LIPO charging

[Jenming]

I’m looking at using 5 4S 20AH LIPO in series for my bike but having trouble thinking of a reasonable charging and balancing solution. What do people recommend?

Alternatively, I’m considering 3 6S 20AH LIPO which seems relatively straightforward to charge using a 6S 4 port charger connected to a 1kw pc power supply I have laying around. But I’d rather get the full 20S if possible.

Thanks for the help!

 

[eMark]

5 - 4S 20AH LIPO (72V nominal) - $710 ... Turnigy High Capacity 20000mAh 4S 12C Lipo Pack w/XT90
3 - 6S 20AH LIPO (64.8V nominal) - $651 ... Turnigy High Capacity 20000mAh 6S 12C Lipo Pack w/XT90

What's your reason for wiring up 3 or as many as 5 Turnigy's in series (Turnigy 20AH LIPOs) instead of using a less expenisve LION 72V 19.2 Ah with LG 21700 cells - $600 (Style: 72V 19.2Ah(0-3000W)/LG4800mAh Cell/XT60 - comes with built-in protective BMS and 4A Charger ... [18 Month Warranty & Lifetime technical support] ...
https://www.amazon.com/1500W-Batter...B09NM7SSQZ/ref=asc_df_B09332RG58/?tag=hyprod-

 

[amberwolf]

Just make sure the multiport charger is electrically isolated from port to port. If it is not, then you will have to disconnect all packs from each other (if you weren't already planning to do this) to charge them, and then reconnect them after they're charged and you're running the bike with them.

Note that having to connect/disconnect/reconnect things frequently can lead to connector or wire damage/failure, or an accidental misconnect that can cause a fire.

What are you going to use to monitor the cells on the bike during riding, to ensure you don't overdischarge or overload any of them (either of which can lead to damage or fires)? (a BMS on a typical battery would do this for you)

 

[E-HP]

What's your reason for wiring up 3 or as many as 5 Turnigy's in series (Turnigy 20AH LIPOs) instead of using a less expenisve LION 72V 19.2 Ah with LG 21700 cells - $600 (Style: 72V 19.2Ah(0-3000W)/LG4800mAh Cell/XT60 - comes with built-in protective BMS and 4A Charger ... [18 Month Warranty & Lifetime technical support] ...

40A continuous vs 240A continuous output current might have something to do with it. Ability to charge 20Ah in an hour or less vs 5hrs may be be another reason.

I’m looking at using 5 4S 20AH LIPO in series for my bike but having trouble thinking of a reasonable charging and balancing solution. What do people recommend?

Alternatively, I’m considering 3 6S 20AH LIPO which seems relatively straightforward to charge using a 6S 4 port charger connected to a 1kw pc power supply I have laying around. But I’d rather get the full 20S if possible.

Thanks for the help!

If the lipos are all matched, then cycle them a few times to see if they stay balanced. If they do, I'd just bulk charge the whole pack with a 20S charger. Check the balance every few charge cycles and if they stay balanced it should be good.

 

[amberwolf]

I'm trying to think of any RC Lipo packs that have ever been matched....

 

[eMark]

40A continuous vs 240A continuous output current might have something to do with it.

Seriously, isn't that more of an extended burst rating instead of CONTINUOUS?? Maybe for a two minute ride ... Who's kidding who?

Ability to charge 20Ah in an hour or less vs 5hrs may be be another reason.

RC Lipo enthusiasts may not be all that concerned about cycle life (240A continuous output and charge in 1 hr instead of 5 hrs). It's only $650 to $700 so go for the GUSTO
If say 100A(MCD) life cycles are realistic it would only cost 7 dollars for each thrill-seeking ride ... well worth it

 

[batteryGOLD]

I’m looking at using 5 4S 20AH LIPO in series for my bike but having trouble thinking of a reasonable charging and balancing solution. What do people recommend?

Alternatively, I’m considering 3 6S 20AH LIPO which seems relatively straightforward to charge using a 6S 4 port charger connected to a 1kw pc power supply I have laying around. But I’d rather get the full 20S if possible.

Thanks for the help!

