LiPo Battery Charging Interruption - Page 1
Forum section: electronics / beginners

author: boatanchorguy
author_rank: Newbie
timestamp: January 17, 2018, 12:41:28 am
content: I have a 4S LiPO pack and a CellPro Multi4 balanced charger. I have read that LiPO's do better for long term (>6 month) storage to be left at 50% charge. I was thinking to stop my chsarger at 50% but when I looked at the Balancer status it shows 0% 0% 89% 92%. I believe when all balanced it will read 0% for all. So even though it shows 50% charged am I correct that it's because only half the cells have been charged? I guess I should charge to 100% and put a light load on it till it hitds 50%Seems like a lot of work but it's an expensive battery that I need only every 4-8 monthsthanks in advance

author: james_s
author_rank: Super Contributor
timestamp: January 17, 2018, 01:27:12 am
content: If it's an expensive battery then you should invest in a charger that has a proper storage mode, they're not expensive.Check the cell voltages either with a LiPo cell checker you can get for a few bucks or use a multimeter, you should store them at about 3.8V/cell.

author: paulca
author_rank: Super Contributor
timestamp: January 17, 2018, 01:42:07 pm
content: Yea, it's around 3.8V per cell, not necessarily 50%, but 50% would be grand.Does the charger you have, have any settings? Can you change the "End Voltage?" You could set it to 3.8V per cell maybe. If it's a balance charger it should bring to the cells to "close enough" before beginning the charge and finish up the balance more accurately at the end. However putting a light load on it, you can end up with the cells debalanced by the time you get to 50%, although if that is happening on a light load the battery is probably needing retired.These are cheap and very useful. The only downside is they have a safety margin on their voltages and have removed the "calibrate" option on the new edition. The previous 60W version could be calibrated.http://www.ebay.co.uk/itm/Turnigy-Accucel-6-80W-1S-6S-Lipo-Balance-Charger-LiFe-NiMH-NiCd-XT60-GENUINE/271765167156?epid=1788704589&hash=item3f46775c34:g:DJ8AAOSwYGFU0meU

author: paulca
author_rank: Super Contributor
timestamp: January 17, 2018, 02:05:29 pm
content: An even cheaper alternative is to use your present charger, get it close to 3.8V per cells or slightly above and then use a passive balancer to balance the cells.Passive balancers are often found in "Power Analyser" or "Power monitor" devices which cost about $10.

author: kelchm
author_rank: Regular Contributor
timestamp: January 17, 2018, 09:41:23 pm
content: This seems highly unusual to me. None of the balancing chargers that I have used charge batteries this way. It actually seems like a good way to potentially ruin a battery pack.Typically they charge the entire pack as a whole via the main leads and use the balancing leads purely for balancing individual cells. I'veneverseen a charger that did all the charging via the balance leads.

author: james_s
author_rank: Super Contributor
timestamp: January 17, 2018, 10:35:32 pm
content: A lot of really cheap low power chargers like the sort included in RTF bundles use the balance leads. It works perfectly fine but you are limited to about 1.5A due to the small wires and connectors. The two edge most balance leads are directly in parallel to the main cable so electrically it makes no difference.

author: paulca
author_rank: Super Contributor
timestamp: January 18, 2018, 08:08:40 am
content: As James points out there is nothing special about the balance lead. The outside wires connect to the same place the main power lead connects; pack V+, V-. The balance lead is good for 1-1.5A. Small "Park" class RC models with sub 1Ah packs often come with chargers which only charge via the balance lead.My original recommendation though was a 'passive' balancer. Passive in that it has no power of it's own. It connects on the balance lead, pulls power from the cells and balances cells individually by pulling them through a resistor or connecting them to another cell. The one I have paused, senses the voltages and seem to connect the highest cell to the lowest for 10 seconds or so, then pauses to sense again. It continues until the cells are balanced, then beeps and stops.It "looks" from the voltages that it is connecting a high cell to a low cell, but I'm not 100% convinced. It might just look that way. The highest cell drops 30mV or so and the low cell rises by 30mV or so for a while, then they settle while it senses and the process repeats.These, for example, have a passive balance mode:https://www.ebay.co.uk/itm/RC-LCD-Battery-Capacity-Voltage-Checker-Controller-Tester-for-LiPo-Batteries-A-B/152718973716?hash=item238ec29b14:g:FQkAAOSwgiRZyw1W

author: ConKbot
author_rank: Super Contributor
timestamp: January 19, 2018, 06:00:37 pm
content: On the cellpro multi4, use a storage charge mode to charge the cells to 3.8v or so, it has nothing to do with the balancing feature.Also, the percentage on the balancing page isn't percentage full on the cell, it's how many percent "on" the balancer for that cell is. IIRC it balances at ~15 mA so it will charge at the instructed CC/CV profile until one cell hits the programmed voltage (3.8 for storge, 4.2 for normal) then drop to 15mA charge current, shunt the current on the full cell, and slowly balance the rest with 15mA charge. It's been a long time since I configured my multi4, so look up the manual online to get how too set it up. If you have their isolated uart cable, you can configure it in a lot of ways easier than the 1 button interface, and even do logging.Its a very capable little charger. I have one that I use for all my small battery pack charging.

author: james_s
author_rank: Super Contributor
timestamp: January 19, 2018, 06:40:55 pm
content: I have a few of the Charsoon Antimatter 300W chargers, an identical charger was previously sold as the very popular Turnigy Reaktor 300, cost is about 60 bucks, I haven't seen anything else in that price range that can compete.