CloudSkipper

Hi,
I'm considering buying the following separate Balancer and Charger for LiPo's for charging 2100mah 3 cell 11.1v packs:

Balancer:
http://www.electrifly.com/chargers/gpmm3160.html

Charger:
http://www.dynamiterc.com/Products/D...ProdID=DYN4058

As far as I can tell, they are compatible. Balancer manual suggests certain models of chargers, but it also says relating to compatibility, use with "LiPo chargers and dischargers ONLY (operation based on nominal cell voltage of 3.7V per cell)". Charger manual does not say anything good or bad about using a Balancer with it. Connections look like they will match up.

I have no experience with LiPo's... is there any possibility or reason that these two devices might not be compatible? Anything particular to look for in how each operates?

Thanks

Swift427

A Blinky balancer serves a useful purpose. It's blinking LEDs act as a visual monitor as to which cell has the most voltage and which less while balancing. Also, you can get an approximate idea of the amount of imbalance. For example with a 3S resting it takes approximately 5 minutes to adjust/correct 0.01v and as long as 20 minutes for an imblance of 0.04v

You may want to consider the merits of a Blinky balancer as well as a mAh/watt meter and a battery monitor.

http://www.astroflight.com/index.php...products_id=20

http://www.commonsenserc.com/product...roducts_id=184
(Click the play button below(in this link) to hear an audio discussion on Balancing.

http://www.astroflight.com/index.php...=index&cPath=2

http://www.headsuprc.com/servlet/the...ter-for/Detail

Swift427

Here's something I'm not 100% sure of maybe someone knows if the following two procedures makes any difference with respect to cycle life/performance of a LiPo.

It has been implied that you should charge through the smaller 3S 4-pin connector rather than the larger discharge connector. However, there are many (including me) that charge via the larger discharge connector because our versatile/expensive NiCd/NiMH/LiPo charger doesn't have a built-in balancer. So, we use a Blinky balancer connected to the 4-pin connector before, during and after charging to equalize the cell voltages.

Does it really make any difference whether you charge via the larger discharge connector or via the smaller 4-pin connector as long as you are balancing the cells?

Edited Addition:
I just found out another source for a 3S battery monitor - $12.95
http://www.bphobbies.com/view.asp?id...7&pid=B2632602

My LHS gets 3-5 day service from BP Hobbies. I'm going to order one. It's handy in the field and at home for checking immediate bounce back voltages after LVC as well as after resting before recharging to keep tabs on the condition of your LiPos (A,B,or C condition) through their lifespan.

Swift427

The following is an email reply I recently received from CommonSenseRC

"Our Ultra-Balancer does in fact operate below 3.7v per cell. At the the top of the unit, are three lights, which indicate average cell voltage. Red = 4.15v - 3.7v
Green = 3.7v - 3.2v
Yellow = 3.2v and below
Ultra balancer instructions: http://www.commonsenserc.com/product...ions_final.pdf
As for your question on how much imbalance is tolerable, you don't want to have any imbalance at all on your pack at all. What we define as imbalance is a difference of 50 millivolts between cells, or 0.05v. Anything greater than that needs to be balanced right away."

I've noticed that an imbalance of even 0.03v between cells after being fully charged results in slightly more fallback immediately after charging (0.24v) to say 12.20v instead of 12.43v. Whereas, if all three cells are within 0.01v of each other (4.14v / 4.15v / 4.14v) the Lipo will only fall back to 12.43v from 12.45v. (It is recommended that LiPos be charged to 12.45v not 12.6v)

Is some of this knit-picking? Maybe, but it does make one aware of the need to treat your LiPos with care to get the most performance cycles possible. Some mistreat/abuse their LiPos and then blame the vendor for selling them a crappy battery.

Hopefully, all this is starting to make some sense as you get a better picture of what seems reasonable to your own needs and budget.

MrMulligan

My Feedback: (314)

How about a combination charger/balancer. The ones I use are from www.fmadirect.com. These charge through the balancer connector and are extremely easy to use with readouts on just about everything that is happening. Adapters are available for the different brands of LiPos. The Cellpro 4 sells for about $70 and adapters are about $10. I have both a Cellpro 4 and a Cellpro 10. I've had a Cellpro 4 since they first came out. The Cellpro 10 is much more expensive but charges up to 10 cell packs or two five cell packs at the same time. Both chargers have storage charge mode and a mode for A123 cells.

CloudSkipper

I think it is partly knit-picking, but not without technical merit and can prevent problems from evolving. And I'm sure you can get away with not balancing as some claim.

Whatever the case may be I don't mind attending to some knit-picking if it doesn't cause unreasonable expense.

Thanks for all the info. I'm starting to get a much more detailed knowledge of this now.

As far as I understand that "dynamite" charger in the original post might not be fully compatible with the balancer. Better to use it with one of the tested models... because that balancer balances in-line with the charger.

The Equinox separate balancer that I linked to in this thread does actually charge the pack through the balancing connector. When used with a charger, it balances through selective charging, because it's connected in-line with the charger instead of in-parallel as some other separate balancers (which balance only by selective slight discharging). The Equinox also balances by discharging if used without a charger.

Unfortunately I can't order from that link at the moment, because to reduce shipping I need to order the charger in the same order with my other stuff.

Cheers

Swift427

Both Leo and I have the same kind of charger with: time expired, voltage, and amperage digital readouts. MrMulligan makes the same point about getting a charger with digital readouts. But they don't show you how the individual cells within a pack are performing. For instance with a new pack you should condition cycle it at least once before flying at a lower discharge rate somewhere between 2C-to-4C. With a battery monitor you can then check the voltage of each cell with the pack fully charged as well as the bounce back voltage 10 minutes, 30 minutes and 1 hour after LVC. That is really the only way you know for sure how equally matched are the cells in a new pack. That gives you the best picture possible of your LiPo's condition/quality and how often you need to balance a pack.

No matter what kind of a charger and balancer you get or whether you charge via the discharger connector or the balancer connector get a battery monitor. It will result in you taking better care of your LiPos and prolonging their life. Here are some battery monitor links.

http://www.headsuprc.com/servlet/the...ter-for/Detail
http://www.bphobbies.com/view.asp?id...7&pid=B2632602
http://www.all-battery.com/index.asp...OD&ProdID=1973

My A+,B,C- is my own arbitrary method based on expected flying time as compared with each cell's bounce back voltage after 10 minutes and 1 hour from the LVC. If you can only wait 30 minutes before recharging then check it at 10 min. & 30 min. For example if my flying pattern of a particular plane and a 1000mAh battery is 10 minutes when new, but becomes shorter over its life and the bounce back voltages become more imbalanced I think of its performance as:

10 minutes flying time = 100% = A
8.5 minutes flying time = 85% = B
7.0 minutes flying time = 70% = C
5.5 minutes flying time = 55% = D
( if I find out I bought an under rated 1000mAh that is more like 1100mAh then I'd rate it as A+ )

You do what works best for your own flying intersts and budget, but I would highly recommend you purchase a battery monitor. Then as you get more batteries and your not always sure of the charged or discharged condition you can easily check them out whether at home or at the field. Their individual cell condition also determines what rate you may want to charge them (1C, 0.8C, 0.6C).