Mv ideal battery system

[Boyntonstu]

http://www.hobbyking.com/hobbyking/store/__18560__Turnigy_5000mAh_1S_20C_Lipoly_Single_Cell_.html


Imagine if this cell was 10000 instead of 5000.

Buy 12, wire them in series and you have a 48 V 10000 battery.

Build a battery box that is also a bike mount with a removeable cover.

Each cell would have a 10 amp capable "balance" lead.

Obtain/build 12 4.15V constant voltage supplies. (or whatever V you like to charge)

Charge each cell seperately.

No balancing.

Low cell? Replace.

 

[dogman dan]

Learn to solder, and after testing each cell, build your pack in 2p. Easy.

Charge with a thunder power 12s charger.

Most of the good info on lipo is here on the forum, but in threads from 2009. I'd wager everything you can possibly think of, was done in 2009-2010.

You can just rig your packs with larger balance wires, and clip the series connections. Turn a 1p 6s pack into a 2p 3s pack. Everything is possible, including your first KFF. The question is whether what you do is really worth the effort.

Some just rig up 1p 12s packs, and then parallel several of those. It makes the wiring mess a lot less. You gotta get over the obsession about balancing packs that don't need it. Balancing is a lot less hassle when you stop punishing a battery to the point where it needs it constantly.

 

[d8veh]

Most of the good info on lipo is here on the forum, but in threads from 2009. I'd wager everything you can possibly think of, was done in 2009-2010.

That's a very good point. Lot's of people read all that stuff and then they go and make a lipo battery that they're probably happy with because they don't know what alternatives there are.

A 10Ah 48v battery using OP's cells would weigh 3kg. If you made a 12S5P battery out of Samsung/Panasonic GA cells it would also weigh 3kg, but the capacity would be 17.5Ah and it would have double the life and cost about twice as much. Alternatively. you could have a 10Ah one that costs nearly the same, is nearly half the weight and lasts twice as long and still give enough current to run a BBSHD or average 1000W DD motor.

 

[nutnspecial]

That's not what I got from DD's advice. IMO in the early days we saw all this messing around with lipo customization but most have learned it's just not worth it and either use packs unmodified, do custom a123 packs, or go with can-cells.

Also, 48v 10ah of lipo VS 48v 10ah 18650 has something like a 4x price difference for the packs, and usually at least 4x difference in continuous discharge capacity, right?

The only price comparison I've seen close is 48v 4ah echo tool batteries, which are quality built for 50-100$ a piece depending on warranty. Now, a 30a draw on those echo LG cells is still gonna cause alot more cell stress than 30a on similarly priced 48v 4ah of lipo, but I think the ease of use factor is def worth something too.

 

[nutnspecial]

Btw, more on OP, I concur that balancing is rarely (if ever) needed. I don't break my pack down or use a balance charger, other than the occasional cell group charge or drain.

Stu that tweak is on known 'unhealthy' groups- it's always the same ones that drift from the rest. There will always be 'weak links' in the series chain, and when a pack is really pushed that's when you see deterioration and then notable drifting. Otherwise these things stay well balanced, with little or no balancing. Ykick's and DD's advice to test IR and vet cells/packs for use is the key to a healthy self balancing pack (you want very similar IR), along with proper maintanence like Motomech's monitoring method, and proper use, unlike me pushing my packs too hard and low (80a on 25c 5.8ah down to 3.5-3.6v in the beginning, and accidental overdischarge below 3v).

 

[Boyntonstu]

Btw, more on OP, I concur that balancing is rarely (if ever) needed. I don't break my pack down or use a balance charger, other than the occasional cell group charge or drain.

Stu that tweak is on known 'unhealthy' groups- it's always the same ones that drift from the rest. There will always be 'weak links' in the series chain, and when a pack is really pushed that's when you see deterioration and then notable drifting. Otherwise these things stay well balanced, with little or no balancing. Ykick's and DD's advice to test IR and vet cells/packs for use is the key to a healthy self balancing pack (you want very similar IR), along with proper maintanence like Motomech's monitoring method, and proper use, unlike me pushing my packs too hard and low (80a on 25c 5.8ah down to 3.5-3.6v in the beginning, and accidental overdischarge below 3v).

I am VERY careful in charge and discharge. I charge to 4.15 (recently 4.133) and discharge to 3.9V.

A very narrow range of use for 12 miles.

The 49.8V batteries drain about 1V per 6 miles.

Not too shabby.

 

[Boyntonstu]

Interesting video.

However, I would not solder the cells together.

