chargeprep
Newly Enlightened
- Joined
- Feb 9, 2008
- Messages
- 1
Hello,
First off, what a great forum! So much good info on batteries and how to charge batteries!
I have a few questions concerning charging single cell lithium ion batteries. My query stems from the various gadgets that I have that are powered by rechargeable 3.6V/3.7V lithium-ion and lithium-polymer battery packs. When I travel, I usually end up bringing all the chargers for each of my pieces of equipment. This is getting to be a not-so-insignificant amount of volume in my luggage.
What I'd like to do is to get a single charger that can charge all of these battery packs. Not only will this lighten up my packing regimen, this will also have the benefit of allowing me to charge these battery packs externally from my gadget rather than requiring the gadget to be tied to the wall charger for a few hours.
From what I have read on this site, single-cell lithium-ion batteries have a fairly simple charging algorithm: charge at a constant current (Iconst) until the max voltage (Vmax) is reached; then switch to constant voltage until the current drops to the low current threshold (Icut).
So this is where I'd like to get some help. I've noticed from previous searches on the web that there are some universal chargers out there such as the Maha C777Plus2 and the Lenmar BCLC1X. It seems that these devices charge using the same electrical circuit; all that is changed for charging different batteries is to either physically move the terminal contacts to align to the battery (in the case of the Maha) or install a different adapter plate (in the case of the Lenmar).
So here's my questions:
1a. Is it safe to use a universal charger such as those above? From what I have read here, the constant charging current (Iconst) does not seem to be too critical (as long as it is about 0.5C, I presume).
1b. But what about the differing design values for Vmax and Icut depending on the actual battery?
1c. Would the different rated voltage of 3.6V or 3.7V of the battery make any difference?
1d. What about the composition of lithium-ion v/s lithium-polymer?
2. Any usage comments on the universal chargers above? My only concern is that these universal chargers don't look very compact, so I don't know if I'll end up saving any space in my luggage. Are there any other chargers out there that people can recommend?
3. I've seen some oem external chargers that only have 2 contact pins to connect to the battery whereas the batteries themselves have 3 contacts. For instance, on my Fuji camera battery, there is a third contact labelled 'T' - for temperatue, I would think. Would it be wise to charge a battery using only a 2-pin charger?
4. Here's an "ignorant newbie" question.
Assuming that I can physically get the battery contacts connected, are most lithium-ion battery charger circuits similar enough that I can use an external charger that was meant for a 3.6V, 750mAh battery (i.e., for a cell phone) and charge a 3.7V, 1500mAh battery (i.e., for a PDA)?
Wow, this post is longer than I anticipated! Thanks for any help you can provide!
First off, what a great forum! So much good info on batteries and how to charge batteries!
I have a few questions concerning charging single cell lithium ion batteries. My query stems from the various gadgets that I have that are powered by rechargeable 3.6V/3.7V lithium-ion and lithium-polymer battery packs. When I travel, I usually end up bringing all the chargers for each of my pieces of equipment. This is getting to be a not-so-insignificant amount of volume in my luggage.
What I'd like to do is to get a single charger that can charge all of these battery packs. Not only will this lighten up my packing regimen, this will also have the benefit of allowing me to charge these battery packs externally from my gadget rather than requiring the gadget to be tied to the wall charger for a few hours.
From what I have read on this site, single-cell lithium-ion batteries have a fairly simple charging algorithm: charge at a constant current (Iconst) until the max voltage (Vmax) is reached; then switch to constant voltage until the current drops to the low current threshold (Icut).
So this is where I'd like to get some help. I've noticed from previous searches on the web that there are some universal chargers out there such as the Maha C777Plus2 and the Lenmar BCLC1X. It seems that these devices charge using the same electrical circuit; all that is changed for charging different batteries is to either physically move the terminal contacts to align to the battery (in the case of the Maha) or install a different adapter plate (in the case of the Lenmar).
So here's my questions:
1a. Is it safe to use a universal charger such as those above? From what I have read here, the constant charging current (Iconst) does not seem to be too critical (as long as it is about 0.5C, I presume).
1b. But what about the differing design values for Vmax and Icut depending on the actual battery?
1c. Would the different rated voltage of 3.6V or 3.7V of the battery make any difference?
1d. What about the composition of lithium-ion v/s lithium-polymer?
2. Any usage comments on the universal chargers above? My only concern is that these universal chargers don't look very compact, so I don't know if I'll end up saving any space in my luggage. Are there any other chargers out there that people can recommend?
3. I've seen some oem external chargers that only have 2 contact pins to connect to the battery whereas the batteries themselves have 3 contacts. For instance, on my Fuji camera battery, there is a third contact labelled 'T' - for temperatue, I would think. Would it be wise to charge a battery using only a 2-pin charger?
4. Here's an "ignorant newbie" question.
Assuming that I can physically get the battery contacts connected, are most lithium-ion battery charger circuits similar enough that I can use an external charger that was meant for a 3.6V, 750mAh battery (i.e., for a cell phone) and charge a 3.7V, 1500mAh battery (i.e., for a PDA)? Wow, this post is longer than I anticipated! Thanks for any help you can provide!