Soo, U want to build a 20S pack from x5 LiPo packs. good idea!!
The best way to interconnect x5 packs 4S is doin series circuit (converting x5 4S into a single 20S battery.) circuit --> positive from one 4S battery goes into next 4S negative terminal. --> 4S times five = 20S
main negative --- #1 4S +- #2 4S +- #3 4S +- #4 4S +- #5 4S +++ main positive

use a regular BMS (best with balance function), & depends on your application consumption amps. example. a 20S 100A BMS with balance function.. just sayin..
and you need to pick all 21 signal lines from all 5packs to convert into 20S BMS single plug

Now U could use a regular 84V charger to charge your system and it's done! LiPo supports fast chargin. soo could choose high amperes charger for quick charge battery!

PS: you are using LiPo packs at a high power ebike. soo make sure to protect those LiPo packs against any fisical damage. Imagine a rock hits a lipo pack, it could be a very danger situation. a 20Ah LiPo would start a massive fire and spread to other packs!! convert LiPo packs into hard case elements for safety!!
a 20Ah LiPo pack could easy put out +50C out, this means +1000Amps continuous draw..

 

[E-HP]

Seriously, isn't that more of an extended burst rating instead of CONTINUOUS?? Maybe for a two minute ride ... Who's kidding who?

You could derate it by two thirds and still have double the discharge rating with zero voltage sag. I'm just saying you can't assume what the OPs requirements are.

 

[Jenming]

5 - 4S 20AH LIPO (72V nominal) - $710 ... Turnigy High Capacity 20000mAh 4S 12C Lipo Pack w/XT90
3 - 6S 20AH LIPO (64.8V nominal) - $651 ... Turnigy High Capacity 20000mAh 6S 12C Lipo Pack w/XT90

What's your reason for wiring up 3 or as many as 5 Turnigy's in series (Turnigy 20AH LIPOs) instead of using a less expenisve LION 72V 19.2 Ah with LG 21700 cells - $600 (Style: 72V 19.2Ah(0-3000W)/LG4800mAh Cell/XT60 - comes with built-in protective BMS and 4A Charger ... [18 Month Warranty & Lifetime technical support] ...

Combination of amps and mounting flexibility, my frame won’t hold a triangle pack like that.

 

[Jenming]

Soo, U want to build a 20S pack from x5 LiPo packs. good idea!!
The best way to interconnect x5 packs 4S is doin series circuit (converting x5 4S into a single 20S battery.) circuit --> positive from one 4S battery goes into next 4S negative terminal. --> 4S times five = 20S
main negative --- #1 4S +- #2 4S +- #3 4S +- #4 4S +- #5 4S +++ main positive

use a regular BMS (best with balance function), & depends on your application consumption amps. example. a 20S 100A BMS with balance function.. just sayin..
and you need to pick all 21 signal lines from all 5packs to convert into 20S BMS single plug

Now U could use a regular 84V charger to charge your system and it's done! LiPo supports fast chargin. soo could choose high amperes charger for quick charge battery!

PS: you are using LiPo packs at a high power ebike. soo make sure to protect those LiPo packs against any fisical damage. Imagine a rock hits a lipo pack, it could be a very danger situation. a 20Ah LiPo would start a massive fire and spread to other packs!! convert LiPo packs into hard case elements for safety!!
a 20Ah LiPo pack could easy put out +50C out, this means +1000Amps continuous draw..

That sounds simple enough, just use a regular bms and charger.

Still thinking through case options, found some good threads on the topic.

Thanks!!

 

[eMark]

What is/are the reason(s) you need a 72V LIPO battery when a 52V LION might suffice or actually be a better choice/fit over the long haul - as well as less costly. I ask this because more than a few have wondered the same over the years. Why is a 72V LIPO powerplant really necessary for your particular utilization?

 

[eMark]

I'm trying to think of any RC Lipo packs that have ever been matched....

EXACTLY !! ... Even if matched there is a more inportant Lipo consideraton ... whether 5-4S or 3-6S 20AH LIPOs in series is still only 20,000mAh (20AH) capacity not power. For some [un]reason E-HP and thousands more LIPO enthusiasts think a 20AH LIPO rating is the same as a LION 20A MCD rating. As evident in the following post ...

40A continuous vs 240A continuous output current might have something to do with it. Ability to charge 20Ah in an hour or less vs 5hrs may be be another reason.

LIPO manufacturers rate Lipos differently than LION manufacturers. Are Lipoheads easier misled than Lionheads?? One major difference is the way too many RC Lipo users mistakenly consider a 20AH (capacity rating) to be the same as a MaxiumumContinuousDischarge (Lion 20A rating). The actual Lipo cells' 12C rating may only be a 5-8A pouch cell rating and then only for a short burst not a MaximumContinuousDischarge.

