Maxxamps batt always out of balance - RC-Monster Forums

transtalon · 12:55 AM

I was getting tired of this 3S 8000 MAH 25C cell that I got from Maxamps from being out of balance everytime I run it and I decided to open it up. I found that there is a pair of 4200 MAH 25C cell but the other two pair was an older one and it is a 4000 MAH batts. I can't believe this is how they manage to match each cell during assembly. I am just venting here but just warning the new guys on my experience. I am not bashing them but just letting you guys what I discovered today.

Metallover · 01:08 AM

That's maxamps for ya. Is this how you got it new from maxamps? Two 4200mah cells and 4 4000mah cells?

BrianG · 06.06.2009, 01:07 AM

Wow, that kinda sucks. To compensate, you could try setting your LVC higher so that it kicks in earlier. This would reduce runtime, but may keep you within the capacity of the 4000 cells.

glassdoctor · 06.06.2009, 01:38 AM

You need to call them... I think they will want to exchange it for you. No way that they would send out a pack if they knew it has mismatched cells like that.

What's_nitro? · 06.06.2009, 01:40 AM

^^^ It's worth a shot.

Metallover · 06.06.2009, 01:43 AM

You better hope maxamps doesn't get you on voiding the warrenty by opening up the pack. That would be a real dick move....

lincpimp · 06.06.2009, 04:56 AM

Call up Jason and tell him you will personally find him and push this pack where it belongs, up his rear with all of the other crap maxamps markets and pawns off the the unsuspecting public...

I have seen this before with maxamps, not that their cells need any help puffing and going out of balance.

Consider I have taken apart about 150 of their packs, and owned at least 30. The 2p packs puff easier than the 1p packs, but the cell matching is so poor, nonexistent?, that it really does not matter. I have heard that their new stuff is truer to the ratings, but still way overpriced...

transtalon · **lipo -** 06.06.2009, 11:15 AM

This pack started out as a 6S 8400 25C cell according to Josh. I received it and it sit for three weeks while I wait for my Hydra 240 and I checked the voltage on each cell and one of the cell was 3.7 and the rest was 4.17-4.19 volts. I charged it but keeps getting an error even after charging that one cell to 4.17 like the rest of the cells. I called them and they said send it back. It sits for about a month and then was ship back. They said everything was up to specs. They also said if it sits more than a week it tends o go out of balance. So I played along with it but then it's going out more than .5 volts and I sent it back and then they split it into 3S 2X. So it's not a assembly error, I am done with them like last year as I have own a Neu, Polyrc( very good ), Flightpower. None of them go out balance like MINAMPS in every time it sits or used. I guess my Hydra240 did get fried due to voltage ripples as my MINAMPS are not up to the task of supplying voltage to my 1527 1D motor on 6S in my extended Lst2.

sikeston34m · 06.06.2009, 11:32 AM

Quote:

Originally Posted by transtalon

This pack started out as a 6S 8400 25C cell according to Josh. I received it and it sit for three weeks while I wait for my Hydra 240 and I checked the voltage on each cell and one of the cell was 3.7 and the rest was 4.17-4.19 volts. I charged it but keeps getting an error even after charging that one cell to 4.17 like the rest of the cells. I called them and they said send it back. It sits for about a month and then was ship back. They said everything was up to specs. They also said if it sits more than a week it tends o go out of balance. So I played along with it but then it's going out more than .5 volts and I sent it back and then they split it into 3S 2X. So it's not a assembly error, I am done with them like last year as I have own a Neu, Polyrc( very good ), Flightpower. None of them go out balance like MINAMPS in every time it sits or used. I guess my Hydra240 did get fried due to voltage ripples as my MINAMPS are not up to the task of supplying voltage to my 1527 1D motor on 6S in my extended Lst2.

What a story. At the same time, what a lame ass way of taking care of customers.

Sits more than a week, it tends to go out of balance? Self-Discharge? Or how about cut to the chase and say "Bad Cell".

8400mah at 25C should carry a whopping 210 amps continous. More than enough for your application.

The fact of the matter is, this is only true if the mah specs and C ratings are true. If the C ratings were anywhere close, this pack would have no problem handling your truck.

8400mah 15C cells would still be 126 amps continous, which would probably still handle your truck ok. What does that tell you?

Alot of things can be hidden behind a fancy label, down deep, behind the hype of advertising.

With the advancement of Brushless Technology and the fact that packs are being pushed harder than ever, the Era is here that will flush out the false claims and the false advertising.

The "They will never know the difference" Era is gone.