In a way similar to how I mounted the 4 Turnigy 6s batteries, I would solder short wires and use screw connectors at the top of a battery box.

Each cell could easily be removed and replaced with this method.

Edit: I believe that I have discovered a method of assembling a LiPo pack without soldering or welding.

(Cells with aluminum tabs could be also be used.)

[youtube]dtkpQjt5UVc[/youtube]

 

[Hillhater]

Sort of defeats the main advantages of RC lipo !...simplicity of pack build , and low cost .
Waste of time , effort, and money compared to just buying prebuilt packs (on sale even) and using a simple harness to give the voltage and capacity you need.

 

[motomech]

Yeah, I don't see the point of it.
He was doing this before the Multistars were avail. in big capacities.
Now, using the round cells to build Nader-style stealth water bottle packs, that's something I have been working on for a while.

https://www.electricbike.com/mini-hub-motors/

 

[Hillhater]

Stu,
As i said in your other thread on the same topic ( )...
HK have many ready built packs,..often on sale at half price or less..you just have to keep a watch on them.
These 10Ahr , 6 s packs were available for $50. http://www.hobbyking.com/hobbyking/store/__56845__Multistar_High_Capacity_6S_10000mAh_Multi_Rotor_Lipo_Pack.html
I bought the 16Ahr 4s (x3) for the same $50 each , for the extra capacity.
Its just not worth messing with loads of low capacity cells thinking you might save a dolla by spending hours with a soldering iron and duct tape !...you wont.
If a cell goes bad, its just as difficult to fix a DIY pack as it is to split a pro built pack...and even easier to simply replace a "brick" with a spare.
If you want capacity in a pack, (<$100) these seem to get decent reviews on RC sites..
http://www.yabopower.com/products/hobbies-and-uav/24000mah-6s-60c-lipo-battery.html

 

[Boyntonstu]

Stu,
As i said in your other thread on the same topic ( )...
HK have many ready built packs,..often on sale at half price or less..you just have to keep a watch on them.
These 10Ahr , 6 s packs were available for $50. http://www.hobbyking.com/hobbyking/store/__56845__Multistar_High_Capacity_6S_10000mAh_Multi_Rotor_Lipo_Pack.html
I bought the 16Ahr 4s (x3) for the same $50 each , for the extra capacity.
Its just not worth messing with loads of low capacity cells thinking you might save a dolla by spending hours with a soldering iron and duct tape !...you wont.
If a cell goes bad, its just as difficult to fix a DIY pack as it is to split a pro built pack...and even easier to simply replace a "brick" with a spare.
If you want capacity in a pack, (<$100) these seem to get decent reviews on RC sites..
http://www.yabopower.com/products/hobbies-and-uav/24000mah-6s-60c-lipo-battery.html

At $50 a pair is $100 and that is a great deal.

At $90, $180 isn't.

My four 6s 5,200 were $28 each and $112 was a better deal.

If the 10,000 were in sale, I would have chosen them.

What is the price of a yabopower.com/products/hobbies-and-uav/24000mah-6s-60c-lipo-battery?

 

[spinningmagnets]

A while back, the BC168 charger was the new darling of experimenters. It charged through the balance leads. If you were not in a hurry (most of the enthusiastic users had a Meanwell clone as a bulk charger, IIRC), then EVERY charge was a balance charge, treating each parallel string as an individual cell.

Also, along this line of thought, LFP has been promoting the benefits of designing a system with a high kV / low turn-count motor, which has thicker wires. Then using high amps, and modest volts. Doing this simplifies the battery and charger, but it also requires thicker battery and motor-phase wires (not expensive, always go fatter wire in those locations). Where this philosophy is not quite "turn key" yet, is the high-amp controllers. However, when LFP says something, I read it and keep it in mind.

Therefore, I will keep my eye open for developments in high-amp controllers now. LFP mentioned voltages for ebikes that are below 36V. I am currently willing to go from my favored 52V / 14S down to 44V / 12S, due to the available kV's of the motors that are common around here. The Leafbike and Edge motors with 35mm wide stators are especially an interest of mine, due to their broad appeal. I love the MXUS 45mm statored motors, and also the QS 205/50H motors, but I doubt those two will become a widespread phenomenon. They seem to enjoy a niche enthusiast market populated by true hot-rodders (4000W-8000W?). Especially now that we have Ferro-Fluid and rim-fins to shed heat.

For 12S and below, bulk chargers and balance chargers from the RC market are widespread and affordable.

Just some thoughts...