Recurring Charge - November 2003

As many of us are climbing up the lithium-polymer battery learning curve, one of the big questions remains how to get the right charge into them safely and what chargers are suitable. This time, rather than cover another aspect of charger operation separately, I thought I'd provide a look at several lithium charging solutions that are currently available.

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Lithium Chargers - Round Two

As many of us are climbing up the lithium-polymer battery learning curve, one of the big questions remains how to get the right charge into them safely and what chargers are suitable. This time, rather than cover another aspect of charger operation separately, I thought I'd provide a look at several lithium charging solutions that are currently available. First, I'll do a short follow-up on the Kokam 402 from last time. Then, we'll have a look at the Apache 1500, which is another small dedicated 1-4 cell, up to 1.5A lithium-polymer charger. Next, I'll give a short review of Schulze's version 8 firmware for the isl-6 series of chargers, which includes major improvements for both lithium chemistries and nickel metal hydride cells. And finally we'll take a first look at Astro Flight's new lithium-only charger that is based on the hardware of the recently released model 110DX.

General thoughts on charging LiPolys

First some general thoughts on charging LiPolys. As I discussed last time, charging lithium-based batteries is quite different from charging nickel-based batteries. Not only is the charging process completely different, but also making a mistake in either final voltage (selected cell count) or charge rate can not only destroy a battery, but start a fire. We're about a year into the lithium-polymer revolution now (I got my first LiPoly cells a little less than a year ago myself) and just how to safely handle, charge, and store them is something we're still learning. Along the way there have been some nasty incidents. At the NEAT Fair in New York in September there were three reported LiPoly fires - I saw the burnt patch of grass where one battery burned, and was shown a small, rather charred model.

From what I have read and heard, the most common cause of lithium fires is overcharging - and the most common cause of that is selecting an incorrect cell count - in particular setting the charger for one series cell more than the pack being charged actually has. So, GREAT CARE must be exercised EVERY TIME you go to charge a lithium battery to make sure that both the number of cells (where the user is required to set it) and the charge rate are correct.

An exacerbating circumstance, I think, is that those of us who have been flying nickel-based batteries and using currently available chargers have been spoiled by just how automatically the chargers work. In many cases you simply plug in the battery to be charged, maybe push a start button or set a charge rate, and that's it - no worries. Twenty years ago, long before dependable peak detector chargers were available, it wasn't all that uncommon to overcharge and destroy, sometimes explosively, a NiCd pack. We're at the same point now with lithium technology as we were then with nickel, with the added complication that when a lithium battery does start to burn, it does so with vigor, not to mention that the amount of energy stored in a given weight/volume of lithium battery is up to five times what it was in the early days of NiCd-powered electric flight.

That said, if we pay attention, we can safely take advantage of the tremendous increase in run time and/or decrease in weight that lithium batteries bring to our hobby. I, for one, have converted many of my planes to this new technology rather faster than I thought I would.

Charger makers are working like mad to bring us chargers that are easy and safe to use as we have come to expect, as you will see in what follows. In the meantime we need to take extra care as we did back in the days of timer-based NiCd chargers.

So, down, off the soapbox - let's look at some chargers.

Kokam 402 in use - some further thoughts

For several months now I've been using the Kokam 402 I introduced last time to charge my two and three cell packs of Kokam and E-Tec cells. It has continued to perform very well and has given my no surprises or frustrations. There is really very little more to say about it even though I said I'd have more to say in the last column.

Operation is simple - set the jumpers to the right cell count and charge rate, then connect it to the power source and the battery to be charged. Wait for the green LED to come on, and for the last bit of charge, for the "constant voltage" LED to go out. That's it. No buttons to push, no screens of menus. The only real concern is to be sure and select the correct number of cells with the cell-count jumper. Setting it to charge more cells than are connected to it will result (if you're lucky) in little silver balloons. Silver balloons are bad. Lithium fires are worse.

I have noticed that when charging a three-cell pack at 1.0 or 1.5A it does get quite warm to the touch. I don't currently have any 4-series-cell packs so I don't know if it gets warmer still while charging such a pack or not. Even so, it doesn't get really hot, just warm.

