New answers tagged

0

No, it is not safe to use, and you should discontinue use of that cell immediately and store it in a fire-proof container. Normally, protection circuits will have a 'fuse' function that will permanently disconnect the cell, effectively destroying it (unless you bypass the protection circuit, which you shouldn't). Any LiIon cell of that chemistry is destroyed ...


0

I don't think you can tell the difference between a battery that has been used carefully for a long period of time and a battery that has been abused for a short period of time. The degradation of the battery will be very similar. In both cases the capacity of the battery will decrease and the ESR will increase. But there is also manufacturing variation, and ...


0

internal resistance increases when capacity decreases I think this is correct because if you take two 2000 mAh capacity cells in parallel with 100mΩ each, the effective resistance is 50mΩ. So a single 4000 mAh cell of the same chemistry should have the same 50mΩ internal resistance as two 2000 mAh cells in parallel. One can argue that a single 4000 mAh ...


0

The assumption was incorrect to say 19.5V is applied to charge a 11.55V laptop battery pack. Laptops all have a CC,CV,cutoff battery charge control from the now universal 19.5V chargers. Battery life is degraded by heat, undercharge and less likely from overcharge as that is regulated ( unless faulted suddenly when new ) laptop batteries age faster when ...


0

"Where I am a bit lost then is, how can I charge the battery? Do I just wire an input path and output path in parallel" First off, I'm new to this part as well. But this is the idea yes. Your li-ion charger will do it's constant current (CC) and constant voltage (CV) charging. But it is not just charging the battery it is also powering a "...


1

(TY AG I read too fast, and thought load is on the battery rather than on the charger which is OK) Apologies Certainly, you can load the charger and reduce its capacity while charging the batteries at a lower CC rate. Previous Answer to a different understanding. If you had the load on the battery side, you should cut charging to the battery if it is ...


0

It doesn't look safe, no. If I read this correctly, it is 1P2S6P and it's neither cost efficient nor safe. First you connect the cells in parallel. Once you do that they become one self-balancing cell. Then put them in series. So basically 6P2S is what you need, P first, S second, and no more Ps after that. Otherwise single sells in series will drift without ...


1

Either your battery is 10 kWh or 10 kAh but not normally referred to as 10 kVAh (a term we might use in AC circuits due to power-factor). If your battery's internal resistance is 320 mΩ then the maximum current you could draw into a dead short (not recommended) would be \$ I = \frac V R = \frac {50}{0.33} = 150 \ \text A \$ but you would have zero volts at ...


4

When you split a certain capacity battery into two separate (half size, half capacity) batteries, you might be able to have better thermal performance. That means, it gives you more flexibility in where the batteries are located and that could potentially help in keeping the batteries cool(er) during charging. During very fast charging (maximum current you ...


4

Whatever voltage below 12 volts is applied will result in a proportional reduction below the nominal speed at 12 volts. That should cause no problem for the motors.


0

Be careful when charging these cells in series. One cell will always win and get overcharged (too many volts.) If left in this state it will possibly explode. Limiting the current is not good enough (power is watts = amps x volts.) To do the job safely place a clamp Zener diode across each cell. Limit the charging circuit to within the recommended current ...


1

I will just post this comment from above as an answer as handyguy confirmed that it could be useful. Still, somehow drawing out a wire wth the control signal will be simpler of course. Things to pay attention to: The color of LEDs D2-D5 has to be "redder" than that of D1. It wont work if those are e.g. blue LEDs and D1 is green. A safe bet would ...


0

The generally accepted method for grouping Lithium Ion cells in a pack is to start with well matched cells (same brand and model and new ideally, and factories will go as far as to buy a massive batch and group similar cells from that in a process called binning) and bring them to the same voltage before ganging them. in addition, balance parallel cells by ...


0

My 2 cents coz had the same problem with my grandson's rc. The stock battery died after 4-5 charges. Simply, get new 2 pieces 18650 battery. Unwrap the stock battery pack, unsolder the wirings with the balance connector. . Use that same wire exactly on the new batteries. Bingo, you just save couple of dollars for stock replacement battery! Test using the ...


2

"radio" buttons (interlocked push buttons) of a multi-way rotary switch. (wafer switch)


0

Charge them up fully to 4.1v or 4.2v and see if they hold the voltage. Or you could put them in a charge cycle if you have a charger that'll do that (quality RC car chargers work quite excellent for this) for a few rotations and see how they handle that. if there is no issues with the power cycling then I'd say they are just fine. I've taken some 18650's ...


Top 50 recent answers are included