A Lipos 5-8A 12C rating would then be a 60-96A rating NOT 240amps. 12C x 20AH would only equal a MaximumContinuousBurst of 240amps if the cells have a 20A besides a 20AH rate. Also ratings like 12C, 25C, 50C are realistically only possible for a short 2-3 second burst. One would assume a 50C rating is for Lipo pouch cells with at least a 20A burst rating

According to E-HP ... a 10s5p Lion battery with cells having a MCD rate of 20A (25r) would result in a MCD rate of 200amps (10S x 20A - 200amps) and a capacity rating of 12.5AH. BUT only for a specific useful application resulting in a cycle life less than 50 cycles at MCD from say 200 to 150 amps (42V to 30V cut-off ... bounce back voltage
would be considerable).
______________________________________
To: amberwolf
Is my assumption of differences on how Lipo and Lion manufacturers rate of their batteries MCD somewhat correct or somehow incorrect ??

 

[E-HP]

EXACTLY !! ... Even if matched there is a more inportant Lipo consideraton ... whether 5-4S or 3-6S 20AH LIPOs in series is still only 20,000mAh (20AH) capacity not power. For some [un]reason E-HP and thousands more LIPO enthusiasts think a 20AH LIPO rating is the same as a LION 20A MCD rating. As evident in the following post ...

LIPO manufacturers rate Lipos differently than LION manufacturers. Are Lipoheads easier misled than Lionheads?? One major difference is the way too many RC Lipo users mistakenly consider a 20AH (capacity rating) to be the same as a MaxiumumContinuousDischarge (Lion 20A rating). The actual Lipo cells' 12C rating may only be a 5-8A pouch cell rating and then only for a short burst not a MaximumContinuousDischarge.

A Lipos 5-8A 12C rating would then be a 60-96A rating NOT 240amps. 12C x 20AH would only equal a MaximumContinuousBurst of 240amps if the cells have a 20A besides a 20AH rate. Also ratings like 12C, 25C, 50C are realistically only possible for a short 2-3 second burst. One would assume a 50C rating is for Lipo pouch cells with at least a 20A burst rating

According to E-HP ... a 10s5p Lion battery with cells having a MCD rate of 20A (25r) would result in a MCD rate of 200amps (10S x 20A - 200amps) and a capacity rating of 12.5AH. BUT only for a specific useful application resulting in a cycle life less than 50 cycles at MCD from say 200 to 150 amps (42V to 30V cut-off ... bounce back voltage
would be considerable).
______________________________________
To: amberwolf
Is my assumption of differences on how Lipo and Lion manufacturers rate of their batteries MCD somewhat correct or somehow incorrect ??

You read a lot into a couple of sentences I posted. Silly.

 

[E-HP]

I'm trying to think of any RC Lipo packs that have ever been matched....

The Turnigy Graphene lipos seems to be pretty good. I've exchanged one that was off a bit, but the good ones don't really need balancing. I'm coming up on 300 light charge cycles (I run from 4.15V to 3.8V, no lower than 3.7V). When I balanced them last, there were only a couple of cells that were 0.01V to 0.02V off from the rest.

 

[eMark]

You read a lot into a couple of sentences I posted. Silly.

NOT really "Silly", but understandable from a RC mindset (e.g. RC competitive plylon airfold racing with short bursts at high amperage for a +200mph speed.

You seem to think that a RC Lipo rating of 20AH (capacity) is the same as a MCD cell rating of 20iA (i.e. your discharge calculation of 240amps). We really don't know the true MCD rating of those Turnigy Lipo pouch cells because RC Lipo manufacturers misled RC buyers with 12C, 25C, 50C ratings and won't even divulge what the actual MCD amperage rating of their RC Lipo pouch cells. They may only have a 5-8amp MCD rating and then a 12C, 25C, 50C is most likely just for a brief burst rating.

Your previous 240amp rating is based on your assumption that a 20AH capacity rating is the same as a 20A discharge rating. That's how you and thousands of other RC Lipo enthusiasts arrive at a MCD discharge of 240amps when at most a 240amp continuous discharge is realistic for 2-3 seconds. Those RC Lipo ratings are for RC pilots that need a very brief burst of power for a few seconds. RC Lipo pouch cell ratings (12C - 50C) were never intended for ebike battery utilization.

