What charger? Your opinion?

You'll need something that'll plug into the wall (via a powerpack?) more than 12V. 12V will only charge 2 Li-po/ion cells in series ~18V for 3 in series. I'm already using a 3-cell with a Kyosho Spree Sport.

| In article , | snipped-for-privacy@hotmail.com says... ... | > I've looked at and read the reports on the GP Triton. I'd buy it in a | > heartbeat, but for the fact that it is 12V DC powered. I do all my charge | > preparation for flying at home. If necessary, I already have a small field | > charger. The price of the unit is in my price range but to have to go out | > and buy a power supply will take it out of the ballpark.

That's easy and cheap to fix.

Seriously, get the Triton. It kicks ass at the price.

| You'll need something that'll plug into the wall (via a powerpack?) more | than 12V. 12V will only charge 2 Li-po/ion cells in series ~18V for 3 in | series. I'm already using a 3-cell with a Kyosho Spree Sport.

eh?

Charging three Li-po cells in series needs only 12.6 volts. Where did you come up with 18 volts?

And it doesn't matter anyways. The GP Triton (and many other of the better chargers out there) can step up the input voltage if needed. I believe it's rated for up to 4 Li-poly cells in series (I don't know why it won't go higher -- because they're worried about overcharging an individual cell?) but it can obviously produce up to 35 or so volts internally because it can charge up to 24 NiCd or NiMH cells in series.

Howard, I 'second' Doug's opinion and used exactly the referenced article to create the 12 volt supply my Triton needs. I am NOT 'electrically smart' and it took me about 30 minutes and works fine. The 'on' indicator light, connectors and old PC power supply cost me Aus$15. Cheers from Oz.

you.

Hey Clive, Im building one right now as a matter of fact - and not electrically smart either. You used the lightbulb for the 5v load? I wanted to use a resistor instead - bouncing around on my bench and field box would break a bulb i guessed. The "1ohm 25watt" resistor mentioned in the article would be huge, and Radio shack doesnt carry one that big. Could that be a typo? How would a Big-assed resistor be a substitute for a little light bulb? Thanks, mike

Howard,

I have one on back order from Tower Hobbies.

I use Hobbico's Mark II Quick Field Charger in my flight box, and that one is only 12 volt (not 110 volt) & does 2 different NiCd/NiMh/LiPo- LiOn at the same time. Getting into LiPo's recently I've found that charging those off my Mark II drains the field box battery a bit deeper than NiCd/NiMh does (1500maH LiPo's). So I was wanting a newer charger for home &/OR field use.

Tower's description doesn't show off the Elite as well as here......

...look at the bottom lower left hand photo & you'll see it comes with a special set of alligator clips AND a 110 volt converter. So, you can use it at home AND/OR at the field!

PLUS, it can cycle your NiCd/NiMh batteries as well! To me it's a step above all other similar chargers/cyclers currently available. Can't hardly wait for mine to arrive, due end of June. --

Jim L.

Using - Virtual Access(OLR), ZAP 4.5, & WinXP Pro w/SP1

I haven't seen the rest of this thread, but thought I would jump in anyway just to remind you that lightbulbs and resisters have different charactoristics.

If an initial surge is NOT a problem, then a lightbulb can be a handy and convenient load - but be aware that its resistance cold is much lower than than when it is hot - so there is an initial much higher current surge when you first apply voltage to it.

The usual way of getting high wattage, low ohmage (geez is that a word) is to a length of resistance wire - hobby shops carry it and it is rated at ohms per metre (in civilised countries) or ohms per foot elsewhere :>)

David

MikeF wrote:

would break

shack doesnt

Mike, I used the light because I like the idea of something showing when the power supply is on and it's easy. Also, I didn't want to muck around with red and black tape, bolts, insulating disks etc so I just bought 3 things from the local Radio Parts store - one red and one black bannana plug socket and one 'indicator' light. They each simply needed a hole drilled in the PS case and then bolted up and are already insulated and 'neat'. I connected the wires as per the article and away we went. My PS was the ATX variant BTW. I changed the Triton power leads to bannana plugs and I've put 3 pictures up on alt.binaries.radio-control showing the inside of the PS and then the setup when I'm charging on the bench and the setup when charging from a battery in the field. The article mentions the need for only a small

5v load to deliver the maximum 12v output so it may be a typo - that's if I knew what a '1 ohm 25 watt resistor' was!!!! Cheers from Oz.

box would break

Radio shack doesnt

upon

| > Charging three Li-po cells in series needs only 12.6 volts. Where did | > you come up with 18 volts? | | I have a 2-cell charger and a 3-cell charger. The 2-cell runs from 12v | and would need more than 8.4v (2x4.2v) to charge fully in a reasonable | time.

Actually, no. It should need a tad over 8.4 volts, as your charger should never put more than 8.4 volts into the Li-poly battery.

You may put 1.6 volts per cell into NiCd or NiMH cells for a fast charge, but you never exceed that 4.2 volt figure for Li-poly cells. This does mean that your charge rate will taper off when it's almost full, but that's just fine.

| Li-ion/po cells are nominally 3.7v and reach 4.2v at full charge. | So 3 cells in series requires more than 12.6v.

Only a tad more. If it needs a lot more, it's because the charger isn't very efficient or something. It's not putting more than 12.7 volts or so into the battery if it's smart.

| My 3-cell charger specifies 15-18v input and charges at 0.8A. 12v | wouldn't do it. If I get a pack with more cells in series then I | will need to use an even higher input voltage. What I'm saying is: | think ahead to when you may use bigger packs when you buy charging | equipment.

Get a Triton. It can charge up to 24 NiCd cells in series even with only 12.5 volts of input.

| So, as for your question, I came up with ~18v from the instructions for | my 3-cell charger (~ means approximately). It is related to number | of cells-in-series -more cells means more input voltage required and your | input voltage must be greater than number of cells times 4.2v to charge | them fully.

That reasoning is true for NiCd/NiMH. It is not for Li-Poly. With

4.2 volts, you can get a Li-poly cell around 95% charged. With 4.3 volts or so, you can get to 100%. Throw more voltage at the battery, and you can get it to puff up all pretty like :)

Doug,

LOL! Same effect if you drain a LiPo cell below it's minimum:-( --

Jim L.

Using - Virtual Access(OLR), ZAP 4.5, & WinXP Pro w/SP1