I have read on R/C Groups one person who had the power input lead become frayed and short out where the leads are soldered to the charger's circuit board. It is true that no strain relief for this lead is provided, but it looks like it would take lots of flexing of the input lead very close to the body of the charger for this to happen.

All in all it does its job very well with no fuss. It's also the most compact charger of its type that I am aware of, which saves space in your field box or on the workbench.

For more on dimensions, lead lengths and for a number of pictures, see my March 2003 Recurring Charge.

Apache 1500 LiPoly Charger


Apache Smart Charger 1500
Distributed By:Aircraft World and available from several Ezone sponsors
Price:$84.95
Type:Constant current/constant voltage charger for lithium-polymer batteries
Charge current range:100 mA to 1.5A in five steps
Cell count range:1 to 4
Input power:12 V DC
Input lead lengths:Approximately 20 inches (51 cm) ending in alligator clips
Output connections:Approx. 2.75 inch (7 cm) lead ending in a JST connector
Dimensions:4.4 W X 2.5 H X .6 in. D (11 x 6 x 1.4 cm)
Additional Features:-> Charger checks battery and warns with flashing LED and beeping tones if cell count jumper is incorrectly set or if either jumper is not installed.
-> Protection for reversed connections on input or output.
-> Two LED status indication.

Another Korean-made 1-4 cell lithium polymer charger is the Apache Smart Charger 1500. Its basic capabilities are pretty much the same as those of the Kokam 402 in that is designed to charge one to four cells in series at a maximum of 1.5A, off of a 12V nominal power source.

The Smart Charger 1500 is in a metal case about 4 3/8 x 2 1/2 x 9/16 inches (11.1 x 6.4 x 1.4 cm). The input leads come out of the left end of the charger and are about 20 inches (51 cm) long and end in small insulated alligator clips. They seem to be of a fairly small gage silicone-insulated wire, but they are adequate for the current the charger will draw even when charging a 4 cell pack at 1.5A.

The short output lead, which is permanently attached, comes out from the other end, and is about 2 3/4 inches (7 cm) long ending in a JST connector. I've phased out the use of these connectors in my own fleet, so I made up a short JST-to-polarized-mini-Deans patch cord to make it compatible with my LiPoly batteries.

There are red jumpers on the right end of the charger for setting the charge rate and number of cells to be charged. There are five charge rates from 110 mA to 1.5A available. (No spare jumpers are supplied as with the Kokam 402.)

Visible through the face of the charger are two LEDs. One (which is red) indicates that the charger is powered up and flashes when there is an error in connections. The other is a green charge completion indicator which comes on when the battery is more than 90% charged. It will continue to charge, tapering to zero current, if left connected at this point.

One of the special features of the Apache 1500 (at least among currently available chargers) is that it is able to sense whether or not you have selected the correct cell count and it lets you know immediately if the setting is incorrect by beeping repeatedly (and flashing the red LED) until you either get the jumper set correctly or disconnect it from the power source. As I understand it, the charger puts a brief load on the battery to be charged and it uses that as well as the battery's voltage to determine whether or not the jumper setting is correct. I have tried both charged and discharged two and three cell packs using jumper settings for two, three, and four cells. In every case it identified the incorrect jumper setting immediately. The same error signal sounds if either the cell count or charge rate jumper is not installed and the charger is powered up.

Operation is quite straightforward. First, use the jumpers to select the appropriate charge rate and cell count. Then connect the charger to a 12-13.5V power source. It'll do a quick self-diagnosis and beep a couple of times - one long and one shorter beep. Then connect the battery to be charged. It will beep again and the red LED will light steadily. At this point the charge has started. The green charge complete LED comes on when it's reached at least 90% charged and it will continue to charge until it is finished. That's it.

I found the voltages at the charge-completion point to be very accurate and right at the recommended 4.23V per cell, giving a full charge without overdoing it. The output currents I measured with my micro-Whattmeter are within measurement error of the marked values as well.

