## A few really basic Lipo definitions.

Batteries, Chargers, and Battery Management Systems.

### A few really basic Lipo definitions.

Lipo.
Nowdays refers to lithium polymer RC batteries. Often sourced at hobby king.

C rate
Describes the quantity of amps a battery can put out without major damage. 1c means a 5 ah pack can put out 5 amps, 10 c means a 5 ah pack can put out 50 amps. 30c, 150 amps.

4s,5s,6s, etc
"S" means cells connected in series. So a 4s 5000 mAh pack is a 4 cell pack made of 5 ah pouches connected in series. Each cell charges to 4.2v max, so a 4s pack charges to 16.8 v.

Series connecting packs.
Usually bikes run on 36v, 48v , 72v etc. So several smaller packs are connected in series to make a higher voltage pack. Two 5s packs in series make a 36v 10s pack. four 5s packs series connected make a 72v 20s pack. 6s packs can be used for other, not so standard voltages. 12s is a nice voltage in between 36v and 48v. 18s can be nice, faster than 48v, but not so fast as a 20s pack. 48v is awkward, 14s is safe for most 48v controllers. Some get away with 15s, and some don't.

Paralell connecting packs.
Many buy lipo in a commonly avaliable 5 ah pack. If you need 10 ah or more, the packs are paralell connected first, then paralelled packs are series connected to run the bike at the desired voltage.

Max charge
Charge lipo to 4.2v per cell maximum. Some charge to 4.15 or 4.1 v per cell to maximize lifespan.

Min charge
Lithium batteries are damaged by a complete discharge. The golden rule is never below 2.7v. for lipo. However, there is virtually no useable charge left below 3.5 v. You will go from 3.5v to 2.7 very quickly so consider 3.5 to be the minimum usable voltage. Like the charging, cycle lifespan is thought to increase considerably if you don't discharge a battery 100% . For that reason, many consider a 5 ah pack to have 4 usable amp hours, and discharge only to 3.7-3.8v as their minimum charge voltage.

DOD
Depth of discharge. Consider 3.5v to be 100% discharged.

Cycle life
Cycles generally means the number of 100% discharges expected. If you only discharge 50% theoretically you get twice the rated number. 500 cycles is a common spec for lipo.

4 mm bullets
Bullet connectors are common on hobby king lipo packs. To hook up your lipo, you may need some more of these, or some other type of connector to replace the bullets so your battery can be connected to your controller.

Paralell harness
One way to connect two or more 5 ah packs to creat a 10 ah or larger battery . Often created by soldering many bullet connetors to wire, and then soldering the wires together. Connects several packs to one wire. You need two, one for + and one for -.

KFF
Kentuky fried fingers. The result of a huge spark, when you screw up and connect the + and - of the same battery. Can happen easy when series connecting packs and you get confused which wire to connect.

Melted tab
After KFF, the shorted pack often melts one of the tabs connecting the pouches. The pack will now appear to be 1 cell smaller to the voltmeter since one cell is now disconnected.

Puffy
A bad cell often puffs up, as gas is formed inside the pouch. Sometimes salvageable, but usually indicates a cell that will never go the full cycle life. Charge puffies outside, or in a safe area.

Lipo charger.
A charger intended for charging lipo batteries, and often other types as well. A 6s charger will charge up to 6 cells lipo packs, 8s will charge 8 cell packs, etc. They come in a variety of wattages. 50 watts is sloooow. 150 watts is tolerably fast. Some chargers are as powerfull as 1000 watts, and charge very fast.

Meanwell
Meanwell power supply. A brand name for a switching power supply often used to power lipo chargers. Lipo chargers typically run on DC power, so you need a power supply that matches the voltage the charger likes. 12v power supplies are suitable for the smaller wattage chargers, while larger more powerful chargers may run best on about 20v. A 350 watt power supply can run several 50 watt chargers, two 150 watt chargers, or one 300 watt charger. Power supplies can be used to bulk charge without using a charger.

Bulk charging.
After series connections are made, it is possible to charge the pack straight from a suitable power supply. Often other electronics are added to shut off the charge when the pack is at the desired voltage. Explaining how to bulk charge is beyond my expertice and experience.
Last edited by dogman on Mon Apr 04, 2011 3:37 pm, edited 5 times in total.
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE

Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum

See battery technology section, FAQ thread at the top of the page for lipo noob info.

dogman
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### Re: A few really basic Lipo definitions.

Great work dogman.
I wish this was around a month ago.

shorza
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### Re: A few really basic Lipo definitions.

KFF-
Novara Buzz FS MTB- 18s 15Ah Turnigy Lipo - 12Fet controller @57A - 9C 2807 motor - 600W charging - 4500W peak - 40Mph - 20Mi range

Metallover
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### Re: A few really basic Lipo definitions.

