Xtrema Balancer review

[swatson144]

I just bought the Xtrema dual balancer add-on, the data cable bundle, and some cables etc. for my extrema charger. TME has really impressed me with the xtrema rig.

I'm no battery/charger/balancer guru. I am bull headed and picky. I fly, I don't study battery charging as a hobby, I'm glad there are some that do and share the info! I know what I want. I want simple. I want effective. I want the dang rig to work on most everything I want to charge. I don't want a bunch of adapter cables. I don't want some mamby pamby sissy rig that won't charge unless you have the balance taps connected. Oh BTW I always want more power! Looking through those eyes you find that a good percentage of chargers/balancers become a non starter in the race.

The Xtrema rig is modular. I like modular! Not only is it modular but it is well thought out modular, as most of the pieces work fine alone. The basic part is the Xtrema Balancer (http://www.tmenet.com/Xtrema_balancer.htm) itself
http://www.rchelicoptertown.com/forum/photoplog/file.php?n=616&w=o
This little gadget connects to the pack regardless of the plastic shell on the end. Simply plug it in with the last black wire on the end of the balancer marked black. Don't worry if you goof it won't hurt nothing, just none of the LEDs will come on. It fit's most every pack with .100" pin spacing and the only adapter you are likely to need is the .100" to 2mm (tp) optional adapter. Without any of the other items in this setup (and available seperately) this thing is like a Astro Flight Blinky on steroids, tooling down the alley with an idling chainsaw, It's ready for business! Wow jumper selectable for A123 or LiPO. Over 4 times faster than the Blinky .42 amps while draining a cell verses .1! It has an indecator light that tells you how bad the imbalance is by flashing for each .01V misbalance. It has completely won me over @ 35$ a pop I am glad I bought 3 maybe I won't have to order more. These are well worth it even without the other integrating parts. They also shutoff and stop blinking when done, though should be unplugged soon after.

USB cable, is another optional (well semi optional) portion of the rig. It will update the firmware of the charger and other xtrema products. I really call it Semi optional because you need the newest firmware in the charger to use the Balancer Interface Module (BIM). You could send it to TME and they'll update it free (all the TME products are lifetime free updates) but the shipping is on you. You'd be half way to owning the cable anyway. Without it you miss the rather nifty usage of TME's free software XTRBalancer. Coupled with the Balancer you can get a voltage reading on each cell and watch it balance in 1 second increments. It also allows the changing of the balancers parameters. This would allow balancing 2 of the same packs to the same voltage for paralelling. IE you look at the 2 packs and note the lowest voltage and balance both packs to that voltage via the PC and plug them in parallel 8-) Personally I probably won't use the USB link often but I'm glad I bought it and it'll make trouble shooting a pack much easier.
[/URL][URL="http://www.rchelicoptertown.com/forum/photoplog/file.php?n=617&w=o"] (http://www.rchelicoptertown.com/forum/photoplog/file.php?n=617&w=o)http://www.rchelicoptertown.com/forum/photoplog/file.php?n=617&w=o
That should be of some help periodically. BTW That isn't finished but just a screen shot when it was first started.

Next installment is the integrated charge and balance.

Steve

[swatson144]

If you add the Balancer Interface module (BIM) into the equation you now have a very robust balancing system. It will idle back the charger until the packs are balanced and keep a very good eye on the balance. With the USB dongle and the 2nd piece of software (free) "Xtrema Log" it will log the charge with parameters. Besides the basic balance charger actions, the bim has plugs for 2 balancers allowing the balancing of 2 packs in series or parallel and balances them together. Admittedly this is a feature I haven't used as I run 6s and up so they'd have to be paralled to charge (xtema is 10S limit)and I don't bother with that. This feature would really shine on the helis running 2 3s in series as a 6S or for those running 3S- 5S identical packs you could just plug them in series and let the extrema rig charge them up as a set instead of 2 seperate charges. This has the added feature of balancing the 2 packs together so they both finish at the same voltage as set in the charger parameters.

