do a factory re-set on yer mobile phone Should be able to Google how to do it

On the other hand, I rather like the idea of the lump hammer approach

 

[PhilP]

The gentlemen, who run Vape-Shops, are nothing like the Gentlemen who ran Tobacconists..


PhilP

 

[GAP]

To say nothing of them catching fire in bin lorries when disposed if in ignorance, disposable vapes should never have been called thus. But what you would call them in probably open for debate, to my mind spawn if the devil.

The place where I worked back in the day had a battery disposal bin and it caught fire due to a battery short circuit, the fire investigation revealed there were no Li batteries in the bin and it was NiMH batteries that caused the fire.
Solution was to cover the terminal ends with tape and place in a plastic bag, a roll of packing tape and bags were placed next to the bin for that purpose.

Australia has just banned disposable vapes.
From the Therapeutic Goods Administration website "it will be unlawful to import disposable vapes on or after 1 January 2024, even if those vapes were ordered before 1 January 2024 and have not yet arrived in Australia."

 

[Paul M]

The place where I worked back in the day had a battery disposal bin and it caught fire due to a battery short circuit, the fire investigation revealed there were no Li batteries in the bin and it was NiMH batteries that caused the fire.
Solution was to cover the terminal ends with tape and place in a plastic bag, a roll of packing tape and bags were placed next to the bin for that purpose.

Australia has just banned disposable vapes.
From the Therapeutic Goods Administration website "it will be unlawful to import disposable vapes on or after 1 January 2024, even if those vapes were ordered before 1 January 2024 and have not yet arrived in Australia."

Good for them. And I bet they'll actually enforce it too. When was the last time anyone was fined for anything other than a driving offence here? Apart from of course, innocent post office owners?