 

[Jenming]

What is/are the reason(s) you need a 72V LIPO battery when a 52V LION might suffice or actually be a better choice/fit over the long haul - as well as less costly. I ask this because more than a few have wondered the same over the years. Why is a 72V LIPO powerplant really necessary for your particular utilization?

I can’t fit a 72v lion pack in my triangle and don’t want to wear a backpack battery.

Chaining together multiple lion packs and finding ones that will fit and put out enough amps, or making a custom pack, loses any cost and simplicity advantage lion might have.

And even taking the 12C with a grain of salt it seems there is pretty broad consensus that their amp output is higher than lion at the same weight / cost.

 

[Jenming]

NOT really "Silly", but understandable from a RC mindset (e.g. RC competitive plylon airfold racing with short bursts at high amperage for a +200mph speed.

You seem to think that a RC Lipo rating of 20AH (capacity) is the same as a MCD cell rating of 20iA (i.e. your discharge calculation of 240amps). We really don't know the true MCD rating of those Turnigy Lipo pouch cells because RC Lipo manufacturers misled RC buyers with 12C, 25C, 50C ratings and won't even divulge what the actual MCD amperage rating of their RC Lipo pouch cells. They may only have a 5-8amp MCD rating and then a 12C, 25C, 50C is most likely just for a brief burst rating.

Your previous 240amp rating is based on your assumption that a 20AH capacity rating is the same as a 20A discharge rating. That's how you and thousands of other RC Lipo enthusiasts arrive at a MCD discharge of 240amps when at most a 240amp continuous discharge is realistic for 2-3 seconds. Those RC Lipo ratings are for RC pilots that need a very brief burst of power for a few seconds. RC Lipo pouch cell ratings (12C - 50C) were never intended for ebike battery utilization.

I’m not sure I understand your post. Are you saying these 20AH pouches can only send out a continuous 5-9 amps?

 

[E-HP]

NOT really "Silly", but understandable from a RC mindset (e.g. RC competitive plylon airfold racing with short bursts at high amperage for a +200mph speed.

You seem to think that a RC Lipo rating of 20AH (capacity) is the same as a MCD cell rating of 20iA (i.e. your discharge calculation of 240amps). We really don't know the true MCD rating of those Turnigy Lipo pouch cells because RC Lipo manufacturers misled RC buyers with 12C, 25C, 50C ratings and won't even divulge what the actual MCD amperage rating of their RC Lipo pouch cells. They may only have a 5-8amp MCD rating and then a 12C, 25C, 50C is most likely just for a brief burst rating.

Your previous 240amp rating is based on your assumption that a 20AH capacity rating is the same as a 20A discharge rating. That's how you and thousands of other RC Lipo enthusiasts arrive at a MCD discharge of 240amps when at most a 240amp continuous discharge is realistic for 2-3 seconds. Those RC Lipo ratings are for RC pilots that need a very brief burst of power for a few seconds. RC Lipo pouch cell ratings (12C - 50C) were never intended for ebike battery utilization.

The OP asked a question. Rather than answer the question, you attempt to make him justify using lipos or even for asking the question, by evangelizing about lithium ion batteries, while completely ignoring his question. I use both lithium ion and lipos, and both require handling with caution, and I accept the risks of both. I would prefer lithium ion, but lipos augment my setup enough in order to take more time selecting components for my next pack. The lipos have their place and they perform the function well.

Happy that you are trying to educate folks, but the OP created this thread for specific guidance. I'm not a lipo enthusiast, I'm an ebike enthusiast, but I'm open minded enough to consider lipos as one option to obtain specific results. I'm not going to argue with you, since that's what you seem to want, and I don't need to be converted, since I already prefer lithium ion. I bought RC cars not for a new hobby, but because I was considering using lipos for my ebike and wanted something smaller scale to learn on. So, not an RC enthusiast either, but I do take actions to better understand risks before going all in. The RC cars are all gathering dust now, since they served their purpose. You are batting zero with respect to your uninformed read that I'm a lipo head or have an RC mindset. Care to try again?

 

[E-HP]

That sounds simple enough, just use a regular bms and charger.

Still thinking through case options, found some good threads on the topic.

Thanks!!

If you go this route, or just the bulk charging route, this charger has been great. I charge at around 7A-8A or so normally, but it will charge up to 12A; not as fast as an RC charger, but still pretty fast. The only issue I have it that you can't dial down the ending voltage, so I manually shut if off when I hit 83V.