One could also charge packs from 2 seperate 3-5s flights in series also using the BIM since it would preclude any pack from getting overcharged by idling the charger until they balance together. Again not really using this feature I can only speculate on the effectiveness. I think it'd work great on smaller packs 2100 mAH where the .42 A discharge rate would make short work of keeping the packs in balance and at the same voltage. The balancing overhead could, perhaps, maybe become too much on larger packs where the .42A is a much smaller percentage of say the 5A charge rate of 5000mAH. I'm simply postulating that with small packs the .42A discharge is roughly 25% of the charging current so in theory of a worst case you'd be done with 2 packs with a 75% savings on time. Still it is almost certain that there'd be some savings on time and a large savings of time if the packs are in good shape and run about the same time. Besides if your pack sucks any balance charger will take a long time to get it charged so there isn't that much difference. Good packs will always sail through the balancing.

The BIMs are cascadeable so with 2 BIMs and 4 balancers in theory the typical mini heli pilot could go out and fly 4 like packs and charge them up 2x 2 in series and parallel 2 pairs. IMO though this would be better done as 3X in series as a 9S and do the 4th on another charger. I am particular about matching voltages before paralleling packs.

The major innovation with this rig is that it balances packs together while charging without any adapters. We could always charge 3 3s packs as a 9s but was nearly impossible to make sure we didn't overcharge one pack and undercharge another to come up with the 37.8v cutoff.

I apologize for all the speculation in this post. I simply justify it by saying that even if I tested it throughly with a couple of my 4 pack sets and it was the greatest thing since the invention of the hammer, charged 4 packs in 1.2 hours, and worked great, YOUR packs could very well take longer than it would to charge one at a time. Or vice versa.

I absolutely love the rig. In total it prices out higher than some but watt for watt it's a bargain. It really shines in flexibility. Some of the balance chargers won't work as a simple charger, ie you can't charge a pack you don't have a balancing adapter. This setup allows me to simple balance at the field by just running the charger and the balancer, then do the whole balance charge at home. Or charge / balance for storage at 3.6v/cell. Lots of flexibility, plus it's moduler so you can buy what features you want.

Steve

[basic]

any updates steve? as i will be getting one of these great chargers to use, i'm sure i'll need to get a couple of accesories to go with it.

[swatson144]

Done.

Steve

[basic]

Seems like i have all sorts of questions about this thing now. Anyway, had a question about the data cable. Looking on tower's site, they have 2 different cables, on a r232 (serial) cable and a usb to r232. Would i need both for USB interface or is the USB one enough?

[swatson144]

I'd go straight to TME's site (http://www.tmenet.com/xtrema.htm)as they have combos. To answer your Q it sounds like tower is still selling the old data cable which was a serial cable and if you want USB the other piece was a rs232 serial to usb adapter. It is discontinued and the new cable is 1 piece USB.

Steve

[swatson144]

I have to recommend against this balancer setup. I've had some heat related problems causing me to return them for repair. All three of mine acted in the same manner and on testing the 2 I sent in still have the same problems to a lesser degree. In my case reading cell #5 voltage as higher than the actual value and continuing to discharge it even further which causes more heat and a higher voltage reading in a seemingly endless loop.

I had been in contact VIA PM (TME forum) with Albert tryning to resolve this issue. Upon returning the repaired balancers he indicated that there may be a firmware update coming.

After PM'ing the results of testing the 2 repaired balancers, I received no reply. IMO these things do not work as advertised.

I'm sorry If my delay has caused anyone any grief but I was hoping this would all get worked out. Actually I was almost sure it would get resolved.

Steve

[basic]

I haven't had any issues with mine, but I don't have any 5s or 6s batteries to have any issues.

Would it be possible to set the software to balance to a certain voltage, then balance 3 or 4s at a time? IE - move the balancer to cells 4-6 and balance those to a certain voltage, then move to 1-3?

Also, have you tested with just balancing with the 4-6 leads on the balancer. I'm curious if its the circut setup for the 5th cell or something about having 4 cells before it.

[swatson144]

IMO the thing is suffering from an accumulation of watts. IE the thing will balance at .4A so using a 3S (I have had no problems on 3S either) where only 1 cell is low it's pulling down 2 cells at .4A so about 3.4W and the board is able to dissipate that. OTOH looking at a worst case with a 6S and 1 cell is low you have 8.4W and the heat builds to the point that values shift on components. On all of mine it is cell #5 gets measured as higher voltage and it continues to drain and apparently able to keep it's temp up on the already very warm board. Why cell 5 I have no earthly idea, but all three of mine on all 4 of my 6S packs do the same.

