LBA10 Balancer with M1 Cells?
 

I was looking over the documentation for my LBA10 last night and started wondering if it could be used to balance a pack made of M1 cells. The LBA10 works several ways; it cuts off if the pack discharges down to 2.75v (perfect for the M1 cells?), cuts off if any cells goes over 4.3v, and keeps each cell within 0.05v of each other.

So, if I used an M1 specific charger (or do some type of adaptive CC charging so the max voltage doesn't go over 3.6v/cell), I should be able to use this balancer right? Sure, it won't provide the optimum cutoffs, but that's what the charger is supposed to do. But it should keep each cell balanced with respect to each other.

Thoughts?

BTW: I found out the Hyperion 7i does NOT go into a CV mode with lipos; it's more of an "adaptive" CC. When the voltage reaches 4.2v/cell, it simply constantly adjusts the charge current to keep the voltage to that level. I thought that was kinda interesting. Another thing I found out, the powersupply uses boost mode switching. That probably doesn't mean much to most people, but this charger uses the battery voltage to determine the power supply voltage. The circuitry simply boosts the 12v input to a point a little higher than that. Pretty simple yet effective. :)

Some balancers will only balance packs where the voltage is 3.3v or above. I don't know if this balancer operates that way, but if it doesn't, then it's fine to use on the A123 cells.

Hmmm, it doesn't really say. It just states the cutoff on discharge, cutoff on charge, and the fact it keeps the cells within 0.05v from each other. I really think it does, because when I plug in my depleted (~3v/cell) emoli pack, it starts to balance them right away.

Then I guess the answer is yes, it will work :).

Cool. :dft003:

Now all I need is a charger capable of a 3.6v/cell limit (or do the adaptable CC thing) and the batteries. I may try 6s M1's in my Revo if I can figure out a workable layout.

There are a number of chargers out that already have the capability to charge A123 cells, include the TME Xtrema, TP-1010C (soon), Schulze chargers (upgraded firmware), Orbit Microlader (I believe), CellPro 4s, and the Astroflight 109 should be getting an upgrade chip soon. Otherwise, the LipoDapter will allow any charger to work :).

Not to Hijac a thread here, but I'm curious to what you just said about the Hyperion. Mine will have no problem doing my 4s in series, and as you know all to well Brian, I cannot get the 5s to charge (unless the packs are half charged already), so would this mean that the input voltage is too low to charge my 5s? If so, can I get my powersupply to push enough volts to charge my 5s?:032:

Brian; i am using a Graupner type of thing of these chargers, i can confirm that they are very precise in balancing.

With or without the charging process active, it simple balances them.

If your charging voltage stays at the fixed 3.6V i see no problems for using it for balancing. A nice safety feature is that the 4.3V cutoff really cuts the balancer loose from it's charging signal.

That does sound like a P/S issue. What error message do you get?

If you are getting no charger errors, depending on what amperage you are trying to charge at, you might be hitting the 120w limit of the charger. With a 5s pack, you can only charge at 5.71A (assuming cells are at 4.2v/cell). With 4s, you can charge at 7.14A before you hit the 120w limit. Actually the Hyperion can only go up to 7A, so that will really be the limiting factor at 4s.

That's good to know. I saw that there were several chargers capable of charging M1 cells, but didn't see anything meant explicity for balancing them. Once I realized how the balancer actually works, it made sense that it would work for these cells even though it wasn't explicitly designed for them.

Like I said, the charger will provide the floor and ceiling cutoffs for the pack. The balancer will simply keep each cell equalized with respect to each other.

If I remember right, output voltage too low is the error message. It has been awhile though. Or it said input voltage is too low. It would say it with the 5s even charging at 2 amps. The 4s I can charge at 5 or 6 no problems at all. I was just curious, if I could bump up what the PS is putting to the charger if this would help charge the 5s if ever needed. My 989 can do it no problems.

I'd imagine you got an "input voltage too low" message if it was a power supply issue. As the current goes up, the voltage output of the PS will start to fall depending on the build quaility. However, if it does that at a low 2A, that doesn't make sense.

I've also seen "output voltage too low" and haven't really figured out why it does that. From what I could tell, since the circuitry does an adaptive CC charge for lipos, the sensing circuitry is a bit too sensitive and trips the alarm.

I did notice about 14mV of 53kHz AC ripple (from the charger's power supply) on the output connectors. I thought maybe the sense circuit was seeing this ripple causing the alarm to trip, so I tried using an inductor and capacitor network to kill the ripple, but it still had the "output voltage too high" error. I just have to manually adjust the current for now until I figure out why it does this. Eventually, I plan on getting a better charger that will do higher cell counts at higher currents, but it is a PITA for now.

I see. How would I get my PS to send more juice the charger if this is the case. Anyway, I love the 989 Brian. I'm not a big fan of MRC, but this thing rocks! It charges anything I throw at it. And the price dropped to 135.00 somewhere I saw, can't remember where. sjcrss knows though, you could shoot him a PM if you were interested.

Well, I did a how-to for modding the PS a while back. Basically, you can do two things; load the 5v and/or 3.3v line with about 1A of current. This helps to stabilize the regualtor circuitry and keeps the 12v more stable.