Yeah, somebody should have put something like this up last summer. Feel free to add others, and particularly to point out anything wrong with what I wrote. I'm not trying to give a how to, but somehow it starts to go that way. Better wording of my definitions would be welcomed. This is now linked in the lipo threads sticky post, so we can point folks there from now on.

I guess I've handled 110v AC for a long time. Somehow both my KFF's did not look like that! I always say, handle every wire like it's hot, especially when you think it's not!
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE

Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum

See battery technology section, FAQ thread at the top of the page for lipo noob info.

dogman
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### Re: A few really basic Lipo definitions.

good work.

auraslip
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### Re: A few really basic Lipo definitions.

dogman wrote:So a 4s 50000 mha pack is a 4 cell pack made of 5 ah pouches connected in series.

Good article, Dogman. I think you mean 5000 mAh here...

It might also be good to define Amp-hour, and Milliamp-Hour.

Again, thanks for everything you do for us!
2000 ZAP DX electric bike kit on chromoly MTB - retired
2007 Strong GTS-210 electric bike - melted solder in hub
2007 Giant Revive, Crystalyte 405 20" fr, 35A/72V + Cycle-analyst 2.1

Holocene
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### Re: A few really basic Lipo definitions.

Great idea. If there's not one already, a dictionary sort of thing like this in general would be great. Maybe that could be part of the FAQ in the works.

For C-rates, I would add in the relation formula (A=C*Ah) and what the C-rate originates from (1C == 1 hour 100% DOD). Those confused me for a long time till I ran across a post that explained the relationships.
That we enjoy great advantages from the inventions of others, we should be glad of an opportunity to serve others by any invention of ours, and this we should do freely and generously.
--Benjamin Franklin

x88x
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### Re: A few really basic Lipo definitions.

Thanks for the heads up, it's edited now. I was trying real hard to keep the definitions really short and simple

Maybe somebody with more electronics knowledge could do better on more accurate and complete definitions in a less basic thread.
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE

Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum

See battery technology section, FAQ thread at the top of the page for lipo noob info.

dogman
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### Re: A few really basic Lipo definitions.

Noble task here Dogman - don't wish to nit-pick but you asked and here's proof reader thing to point out -

"So a 4s 5000 mha pack..."

Minor thing, you've mixed mAh for mha. But it brings me to say I always tend to think of Amps with capital A letter. lower case m = mili, h = hour work fine for "modifiers" but when it comes to labeling Ohm's law values I always identify more clearly when I see capital letter.

Based on the tech material I'm used to reading: A - amps, V - volts, R - resistance, W - watts.

Anyway, that's my take - I may be wrong but something to consider may be consensus about what and how to format commonly used electrical engineering terms? There's a ton of guys who know this stuff hands down - they've obviously lived and worked it for years - their input would be most helpful towards the cause IMO.

Maybe it's easier with basic 101 electronics terminology before getting into many of the specific eBike definitions we toss around? Maybe? Maybe not?

What's that line from the movie War Games? "I'd piss on a spark plug if it will help..."
New York, there's no law against being annoying...

Ykick
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### Re: A few really basic Lipo definitions.

Ykick wrote:But it brings me to say I always tend to think of Amps with capital A letter.

That's because it's the SI standard.
http://en.wikipedia.org/wiki/SI
That we enjoy great advantages from the inventions of others, we should be glad of an opportunity to serve others by any invention of ours, and this we should do freely and generously.
--Benjamin Franklin

x88x
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### Re: A few really basic Lipo definitions.

C rate
Describes the quantity of amps a battery can put out without major damage. 10 c means a 5 ah pack can put out 50 amps. 30c, 150 amps.

Probaboly nit picking here but this could be a little confusing to a newbie. May be slightly clearer as below?.

"C Rate
the Amp rate at which the battery can be discharged safely. This is worked out by taking the capacity of the pack and multiplying it by the C rate of the battery so a 5AH (5000mah) pack with a 10C rating can be discharged at up to 5x10= 50Amps. And a 5AH (5000mah) pack with a 30C rating can be dicharged at up to 5x30= 150amps."

Great article, wish i had stumbled on something like this last year, would have saved a lot of reading to work all this out
Fury

current bike

GT frame dual disk - Crystalyte HS3540- Rear (1600 miles of running) - 12s2P 10AH lipo.
Lyen 12FET Extreme MKII controller (awesome controller) - CA-DP.

