NewStats: 3,261,444 , 8,174,018 topics. Date: Thursday, 29 May 2025 at 09:51 AM 5a4t1v

ksmart027:

Pls which inverter will you advise i get? because i dey use am power my appliances.

Psw or replace your fan with rechargeable fan.

dollarnaira:

Psw or replace your fan with rechargeable fan.

I use a DC fan, connected directly to my battery, just my tv is smart.

ksmart027:

I use a DC fan, connected directly to my battery, just my tv is smart.

Ok. But pls save the life of your tv henceforth. 1600w psw is around 70k

ksmart027:

Baba na small set up oo , 100ah battery, I don't know the precise amps and 1,000kva inverter, 100w load last 12 to 13hrs. I am planning to add s.

nice, when building it, how did you single charge each cells?

officialfestus:
nice, when building it, how did you single charge each cells?

Baba no be me build am oo, tetralogyfallot built it for me

dollarnaira:


Ok. But pls save the life of your tv henceforth. 1600w psw is around 70k

Thanks boss

ksmart027:

Baba no be me build am oo, tetralogyfallot built it for me

ok.

officialfestus:
bro go youtube oh, like this my pack never still they alright.

Lol.... But I can still share from the little u Kno nah

Makaveli217:


You'll need a digital multi meter and a timer (clock) or your phone time.

First connect the battery to the meter, if the battery is fully charged, you'll get 4.25v or 4.45v pending on the battery type, now connect the fan to the battery while the meter is still connected, once connected, time it, I time mine 1mins, sometimes 2minis. (This is where the clock comes in). If it's a good battery, it should read 4.24v or 4.28v, now that's the voltage drop. (Eg Below). That's how to know a good battery, if it drops below that, it's bad, even if it drops to 4.00v, connecting it together with other cells in series or parallel is risky.

Let's take for example, if the battery reads 4.25v while connected to the meter, then reads 4.20v when you connect the fan (voltage drop), that is 4.25 - 4.20 = 0.05. After your 1mins has enlaps, disconnect only the fan, now the battery voltage will rise back to the default voltage it was which is 4.25v, some will rise to 4.24v then slowly reach 4.25v. Now that's a good battery. Any battery that doesn't rise back to it's default voltage is close to going bad.

If after your calculations and yours drops below 0.05, don't mix it with others that is above 0.05.

Thanks brodally, this is quite appreciated.

1. I have a digital multi meter

2. My batteries read 3.9 after been charged, maybe not fully charge because I'm not using the right thing to charge it. I'm using power bank charging module.


3. What type of fan am I to use for this purpose? I think same 3-5v motor hand fan would do?


Thanks for your time and contribution.

flotwz:


Thanks brodally, this is quite appreciated.

1. I have a digital multi meter

2. My batteries read 3.9 after been charged, maybe not fully charge because I'm not using the right thing to charge it. I'm using power bank charging module.


3. What type of fan am I to use for this purpose? I think same 3-5v motor hand fan would do?


Thanks for your time and contribution.

1. Ok

2. What type of battery is it, a pic would be better. Charging a battery using power bank circuit board should give you 4.2v - 4.5v depending on the battery type.
If you want to try alternate charging method as seen in some portable speakers where they make use of SMD diodes like (M1, M5, M7 or S1, S5, S7) Etc, you can use any diode like (In4007, 4005, 4008, 4004, 4009) and a resistor in series (1.0ohms - 2ohms) with the diode.
Eg 5v charger (+) > Diode > Resistor > Battery.

3. This is what I use 5v Notebook Cooler 120mm in size. Picture included.
I haven't tried DVD DC motors, so I have no idea how much voltage they draw.

This is ok for me.
Please what's the cost outlay?

ksmart027:

Baba na small set up oo , 100ah battery, I don't know the precise amps and 1,000kva inverter, 100w load last 12 to 13hrs. I am planning to add s.