The instructions supplied are for both the two - and four-cell Apache chargers. They are brief but cover operation pretty well except that they seem to refer to an earlier version of the charger. For instance, there is no mention at all of the beeper in the instructions. They do say that the charger is protected for backward connections on the input and output and that the red LED won't come on if either is backward. I find it won't do the power-up beeps either, if hooked up backward to the source supply or battery. I don't have a quick way to test for a backward connection to the battery to be charged, so I haven't checked that.

The only negative comment I have about the charger's operation is that it is less tolerant of input voltage variations than other chargers. In particular it doesn't like input voltages above about 13.7V. This can be a problem with some DC power supplies. If the charger gets too much voltage (or too little) it gives an error beep and shuts down. I understand that the charger has since been updated to take input voltages up to about 15V to address this. Another alternative, of course, is to turn down the voltage on your power supply just a bit. I won't comment about using this or any other lithium charger while driving.

Overall, it seems to do the job it is designed to quite well, and I very much like the added safety afforded by it checking to make sure I've set the cell count jumper correctly.

Schulze isl-6 Family of Chargers with Version 8 Software

Up to this point I've been writing about chargers capable of handling at most four lithium cells in series and at charge rates of 1C for no larger than 1500 mAh cells. For those who want to use LiPoly technology in larger airplanes and higher powers, for example using big packs such as those from Thunder Power, charging has been problematic.

Matthias Schulze saw the need to handle higher cell counts and capacities and his firm has recently released a software upgrade for the isl-6 family of chargers (-330d, 636+ and others). This new version 8 software adds two significant additional capabilities to these already very versatile chargers. The first is the ability to use the full output voltage and current capability of output 1 of these chargers for lithium-based batteries. For the relatively inexpensive isl 6-330d this means the ability to charge up to eleven(!) lithium cells in series, and a maximum charge rate of 5.6A at lower cell counts. For the 636+ this means up to 13 cells in series and maximum charge rates of 8.2A (though not at the same time) - just the ticket for the new 7800 and 8200 mAh Thunder Power packs.

The other significant improvement is the ability to automatically charge and cycle nickel metal-hydride cells. Up to now, it has always been recommended to select a fixed charge rate for NiMHs, as I mentioned in the discussion of the FMA SuperNova in my last Recurring Charge. This also precluded use of the Schulze chargers' built-in cycling capabilities with NiMH batteries as they use automatic charge rate setting.

With Schulze's new software you can charge NiMH batteries and let the charger set the charge rate as with NiCds. And as with NiCds it starts off slow, increases the charge rate in the middle of the charge to rather higher than would be safe as a constant current charge. Then it decreases the charge rate as the voltage peak approaches, so the cells are not overheated as they reach full charge. Also, you can now safely use the 3DC (three discharge-charge) cycling program with NiMHs.

Version 8 software upgrades are available from R/C Direct for $29.99 plus shipping. If you have an isl-6 with version 7 software. If your charger is at version 6 or older a hardware change is also required and it will need to be sent directly to Schulze.

Installation is straightforward - the only trick is getting open the case of the isl 6-330d (and the supplied instructions tell you how to do it). Once the new EPROM is installed, you do a brief test, and then put it back in its case, the new features are available for use.

With the addition of the new features necessarily comes a more complex user interface. Before you charge any battery you should ALWAYS verify on the display that the correct battery type, cell count (for lithium or lead batteries) and charge rate (or automatic program for nickel batteries ONLY) is selected before connecting up the battery to be charged.

To change either battery chemistry or cell count, one has to hold down both buttons with the charger powered up, then release the left one while continuing to hold the right one down until the "????selectBatTyp" prompt appears in the display. You then cycle through the available cell types by pressing the right (+) button until the correct one is displayed. Note that there are separate choices for lithium-ion (li-io) and lithium-polymer (li-po). Lithium ion batteries are not charged to quite as high a voltage per cell as LiPolys.

