Capacity Controller

[Knackered Sailor]

I bought a capacity controller (as pic) for easy checking of batteries but got myself somewhat confused. 

On a fully charged one it showed 12.6v and 99% charged. Fair enough.

After putting one on 'Storage' it showed 9.74v and 1% charged. 

Now the 9.74v seems to me about right but surely it should show as more than 1% charged? 
(I did say elsewhere electronics are foreign to me so learning) 
Advice or education welcomed.

Attachments:

[flydiver]

You don't want to discharge batteries below about 3.5v/cell. 3.85v/cell is generally accepted as 'storage'. In reality anything from about 3.7>4.0 is fine for shorter periods. 9.74v for a 3S is not so good. It's telling you honestly it's d**n near dead.

Here's an APPROXIMATE chart showing voltage vs %remaining.
Hmm, the formatting comes out kind of poor but I think you can work with it.

Voltage per cell (no load) - capacity remaining in % - 3S voltage
cell -- % --3S
4.2 - 100 -12.60
4.17 - 98 -12.51
4.13 - 95 -12.39
4.1 - 92 -12.3v
4.07 - 89 -12.21
4.03 - 86 -12.9v
4.0 - 82 -12.0v
3.96 - 78 -11.88
3.93 - 74 -11.79
3.9 - 69 -11.7
3.87 - 64 -11.61
3.83 - 59 -11.49
3.8 - 53 -11.4v
3.77 - 47 -11.31
3.73 - 36 -11.19
3.7 - 22 -11.1v
3.66 - 12 -10.98

Lipo (all rechargeables) discharge is not linear. They all usually have a place where there is a notable drop (knee). Take a look at this curve. Click on the graph to enlarge.
www.wattflyer.com/forums/showpost.php?p=841284&postcount=4

If you didn't do something wrong to set that up for storage....I would no longer trust it for that function.
Are you sure you didn't set it in [discharge] instead of [storage]? What you ended up with is kind of consistent with [discharge]. I'm not familiar with that device so can't comment on it's use.

[Knackered Sailor]

Thank you so very much Fly (another page to bookmark) I used an Imax B6 to set it on Storage. I'm doing it again now. I take it you still plug in the balancing lead whatever you do?

The Imax automatically sets 9v as it's storage level!

[flydiver]

Jan 24, 2014 19:02:39 GMT 1 @thingy said:

Thank you so very much Fly (another page to bookmark) I used an Imax B6 to set it on Storage. I'm doing it again now. I take it you still plug in the balancing lead whatever you do?

The Imax automatically sets 9v as it's storage level!

The IMAX does NOT set storage at 9v. That's full discharge for 3S, a BIG difference. Check your menu again. It's not "automatic", you have to SET [storage] and SET the # of cells.
Do it improperly > you get results you won't like.
You don't have to plug in the balance lead, but if you have it, I'd use it. When you fly you discharge a battery. It is not balanced while this is happening so is not a critical function. It's just another layer of safety. OTOH, balancing while charging is far more important.

I do discharges and storage all the time on single cell lithium ion cells with an Accucel-6 (same menu and functions). Single cell > no balance lead. OTOH, you don't need it for 1 cell.

Advanced option: Nimh and NiCad also do discharge. You can set that to the EXACT voltage you would like it to stop. It really does not care what kind of battery you have attached to it. You want a 3S to stop at 11.7v > put it in NiMh, set it to discharge, and key in that exact stop voltage. Works fine. I do suggest you watch it the first time to make sure you haven't set something wrong. Set it right, it works well. It will not balance in this mode, but like I said, doesn't really matter.

Note-The IMAX and similar chargers are limited to a MAX of 1A discharge, pretty slow, esp. for larger batteries. I often use a bank of 12v tail lights and an alarm. I've learned the alarm is necessary for me. I've sat with a lipo being discharged right next to me while browsing the net and then noticed the light had gone out, dead out. Not a good feeling.
Almost everyone seems to do this....once if they try light bulb discharge.

[Knackered Sailor]

More good info thank you for taking the time to write, maybe in a few years I'll be able to help others. :-)

I've tried again but there is no way the Imax will allow me to set Storage level. I go to the Storage option where it recognises that a 3S 11.1v Lipo is connected, no storage level option comes up so I press and hold the start button and off it goes. If I then press the left status button it shows final level as 9.6v. I'll just have to keep an eye on it and stop it somewhere about right or get your car lights idea.

Cheers

[flydiver]

Jan 26, 2014 13:30:34 GMT 1 @thingy said:

More good info thank you for taking the time to write, maybe in a few years I'll be able to help others. :-)

I've tried again but there is no way the Imax will allow me to set Storage level. I go to the Storage option where it recognises that a 3S 11.1v Lipo is connected, no storage level option comes up so I press and hold the start button and off it goes. If I then press the left status button it shows final level as 9.6v. I'll just have to keep an eye on it and stop it somewhere about right or get your car lights idea.

Cheers

Go into NiMh mode > Discharge at 1A > final voltage @ 11.4v (for 3S). Try that.
Or set it at 12V to see if it stops OK. Then reset to where you want it.

Something isn't right with your IMAX or your setting. Did you get one of the fake IMAX (cheapo from eBay)? They can have problems. Newbies don't know about them and are buying them by hoards since they are cheap and they can't tell the difference between the 4-button chargers.
www.skyrc.com/antifake/indexen.php
www.youtube.com/watch?v=kziSFSQvxr4

Yes, HK will sell you a crap charger with it's left hand and warn you about it with the right.

Addendum: Do you have the manual? www.skyrc.com/index.php?route=product/product/download&download_id=17
If so look at the flow chart on pp. 10 (3rd main row).
Are you SURE you are in Lipo mode? Not LiLo or LiFe? Setting these can be a bit of a trial. I have to screw around every time I do it.
Then check pp. 19 for details.

If you are doing everything right, and the charger will not cooperate, I would suspect a bad charger.

[Knackered Sailor]

Thanks again for informative reply. I guess I must have a fake Imax as it does not have the authentication scratch off thing. It works fine apart from Storage Mode which, as you say, is actually discharging. I've been keeping an eye on it and switch it off at right levels. When I have a moment I'll get on to suppliers for a refund and then inform Trading Standards Office.

[flydiver]

Jan 30, 2014 23:04:03 GMT 1 @thingy said:

Thanks again for informative reply. I guess I must have a fake Imax as it does not have the authentication scratch off thing. It works fine apart from Storage Mode which, as you say, is actually discharging. I've been keeping an eye on it and switch it off at right levels. When I have a moment I'll get on to suppliers for a refund and then inform Trading Standards Office.

Ack, too bad. I wish people would stop promoting those things. Clones are problem enough. Low quality copies/fakes of clones is pushing it a bit far, especially with lipos.
The 'failure/problems' are not all the same. Some overcharge, some screw up charging NiXX, some don't balance right. I think they are thrown together with whatever cheap parts they can get their hands on.

Interestingly the early (real) IMAX of about 4 years ago had balancing problems. There was a long thread in RC Groups about it and one guy came up with a kit to replace some components and fix it. It must have impacted the parent company as they fixed the issue and it regained popularity. About a year ago these fakes started showing up. I think there more of them then the real thing now. Of course the people who buy them generally don't have a clue about it, nor do they have the tools or the knowledge to check them out. Unfortunate state of affairs.