Hello,
I was doing some measurements on two Li-ion battery packs.
What i do is first charge them both fully. Then i use one to charge a phone from about 85 percent to 100 percent. Then i drain the phone back down to about 85 percent, then use the other pack to charge the phone.
In both cases the phone takes close to 2 watt hours of energy to charge.
But in both cases the battery packs take about 10 watt hours to recharge back to 100 percent.
This doesnt make much sense because that would mean the battery pack and charge and discharge combined efficiency must be only about 20 percent. That does not match other tests i have done on single cells of different chemistries where the energy in is much closer to the energy out, although those tests do not take into account the charging system losses.
I might do some more tests, but any idea what might be the cause of this?
The two packs are very different types from two different manufacturers and have different internal voltages, where one has close to 15v internal and the other i think is lower but i dont know because i cant measure that one.
I was doing some measurements on two Li-ion battery packs.
What i do is first charge them both fully. Then i use one to charge a phone from about 85 percent to 100 percent. Then i drain the phone back down to about 85 percent, then use the other pack to charge the phone.
In both cases the phone takes close to 2 watt hours of energy to charge.
But in both cases the battery packs take about 10 watt hours to recharge back to 100 percent.
This doesnt make much sense because that would mean the battery pack and charge and discharge combined efficiency must be only about 20 percent. That does not match other tests i have done on single cells of different chemistries where the energy in is much closer to the energy out, although those tests do not take into account the charging system losses.
I might do some more tests, but any idea what might be the cause of this?
The two packs are very different types from two different manufacturers and have different internal voltages, where one has close to 15v internal and the other i think is lower but i dont know because i cant measure that one.
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