Top speed - 32MPH
http://www.flickr.com/photos/63335907@N06/sets/72157627869504840/ (New build pics now added)

theRealFury
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### Re: A few really basic Lipo definitions.

wow this article helped me work out that mysterious C rating problems
quick question: any way of working out estimated maximum travel distance on flat?
example, say 48v 10ah, average speed 25mph now how far can i travel? (say total weight 200lb)
Project 1: Apollo slant hard tail MTB 52v lifepo4, conhismotor, 52T-11T gearing 39.6mph top speed (with pedal)
Project 2: Diamondback s:10 Full suspension 20s2p (83.5v 10ah Lipo), 35kg, HS3540 sensored (MethTek), 12FET lyen controller, Bulk 600w balance charger.
Top speed 45mph(72.4km/h)
Project 3: DOPPELGANGER d2 Visceral
Project 5 Specialized Epic20s2p (83.5v 10ah Lipo), 30kg,HS3540 sensored (MethTek), 12FET lyen @ 50A
Top speed 45mph(72.4km/h)

rui_fujino
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### Re: A few really basic Lipo definitions.

rui_fujino wrote:wow this article helped me work out that mysterious C rating problems
quick question: any way of working out estimated maximum travel distance on flat?
example, say 48v 10ah, average speed 25mph now how far can i travel? (say total weight 200lb)

that depends on just too many factors to give you a figure, for instance, wind, rolling resistance, frontal area, aerodynamics, elevation above sea level, how much you pedal, Efficiency of motor, efficiency of controller, if you run the battery above or below its rated discharge rate, the wiring you use for electricity supply. There are others that i cant think of right now as well but as you can see, its practically impossible to work out a maximum distance you can travel with a given setup unless you try it until it runs out of juice.

Average distances for motor alone have been guestimated to be ~13 miles with a 36v 10AH and ~16 miles with a 48v 10ah (travelling at the same speed with both.) Although i took my 36v 10AH li-ion on a ride a few months ago to find out how far i could go and i got 41 miles out of 9.6AH. this was at 12-15mph on a calm sunny day, mostly flat and with a lot of pedalling.

Only real way to find your limit is to try and exceed it
Fury

current bike

GT frame dual disk - Crystalyte HS3540- Rear (1600 miles of running) - 12s2P 10AH lipo.
Lyen 12FET Extreme MKII controller (awesome controller) - CA-DP.

Top speed - 32MPH
http://www.flickr.com/photos/63335907@N06/sets/72157627869504840/ (New build pics now added)

theRealFury
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### Re: A few really basic Lipo definitions.

rui_fujino wrote:wow this article helped me work out that mysterious C rating problems
quick question: any way of working out estimated maximum travel distance on flat?
example, say 48v 10ah, average speed 25mph now how far can i travel? (say total weight 200lb)

Many of us ballpark estimate 1 mile per 1Ah battery capacity. Using your 10Ah battery spec it's fairly safe to assume about 10 miles range with 20-30A controllers. In most cases you'll actually experience much more range than that but it's always best to err on the side of too much battery capacity. Leave yourself excess capacity for hills, headwinds, getting lost while minimizing deep discharge of your cells.

On my 15S Lipo with 9FET Lyen controller cruisng about 25mph I cover 20 miles using only 12Ah but from what I've learned it's best to have too much than not enough. So if I want to go 20 miles I make sure I have 20Ah battery.
New York, there's no law against being annoying...

Ykick
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### Re: A few really basic Lipo definitions.

Im upgrading my battery and controller to 72v from 48v after the summer hols. controller will be either 40a or 45a...
i havent decided on what controller or battery for it! but will this 1Ah = 1mile work the same?

PS: could you give me any suggestion of controller? (i use conhismotor 48v 1000w)
Project 1: Apollo slant hard tail MTB 52v lifepo4, conhismotor, 52T-11T gearing 39.6mph top speed (with pedal)
Project 2: Diamondback s:10 Full suspension 20s2p (83.5v 10ah Lipo), 35kg, HS3540 sensored (MethTek), 12FET lyen controller, Bulk 600w balance charger.
Top speed 45mph(72.4km/h)
Project 3: DOPPELGANGER d2 Visceral
Project 5 Specialized Epic20s2p (83.5v 10ah Lipo), 30kg,HS3540 sensored (MethTek), 12FET lyen @ 50A
Top speed 45mph(72.4km/h)

rui_fujino
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### Re: A few really basic Lipo definitions.

My bad, sorry Dogman - this is not the thread to discuss batteries, controllers, range, etc. rui_fujino - start a new thread with your questions. Mods, please clean thread up so that it may have a chance to continue as a Lipo FAQ. 'sorry folks, 'better off lurking...
New York, there's no law against being annoying...

