Re: A couple charging questions (Using the Triton charger)

The Triton is an excellent charger, capable of correctly and safely charging NiCd, NiMh, Li-Ion, Li-Poly, and Pb chemistries.

Has an optional temperature probe for NiMh and Lithium battery types.

You can handle the majority of your charging needs with the standard battery configurations/settings, and you can modify those standard 'profiles' to suit specific needs.

Everything except Li-Po settings are adjustable, should you have the need.

I recently bought an additional unit, it's that good.

| The Triton is an excellent charger, capable of correctly and safely | charging NiCd, NiMh, Li-Ion, Li-Poly, and Pb chemistries.

Agreed.

| Everything except Li-Po settings are adjustable, should you have the | need.

Well, to be precise, the Pb settings are just like the Li-Po settings

-- not very adjustable. Not that further adjustment is really needed.

In fact, the Pb charging program seems to work EXACTLY like the Li-ion program, except that the cutoff voltages are different. Not really that important, but interesting.

I'm sort of surprised that it won't let you pick the number of Pb cells directly -- instead it just does 6, 12, 18? or 24 volts. But 2,

4, 8, etc. volt Pb batteries do exist. Not that it's been a problem for me, but it struck me as odd.

| I recently bought an additional unit, it's that good.

I'm tempted. I find myself wishing for two from time to time.

I like mine. Very versatile. Clever design and good software. The hardware seems kind of second rate compared to my AstroFlight, but it will do lots of things the Astro cannot.

It seems this is just thread I need. I also have a Triton charger. But it could charge one of my packs of 3S3P Li Poly batteries to 11.77 volts, while the other pack of the same configuration to almost 12.6 volts.

I understand the nominal voltage per cell is 3.7 volts. And 3 cells in series gives 11.1 volts.

These packs are Kokam, 11.1 volts, 1500 mAh. I was wondering if 11.77 volts is enough for use? And why the difference of about .83 volts?

Puzzled, Wan

Wan,

All the lipolies should charge up to 12.6 volts. That is the point where they are full. Is there any way you can break down that pack and check individual voltages? Something is wrong with it. If you have a big unbalanced pack like that, then you can severely overcharge one or more of the cells. The overcharging is what causes the catastophic "incidents" with these pack.

Lots of the new packs are being made with extra pigtail leads to monitor individual cells and allow individual charging if needed to balance packs.

Mike,

Thanks, but unfortunately the packs are already sealed by the manufacturer. They did not come with tabs for individual cells. I will discharge them during flight and then recharge. Both packs have been up to 12.6 volts when recharged after flights.

When I first discovered LiPolies, I thought they would be a panacea for electric flight. Now I wonder if I should have sold all my NiMH batteries.

Think discharging during flight is worth a try?

Somewhat distraught, Wan

Wan,

The battery forum at rcgroups.com is where you will get the highest quality and number of replies on this problem. But I'll throw in my two cents anyway.

Is your Triton timing out before filling this big pack? The Triton can only charge at 2.5 amps and that means several hours for a big pack like this. Also make sure that the Triton is set for 11.1 volts rather than the 10.8 setting.

Make sure to charge any suspect pack in a fireproof enclosure while monitoring the progress. I'm not sure a discharge cycle will help balance the pack. Be real careful not to take it down past 9v while under load. I would try topping off at a slow rate while watching the pack for puffing in any cells. If it doesn't go up to 12.6 volts, then I would do surgery on the pack. Remove the shrink wrap covering and carefully check the voltage on each individual cell. If you find one or more that are low, then top them off individually. I have made charge leads with alligator clip ends just for this procedure.

If I took that pack apart, then I might add individual Deans Micro connectors with leads to each individual cell for monitoring and balancing. I think that's the way that all such packs will be built in the future (if not with dedicated circuitry to automatically balance during charging).

Don't get discouraged with a problem with one pack. We are all on a learning curve with them. The nimh packs were holding us back and it is time to move on. Lipolies are far from perfect, but are a huge step forward. At rcgroups.com you will be able to tap into the largest group of experienced users.

Mike,

Thanks again for all your commentary. I've tried to join the Ezone group discussions, but I found it's difficult for me to navigate. Is this the same as rcgroups.com? True, I am on a very steep learning curve and need all kinds of advise.

If worst comes to worst, I will attempt to disassemble the pack and add the individual Deans Micro connectors. As I've mentioned earlier, I have 2 packs of 3S3P, this makes 18 cells that I have to add the smaller connectors. Though the other pack is charged up to 12.6 volts already, I'd like the convenience of being able to check the cells once in a while.

I read the manual and the Triton charger is able to charge at a 14.8 volts for LiPoly and my friend said I should try 4.5 amps. Though the Triton can only do 2.5 amps, is the combination of 4.5 amps and 14.8 volts advisable?

I've read that the batteries with tabs for individual cells are available, but where?

I'm waiting for the packs with dedicated circuitry!