So in a nut shell you are IMO correct. Anything you do to lower the total watts the board has to dissipate will probably solve the problem. Or anything you can do to help the board dissipate the heat seems to help. I have added a heatsink to 2 of mine and they work great as a standalone balancer but have to be watched on balance charge. Also they wouldn't show the problem on cells that were so well balanced they didn't need balancing (though none of mine are very far out and a blinky finishes them in a short time)

Frankly they work good enough for me as they are but I'm not hard to please. I just don't balance charge using the BIM where it gets a good chance to get hot.


Steve

[estarter]

I am using my old Triton charger in the 24V Lead acid batt mode to charge the 7S pack, takes less than half hour to charge at 5A, after 12 cycles, so far the cells are pretty balance.

It looks like the pack performs better after 10 cycles.

[swatson144]

I just found out they have a new firmware out http://tmenet.com/forums/index.php?topic=318.0 for details I'll give it a try with the one that was repaired but no heatsink installed.

Steve

[basic]

it's interesting to note they mention the problem you were having, and say that they have fixed it; yet you continue to have problems.

The extra features of the balancer look nice, especially the auto-rebalance and the interenal resistance measurements. Especially since internal resistance is one of the best ways to tell if a cell has gone bad. I'm curious to see what kind of numbers I get from what I'm used to on a cadex battery charger. When i worked as a cell phone tech, we used the cadex to do our battery stuff, and it would check the internal resistance of batteries. Basically if the internal resistance was above like 250-300 milliohms (i think it was milliohms) we considered the battery bad and replaced it under warrenty. It was amazing when you seen batteries with almost 2 ohms of resistance across the poles; those were generally the ones that were 3 years old and had maybe 20-30 mins talk time on them.

The internal resistance recorded by this will of course be higher, as it has to measure through the balancing tap, but i'm curious to see how good it really is. They say you should only use them for compartive measurements, so if i had any new packs I could make a spread sheet with battery info after a bunch of charge/discharge cycles.

[swatson144]

it's interesting to note they mention the problem you were having, and say that they have fixed it; yet you continue to have problems.



well if they'd fixed it and knew they had fixed it why add this to the firmware "2. We added current limiting firmware that reduces discharge current as the number of cells to be discharged increases. This will help keep the overall temperature of the balancer lower." I mean the major feature of the setup was the huge discharge current (faster balancing) this may actually do the trick as it would lower the accumulative wattage of the board.

Maybe I can get Skytrek to run my packs down again this weekend.

Steve

[Skytrek]

Well Heck,
I guess I can do you that favor but it will cost you! You know I hate to fly and running your packs down, will just mean more of it!

The things you have to do for friends sometime, Geezzz. :D

[swatson144]

Skytrek being the gentleman he is discharged all four of my 6S packs Sat.

I balance charged 3 of them and had no problems. pack #3 has always been a little more out of balance than the other 3 but the Xtrema balancer never got more than warm.

One of the balancers with a heat sink, and new firmware, was used this morning to balance pack #4 which was just field charged to get an idea of the difference in balancing times. It does take longer with the new firmware but not a gross difference. More like 40 mins verses 10. That sounds pretty bad on the surface but when you figure it now has the restart ability it's not bad at all. In the field I tend to charge with a balancer attached to the pack but not balance charge so the pack should come off balanced pretty well anyway at the end. Balance charging takes too long for the field.

Begin
alancer Rev 2.0.2b
Cell Count = 06
00:00:01, 4.137, 4.165, 4.142, 4.153, 4.119, 4.155, min: 4.119, max: 4.165, Delta: .046

00:00:02, 4.137, 4.165, 4.142, 4.153, 4.121, 4.153, min: 4.121, max: 4.165, Delta: .044

00:00:03, 4.138, 4.164, 4.142, 4.154, 4.120, 4.150, min: 4.120, max: 4.164, Delta: .044
Time elapsed
00:37:27, 4.129, 4.146, 4.133, 4.138, 4.126, 4.135, min: 4.126, max: 4.146, Delta: .020

00:37:28, 4.130, 4.145, 4.132, 4.139, 4.124, 4.138, min: 4.124, max: 4.145, Delta: .021

00:37:29, 4.130, 4.145, 4.133, 4.136, 4.128, 4.135, min: 4.128, max: 4.145, Delta: .017

So it took about 40 mins and likely would have kept up fine with the charge process. Albert has apparently lowered the total wattage the board sees by changing the drain time from 1 sec on/off to 1 sec off and a part of a second on whenever more than 4 cells are being drained. Seems to work well but slower. So if I'm right if only a few cells are out of balance it's still 4X faster than a blinky, but if 1 cell is low it's about the same or maybe a little faster than a Blinky. I'll take that.