To go on to the next menu push the left (-) button. For both lithium types and lead acid you then cycle through the available cell counts with the right (+) button until the correct one is displayed. For NiCd or NiMH (also separate choices from the first menu) the cell count is shown as "0", which means that it is automatically taken care of.

Press (-) again to go to the charge capacity limit menu, where you can set the charger to terminate the charge after a certain capacity is put into the battery. This is intended to be a backup safety feature in case the peak is missed (NiCd/NiMH) or the maximum voltage is for some reason never reached (LiPo/LiIo/Pb). Selecting "99999" means "no limit defined". Pressing (-) one more time returns the charger to ready-to-charge state with the new settings in effect.

At this point you can select the desired charge or discharge rate or automatic charge, discharge or cycle program by scrolling through the choices with the (+) and (-) buttons. The cycle programs (CD, DC, 3DC and a new 3CD) are only available if either NiCd or NiMH has been chosen. Also, automatic charge rate (Auto) is only available for nickel-based batteries.

All of this sounds complicated and to some extent it is, but once you've done it a few times it becomes pretty easy, and the process is helped by the charger retaining settings between power cycles. Also, the settings in effect before you invoke the change-chemistry menu are the defaults offered for each menu, so if all you need to do is change the cell count, for example, all you do is press (-) to bypass each of the other menus.

The information you get when pressing and releasing both buttons together (amount of charge, amount of discharge for up to three cycles if 3DC or 3CD are selected) is still accessed that way. Also, changing the parameters of output 2 and the low-source-voltage warning are still done as in version 7 of the software. The old peak sensitivity selection is gone - replaced by the NiCd vs. NiMH choice.

Another important point is that when in the NiMH setting, peak detection is DISabled for the first five minutes of the charge. This means you can't repeak a nearly fully charged NiMH battery in this mode without overcharging.

For several months now I have been happily using my Schulzes with version 8 software for charging NiCd, NiMH and LiPoly batteries, and as I mentioned, once you start using it, switching modes becomes easy. I admit that I had the manual with me in the charger case for the first meet at which I used it, though.

The automatic charge programs for NiMH are very welcome additions and seem to work quite well. I've used them both for field charging some 10 cell P3000 packs (with maximum rates up to 8.2A on the 636) and for cycling packs that have been sitting awhile. I have long wanted to be able to do this with NiMH like I have been able to for NiCds since I got these chargers.

I like the added option of 3CD which does three cycles and leaves the batteries discharged (great for preparing NiCds for storage), too.

I've also used the Schulzes to charge LiPoly packs ranging from 2s E-Tech 700s up to a 3s4p Thunderpower 1950 (effectively 7800) pack - the pack pictured in my last Controlling Interest - as well. The charge algorithm seems to work exactly right and brings the batteries exactly all the way up to the 4.23V per cell that Kokam recommends. As with the nickel-based charge modes, the current is ramped up slowly over a couple of minutes when the charge is started, and of course tapers down to nothing in the constant-voltage portion of the charge.

Note that Schulze has recently released version 8.06 and is offering a free upgrade to people who have versions 8.00 through 8.04. The upgrade corrects a bug in the charge quantity limit function and adds a basic cell-count checking function. Contact your country's Schulze distributor to arrange the upgrade.

Some concerns

I have two concerns, though, about using these chargers for charging lithium batteries.

First, they rely on me to get the cell-count correct, just as the Kokam charger does. It does have a cell-count checking function (from version 8.05 on) but it may or may not detect an incorrect setting. For example, just after installing V8.06 software I set my isl 6-330d for four lithium polymer cells and tried two different three cell packs. It warned me about one (which was about 2/3 charged at the time), but I pulled the other one (which was very close to full to begin with) off after the voltage went through 12.7V without a warning from the charger. Based on that I do NOT recommend relying on the charger to catch your mistakes as it seems you can with the little Apache charger. Schulze's manual points out that user knows the correct cell count better than the charger. That may be true, but if the user is me, sooner or later a mistake will be made - most likely by putting on a lower cell count pack and forgetting to change the programmed cell count.