Makaveli217:


1. Ok

2. What type of battery is it, a pic would be better. Charging a battery using power bank circuit board should give you 4.2v - 4.5v depending on the battery type.
If you want to try alternate charging method as seen in some portable speakers where they make use of SMD diodes like (M1, M5, M7 or S1, S5, S7) Etc, you can use any diode like (In4007, 4005, 4008, 4004, 4009) and a resistor in series (1.0ohms - 2ohms) with the diode.
Eg 5v charger (+) > Diode > Resistor > Battery.

3. This is what I use 5v Notebook Cooler 120mm in size. Picture included.
I haven't tried DVD DC motors, so I have no idea how much voltage they draw.

Your response is much appreciated.

1. I extracted the batteries from laptop power pack, and Samsung is not written on it. I'm not at home presently I would have snapped it and it here. (I would do so on Monday once I get home)

2. As for alternative charging illustrated (use of SMD diodes and resistors). I'm not well too grounded in electronics.

3. I can easily get 5v notebook cooler

On Monday, I'll the batteries. Thanks once again

officialfestus:
bro go youtube oh, like this my pack never still they alright.

What happened to your pack?

Building lithium battery takes a lot of patience to have a good build.

Still have this going for 50k.

24v, 800w continous power.

flotwz:


Your response is much appreciated.

1. I extracted the batteries from laptop power pack, and Samsung is not written on it. I'm not at home presently I would have snapped it and it here. (I would do so on Monday once I get home)

2. As for alternative charging illustrated (use of SMD diodes and resistors). I'm not well too grounded in electronics.

3. I can easily get 5v notebook cooler

On Monday, I'll the batteries. Thanks once again

You're very much welcome.

1. OK, you'll get 4.2v - 4.4v when fully charged.
Do ensure to charge it full and leave it for sometime before you begin the test, I recommend overnight or a whole day, I call it the cool down period or break in period, reason because immediately after charging, there's a voltage rise, eg, a battery rated 4.2v when fully charged will read 4.4v, so that's to ensure any over flow voltage to properly settle.

2. That's not an issue, I can put you through in some part you don't understand.

3. Cool, desolder the blue led that's connected with the fan, I removed mine.

flotwz:


Your response is much appreciated.

1. I extracted the batteries from laptop power pack, and Samsung is not written on it. I'm not at home presently I would have snapped it and it here. (I would do so on Monday once I get home)

2. As for alternative charging illustrated (use of SMD diodes and resistors). I'm not well too grounded in electronics.

3. I can easily get 5v notebook cooler

On Monday, I'll the batteries. Thanks once again

Pls never charge li-ion cells over 4.2v for any reason unless the manufacturer states it in the battery specs, better you charge below that voltage to extend the life of the cells. Lithium ion is not forgiven of over-voltage

ewizard1:

What happened to your pack?

Building lithium battery takes a lot of patience to have a good build.

I noticed one of series was self discharging.
Others will be at 4.15, while the serie with the bad cell will be at 3.59.
For that reason, it wasn't performing very well because the bms will cut flow when the pack hits a certain voltage, I had to dismantle the pack to spot the bad cell, after dismantling, I decided to charge the serie that was self discharging via a buck converter connected to a laptop charger, then I spotted the cell that was bad, it was getting hot, Asap I disconnected the cell from the serie and boom the serie was able to charge to 4.15 without stress.

(Connected a multimeter to the bad cell, with a minute it drained from 3.59 to 0.2v).

flotwz:


Lol.... But I can still share from the little u Kno nah

I posted everything on this thread.

officialfestus:
I noticed one of series was self discharging.
Others will be at 4.15, while the serie with the bad cell will be at 3.59.
For that reason, it wasn't performing very well because the bms will cut flow when the pack hits a certain voltage, I had to dismantle the pack to spot the bad cell, after dismantling, I decided to charge the serie that was self discharging via a buck converter connected to a laptop charger, then I spotted the cell that was bad, it was getting hot, Asap I disconnected the cell from the serie and boom the serie was able to charge to 4.15 without stress.

