Hello, I have a question: RC car has a lion battery. Why can't the ordinary 7.5

[jzx]

Sir, I do not understand your language. My question is very clear. There is an RC car that works at 7.5 volts. What is important here is not how many volts the RC car is, but how many volts the battery is charged. It needs 7.5 volts, the battery itself, this question is a simple problem, there is no need to discuss it, after all, it charges the battery, I took the adapter back. This is the adapter itself in the same picture

Some batteries can be charged with a fixed voltage (lead or lithium), others with a constant current (NiCd, Nimh), but always there is some "protocol of charge" (start chaging with x current or voltage, later continue in another mode, cut current when something occurs..)  that charges better the battery (faster and with less probabilty of damage the battery). So normally no battery is charged connecting directly to a power supply, but through a special circuit, the charger. Many people call "charger" to any adapter, but they are not the same.

There is no battery that can be charged with 7.5 V, if you use lead, you need 2.4 volt per cell, if you use liion, 4.2, so 7.5 V is not adecuate. Also, be very carefull with liion, they do not tolerate any overvoltage, the voltage has to be very precise. Other batteries normally fail without too much viloence, but liion explode easily.

[BILLPOD]

Good Morning David, I agree with others that your battery pack is not Lithium.   It 'looks'
like it is comprised of 6 cells.   Nimh cells are 1.2 VDC, so that would give your pack a 'NOMINAL' voltage of 7.2 VDC.   The word nominal is important in battery descriptions.

[tooki]

Sir, I do not understand your language. My question is very clear. There is an RC car that works at 7.5 volts. What is important here is not how many volts the RC car is, but how many volts the battery is charged. It needs 7.5 volts, the battery itself, this question is a simple problem, there is no need to discuss it, after all, it charges the battery, I took the adapter back. This is the adapter itself in the same picture

Some batteries can be charged with a fixed voltage (lead or lithium), others with a constant current (NiCd, Nimh), but always there is some "protocol of charge" (start chaging with x current or voltage, later continue in another mode, cut current when something occurs..)  that charges better the battery (faster and with less probabilty of damage the battery). So normally no battery is charged connecting directly to a power supply, but through a special circuit, the charger. Many people call "charger" to any adapter, but they are not the same.

Lithium-ion batteries require CC/CV charging, with most of the charging done at constant current until the maximum voltage, then a constant voltage phase to finish charging.

[pcprogrammer]

Some batteries can be charged with a fixed voltage (lead or lithium), others with a constant current (NiCd, Nimh), but always there is some "protocol of charge" (start chaging with x current or voltage, later continue in another mode, cut current when something occurs..)  that charges better the battery (faster and with less probabilty of damage the battery). So normally no battery is charged connecting directly to a power supply, but through a special circuit, the charger. Many people call "charger" to any adapter, but they are not the same.

There is no battery that can be charged with 7.5 V, if you use lead, you need 2.4 volt per cell, if you use liion, 4.2, so 7.5 V is not adecuate. Also, be very carefull with liion, they do not tolerate any overvoltage, the voltage has to be very precise. Other batteries normally fail without too much viloence, but liion explode easily.

Please don't tell porkies.

A lithium ion battery can not be charged with a fixed voltage, there has to be current limiting. Why because the internal resistance of a very good lithium ion battery is ultra low and when empty the voltage is maybe 3.2V or less. When you then attach a fixed voltage of say 4.2V to the battery the current will go up to as much as the supply will give and the cables can handle. 1V / 0.05 Ohm means 20A, but the resistance can be much lower. At the moment I'm using Sony VTC4 batteries which have a Ri of ~12.5 milli Ohm. 1V / 0.0125 Ohm means 80A. The battery is rated for 1C charge current which in this case is only 2A.

So you start with a constant current until the voltage reaches 4.2V. Then you switch over to constant voltage and stop charging when the current is less then 10% of the start of charging current. That is why you need a good charger for a lithium ion battery.

Ah, tooki was faster with typing then me. 

[pcprogrammer]

Good Morning David, I agree with others that your battery pack is not Lithium.   It 'looks'
like it is comprised of 6 cells.   Nimh cells are 1.2 VDC, so that would give your pack a 'NOMINAL' voltage of 7.2 VDC.   The word nominal is important in battery descriptions.

If you count the buds of the batteries you will see only 5. So 6V is more likely. But I do not see a wire going to the bottom of the pack, so it is a bit of a guess on how the pack is made up.

Edit: they are also a bit weird with the indents in the middle of the battery. As if they stitched two together some how.

[david smth]

Sir, please allow me to explain, there are 10 cells in total and only two of them are connected.

[david smth]

Good Morning David, I agree with others that your battery pack is not Lithium.   It 'looks'
like it is comprised of 6 cells.   Nimh cells are 1.2 VDC, so that would give your pack a 'NOMINAL' voltage of 7.2 VDC.   The word nominal is important in battery descriptions.

There is no writing on it. So far, I have charged it with an adjustable adapter. Even though it is 7.5 volts and 12 volts, it will definitely not harm the battery. I tried it at least a few times and it did not harm the battery.