Second, I know that as long as I have different types of batteries with me at the field and I'm using either of my isl 6s to charge more than one type from the main output the chance exists for me to make a mistake and charge one type of battery with the charger set to charge another type. For multi-chemistry chargers such as these (and the Triton and the Orbits, among others) this is an inherent danger that there's really no way around that I know of. Dedicated chargers for each battery type are the only way I can think of to lessen this concern. Of course the Schulze chargers can be used as dedicated chargers for any of the battery chemistries they can charge, as they retain all settings (except manually set charge rates) through power cycles.

This leads to the final charger to be discussed this time.....

Preview: Astro Flight Model 109 Lithium Charger


Astro Flight Model 109
Price:$124.95
Type:Constant current/constant voltage charger/discharger for lithium-polymer batteries
Charge current range:50 mA to 8A continously variable
Cell count range:1 to 9
Input power:12 V DC nominal (10.5 to 15V)
Input lead lengths:Approximately 40 inches (102 cm) ending in alligator clips
Output connections:Approx. 9 inch (23 cm) lead ending in a Zero Loss connector
Dimensions:7 W X 5.1 H X 2.8 in. D (17.8 x 13 x 7 cm)
Additional Features:-> Automatic detection of cell count with conservative algorithm.
-> Pulsed rather than tapering rate "constant voltage" charge stage.
-> Real time charge current, calculated cell count, charge stage, voltage, charge time, cumulative Ah delivered on two-line backlit LCD display.
-> Fixed-rate discharge function (connect battery to be discharged before applying power to charger).
-> Cooling fan.

One of the brand new products shown at the NEAT Fair in September was Astro Flight's entry into the lithium charging game. Their new model 109 lithium charger is based on their recently updated version of the stalwart 110D Nicd/NiMH charger - the 110 Deluxe. For those not familiar with the 110 Deluxe, it increased the capability of the 110D to be able to charge up to 24 NiCd/NiMH cells (from 18 of the 110D) and at lower cell counts raised the maximum charge current from 5A to 8A. It also added the ability to discharge batteries, did away with the start button (and having to choose between slow and fast charge modes), added a cooling fan, and replaced the display with one that is backlit.

The new model 109 takes the same hardware as the current production 110DX and replaces its software with software for charging lithium batteries. This yields a charger than can charge up to nine series lithium cells at up to 5A and up to five series cells to 8A. It retains the elegantly simple user interface of the 110DX. To charge a battery, just turn the current adjust knob fully to the left and connect the charger to input power. Then connect the battery to be charged and dial in the appropriate charge rate. That's it. To discharge the battery, just connect the battery to be discharged first, then connect the charger to power.

The 109 uses a clever and conservative auto-cell-count-detection algorithm. It is designed to detect the cell count in such a way that if it errs, it will err towards a lower count, which is the safe way to go. Once the charge is underway, the charger regularly reevaluates the cell count calculation and adjusts if need be. In my preliminary tests I have yet to see it miss the correct count from the beginning of the charge. I'm going to have to come up with a way to at least temporarily create some 5s to 9s packs just to explore this further.

It also approaches the final stage of the charge differently than all the other lithium chargers I've looked at so far. Instead of going into a continuously decreasing charge rate once 4.2V per cell is reached at the 1C rate, when the end voltage is reached it starts pulse charging at the set charge current. Initially this is one second on then one second off, but as the battery reaches closer to full charge (where the voltage stays at 4.2V per cell even when it's not being charged) the proportion of "off" time increases. Finally when the voltage holds for a preset period, the charge shuts off and signals this with three beeps.

I've just begun using the Astro Flight Model 109 (actually what I am using at the moment is a 110DX with the pre-production 109 software installed - version 0.4 it says) but so far I am very impressed. It looks to me to be the most capable of the dedicated lithium chargers available today and favorably comparable to the lithium functions of high-end multi-chemistry chargers. One advantage of a dedicated charger is that there is no way to ever start to charge a battery with the wrong setting for battery chemistry - at least as long as I don't connect a battery to the wrong charger! And while I'm still using a mix of NiCd, NiMH, and LiPoly batteries in my planes, this is a safety feature not to be underestimated. As much as I like my Schulzes with their new version 8.06 software, as I mentioned above, I worry that I may one day forget to change from one mode to another and destroy a battery.