BL_RV0 · 06.06.2009, 01:26 PM

Quote:

Originally Posted by sikeston34m

The "They will never know the difference" Era is gone.

Unfortunately not for everyone. The noob market still doesn't know the difference, and with all of maxamps' ads, the typical noob wants lipos without shopping around and discovering better/cheaper brands and just buys maxamps.

BrianG · 06.06.2009, 01:52 PM

Guys, let's keep the MA-bashing posts down. Stick to facts and observations.

lincpimp · 06.06.2009, 02:15 PM

Quote:

Originally Posted by BrianG

Guys, let's keep the MA-bashing posts down. Stick to facts and observations.

Good point, big guy!

I will add one more thing that is pretty good info for all lipo choices. Lipo construction is pretty much universal, so cell dimension and weight are pretty good comparison info when looking at various cells. If both cells are the same size and weight, and one is rated higher you may want to take a step back and ask why... Since I have handled a bunch of various pack cells I have seen the maxamps 4000 mah "20c" cells grow in thickness and in weight over the last 2-3 years. So I guess it got better? Not sure as I still get 8000 packs (4000 cells in paralleled pairs) that puff one or more cells.

The puffing is due to poor cell construction, either materials or testing (or whatever they do). Matching also comes into play, but maxamps has always said that they match the cells. If so then all of the problems are due to a cheap cell that has varying quality issues during the manufacturing process.

Comparing MA's 4000 cell to a similar polyquest cell (older 20c series) the cells were thinner and lighter. So the capacity may be correct (easy to measure that, discharge the pack to lvc and record what it takes to charge fully) but I doubt the C rating is.

I also directly compared MA 5000 pack with a polyrc (enerland) 3700 25c pack And found the polyrc pack could outperform the MA in runtime and punch. Turned out the 5k MA pack could not even deliver the rated mah under the load I had on it, where the polyrc had no issues. These cells should have similar amp output capabilities given the specs, and the 5k MA should have had the advantage on runtime. Pack weights and dimensions were very close with these 2 packs, so I deduce that the MA 5k cells were more like 5000mah 10-12c given the performance.

Bottom line is that people get greedy and want 8000mah packs (MA even base some of their advertising on this) and think that the rated specs will be enough to push a buggy or truggy around on 4s. 4s is hard on lipos in larger scale stuff, going up to 5-6s is much better. lipos that put out 80-100 amps are just not enough for 4s.

I have some informal testing on alot of cells, so I have a good feel for what works and what does not. Plus having dismantled and reassembled a bunch of packs I have seen the pack construction techniques, some of which leave alot to be desired.

transtalon · **lipo -** 06.06.2009, 04:30 PM

I agree with lincpimp. I have the Polyrc 4350 and it was taking close to 4200 when I charge it one time. I think Polyrc is not a popular name like Polyquest or Flightpower but they are real good and it outperform my 5S 8K MAXAMPs
but don't have the runtime like the 8K with the 4350 mah 5S Polyrc that I score for 50.00 shipped from the fellow member at Lstforum. It is like new, the best 50.00 I spent.

lincpimp · 06.06.2009, 04:42 PM

Quote:

Originally Posted by transtalon

I agree with lincpimp. I have the Polyrc 4350 and it was taking close to 4200 when I charge it one time. I think Polyrc is not a popular name like Polyquest or Flightpower but they are real good and it outperform my 5S 8K MAXAMPs
but don't have the runtime like the 8K with the 4350 mah 5S Polyrc that I score for 50.00 shipped from the fellow member at Lstforum. It is like new, the best 50.00 I spent.

I have bought alot of used enerland based packs, like the polyrc pack you bought. I have never had an issue with them puffing, or having weak cells. I can only remember seeing/hearing about a handful of enerland packs that have had issues, and I am not sure if that was user error or bad cells. Enerland have tight QC or something, and the factory matching is pretty good.

Flight power have a in house matching process, as they buy cells from enerland and assemble them in house. Their packs seem to be the best I have tired, also the most expensive new.

Polyquest are enerlands own brand, and they assemble those packs and sell the direct, that is why HC carries them. All good cells, well worth the cost, especially if you can score a deal like you did!

suicideneil · 06.06.2009, 08:41 PM

Quote:

Originally Posted by BrianG

Guys, let's keep the MA-bashing posts down. Stick to facts and observations.

Max amps lipos are over priced and sub-par quality for what you get?

I would post the sorry story over on the traxxas forum, along with any pics you have of the offending cells (just so theres no doubt)- get the truth out there and see how well the fan boys do trying to defend maxamps afterwards....