So next was to check the balance of some packs that where balance charged last night (note this may be more about pack condition than balancer checking but it's more info).

Begin
ncer Rev 2.0.2b
Cell Count = 06

00:00:01, 4.151, 4.159, 4.145, 4.154, 4.150, 4.163, min: 4.145, max: 4.163, Delta: .018

00:00:02, 4.151, 4.159, 4.146, 4.155, 4.149, 4.164, min: 4.146, max: 4.164, Delta: .018

00:00:03, 4.151, 4.159, 4.146, 4.154, 4.150, 4.164, min: 4.146, max: 4.164, Delta: .018
Time elapsed
00:07:14, 4.150, 4.152, 4.142, 4.152, 4.144, 4.154, min: 4.142, max: 4.154, Delta: .012

00:07:15, 4.150, 4.152, 4.142, 4.152, 4.145, 4.153, min: 4.142, max: 4.153, Delta: .011

00:07:16, 4.150, 4.152, 4.142, 4.152, 4.145, 4.152, min: 4.142, max: 4.152, Delta: .010

Balance Complete:

If left on the balancer every 2 mins (default time that can be adjusted in the Xtrema balancer software) it re checks for balance and adjusts for about 30 seconds then decides it's good. Watching the numbers it all appears to be working correctly. I'm liking it.

The resistance check is (as mentioned) a look and feel thing for comparison purposes more than an accurate measurement due to the low quality of balance tap wiring etc.
Pack #1
Resistance: .120, .157, .161, .159, .136, .158
Resistance: .120, .158, .161, .160, .137, .160
Resistance: .120, .158, .161, .159, .135, .159
Retest
Resistance: .141, .179, .118, .106, .103, .145
Resistance: .142, .178, .117, .105, .105, .142
Resistance: .141, .178, .117, .104, .103, .142


Pack #2
Resistance: .094, .149, .275, .330, .181, .085
Resistance: .094, .150, .270, .323, .181, .084
Resistance: .094, .149, .269, .320, .182, .084
Retest
Resistance: .088, .106, .128, .215, .175, .089
Resistance: .087, .107, .127, .214, .178, .085
Resistance: .087, .106, .127, .215, .176, .087

Pack #3
Resistance: .150, .155, .113, .123, .145, .096
Resistance: .150, .154, .114, .122, .151, .094
Resistance: .150, .154, .113, .122, .151, .094
Retest
Resistance: .099, .112, .098, .096, .097, .106
Resistance: .099, .113, .096, .096, .100, .104
Resistance: .099, .113, .096, .097, .096, .106


Pack #4
Resistance: .150, .155, .113, .123, .145, .096
Resistance: .150, .154, .114, .122, .151, .094
Resistance: .150, .154, .113, .122, .151, .094
Retest
Resistance: .086, .100, .092, .086, .098, .113
Resistance: .085, .101, .092, .086, .098, .112
Resistance: .085, .101, .092, .085, .097, .111

In the resistance check above the packs were checked 3 times one after the other (balance was aborted after plugging in) then cycled back through the resistance check immediately (after I got #4's, I started with #1 again in the retest). Seems to be some pretty big variances so I don't know what good they are I won't be having much stock in them. You have to remember that dealing with mV the connection is a huge part of the result so I'm quite sure that simply disconnecting and reconnecting is the cause of the variance above. IE it seems to be more a connection resistance check than a cell check. I'm pretty sure any other device would work just as inconsistantly due to the connectors.

I can no longer find any fault in their designed usage and would now recommend them. I'm even gonna ship #3 back and have it repaired.

Steve

[basic]

After updating the firmware on my balancer I agree that balancing does take a bit longer, even on 3 cell batterys. However, it's good that they did get it fixed. Now if only they would come out with a slightly more capable charging firmware (i want my extrema to charge NiMH and output a programmable constant voltage for motor break in)