At any rate, I hope to have a more complete write-up on a production Astro 109 in the next Recurring Charge. Perhaps, too, we can take a look at a new offering from Bishop Power Products at that time. Until then, especially when using LiPolys, PAY ATTENTION! Then have fun!

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Nov 10, 2003, 08:40 AM
atlav8r's Avatar

Astro 109 and Li-Po Chargers


Loved it,
The Astro 109's have been flying off my shelf and I am hearing great feedback on them Especially for large packs. Owners of the 110 Deluxe can also just add a chip to turn it into the 109 for Li-Poly making for a great dual purpose charger.

Cliff Whitney
Atlantahobby.com
Nov 10, 2003, 12:45 PM
Registered User
Orbit charger
Are you going to evaluate the Orbit 6.2 ??
TIA.
guyde
Nov 10, 2003, 11:02 PM
led
led
Registered User
led's Avatar
Nice coverage but I really think the Orbit should have been included, no?
It does very well with my lithium packs in that it *prompts* me to confirm cell count, and adjust if necessary, before starting the charge.
I loved the $10 upgrade to go from 6.0 to 6.1 software as well.
No overcharges to date!

pd
Nov 11, 2003, 04:26 AM
now that's a wattmeter...
simingx's Avatar
I'd like to point out something..

"... as they retain all settings (except manually set charge rates) through power cycles."

You can set it to remember the last used charge rate by doing this:
1) Power off the charger
2) Press and hold BOTH +/- buttons together
3) While keeping the buttons pressed, power on.
4) It will prompt: "b1.cur.aft.reset" then "last - + Auto C"
Press the "-" key to let it "remember" the last current setting to use or "Auto C" to have it use the Auto program on power on (only for NiCDs and NiMHs".
Nov 11, 2003, 01:21 PM
Registered User
Philipp's Avatar
I have always been a fan of AF Products - glad to hear that their new charger came out so good.

How does the Triton fit into this?
Nov 11, 2003, 07:17 PM
Registered User
Daniel Mc Crae's Avatar

Schulze is great !


I just got my isl 6-330d from ICARE www.icare-rc.com and I am very pleased with it
Like you said, with the addition of new updated features it's new firmware version makes for a little more complex user interface but I really agree that once you've done it a few times it becomes pretty easy. It took me about 15 minutes to get accustomed to the new menus and options. Then I picked up my brand new 2S LiPo packs that I bought for my GWS Beaver...
Selected # of cells (2), max charge quantity (1200 mAh) and charge rate ( 1C=1.2Ah) Plugged it in and GO !

The first battery I plugged in wasn't completely empty so my Schulze charger automatically shut off after putting in 1064 mA.

On the second pack 1201 mA went in and the charger again stopped telling me that the pre programmed charging quantity as been reached.... cool and safe ! Price is cool too...
Nov 11, 2003, 08:13 PM
BEC
BEC
Registered User
BEC's Avatar
Orbit: If I get one, I'll be glad to check it out and write it up in the future......

Triton: same story, though there is a Triton review about to go live on the Ezone. Perhaps you can then see where it fits in. I won't anticipate the reviewer's comments here at least until after the review is put up.

I don't have either an Orbit or a Triton.

simingx - great - I'll have to go set my 636 this way.

Cliff,

Bear in mind that neither the chips nor the chargers (110DX/109) are designed to have you swapping CPUs back and forth, and putting BOTH chips (and some sort of switch) in would be a fairly major void-your-warranty-forever harware hack, not to mention setting one up for the worst-case "oh, bleep!!!, I forgot" scenario - charging a lithium battery on a nickel charge setting. Please don't go there.

