Charging 3 D size liion cells in series
- Thread starter CM
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Hi there!
Im going to do a new P7 Mag mod.I want to use 3 protected D size liion cells in series,so my question is:
- They are indivudually protected...Can i charge them in seires?
- If not...what charger should i use? Because i want to use an externall socket to easily charge my flashlight.
Thanks !
Im going to do a new P7 Mag mod.I want to use 3 protected D size liion cells in series,so my question is:
- They are indivudually protected...Can i charge them in seires?
- If not...what charger should i use? Because i want to use an externall socket to easily charge my flashlight.
Thanks !
mdocod
Flashaholic
You'll need to wire them into a pack with balance taps. The balance taps will need to be welded to the cells (more than likely). You'll need a li-ion hobby charger that can do "11.1V" li-ion packs with full balancing. For a 3 cell pack, I believe you will need a 4-pin charging jack.
Northern Lights
Flashlight Enthusiast
Yes or er... no... Generalizations do not take in account all factors. Definately unprotected cells are a danger. Up to three in series will respond to imbalances if you use a good lithium smart charger and good protected cells. The circuits will shut down the process and you need to keep an eye on it. Those D Lithiums have awful protecrtion circuits that did not work as intended. I build rechargeable lights and find that AW c-cells usually charge ok in series. Quality pcbs. That aside you can build a pack that will do the balancing and you will not need to use the circuitry of a balancer or balancing charger. Batteryspace.com sells PCBs that you build into the packs and then use smart chargers. Usually there is much wasted space on the boards that can be cut away on the boards. You can see these charger do not have balancing circuits, many rc chargers do not as the manufacturers leave the choice of how to balance to the end user. That is use an external balancer of a pack with a balancer built into the protection and that is what BS sells.
Here is an example where I made a pack with two of those Ds, I removed the on board protection circuits and used the onboard connectors but I found the batteries underneath were shrink wrapped adn probably were the un-protected ones sold as a different sku. Cheaper to buy that and add the pcb than buy the protected and tear it down. I scrounge flexible circuit tapes like those that connect moveable carriages for thin connectors that can run down the side of a battery. The rc guys, from rcgroups.com build packs all the time, good info there. Here is mine.
Another M*gCharger 5761, but why
From the out ward appearance, and the view point of the charger I am charging in series. From the pack, the internal balancer keeps things equal.
I never had AW cells in two cell 5761s get out of balance and I recharged them in the lights. When I found emoli and A123 cells I then used those cells as they do not sag voltage on the 5761 like the AW cell as that is the top of the AW limit. A123 is a Lithium iron compound, e-molli is a Lithium manganese. Both of these are considered safe lithium. If used in a light you need not worry much of about imbalances. They do not burn or explode and if you got a cell that charged and discharged differently, well that is all you would have one with different capacities and voltage on the meter. Lithium Ion cells, unprotected treated like you can e-moli or A123 is a problem that can cause fire.
Well, you see, the answer is not a simple No or Yes, not even a simple Maybe.
I am buiding a tri-P7 with three of those Ds. I will remove the protection circuits and use the onboard connectors and hook up a batteryspace.com pcb in the light making this a 3D liion pack. I will put a series charging jack up by the switch. I have used these pcbs like this before with the chargers offered by bs with no problems.
Here is an AW cell set up- CLICK TO ENLARGE
This is a 5761 on A123 and you can see the jack set up behind the switch
- CLICK TO ENLARGE
Here is an example where I made a pack with two of those Ds, I removed the on board protection circuits and used the onboard connectors but I found the batteries underneath were shrink wrapped adn probably were the un-protected ones sold as a different sku. Cheaper to buy that and add the pcb than buy the protected and tear it down. I scrounge flexible circuit tapes like those that connect moveable carriages for thin connectors that can run down the side of a battery. The rc guys, from rcgroups.com build packs all the time, good info there. Here is mine.
Another M*gCharger 5761, but why
From the out ward appearance, and the view point of the charger I am charging in series. From the pack, the internal balancer keeps things equal.
I never had AW cells in two cell 5761s get out of balance and I recharged them in the lights. When I found emoli and A123 cells I then used those cells as they do not sag voltage on the 5761 like the AW cell as that is the top of the AW limit. A123 is a Lithium iron compound, e-molli is a Lithium manganese. Both of these are considered safe lithium. If used in a light you need not worry much of about imbalances. They do not burn or explode and if you got a cell that charged and discharged differently, well that is all you would have one with different capacities and voltage on the meter. Lithium Ion cells, unprotected treated like you can e-moli or A123 is a problem that can cause fire.
Well, you see, the answer is not a simple No or Yes, not even a simple Maybe.
I am buiding a tri-P7 with three of those Ds. I will remove the protection circuits and use the onboard connectors and hook up a batteryspace.com pcb in the light making this a 3D liion pack. I will put a series charging jack up by the switch. I have used these pcbs like this before with the chargers offered by bs with no problems.
Here is an AW cell set up- CLICK TO ENLARGE
This is a 5761 on A123 and you can see the jack set up behind the switch
- CLICK TO ENLARGE
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+1 for the aw cells. I charge 2 of them is series with the charger I got from KD with 2d cell pack. They charge within a few points of each other most of the time. The protection circuit on them is far better than the KD ones. Kd cells will only discharge around 3amp unless NTC is used.