Wan AMA 773188

Wan,

RCGroups is where the Ezone discussions are. They recently had a format change, so maybe it will work better for you. You might need to try some other browser software if that site is troublesome for you. This is the site where I've gotten my e-education and have even found friends who I now fly with. It is an immense repository of electric info.

DO NOT use the 14.8v setting to charge a 3sXp pack! That will allow the charger to continue pumping the cells with current past 4.2 volts per cell. This will lead to catastrophic destruction of the pack (and anything near it). Your pack has 3 cells in series, so the charger should be set for 11.1 volts only. This will bring them up to their max of 12.6v. Go past that and you might end up with a fierce fire.

The cells are 1500 mah each with 3 parallel, so 4.5 amps is the max charging rate. If you can borrow another charger, such as an Astro 109, that will charge at 4.5 amps. then it is worth a try. Just keep a close eye on things.

I think the new generation Kokams are shipping with leads for individual cells. I've also seen Tanics or Apogees with them. Tower Hobbies is selling some kind of Hobbico packs that look like they have on-board monitoring circuitry. Things are developing on a weekly basis. Hard to keep up.

You should probably call or email Fred Marks at FMA Direct regarding the problem with your Kokam pack. He is the US Distributor for Kokam and is responsible for some new developments in the care and use of lipoly for RC.

Mike

Try this:

You only need one connector for each parallel cell. ie: thre cells in parallel need one connector.

snip

Try

Hope that helps.

Regards,

Art

Mike and Art,

You have been of great help. I will try again with Ezone and see if I could do better. Now I know better than to charge the batteries at

14.8 V. I surely don't want a disaster. But you do think charging at 4.5 amps is OK?

When I return home, I will look into the Tanic and Apogee batteries. Things in the battery field are developing way too fast.

The part that confuses me is, my packs are 3 series and 3 parallel (3S3P). Would not each cell is the series need a tab?

Thanks again, Wan

| The part that confuses me is, my packs are 3 series and 3 parallel | (3S3P). Would not each cell is the series need a tab?

Not nessesarily. If you've got three cells wired in parallel, then each cell will have the same voltage, so they only need one tab. If you then duplicate this two more times, then take the three groups of three cells wired in parallel and wire them in series, then you've got a 3s3p pack that only needs three tabs.

Have I confused you yet? :)

4.5 amp rate is good. A buddy of mine showed me the system he added to monitor or charge the individual cells. He only had to add two wires to each pack of three cells in series.

You would have to break down your pack to (3) 3s1p packs with connectors between them. Then add another connector to either the two negative or positive terminals not already connected to a connector in each 3s1p pack. Now you have access to each individual cell for monitoring and balancing. It would also be quick and easy to locate and replace any bad cells. You could then also use 1 or two packs together on a smaller plane. My buddy made a breadboard circuit that plugs into both connectors on a pack and provides two bananna jacks (+ & -) for each individual cell. No danger of getting confused which cell is which that way. I was real impressed with his rig. I wish he would document it so simpletons like me could make our own.

I can't understand these things without a diagram. I just drew a picture to convince myself. Sounds like Doug has a handle on it though..

And Irate.

Same cells as tanics. Buy where the deals are best.

They have em, but unless you want to individually monitor/charge each part of the bank seperately, they need not be accessible.

Yes. If there are three cells in series, I can see a case for two, or four tabs, but not three...:-)

Doug,

Well, kind of confused. But when I drew a diagram of what you described, it made sense. By golly, you need only three tabs! :)

And Mike's buddy in article #16 of this thread has a very good idea similar to yours. I am a visual learning person. I wonder if I gave my address to you or Mike in this usenet, could I have a diagram if the connections?

Wan

TNP,

Thanks for the web site; Irate,

I read their policy and found that it may take up to 6 weeks for delivery for some of their batteries. That's about a month and a half. They said it was due to high demand for their goods.

FMA usually delivers in about 4 to 5 days. I don't have the web site for Tanic batteries until I return home in about 8 days. Is it true that Tanic cells have tabs for individual cells? I know you said individual cells don't need monitoring, but I'd like to do so because I don't know what's wrong with my battery pack.

Wan

| > Not nessesarily. If you've got three cells wired in parallel, then | > each cell will have the same voltage, so they only need one tab. If | > you then duplicate this two more times, then take the three groups of | > three cells wired in parallel and wire them in series, then you've got | > a 3s3p pack that only needs three tabs. | | Yes. If there are three cells in series, I can see a case for two, or | four tabs, but not three...:-)

Let's see if I can make an ascii picture of it for you.

Here is one cell, in ASCII :

• | -

where + = the plus side, and - is the minus side.

Now, you've got three cells in parallel. Since they're in parallel, they all have the the same voltage, and only require one tab.

positive --------- + + + | | | - - - --------- negative

Man, that's bad. So much for my chosen career as an ASCII artist!

Now let's put three of those together, and show where the tabs go --

positive ---------