So saying the 110DX with a 109 chip is a dual purpose charger is stretching things a bit.
Nov 11, 2003, 08:39 PM
atlav8r's Avatar
Quote:
Originally posted by BEC
Cliff,
Bear in mind that neither the chips nor the chargers (110DX/109) are designed to have you swapping CPUs back and forth, and putting BOTH chips (and some sort of switch) in would be a fairly major void-your-warranty-forever harware hack, not to mention setting one up for the worst-case "oh, bleep!!!, I forgot" scenario - charging a lithium battery on a nickel charge setting. Please don't go there.
So saying the 110DX with a 109 chip is a dual purpose charger is stretching things a bit.
I agree with you but Astro has the chips available and my 110 customers are loving the flexability. If a customer has a 110 the $25 chip is a much better option than a new charger.

I also agree that you will have to develop "new habits" if you are to be swaping a lot but most of the LI-Poly customers I have, have "Made the switch" and as such do not move the chip back and forth that often.

Cliff Whitney
Atlanathobby.com
Nov 11, 2003, 10:56 PM
BEC
BEC
Registered User
BEC's Avatar
I agree that the ability to convert from one to the other is a real good deal for those "making the switch" and who already have a 110DX. I just don't think event attempting to go back and forth is advisable.

I relabeled the front panel of the one I have that is converted from 110DX to 109 just to make sure I don't get confused.
Nov 14, 2003, 03:58 PM
Registered User
It appears that the AF can make a mistake on the cell count, with pretty nasty consequences:
https://www.rcgroups.com/forums/show...5&pagenumber=6
ALWAYS check your cell counts on auto-detect chargers. They are not 100% reliable.
Nov 14, 2003, 08:00 PM
BEC
BEC
Registered User
BEC's Avatar
I have been in touch with AF and they have been in touch with the fellow who had the fire. It is NOT clear that the charger goofed - there were several things going on including mixing packs that were charged and not and pulling 50% more current than the cells were rated for.

He also obviously didn't look at the display to confirm that the correct cell count was selected as you are quite correct in admonishing.
Nov 14, 2003, 08:49 PM
Registered User
Daniel Mc Crae's Avatar

Schulze safety solution !


Quote:
Originally posted by BEC
I have been in touch with AF and they have been in touch with the fellow who had the fire. It is NOT clear that the charger goofed - there were several things going on including mixing packs that were charged and not and pulling 50% more current than the cells were rated for.

He also obviously didn't look at the display to confirm that the correct cell count was selected as you are quite correct in admonishing.
Hey boys get a Schulze and feel safe ! Never heard anything like this whit them !

Jason Shulman made history at the last 2003 F3A championship finishing 7th overall whit an electric model flown on a 10s3p LiPo pack charged whit Schulze chargers !
Nov 15, 2003, 01:28 AM
BEC
BEC
Registered User
BEC's Avatar
And Gary Wright burned a Funtana, an isl6-636, a bunch of cells and nearly a trailer by setting the Schulze for 10s while he actually had a 9s in the airplane. (See the "Lipo Fire!" thread in Batteries/Chargers).

The point is, one has to pay attention to what one is doing. The guy who just toasted his Tanics and his heli did several things that were suspect, to put it diplomatically, including not looking at the information available on the charger's display and verifying that it is correct (something you MUST do with schulzes as well).

I have and use both the AF 109 and a schulze isl 6-636.
Last edited by BEC; Nov 15, 2003 at 01:30 AM.
Nov 19, 2003, 02:32 PM
Registered User
Quote:
Originally posted by BEC
I have been in touch with AF and they have been in touch with the fellow who had the fire. It is NOT clear that the charger goofed - there were several things going on including mixing packs that were charged and not and pulling 50% more current than the cells were rated for.

He also obviously didn't look at the display to confirm that the correct cell count was selected as you are quite correct in admonishing.
BEC,

I didn't think the AF 109 Lithium charger allowed you to confirm the cell count with some operator entry or change the cell count if it was wrong. I thought you set amps and connected the Lithium battery and the charger computed the cell count and in some instances could change the cell count in Mode 2. Where did I go wrong in my thinking?

Regards,

Ed


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