There might be a small poteniometer somewhere inside. You could tweak that if there is one. Be careful though! Just because there is a pot in there doesn't mean it's for the voltage, it could be for other parts.

You mean putting resistors on. I did the 5v (red) ones. I put two on like you showed. Could I do another set?

I just read that Astroflight is coming out with an A123 Blinky balancer and a 109 charger that will support A123 cells (not sure on the specifics, though).

that will make brian happy!

Me too! I was planning on getting the AF-109 soon, and doing a certain hardware hack to it that would cause it to charge to 3.6v/cell. But if this can be done through software in a way that won't void the warranty, then I'm all for it :D.

So these M1 cells must be pretty good to go through all this eh?

Newe: If you already have resistors on there, it's probably enough. You generallay want to draw about 1A or a tad more. Just be sure you size them appropriately to take the heat!

Well, now that I know the LBA10 will balance the M1's OK, I really don't need another balancer. Whatever charger I get will have a high cell count capability (10s), high current charge (~10A), able to have an adjustable peak v (for any future chemistries), and higher power limit (preferably about 400w).

I would love to send you a pic of the inside, i know there are adjusters (2 I believe) but my camera sucks at close ups. Anywho, my resistors are about a 1/2 inch apart and right under the fan on the PS. So I think they are ok. If I add one to another set of 5v lines, would that hurt anything?
The 989 can do 10s and has the 10amp PS, I know that it's not adjustable though. You are looking for an adjustable PS?

Brian, you're going to need to spend at least $350 for a charger with a 400W output. But at that point it might be more worth it to get a lab-quality CC/CV variable-voltage variable-current power supply. You could get something like a 30v 20amp one for less than the cost of a 400W charger.

Yeah, I figured, but why is that? There's not much different from a 120w charger and a 400w charger except bigger wire, a couple extra turns on the step-up coil/transformer, a few extra support components, and a couple extra FETs for the current handling. :sigh: I guess I'm electronically jaded. It's rare that I buy something electronic and not disgusted at the quality to price ratio when I take it apart.

The advantages of a dedicated charger vs a CC/CV power supply are pack memory functions, the algorithm to verify cell count, the auto switchover from CC to CV for Li batts, peak detection for Ni batts, etc. The closest charger I've seen that meets my wishes is the TP1010D.

Just because I have a pic doesn't mean I know which one does what. I'm not a god you know. :dft012: One of my converted PS units had two pots. What I did is attach a meter to the 12v line and S L O W L Y turned one of the pots and watched for a change in voltage. If there was none, I returned the pot back to the exact setting it was at before I adjusted it. In my case, one pot was an adjustment for the voltages (it adjusted them all up or down a few hundred mV), the other I still don't know what it does.

A CC/CV power supply will automatically switch from CC to CV like many chargers do (like the ICE). This is just another option for you that is the cheapest way. Several of the LiPo-experienced airplane guys do this as a way to get past the (relatively) low wattage of commercial chargers.

Here's another charger, it's possibly the best for it's price:
http://www.rcgroups.com/forums/showthread.php?t=592368
$300 is a lot, so maybe you would end up spending at least $450 for a 400watt charger.

While I'd actually love a power supply like that for other uses besides battery charging, it doesn't have some of the features found in dedicated chargers. I think I'll just wait. My current charger has its issues, but it does do the job.

I was looking at the Xtrema charger and while at the website, entered in the drawing for a free charger. Shortly after entering, I got an email for a coupon to get this charger for $189. It's pretty tempting. It doesn't have the exact specs I was looking for, but it's still pretty good.

Anyone here have this charger? From what I've read at RCGroups, it seems pretty nice. I like the future proof firmware updates.

It would have been nice if it had a NiMH capacility though. Lipos have a CC charge cycle, so the base functionality is there...

EDIT: Where's MetalMan tonight??

Brian, you can get the Xtrema from Tower Hobbies for $189. Then, Tower Hobbies has a $15 off deal if you spend $150-200.

http://www2.towerhobbies.com/cgi-bin...?&I=LXMUL4&P=7
http://www.towerhobbies.com/

I sure wouldn't mind getting this charger for $170 :D. Only problem is, I don't have any money for it :019:.

Working at the LHS, then prepping my $5 TC4 to take in to work tomorrow.

Seems like a nice charger.

How many watts can it do?

On their website they say it can charge at 4000ma max at 10 cells. From that, it can put out about 170watts.

Okay, that's not bad.. My graupner does 150 watts, so that last few watts won't make the big difference. It can do upto 10S too, and costed about the same, but also likes NIMH, lead and nicd batteries. This one is nice though..

The only thing stopping me from getting it now is the fact it doesn't do NiMH. Sure, I have two other chargers that can do Ni, but I'd like to bring just one with me to the field. I'm going to write the guy who makes the Xtrema to see if he plans on a firnware update to add this. Like I said, Lipos use CC for part of the charge, so the base functionality is there.

I actually saw it TowerHobbies too, but it doesn't have the update cable (and it's not a simple wire adaptor). I figured that getting it direct would be cheaper overall because it includes the cable and free shipping.

I don't know yet. First, I'll wait to see if I can win one on Dec 15th. That would be sweet. :)