Bulk charging 12 x 18650 cells - failing to charge with RC Charger.

deswong

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Jan 20, 2021
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Hi all,

This has had me stumped for a few days - and I can't really work out what is happening.

I've been using my Turnigy Reaktor charger and charging 1s4p cell configuration 18650 cells quite happily for a while now, and thought it would be good to charge more cells - although slower, by expanding this to a 1s12p cell configuration.
Charger information: https://hobbyking.com/en_us/0620-20...428&indexName=hbk_live_magento_en_us_products

I've only got a few hundred cells left to go to charge/test, and thought it might make it quicker to get through the initial charge by expanding this from 4 to 12 cells per charge session, and then I can just put them on before I go to sleep.

In the 1s4p configuration, I could charge at a maximum rate of 5A and it would start at that and complete the charge in a reasonable time.

However, in a 1s12p configuration, despite me starting at the same maximum rate of 5A, I am consistently finding (despite different cells and cell location in the holder) that it will start a maximum rate of 0.5A, and never complete the charge. The cell(s) seem to reach 3.6v (set at LiPo setting) and the charge rate drops to 0mA at this time. Even after 12 hours the cells never seem to get past the 3.6v.

Most of the cells are around 15mΩ, INR18650-20R.

Even if I put one or two in the holder, closest to the battery terminal connector from the charger, it is still attempting to charge really slowly.

Is there something fundamentally wrong with my logic in that I can charge them in a 1s12p configuration? Should I do what I was planning to start with and set it up in a 3s4p configuration instead? Or could it be the charger - being a RC charger it may have something that is limiting this in its software?
 

daromer

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Yes something is wrong and its something you have changed. either settings in the charger or a cable issue itself. The charger itself have no clue of if you have 1 cell or 100 cells in paralell connected. It can only sense the voltage on the output along with the current. It can then potentially calculate the IR but more cells is lower IR and unless you have a shorted cell it should be fine. The ir even with 12 cells is not low enough to trigger a short detection in that charger.

Meassure the voltage on the chargers output at charger and at the battery.
Also attach an image of the contraction. Both the older one and this newer one.
 

floydR

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Aug 23, 2017
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Do you have a 1s balance lead not familiar with the Turnigy Reaktor but on the icharger x series of chargers using a 1s balance lead is needed when charging/discharging 1s lithium batteries.

Later floyd
 

daromer

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You dont need the balance lead and it should not create above issue. the Balance lead is only needed if you have larger voltage drop over your normal wires or need to be very accurate :)
 

floydR

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Aug 23, 2017
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Looks like I have a voltage drop quite a big one .14v I need to redo my xt-60 hookup, Since i always have the balance connector hooked up. I was unaware that it wasn't needed. ty daromer
later floyd
 

daromer

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Its not needed but you get better result with it connected :)
Especially if you want to max out the current.
 

deswong

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Jan 20, 2021
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27
Ok - so after I have had a little bit of time this evening I have found the issue to be the RC charger itself - it just won't deliver much in the way of amperage to charge.
I have tested it with my normal RC LiPos as well, and none of these will charge - all of them show the right voltages, but the charger will attempt to charge between 0.05A and 0.06A. After an hour there is no difference in the voltage on the cells for my RC LiPos, so I guess it has reached the end of its useful life!

It's hard to tell whether it was the high amount of cells that upset this, or just co-incidence this charger (quite a few years old now!) as died. It has had a hard life in the RC world so it wouldn't surprise me that something inside has given up. I might pull it apart one day for fun.

This gives me a good reason to go get one of the new fancier chargers :)
 

daromer

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:) Get an iCharger :p
 

floydR

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Aug 23, 2017
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The iCharger X8 is great. The manual can be confusing. Many of the members here have one of the X series of iCharger.

Later floyd
 
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