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That's asking a lot. :-)

I have 2 of them and I'll tell you a bit about them.

The fist is a Hobbico Quick Field Charger MkII.

It is somewhat expensive. Does 1-3 cells.

You can set the charge rate which is nice but it does not give you a full charge. I suppose they are paranoid about cells catching fire.

The second one I have cost 29$ from wildrc.com.

It was made in the Tzech Republic and charges only at a very small rate. I measured it but don't remember what it was. However it does give me a full charge which is nice.

So basically when charging my Li-ion cells I start off on the Hobbico, and when they are fully charged I move them to the small Tzech one.

Not the ideal setup.

All the other ones I've seen have a max of 3 cells.

Let me know if you find something that fits your criteria.

Mike

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I have been using the Triton charger for about a year now. I've used it with convenience and reliability with Li-Ion cells. Have not used it with Li-Poly, but that should not be any different than the Li-Ion. Charger works with other chemistries also.

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I have a similar version of it that I love but it does not do Li-Io. :-(

I just took a look and it says 3.6V for the Li-Ion. I would like to know what you get. It's one of the reasons I don't like my Hobbico.

On a 2 cell pack I get 7-7.1V fully charged.

With my cheapo Tzech charger I get 7.4V for my 2 cell.

It makes a big difference to my GWS motors.

So once you get it, please come back and let me know up until what voltage it will allow you to charge a 2 cell Li-Ion.

Thanks,

Mike

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the word is the astro flight 109 ($125)is very good and the schulse 6330 (or something like that) is even better and of course even more expensive ($220) they say Triton is slow as sh*t comparatively and hobbico doesn't fully charge

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I have a similar version of it that I love but it does not do Li-Io. :-(

I just took a look and it says 3.6V for the Li-Ion. I would like to know what you get. It's one of the reasons I don't like my Hobbico.

On a 2 cell pack I get 7-7.1V fully charged

The Triton actually lets you select the lithium chemistry voltage you want. So for example, you can select 7.2 or 7.4 V for a 2 cell battery. Some chemistries require one voltage or the other.

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I have the triton and have been very pleased with it.. My typical charge is a 7.4v 1500 kokam li-po in about 1 hour.. 50-70 cycles so far and no problems... Only limitation I have run into so far is does not charge over 6AH li-po or ion.. It will charge my 10AH LI-ion , but takes two charge cycles.. Other than that, it has been great.

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I have to agree with the Triton users, it works extremely well. I use it

to charge my NIMH transmitter battery, NiCAD receiver battery, my Lead acid

field box battery, and my starter (torqmaster) battery, and my

Li-Poly video setup battery all from the same charger.

Its good!

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I have MANY LiPo chargers. MAHA by Powerex, Triton from Great Planes, Hobbico field charger, 2 cell "chip charger" from Bob Selman, Apache 1 or 2 cell charger and Apache 1 to 4 cell Smart Charger. Hmm, Any more?

MAHA $80 does up to 4 cells. max rate is 400ma for Li. No settings. As long as you have it on Li (instead of Ni) just plug it in and wait. It has a screen to let you know what is up. It charges for 3 minutes then analyzes and charges. I have charged a single cell 45 mAh up to a 12 cell 3S4P 4800 mAh pack without a problem. It does seem to over charge a little but the cells don't puff up and work great. My 3 cell packs (most of what I use) come out at 12.8 to 12.9v. Supposedly the biggest no no is overcharging but I use the MAHA for the bulk of my charging. It needs 24 v from its adapter to charge 3 or 4 cell Li. It can be used from a car battery for 1 or 2 cells. It has a temp probe but I wouldn't rely on it for Li.

I got the Triton early and it is OK. They were cautious at first and it only charges about 90% full. The scuttlebutt is that the factory will fix this if you send it to them. It costs $130 and I think has a 2.5 amp upper rate. It has an optional temp probe but I think that is for Ni and by the time your Li triggered it you'd be screwed. It works from a car battery or power supply. "a field charger"

Hobbico Field Charger is $50 and is actually 2 seperate chargers in one. It has no screen but does have separate banana jacks for a DVM which is cool. You don't pay for something you don't use but it is easy to work around. It has a max rate of 1 amp I think and also doesn't fully charge. It does about 95%. It also says it supports other cells but I wouldn't use it for NiMH. It will cook 'em. Runs on 12volts also.