72V12A10A 48V Fast Charge Li-ion Lifepo4 Lithium Battery Charger for Ebike SUK | eBay

Find many great new & used options and get the best deals for 72V12A10A 48V Fast Charge Li-ion Lifepo4 Lithium Battery Charger for Ebike SUK at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[eMark]

You are batting zero with respect to your uninformed read that I'm a lipo head or have an RC mindset. Care to try again?

I'm merely pointing out that your assumption about that Turnigy RC Lipo Battery is incorrect. You're not alone as there are more than a few that figure likewise (wrong). It's a mistaken assumption by many RC Lipo enthusiasts. You are mistaken in thinking that a 20AH rating of that RC Turnigy Lipo Battery is the same as a 20A MCD power rating. Many RC enthusiasts are hood-winked into thinking that a RC 20AH Lipo with a 12C discharge rating has a usable discharge rating as high as 240 sustained amps (12C x 20AH = discharge rate of 240 amps).

Although i'm sure they know better and believe that if they tried to see how much juice their RC Lipo can deliver at 240amps for how long they would wakeup quick or endup in a hospital. Your previous post was evidence that you may still believe (hopefully not) that 240amps discharge is sustainable. I hope by now you realize your 240amp calculation is based on marketing gimmickry (12C x 20AH = 240amps of available sustainable Power ... but for how long if even justifiable).

It is long overdue to expose this RC Lipo marketing gimmickry as quite misleading. Instead of you brushing it off (12C x 20AH as equallng 240 amps of continuous power) and the need to bring it to your attention as "Silly". Where better to expose this marketing eXXaggeration, but in an ES thread where RC Lipo enthusiasts sometimes post about wanting to build a powerful e-bike RC Lipo battery (240amps of potential power) when they really should be building a 2170 Lion battery.

Likewise i'm not out of line in also informing the OP that he could very well be better off with a Lion battery that comes with a charger and built-in BMS costing less. You might agree that one reason he decided on powering his e-bike with those RC Turnigy was because of Turnigy's marketing comeon (240amps of potential POWER). If in ain't a 72V battery it won't be able to go at least 35mph up hill with a 100amp Controller with powerful RC Lipo batteries.

Just because the majority of ES threads are more about POWER than Capacity doesn't mean Common Sense is now out of favor in the 21st century or maybe it is going out of style. It doesn't take a stretch to see how RC enthusiasts thirst for power can easily mislead one to think a RC Lipo 20AH rating is the same as a 20A power rating. It very well could be a 20A rating if it's a [exaggerated] 50C rating. If truly only an 8amp rating then 12C x 8A = 96amps (not 240amps).

The OP, You, others and myself can get along that RC marketing impressive gimmictry as acceptable ... as long as one understands the deception so that they don't have puffed/swelled packs well before their time -

 

[Jenming]

I'm merely pointing out that your assumption about that Turnigy RC Lipo Battery is incorrect. You're not alone as there are more than a few that figure likewise (wrong). It's a mistaken assumption by many RC Lipo enthusiasts. You are mistaken in thinking that a 20AH rating of that RC Turnigy Lipo Battery is the same as a 20A MCD power rating. Many RC enthusiasts are hood-winked into thinking that a RC 20AH Lipo with a 12C discharge rating has a usable discharge rating as high as 240 sustained amps (12C x 20AH = discharge rate of 240 amps).

Although i'm sure they know better and believe that if they tried to see how much juice their RC Lipo can deliver at 240amps for how long they would wakeup quick. Your previous post was evidence that you may still believe 240amps is sustainable. To do so gets expensive until you realize it's a marketing gimmick (12C x 20AH = 240amps of available sustainable Power .. but for how long).

It is long overdue to expose this RC marketing for what it really is. Instead of you brushing it off (12C x 20AH as equallng 240 amps of continuous power) as if i'm wrong it would instead be helpful if you don't accuse me bringing it to your attention as "Silly". Where better to expose this marketing gimmick, but at ES where RC Lipo enthusiasts sometimes post about building a powerful e-bike RC Lipo battery

Likewise i'm not out of line in also informing the OP that he could very well be better off with a Lion battery that comes with a charger and built-in BMS costing less. You might agree that one reason he decided on powering his e-bike with those RC Turnigy was because of Turnigy's marketing comeon (240amps of potential POWER).