Ykick
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### Re: A few really basic Lipo definitions.

dogman wrote:Lipo.
...
Min charge
... However, there is virtually no useable charge left below 3.5 v. You will go from 3.5v to 2.7 very quickly so consider 3.5 to be the minimum usable voltage.
...
DOD
Depth of discharge. Consider 3.5v to be 100% discharged.

In my limited 2+ months of experience with Li-Cobalt, I find that there's still some useable charge left between 3.5 and 3.0V. My measurements indicated 3 to 4% of total capacity in that range. For my battery, 12S 10AH, that represents 13 to 18 whs or 1.5 to 2 miles additional range on my low power 350W ebike. Below 3.0V, there's at most 1%, definitely not worth bothering with.
SamTexas
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### Re: A few really basic Lipo definitions.

SamTexas wrote:
dogman wrote:Lipo.
...
Min charge
... However, there is virtually no useable charge left below 3.5 v. You will go from 3.5v to 2.7 very quickly so consider 3.5 to be the minimum usable voltage.
...
DOD
Depth of discharge. Consider 3.5v to be 100% discharged.

In my limited 2+ months of experience with Li-Cobalt, I find that there's still some useable charge left between 3.5 and 3.0V. My measurements indicated 3 to 4% of total capacity in that range. For my battery, 12S 10AH, that represents 13 to 18 whs or 1.5 to 2 miles additional range on my low power 350W ebike. Below 3.0V, there's at most 1%, definitely not worth bothering with.

3rd generation RC lipo has an actual nominal voltage around 3.82-3.85v (though always listed as "3.7v", it's a modified cobalt chemistry with higher potential), and has given it's useful capacity by ~3.6-3.5v. Laptop lithium dioxide cells have a nominal voltage of ~3.7v, and you get a little bit of useful energy in taking them down to ~3.2v (though at the cost of greatly accelerated wear on the cells).
For ebike parts, don't be a douche, buy from http://www.ebikes.ca or http://www.MethTek.com

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liveforphysics
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### Re: A few really basic Lipo definitions.

Thanks for all the info-now I can pick my lithiums more wisely..
Lisa
Yuba Mundo 2012 cargo
BMC V4 cruiser
40 amp Grin Cyclery V 2.5 controller (to be updated in the future)
20 amp hour 50 volt Ping bat. with High rate BMS
Cycle Anaylst V3
I am, officially, in heaven with this rig.
10 mW

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### Re: A few really basic Lipo definitions.

Great list! Needs to be stickied. I could have used this when first getting to ES.

2 suggestions:
1) Since you are getting into explaining terms used specifically on this site only - like KFF - how about keeping those in a section together?
eg You could include things like MENS and frock etc...

2) Some other things: Wh/mi, Power = Voltage X Current, ESC = Electr Speed Contr.
Get a Cycle Analyst and a Multimeter, you're still a noob if you don't have at least one of each.

Planning on posting questions or buying anything on this site? Put up your country (at minimum) on your profile. This is a worldwide forum and we haven't reached clairvoyance.
cal3thousand
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### Re: A few really basic Lipo definitions.

Dogman said....

"12s is a nice voltage in between 36v and 48v. 18s can be nice, faster than 48v, but not so fast as a 20s pack. 48v is awkward, 14s is safe for most 48v controllers. Some get away with 15s, and some don't.'

I bought 4 4s Lipos for a 48volt controller----that's 16s. 14.8 x 4 = 59.20 volts
14.8 x 3 = 44.4 volts

seems 3 4s Lipos not enough but 4 4s Lipos too much...will 4 4s Lipos wreck my controller? Anybody?
pff7
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### Re: A few really basic Lipo definitions.

Maybe, if it's got 63v capacitors, and you are charging the battery to 4.2v per cell. You'd be at abouty 67v fully charged.

If you charge to 4.1v, only 65.6v. And it will drop to 63v or below fairly quick. Much would depend on how reliable you need it to be. Fun bike vs vital transportation. Get some 2s packs if vital to be reliable, and run 14s.

Or,, get a 60v controller with 100v caps in it.
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE

Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum

See battery technology section, FAQ thread at the top of the page for lipo noob info.

dogman
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### Re: A few really basic Lipo definitions.

Thanks dogman
Just got my turngy's yesterday, yeha!(but no charger I ordered wtf?)

It's a yescomusa.com subsiduary LAshop.com 48volt 500W controller, no idea who manufactors it, if that helps any,

It's hard to believe those little packs can power my hub motor, seem so small...lipo really does seem the way to go.
15.5volts on each pack fresh from the delivered package,so I'm assuming no duds either. No warning labels on package either, I'd think with all the hoopala about the dangers of lipo I was expecting at least a don't drop or overheat warning...just a generic,plain box.
pff7
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