I just want to ask if I can charge 4pcs. 18650 protected li-ion batteries in parallel using 7.4v 1500mah charger?
thanks....
thanks....
charging 4 pcs. 18650 in parallel
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the charger can be set to 4.5volts... would this voltage safe to charge 4 pcs. protected li-ion 18650 batteries in parallel?
If the batts are protected, then the protection will trip at 4.2V. So in theory, you should be ok, but you really should get a Li-Ion charger that puts out 4.2V max.
You can not charge lithium batteries counting on protection boards. These boards are for extreme situations only. Don't do it! You must use a special charger only.
There's also the issue of high equalization currents when charging batts in parallel. If the state of charge is different by only a few tenths of a volt when the batteries come in contact with eachother, high currents will flow from one battery to the other. It can cause a battery to vent, especially if unprotected.
For charging four 3.7V Li-Ion batts at the same time, you should use a 4 channel 3.7V Li-Ion charger or a couple of 2 channel chargers.
The terminal charging voltage for a 3.7V Li-Ion is 4.2V so it's possible to use a 4.2V source, but requires current limiting and it would have to be exactly 4.2V. Li-Ions are very sensitive to over-current during charging and terminal charging voltage. Typically, charging currents are limited to half the maximum output current, but it's still a good idea not to charge them anywhere close to the limit. They can vent if currents or voltages are too high. When a battery vents, it expells super heated gasses at a high rate and can catch fire as well. Definitely not something to take lightly.
For charging four 3.7V Li-Ion batts at the same time, you should use a 4 channel 3.7V Li-Ion charger or a couple of 2 channel chargers.
The terminal charging voltage for a 3.7V Li-Ion is 4.2V so it's possible to use a 4.2V source, but requires current limiting and it would have to be exactly 4.2V. Li-Ions are very sensitive to over-current during charging and terminal charging voltage. Typically, charging currents are limited to half the maximum output current, but it's still a good idea not to charge them anywhere close to the limit. They can vent if currents or voltages are too high. When a battery vents, it expells super heated gasses at a high rate and can catch fire as well. Definitely not something to take lightly.
I just want to ask if I can charge 4pcs. 18650 protected li-ion batteries in parallel using 7.4v 1500mah charger?
thanks....
I smell smoke not vapor .......
The problem is trying to charge batteries set up to charge( parallel ) @ 3.7 volts @ 7.4 volts ( nominal voltages )
It could work out if you did a hybrid config and ran 2 batteries in series and a the other 2 in series separate from each other then parallel the two two packs.
I smell smoke not vapor .......
The problem is trying to charge batteries set up to charge( parallel ) @ 3.7 volts @ 7.4 volts ( nominal voltages )
It could work out if you did a hybrid config and ran 2 batteries in series and a the other 2 in series separate from each other then parallel the two two packs.
i thought i read somewhere in this forum that charging batteries in series would not be advisable because one battery will charge faster than the other?. correct me if i'm wrong...
You're right, hence all the discussion about balancing chargers.
Not really they will charge pretty evenly when in series. Especially in a S2 configuration. When you go over 2 batteries in series is when you want to balance them for sure. When i did RC airplanes I had S4 li po packs the charger was separate from the balancer. So i would charge the batteries till the charger finished then plug the pack into the balancer . So balancing is not required while charging. IF you look up safety on Li ions you will see protection circuits and balancing is required but it also says standards can be relaxed on 1 and 2 cell configs. You still want a protection circuit but balancing is not really required. You cant really balance one cell since there is no other battery to balance it with. Really as long as your using a S2 protection circuit it is pretty safe. If done right there is no reason why you cant set up a S2 charger in a mod. If you take two brand new matching batteries and solder them into a S2 protection circuit then heat shrink them together is the ideal way. If you made it to where you could plug in your 2 year old AW battery and your one week old AW battery one being 2600mah and the other 2900 mah then no this is for sure not a good idea. So i am going to stick by if done correctly there is no reason why you cant charge 2 batteries in series without balancing.
Here is a picture of a professionaly made 2S pack only difference is this is a 3x3 hybrid config. So it has 3 cells in parallel then another 3 cells in parallel then they are wired in series. Only way i recommend charging like this is if you do what the pros do. They use all matching batteries made from the same lot /batch. They Use a 2S protection circuit . An on top of that a lot of them will add a fail safe by adding a PTC device like a polyswitch . Here is a link to that packs web page some good info there Customize Li-Ion 18650 Battery: 7.4 V 6600 mAh (44.84 wh) battery module with PCB
Having said that, in your diagram you have the batteries in series then paralleled them. You would parallel them then put the two separate parallels into series to properly wire them into a S2 protection circuit .
Here is a pic of a 2S protection board the com or common is where you would link the two parallel packs together. Soldering one positive and one negative from the different parallel pack to the com putting them in series. The remaining two go to B+ and B- . This way the protection circuit can monitor the separate parallel packs. The p- and p+ go to your load /charger
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else find a good charger and charged them in serial ..... not wise to parallel charge the batteries ......
i using this cellpro 4s .... but this product is no longer in production, theres better ones from that company ....
example >>> cellpro 4 multli
i using this cellpro 4s .... but this product is no longer in production, theres better ones from that company ....
example >>> cellpro 4 multli
The protection circuits do not trip at 4.2V. Many chargers routinely charge cells to over 4.2V. Most circuits may trip at ~4.3V.
Relying on a standard Li-Ion battery's protection circuit to terminate charging is neither safe nor recommended. It's the chargers job to establish and correctly terminate charging.
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