tell me about your charging setup. NiMH and Li Ion

jayhackett03

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i have a NiMH 3D Mag 85 with the Fivemega 9AA to D adapter.

I'm going to be building a ROP 2D soon. I've considered switching over to Lithium Ion at this point, but not sure yet. If i don't switch over i'll be just using Eneloops in my ROP.

I'm curious about how you charge your:

  • NiMH with Fivemega D adapter
  • NiMH loose
  • Lithium Ion with Fivemega D adapter
  • Lithium Ion loose
please post pictures of your charging setups, give me links, costs, info, etc.
 

DonShock

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jayhackett03

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DonShock said:
I have been using a 6-10 cell smart charger for FM's 6aa and 9aa packs. But I was still having to remove the cells from my 4AA and Li-ion packs to charge them individually. So I recently purchased a 2-12 cell smart charger and a Li-ion smart charger. With just these two smart chargers, the FM charging plug end, and my homemade rig for non-FM style holders, I pretty much cover all the bases.

ok, so i think i just decided to go Nimh. i found someone with a FM battery holder.

now, i hava 6aa and a 9aa holder. would you suggest i go with the 6-10 cell smart charger and that special "plug" that goes into the butt of the holder? whatever that plug is called.
 

SilverFox

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Hello DonShock,

While series charging of NiMh cells is good, I would not recommend it for Li-Ion cells, unless you have a way to balance the cells at the end of the charge.

A series Li-Ion charger charges to a maximum voltage. It is possible for your cells to age at different rates and develop different internal resistances. Since the maximum voltage is the sum of the voltages of each cell, you could end up with cells charging to different voltages.

Ideally, when charging 4 cells in series, all of the cells would end up at 4.20 volts and the maximum voltage would be 16.80 volts. However, what happens if there is some additional resistance in a connection or cell? If we have 4 cells at 4.0, 4.1, 4.2, and 4.5 volts, we still have the maximum 16.80 volts, but the cell that is at 4.5 volts will most likely "rapidly vent with flame."

The RC people have burned down houses, garages, and automobiles charging like this.

The solution is to charge Li-Ion cells individually, in parallel, or to use a charger that monitors each cells voltage during the charge and balances each cell so none of them ends up overcharged.

Protected cells will work, but you still may end up with an imbalance that will hurt performance.

CPF people have an excellent record using Li-Ion cells. Please, think through your Li-Ion charging so we can continue to enjoy that excellent record.

Tom
 

jayhackett03

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viorel00 said:
what's a ROP?

oh wow.

ROP - Roar of the Pelican.

its when you put a high powered Pelican brand lightbulb into a maglite, then cram the necessary batteries in there to power it.

do a search, this is very popular and theres alot of info out there for it.
 

DonShock

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SilverFox: I am aware of the dangers and have two different chargers for individual cells that I mostly use. But I also wanted the ability to just do a quick "top-off" charge of the entire holder with a smart charger. I routinely use the NiMH smart charger for packs but haven't used the Li-ion smart charger yet. I just wanted to have the option even if it's not perfectly safe. I probably should have taken the time to make this clearer for the newer members, but it was getting late and I didn't think to target the response to the audience. Thanks for taking the time to point this out.

BTW: if that gets you going
str.gif
, then the light I am using some of the Li-ions in would make you run for the bomb shelter. A Mag85 in a MagSD body running off three unprotected 14500 cells. Over twice the max rated current for these cells and dangerous as all get out. But I only use a momentary switch, treat it like the potential bomb it is, and I don't let anybody but me use it. I know and accept the dangers of this light, but I can't vouch for anybody else.
 

lrp

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Aug 16, 2003
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I just got the Pila ICB charger for Lith ions and it is very high quality and does a very good job and was under $50!! Thanks Tom for the recommendation!!
 
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