Maxxamps batt always out of balance - Page 4 - RC-Monster Forums

glassdoctor · 06.09.2009, 10:15 AM

When you balance charge, they won't be out of balance unless something is really wrong with one of the cells. If one cell has less capacity than the others, it's possible to over discharge that cell (or just have it at a lower voltage than the rest) when you run the pack to LVC. It would be out of balance at that point... but will be "fixed" on the next charge. No damage would occur as long as no cells go below 3v.

If you are curious, you can check the cells voltage when the pack is first hooked up to charge. If the charger doesn't display the individual cell voltage, you can use dvm.

lincpimp · 06.09.2009, 10:31 AM

Quote:

Originally Posted by himalaya

Some tests done by EveryDayFlyer from rcgroup showed up something that's really interesting, the Hyperion new Chinese packs have their IR keep getting lower and lower when being cycled, making used packs more powerfully than new ones, aren't that ridiculous?

Enerland cell user posts show their batts have reverse behavior, higher and higher IR as time goes, which sounds more normal and reasonable. (Enerland datasheet specs only 50 cycle life typical when discharge at full C rating)

I bought myself a G3 4200mAh 35C 6S pack for my boat(you know fast boats are battery eating beasts ), looks good for the first runs, IR is 2.3mΩ/cell new, I'll watch how it's going.

That IR is pretty damn good. I will be very interested to see how these new cells perform. 80% DOD seems to be about the correct discharge amount to retain the most useable life out of a lipo. Your boat should be a good test bed to pull the pack hard. Boats are just amp hungry!

Quote:

Originally Posted by jocktheglide

I guess being a newbie into this lipo stuff I should of asked the question: how can you tell if they are out of balance? I have a hyperion charger the AC/DC version and I always balance and charge at the same time...so would they still be out of balance?

A decent cell meter that plugs into the balance port is a good investment to check the individual cells before a charge and after you have stored the pack. Not sure if your hyperion has a balancer readout screen, but I am pretty sure it does. During the charge I think you press the mode button to get to the balancer screen and then you can use the up and down keys to get to the individual cell readings.

Quote:

Originally Posted by glassdoctor

When you balance charge, they won't be out of balance unless something is really wrong with one of the cells. If one cell has less capacity than the others, it's possible to over discharge that cell (or just have it at a lower voltage than the rest) when you run the pack to LVC. It would be out of balance at that point... but will be "fixed" on the next charge. No damage would occur as long as no cells go below 3v.

If you are curious, you can check the cells voltage when the pack is first hooked up to charge. If the charger doesn't display the individual cell voltage, you can use dvm.

Just for info purposes, not all balancing chargers will be able to fully balance a pack during the charge. The hyperion chargers with built in balancers will drop the current way down near the end of the charge to balance the pack, but it may take hours if the pack is way out of balance. If you are using an external balancer it is likely that it will not get the job done during the charge. I went thru this with the various MA packs I had with bad cells, one pack took 48hrs to balance out, then puffed one cell (the low cell).

General rule of thumb is that if your pack is getting out of balance during the run you either have some very cheap unmatched cells, or your setup is drawing too much current. Either way it is time for a better lipo.

jocktheglide · 06.09.2009, 10:34 AM

should one always tell the charger that it has a lower mah than indicated on battery to be safe? Lets say you have a 5400mah battery and you tell the charger 5200 would that help from overloading the cells?

BrianG · 06.09.2009, 10:39 AM

As long as the charger uses a CC/CV scheme, it will not overcharge the cells. You could do that, but the charger may shut off once it puts 5200mAh back in as a safety. Not need to do this IMO.

lincpimp · 06.09.2009, 10:40 AM

Quote:

Originally Posted by jocktheglide

should one always tell the charger that it has a lower mah than indicated on battery to be safe? Lets say you have a 5400mah battery and you tell the charger 5200 would that help from overloading the cells?

Since you are using a balancing charger you will be fine. The balancer communicates with the charger and will interrupt the charge if one cell goes under or over voltage during the charge. That is the main benefit to using a charge with a built in balancer (or using and external charge thru type balancer). This is mainly a safe guard to prevent lipo heat/fires from being over charged, or over discharged. You can set the charger to a lower mah, but you will find it will only charge the pack to that lower setting. If you have a 6000mah pack, and set your 6i to 3000mah for a 3 amp charge the charger will only put 3000mah back into the pack, so you will have a half charged lipo. That is one of the only problem with the cheaper hyperions, they do not have separate capacity and current settings. I used to use the 5i chargers alot, and if I desired a lower charge rate, I would just let the charger cycle once, the restart it again. To be honest, just use the correct mah setting and charge at 1c.

jocktheglide · 06.09.2009, 10:49 AM

AHH..THX lincpimp...I didnt know if the charger has a sensor when to stop putting in mah like nimh they stop it basd on heat and other factors.

Quote:

Originally Posted by lincpimp

Since you are using a balancing charger you will be fine. The balancer communicates with the charger and will interrupt the charge if one cell goes under or over voltage during the charge. That is the main benefit to using a charge with a built in balancer (or using and external charge thru type balancer). This is mainly a safe guard to prevent lipo heat/fires from being over charged, or over discharged. You can set the charger to a lower mah, but you will find it will only charge the pack to that lower setting. If you have a 6000mah pack, and set your 6i to 3000mah for a 3 amp charge the charger will only put 3000mah back into the pack, so you will have a half charged lipo. That is one of the only problem with the cheaper hyperions, they do not have separate capacity and current settings. I used to use the 5i chargers alot, and if I desired a lower charge rate, I would just let the charger cycle once, the restart it again. To be honest, just use the correct mah setting and charge at 1c.

NoControl · 06.09.2009, 07:10 PM

Quote:

Originally Posted by lincpimp

A decent cell meter that plugs into the balance port is a good investment to check the individual cells before a charge and after you have stored the pack. Not sure if your hyperion has a balancer readout screen, but I am pretty sure it does. During the charge I think you press the mode button to get to the balancer screen and then you can use the up and down keys to get to the individual cell readings.

The Hyperion 610i does read off cell voltages in main options you'll need to press mode till it goes to balancer then it will give you the readings, its most likely that if a hyperion charger has the balance tap option built in it will offer all these features I may be wong though.

lincpimp · 06.09.2009, 07:15 PM

Yeah, I have a few hyperion chargers. I like the little cell meters cause they are handy for checking a few lipos in a short time..

Unsullied_Spy · 06.10.2009, 04:01 AM

The Hyperion voltage checking screen is how I always check mine. With the Hyperion Balancers (and I'm sure the chargers with integrated balancers) the balancer will basically send a signal to the charger telling it to stop charging if one cell's voltage gets too high and then it will continue to balance until the pack is balanced, then it turns itself off. I'm sure the chargers with an integrated balancers will slow or stop the charge to allow the cells to even out.

BP-Revo · 06.10.2009, 04:05 AM

The in-line balancers do not "send a signal" to the charger, they simply just cut the circuit that allows the main leads of the pack to feed through into the charge ports of the charger, making the charger think the battery has been disconnected. If this happens with my charger, my charger will began sounding an alarm indicating an error has occurred.

However, if you have a Hyperion Charger, you can connect the Hyperion Balancers to them with a data link and then they function just as the chargers which have built in balancers, they will adjust current rate if one cell is already full while the others are not to allow the other cells to come back to balance.