The 1-4 cell Apache is my new favorite. It is $55. It has a max rate of 2.5 amps which is good. it is easy to use. You set jumpers to tell it how many cells and the charge rate. At first I was put off by this as dangerous but note they call it a Smart Charger as it has protection circuits so if you set it to the wrong number of cells etc it won't charge and damage the batts. It is easy and fast. Is a small charger and runs off of up to 13.5 volts, ie a car battery.

I have never used my Bob Selman charger.

By the way as far as safety you hear all the warnings. OK, be careful.

The charging of Li-ion, Li-polymer (or more accurately Li-ion-polymer hybrids) is the same. So if your charger like the Triton only says Li-ion it is OK.

I would be glad to answer any questions.

Marty

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Oh yea, I forgot to add some things.

Lithium cells are rated at 3.6 or 3.7 volts NOMINAL. That is a spec and a term that is worthless to us. Nominal doesn't even have a consistent definition. It is a design voltage or something. I am sure somebody will say it means something but for Lithium batteries it is of no help.

Lithium batteries are charged at a constant voltage and a constant current and the charge is terminated by voltage and not an algorithm after "peaking."

A lithium cell or pack is full when it has reached 4.2v per cell. That is 8.4v for a 2 cell pack and 12.6v for a 3 cell pack. Lithium cells should NEVER be taken below 3v per cell. The person that reported his Hobbico was cutting off at 7.4 or some such voltage should either check his charger or volt meter. If it is indeed stopping there it needs repaired. I think mine stopped at 8.2v or 8.3v hence my statement about not getting a full charge.

These are not like Nicds where at the end of charge they are way over voltage and then settle down. There is very lilttle settling. If you notice your batteries are over 4.2v while charging, STOP.

The Astro Flight 109 is reported to be a good charger (and Astro Flight has a good rep) and will do many cells and at high rates.

The gold standard is the Schultze as someone mentioned. It is about $200 ($250 with the PC interface.) Can you tell I am lusting after one? I don't have enough chargers yet. Must Have. Must Have. (anybody want to buy a used _____ fill in the blank) just kidding.

Marty

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A lithium cell or pack is full when it has reached 4.2v per cell.

Is this correct ? The way I understood it is that the cell is charged at constant current until the voltage reaches 4.2v then is held at this voltage. As the internal resistance climbs in the cell the current drops away until it is at 1/10 of the start current. Only at this point full charge is reached.

Terry

UK

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I have noticed something quite interesting with my Li-Ion Poly cells.

I use 2 cell 950mhA packs.

I will use the battery and it will go down in voltage. All normal there.

Then the other day I was about to go fly and put the cells on the charger and they would not charge. At first I thought my charger had a problem. I check everything out and could not figure out what was going on.

When I measured the voltage of the packs they were between 8.1 and 8.2V.

I did not measure them after the last time I used them, however I had used them for about 10-15 mins each on a GWS "A" drive.

Is it simply a buildup of reaction products around the plates and letting the battery rest gives the reaction products a chance to dissipate?

Edited by mikep

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Terry,

Technically, yes. See http://www.buchmann.ca/Chap4-page8.asp

This is from Batteries in a Portable World. I wasn't trying to mislead anyone but merely to point out that 1) if your charger cuts off at 4.0 or 4.1 volts then the battery is not full and 2) if you see the battery going much past 4.25v I think you should stop it. Also they should not get hot.

I think the Astro 109 probably uses the correct charging method but I wonder about the others. I have seen schematics for homemade chargers which clearly don't. Of course the Schulze ISL 6-330d (version 8) should be fine.

Marty

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Sorry mate, I must have missed your point .....

Terry

UK

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