RC Lipo pack inspection, series/parallel charging, and lifespan/safety tips

[neptronix]

Cycle graph them and you will find out.

 

[longwise_suck]

I am sorry to be so ignorant but what do you mean?

 

[MrDude_1]

I am sorry to be so ignorant but what do you mean?

Most RC battery chargers will log data to a PC... you can run a "cycle" where the charger will charge, discharge, and recharge it.. and log all the data for the PC.

You can use that to test your cells, and find out if any are bad or not.

 

[neptronix]

I am sorry to be so ignorant but what do you mean?

I take it you haven't read the first post that this thread is all about?

 

[tomjasz]

Cycle graph them and you will find out.

I almost hate to ask, since Grin seems the only group to provide Macware. Is there any OS X version that will work with iChargers?

Once again, simply the best primer I have found. Written so well even my dulled brain can grasp the steps.

 

[neptronix]

Is there any OS X version that will work with iChargers?

No, but there's always virtualbox (free), vmware(paid), parallels(paid) and a copy of windows xp(don't ask, don't tell.. :lol: ). I know that virtualbox allows external USB devices to be plugged in to it, and the operating system will indeed allow you to install the proper drivers supplied with your charger, etc. It can be done.

Once again, simply the best primer I have found. Written so well even my dulled brain can grasp the steps.

I appreciate your kind words; thanks.

 

[MrDude_1]

No, but there's always virtualbox (free), vmware(paid), parallels(paid) and a copy of windows xp(don't ask, don't tell.. :lol: ). I know that virtualbox allows external USB devices to be plugged in to it, and the operating system will indeed allow you to install the proper drivers supplied with your charger, etc. It can be done.

And all of these work much better than they used to, since your "mac" is really a PC that's just running a different OS.... really. it is 100% a PC and you could install windows or linux on it if you wanted.
I would go with Virtualbox unless you can get vmware for free.

 

[longwise_suck]

So mystery solved! this pack was lent out to a neighbour whilst i was at work and returned some days later, he ran his lawn mower with it and totally drained the pack and then recharged it with a nicad charger...safe to say the pack is retired

 

[neptronix]

See.. a cycle graph could be used for entertaining purposes here, too. 8)

You wanna see the biggest fail i've seen on logview so far?
I got suckered into buying a supposed pre-multistar density lipo by this RC company that a bunch of people talked up..

Checked 6S pack with a cellLog 8S.. not bad.. everything's balanced pretty well.

Hooked up the iCharger 1010b+, set it to monitor mode and hit start.
Applied a 3 amp load to the battery ( 24v halogen bank ).

..and saw this:

This is why we graph. Otherwise you're sitting there wondering why your pack just dipped to 0v on the 40A load you thought you could apply to it. Turned out that this was a pack made of recycled junk cells. IR for all the cells is obviously ALL over the place.

 

[longwise_suck]

Yep I know exactly what that is now i have logview i had completly forgotten about it as the pc the program and files where on had the hard drive fail i should graph this pack for a chuckle

 

[YonderGod]

Thank you for all this information!

Will I run into any problems running 2 6s packs in series, and charging in parallel?
I have this charger already. It can charge up to 6s.
and I plan on getting 2 of these: http://www.hobbyking.com/hobbyking/store/__64439__Multistar_High_Capacity_6S_10000mAh_Multi_Rotor_Lipo_Pack_US_Warehouse_.html
(for use with http://www.ebay.com/itm/48V-1000W-26-Rear-Wheel-Electric-Bicycle-Hub-Motor-Kit-Conversion-Speed-Control-/291422862729?hash=item43da27fd89)


Just to make sure, am I missing anything that I need?
http://www.hobbyking.com/hobbyking/store/__53678__XT90_Series_Adapter_1pc_.html (for discharge)
http://www.hobbyking.com/hobbyking/store/__46612__Nylon_XT90_Connectors_Male_5pcs_bag_UK_Warehouse_.html (for controller connector)

For charging:
http://www.hobbyking.com/hobbyking/store/__53677__XT90_Parallel_Adapter_1pc_.html
http://www.hobbyking.com/hobbyking/store/__27080__JST_XH_Parallel_Balance_Lead_6S_250mm_2xJST_XH_.html
http://www.hobbyking.com/hobbyking/store/__25660__XT90_to_Banana_Plug_Charge_Lead_Adapter.html


OR http://www.hobbyking.com/hobbyking/store/__31676__Hobbyking_Parallel_Charging_Board_for_6_Battery_Packs_2_6S_XT_90_.html ?


Thanks :wink:

 

[longwise_suck]

I also looked at those packs you will have to let us know what you think of them but yes I run mine in series and then parallel charge with no problems apart from pulling them apart for charging is a pain in the ass, don't let your wife lend them to a neighbour for his lawn mower....