(Connected a multimeter to the bad cell, with a minute it drained from 3.59 to 0.2v).

That's usually the issues when you don't perform what I term "Self-discharge test"

Like I said previously, building requires patience. But I understand the excite-rush when first assembling .

Been there, done that.

ewizard1:


That's usually the issues when you don't perform what I term "Self-discharge test"

Like I said previously, building requires patience. But I understand the excite-rush when first assembling .

Been there, done that.

please sir,I want to embark on this kind of diy project,and I want to source for laptops battery to extract this smaller batteries from....
Will I be able to achieve this assembling with these kind of batteries?...
I also need help with necessary steps and mentoring.. could you please put me through sir?..

psucc:
This is ok for me.
Please what's the cost outlay?

I don't know the cost now because i bought mine six months ago. I mentioned the name of the person who build it above, you can chat him up. You can also buy cells from him and build if you are into diy.

sholikay:
please sir,I want to embark on this kind of diy project,and I want to source for laptops battery to extract this smaller batteries from....
Will I be able to achieve this assembling with these kind of batteries?...
I also need help with necessary steps and mentoring.. could you please put me through sir?..

- Know the basics.
- Get your cells.
- Test them! RIGOROUSLY!!!
- Design
- Build.
- Install. With necessary protection in-place.
- Enjoy.

ewizard1:


- Know the basics.
- Get your cells.
- Test them! RIGOROUSLY!!!
- Design
- Build.
- Install. With necessary protection in-place.
- Enjoy.

is there any basic I need to study well?. I have followed how officialfestus/dollarnaira did theirs ..but my kind of batteries sourcing will be different from theirs...I'm sourcing for laptops batteries,and see if I can get good ones from them ..is that a good idea or i should buy a particular brand of battery cells instead of the different cells I will be assembling...

Or does the battery cells have different type,codes or power outputs,which may not allow them to be connected altogether?

Thank you sir for your responses..

ewizard1:


That's usually the issues when you don't perform what I term "Self-discharge test"

Like I said previously, building requires patience. But I understand the excite-rush when first assembling .

Been there, done that.

I've learnt a lot from my mistakes.

Makaveli217:


You're very much welcome.

1. OK, you'll get 4.2v - 4.4v when fully charged.
Do ensure to charge it full and leave it for sometime before you begin the test, I recommend overnight or a whole day, I call it the cool down period or break in period, reason because immediately after charging, there's a voltage rise, eg, a battery rated 4.2v when fully charged will read 4.4v, so that's to ensure any over flow voltage to properly settle.

2. That's not an issue, I can put you through in some part you don't understand.

3. Cool, desolder the blue led that's connected with the fan, I removed mine.

Thanks for the ur detailed information brodally.

The attached iss the picture of the battery

Penuelseun:
Pls never charge li-ion cells over 4.2v for any reason unless the manufacturer states it in the battery specs, better you charge below that voltage to extend the life of the cells. Lithium ion is not forgiven of over-voltage

Thanks for the instruction

flotwz:


Thanks for the ur detailed information brodally.

The attached iss the picture of the battery

Google that battery inscription to know d more abt it especially d capacity

okikigsm:


Google that battery inscription to know d more abt it especially d capacity

There isn't need. Cells like those obviously don't have data online.

Brand new open box
PowMr 20A mppt
40k

I have finally decided to the lithium pack Geng.

Below is a picture of the battery pack, a capacity tester and a charger

flotwz:


Thanks for the ur detailed information brodally.

The attached iss the picture of the battery

You're welcome
I hope it's good. You can follow the steps I mentioned before, charge and test run it, if you have more, do the same for all, I wish you luck.

Obnoxious2001:
I have finally decided to the lithium pack Geng.

Below is a picture of the battery pack, a capacity tester and a charger

Have always wanted to make a smal pack for a rechargeable fan, but my concern is charger to use and where to get bms. Can you pls detail your process.