[david smth]

I'm as skeptical as the people here since this battery is not lithium, so I bought it from the store but they didn't say anything, it will require a special charger for the lithium battery. The page only says lithium, I have no knowledge, I don't want to waste people's time here, what are the good and bad aspects of lithium and Ni CD? Are these dangerous? Charges between 7.5, 9 and 12 volts, 12 volts charges quickly

[david smth]

Interesting page says lithium, this seems like a scam

[IanB]

It really would help if you could tell us more about the battery, what packaging it came with, how it was described by the seller, anything like that?

Typically, a removable battery for an RC car or plane would have a special RC charger, it would not just be charged with a simple power adapter.

[tunk]

What's the size of the battery pack and the individual cells?
If the cells are 18x65mm (diameter x length), most likely they're Li-ion.
If they're 14x50mm, then most likely NiMh (though they could be Li-ion).

Edit: Even if they don't look like they're harmed, they could still be damaged.

[BeBuLamar]

I'm as skeptical as the people here since this battery is not lithium, so I bought it from the store but they didn't say anything, it will require a special charger for the lithium battery. The page only says lithium, I have no knowledge, I don't want to waste people's time here, what are the good and bad aspects of lithium and Ni CD? Are these dangerous? Charges between 7.5, 9 and 12 volts, 12 volts charges quickly

If it's NiCad or NiMH it would be more difficult to charge than Li-Ion.

[david smth]

this charging adapter

[david smth]

It usually charges at 7.5 volts and 9 volts, the adjustable adapter charges faster than the original adapter.

[Gyro]

It usually charges at 7.5 volts and 9 volts, the adjustable adapter charges faster than the original adapter.

How are you deciding when the battery is fully charged? I don't  see any indicators. This is a very important question if they are Lithium cells.

[BeBuLamar]

The adjustable adapter is capable of 500mA and the fixed voltage adapter is capable of only 250mA. If the battery is Li-Ion it can be charge with higher current than those and the 500mA would charge faster.

[pcprogrammer]

To get things more clear the question is if the OP has a multi meter to measure the voltages on the battery pack, but more importantly the voltages of the individual cells, at least for as far as possible.

A better picture of the connections on the battery pack, preferably with the insulation removed, would help a lot in determining what is wise in this case.

A picture of the inside of the original adapter would also provide a lot of information.

Based on what I have seen so far, the original adapter connects to the battery pack directly with the same type of (Molex ?) connector. The connector looks a bit like what is used for PC mother board power supply, but with only two pins.

[tooki]

It really would help if you could tell us more about the battery, what packaging it came with, how it was described by the seller, anything like that?

It’s clear that OP is intent on not answering any questions, since he’s already certain he knows better…   

[CaptDon]

Reading through the O.P. who is trying to educate the teachers.....His 7.5 adapter does seem to charge but slowly. Now look at the stupidity of his next statements, "It charges faster at 9 volts and even faster at 12 volts". Fortunately for him, that feeble piece of shit 'adjustable adapter' is only capable of a current limited by the core size of the transformer, otherwise he would have blown the battery pack apart by now. We can only guess how the pack is wired since we can't really see the cell to cell connections. Could be 7.2 nominal NiMH or 7.6 nominal Lithium Ion, doesn't really matter when you are improperly charging in the first place. Either of the battery styles I mentioned would charge from 9 volts or 12 volts provided by a craptastic P.O.S. variable supply. Either type of battery would also charge very poorly from 7.5 volts as the O.P. observed. Surely if he was stupid enough to set the charger on 12vdc and leave the battery charging for several days the absolute outcome would be a destroyed battery, possible fire/explosion or a burned out 'adjustable adapter'!!! Go ahead, try it and see!!! To the O.P., do you think anyone could even guess as to how the cells are wired when showing us a picture of a multi-cell battery that still has the shrink wrap surrounding the cells? IF it is lithium ion my guess from looks is 5 parallel pairs of cells needing a minimum of 8.4 volts to charge and also an EXTREME fire explosion hazard with that many parallel cells should any one cell short do to the ignorant un-certified way you are charging them. Ignorance is bliss!!!

[david smth]

Is this stupid? The photo you sent has a high IQ. I will send you a video. It doesn't matter if it's 7, 12 or 9 volts. Buy any charger. These batteries will definitely not charge. If it happens, I'll give you 100,000 thousand dollars.
I'm giving you this battery as a gift. Buy it and charge it. If it works, I'll admit I'm stupid.

[david smth]

It only charges with a regulated adapter. I tried with many adapters but it didn't work. I don't train anyone, I'm not a teacher.

[david smth]

I left it charging for 2 days but it didn't explode. What do you think about it? Well, I charge it every day. I will send it to you as a gift. You can try it with your friend in the picture. Please don't tell me the result.

[valcher]

Judging by the photo provided, these are ten AAA NiMh (NiCd) batteries connected in parallel and series to form a 6.0 volt battery. I dare to assume that this is a Chinese car model, which should indeed be equipped with a 7.4 volt Lion battery. But for some reason, the manufacturer equipped them with a different type of battery, and did not display this in the description.
Sorry for the English.

[david smth]

How do you know these? Thank you for the correct answer.

[tooki]

How do you know these? Thank you for the correct answer.

Like everyone else here he is guessing, since you stubbornly refuse to provide basic information that has been requested repeatedly.