 

[YonderGod]

Got my batteries today, get my motor/kit tomorrow

1 question; do I leave the parallel balance lead connected when the batteries are in series for discharge?
I would assume I disconnect it, but looking at the graph, if I discharge below ~3.6v per cell, the variance in the cells will most likely be more than .05v, and the guide says not to connect it when they are.

 

[longwise_suck]

I never have them connected unless they are on the charger then i use a balance board, avoid discharging your packs to less than 3.8 and dont charge over 4.15 and the packs will live a lot longer, they will go out of balance until you get some cycles on them after that providing all the cells are good they should stay pretty much balanced i check mine every few days and once a week i balance them now

 

[YonderGod]

I never have them connected unless they are on the charger then i use a balance board, avoid discharging your packs to less than 3.8 and don't charge over 4.15 and the packs will live a lot longer, they will go out of balance until you get some cycles on them after that providing all the cells are good they should stay pretty much balanced i check mine every few days and once a week i balance them now

Got it.

Also I did some googling and found that .05v variance is on the extremely safe side. In the post I found they said they tested at .2v difference and it was fine.

 

[longwise_suck]

I just reread your post, I forgot to say never connect the balance wires in parallel when the mains are connected in series

 

[kiwiev]

Hi guys

I have an 18s pack of 6 x 6s 15Ah Lipo.

I balanced charge them every 6 bulk charges, but my bulk charger died.

So my question is.

If I have 3 packs of 2 parallel with balance leads of 2 p together can I leave the whole pack together and plug the 3 leads from charger 6s into each 2p pack with balance lead in.

I want to leave the pack in series wired into the bike and run the 3 power leads and balance leads to the outside.

Is this possible with the pack still together as 18s

Thanks in advance.

Cheers Kiwi

 

[wesnewell]

So, you have an 18s2p pack made up of 6 6s packs. Sure, you can balance charge each 6s 2p section as long as you have access to both the positive and negative of one or both of the 6s packs. But I found it just as easy to unplug all 6 packs and then parallel charge all 6 at once.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=39666

 

[kiwiev]

So, you have an 18s2p pack made up of 6 6s packs. Sure, you can balance charge each 6s 2p section as long as you have access to both the positive and negative of one or both of the 6s packs. But I found it just as easy to unplug all 6 packs and then parallel charge all 6 at once.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=39666

Thanks Wes I thought I could its in a Vector frame and I just want to bring the leads to the front cover for a plug and play set up

Cheers Kiwi

 

[YonderGod]

edit: nevermind, I'm slow.

 

[liveforphysics]

A pair of 10Ah cells in parallel makes a 20Ah cell.

 

[YonderGod]

A pair of 10Ah cells in parallel makes a 20Ah cell.

facepalm. Idk why I thought of it differently when charging.

 

[cycleops612]

As a noob, and merely an ebiker, would you guys invest the required neurons in this if you were in my shoes?

Man its complicated and fraught & it seems, time consuming, even for old hands.

I dont need more than 2-3c really on an ebike, though faster charging may be nice.

I notice there are 22v 16 ah lipo modules about (352 wh, ~1.8kg, not bad), and probably bigger. Surely THEY are simple to charge?, and could perhaps be used to good effect on a stock 24v ebike, if say, fast charging & weight was a boon for the user.

So my question is, what are your views on lipo being a practical/convenient/safe (ie no balancing modules, charge in situ) alternative battery pack for an ebike?

as a careless person, i am leery of complex storage rules also.

 

[amberwolf]

I notice there are 22v 16 ah lipo modules about (352 wh, ~1.8kg, not bad), and probably bigger. Surely THEY are simple to charge?, and could perhaps be used to good effect on a stock 24v ebike, if say, fast charging & weight was a boon for the user.

If you don't mind losing much of the capacity of the pack, they might work. 24v bike's LVC is probably about the midpoint (or even higher) of a "22v" pack. Uusally full charge for a 24v bike's pack would be around 28v. Full charge for a "22v" (6s) pack would be around 25v, so you would also never get full speed/power out of the 24v bike.

So my question is, what are your views on lipo being a practical/convenient/safe (ie no balancing modules, charge in situ) alternative battery pack for an ebike?

Compared to the availability of good-quality reliable non-RC-Lipo packs these days, I would rather get something else that's less likely to have QC problems in the cells causing failure of one kind or another. While it's relatively rare, dramatic failures of RC LiPo cells are still more likely to happen than with the other packs available these days, and more of the fires reported here on ES are of the RC LiPo type.

as a careless person, i am leery of complex storage rules also.

Then RC LiPo is not for you.

 

[neptronix]

^-- i second that.

Go buy a prebuilt pack unless you are willing to nerd out on something that is extremely dangerous if mistreated. The price difference between a prebuilt pack and a lipo pack is not as extreme anymore.