Just because the majority of ES threads are more about POWER than Capacity doesn't mean Common Sense is now out of favor in the 21st century or maybe it is going out of style. It doesn't take a stretch to see how RC enthusiasts thirst for power can easily mislead one to think a RC Lipo 20AH rating is the same as a 20A power rating. It very well could be a 20A rating if it's a [exaggerated] 50C rating. If truly only an 8amp rating then 12C x 8A = 96amps (not 240amps).

The OP, You, others and myself can get along that RC marketing impressive gimmictry as acceptable ... as long as one understands the deception so that they don't have puffed/swelled packs well before their time -

I think your terminology is wrong. 12C is supposed to be multiplied by the capacity to get the amp rating.

Whether the 12C is realistic for something other than very short bursts is a different question… If you have any useful information on sustained performance that would be helpful. If your point is just that 12C isn’t sustainable, well, point taken, but also factored in.

 

[amberwolf]

The Turnigy Graphene lipos seems to be pretty good. I've exchanged one that was off a bit, but the good ones don't really need balancing. I'm coming up on 300 light charge cycles (I run from 4.15V to 3.8V, no lower than 3.7V). When I balanced them last, there were only a couple of cells that were 0.01V to 0.02V off from the rest.

I guess they're better than they used to be when they were very commonly used around here. (and much better than the ones I had experience with, whihc were before the Graphene era).

 

[BVH]

For unbiased, professional Lipo testing carried out annually, see this thread on RCGroups. The charts on post one are always up-to-date. It may surprise a lot of Lipo fans.

Battery Load Test Comparisons - RC Groups

Battery Load Test Comparisons Batteries and Chargers

www.rcgroups.com

It would be great if you could read it from the beginning but it's waaay too long. Just remember, post one is always current.

 

[Jenming]

For unbiased, professional Lipo testing carried out annually, see this thread on RCGroups. The charts on post one are always up-to-date. It may surprise a lot of Lipo fans.

Battery Load Test Comparisons - RC Groups

Battery Load Test Comparisons Batteries and Chargers

www.rcgroups.com

It would be great if you could read it from the beginning but it's waaay too long. Just remember, post one is always current.

Thanks, that is helpful.

 

[eMark]

I think your terminology is wrong. 12C is supposed to be multiplied by the capacity to get the amp rating.

Whether the 12C is realistic for something other than very short bursts is a different question… If you have any useful information on sustained performance that would be helpful. If your point is just that 12C isn’t sustainable, well, point taken, but also factored in.

12C, 25C, 50C are arbitrary. The best way to explain is with IR. For example a cell with a 12C rating has say an IR of 3-milliohms, 25C 2-milliohms, 50C 1-milliohm.

RC Lipo manufacturing marketeers are tricky. An RC Lipo Maximum Continuous Output (MCO) should be understood to be a brief/peak burst rating NOT Maximum Continuous Discharge (Lion rating method).

• 1500mah battery x 30C = 45,000mA[h] = 45 Amps maximum continuous [burst] output.
• 1500mah battery x 60C = 90,000mA[h] = 90 Amps maximum continuous [burst]output.
• 3000mah battery x 30C = 90,000mA[h] = 90 Amps maximum continuous [burst] output (MCO)

It's going great! Burst rate = 35C x 2200mah = 77000mah = 77A. That is plenty for most setups. FYI it's 855W which is just over 1 horsepower at full noise.

What's wrong with the above is that 35C x 2200mAh = 77000mAh = 77Ah (NOT 77A power rating). In other words MCO (Continuous) is for peak burst which could be as short as 2-3 seconds or 5 at most before a RC Lipo cell reaches 140-145 °F. Beyond that the cell will start to puff/swell and beyond that good chance for an unfortunate explosion.

RC Lipo manufacturers arbitrary rating system was never meant to be an applicable rating formula for e-bike lithium battery Maximum Continuous Discharge. Believe it or not my posts are an attempt to save you the time and cost fabricating a 72V RC Lipo powerplant that more likely than not will be a frustrating disappointment.

A 52V Lion powerplant may be an all-around better fit for both enuf power and better range (riding enjoyment). Comes with a built-in BMS and Charger for considerably less $$$ than your current RC Lipo 72V battery. If for whatever reason(s) you are still set on a 72V powerplant you try to make a 72V Lion fit by having two 36V Lions in series. Although i wouldn't recommend doing that anymore than having 5 of those 20AH 4S Turnigy in series.