Battery Advice Needed For Middle School Competition
- DrkAngel
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Re: Battery Advice Needed For Middle School Competition
Sonas @ $150 per 100 cells = 4 x 24 cell battery builds
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I enjoy enlightening ... and enlivening the spirit of the innovators.
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Re: Battery Advice Needed For Middle School Competition
OMG, you should see what I get when Googling this!DrkAngel wrote:Sonas @ $150 per 100 cells = 4 x 24 cell battery builds
Can't seem to find Sonas lipo's on-line...
- DrkAngel
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Re: Battery Advice Needed For Middle School Competition
Can't confirm Sona cells as 2000mAh ...BlueBell wrote:OMG, you should see what I get when Googling this!DrkAngel wrote:Sonas @ $150 per 100 cells = 4 x 24 cell battery builds
Can't seem to find Sonas lipo's on-line...
Not sure of replacement candidates.
Need:
180Wh ÷ 3.6V cells = 50Ah
12s2p (≤ 2080mAh cells) 43.2V 2000 or 2050mAh
13s2p (≤ 1923mAh cells) 46.8V
14s2p (≤ 1785mAh cells) 50.4V best ... if available
15s2p (≤ 1666mAh cells) 54V 1650mAh cells max recommended
16s2p (≤ 1562mAh cells)57.6V
180Wh ÷ 3.7V cells = 48.64Ah
12s2p (≤ 2026mAh cells) 44.4V
13s2p (≤ 1870mAh cells) 48.1V best ... if available
14s2p (≤ 1737mAh cells) 51.8V
15s2p (≤ 1621mAh cells) 55.5V 1600mAh cells max recommended
16s2p (≤ 1529mAh cells) 59.2V
Reputable possibilities:

Lipo ...
.
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
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Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
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- DrkAngel
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Re: Battery Advice Needed For Middle School Competition
Hobbyking!
11.1V 3200mAh Turnigy LiPo - $20
3s 11.1V x 3.2Ah =35.52Wh x 5 = 177.6Wh
15s LiPo 55.5V 3.2Ah = 177.6Wh
3s 11.1V 4000mAh LiPo
3s 11.1V x 4.0Ah = 44.4Wh x 4 = 177.6Wh
12s LiPo 44.4V 4.0Ah = 177.6Wh
11.1V 3200mAh Turnigy LiPo - $20
3s 11.1V x 3.2Ah =35.52Wh x 5 = 177.6Wh
15s LiPo 55.5V 3.2Ah = 177.6Wh
3s 11.1V 4000mAh LiPo
3s 11.1V x 4.0Ah = 44.4Wh x 4 = 177.6Wh
12s LiPo 44.4V 4.0Ah = 177.6Wh
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
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Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
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Re: Battery Advice Needed For Middle School Competition
DrkAngel,
I'm really starting to feel like an idiot here.
Not really sure what you're trying to beat me over the head with.
It looks like four different battery options...?
Is that right?
Is the C-number relevent here or are they all the same?
Knowing our requirements, is there one combination you would recommend over another?
If it's all the same then I would think the fewer number of pieces the fewer connections we'd have to make.
And what about charging?
The IMax B6?
Does that go between the panels and the battery?
What A/C charger were you thinking of or should we just use the panels leading up to the race?
I'm starting to get discouraged here, it seems like I'm missing something... something obvious.
<sigh>
I'm really starting to feel like an idiot here.
Not really sure what you're trying to beat me over the head with.
It looks like four different battery options...?
Is that right?
Is the C-number relevent here or are they all the same?
Knowing our requirements, is there one combination you would recommend over another?
If it's all the same then I would think the fewer number of pieces the fewer connections we'd have to make.
And what about charging?
The IMax B6?
Does that go between the panels and the battery?
What A/C charger were you thinking of or should we just use the panels leading up to the race?
I'm starting to get discouraged here, it seems like I'm missing something... something obvious.
<sigh>
- DrkAngel
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Re: Battery Advice Needed For Middle School Competition
Sona 18650 cells may not qualify due to lack of documentation-verification of capacity.
2 different Lipo possibilities.
Higher C rate provides less sag but very high C rate tends to sacrifice reliability-durability.
Under your planned discharge C rate will be less than 3 C, so possibly 20-30C might be optimal.
iMax B6 is for testing, charging and balancing (equalizing) individual 3s LiPo, 4 individual charges for 3s LiPo packs.
Use panels to "top off" battery.
I recommend the 4 x 4000mAh as best choices. 5 x 3200mAh pushes charged voltage to 63V which is the probable controllers capacitor rating-limit. I don't recommend pushing to limit.
2 different Lipo possibilities.
Higher C rate provides less sag but very high C rate tends to sacrifice reliability-durability.
Under your planned discharge C rate will be less than 3 C, so possibly 20-30C might be optimal.
iMax B6 is for testing, charging and balancing (equalizing) individual 3s LiPo, 4 individual charges for 3s LiPo packs.
Use panels to "top off" battery.
I recommend the 4 x 4000mAh as best choices. 5 x 3200mAh pushes charged voltage to 63V which is the probable controllers capacitor rating-limit. I don't recommend pushing to limit.
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
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Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
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Re: Battery Advice Needed For Middle School Competition
High Ah trades off Discharge in 18650 format, so 3.5Ah is the highest these days, best guess is 10A discharge. But them 2.0-2.5Ah's can get 25A-30A discharge.
I have not looked at pouches or other formats.
I have not looked at pouches or other formats.
Last edited by markz on Nov 14, 2017 2:38 pm, edited 1 time in total.
Re: Battery Advice Needed For Middle School Competition
I know it takes a lot of energy to get the prop started
So what is the amp draw of the controller and add a few ? So 12s 2p of Samsung 25r cells 25amp cell. Price is going down. Maybe 3.75- 4.00 usd each.
So what is the amp draw of the controller and add a few ? So 12s 2p of Samsung 25r cells 25amp cell. Price is going down. Maybe 3.75- 4.00 usd each.
Re: Battery Advice Needed For Middle School Competition
"Sona 18650 cells may not qualify due to lack of documentation-verification of capacity."
Yes, you hit the nail on the head there.
They require documentation of battery specs.
Max 180 Watt-hours
Not sure which Turnigy 4000 you meant.
This one: https://hobbyking.com/en_us/turnigy-bat ... xt-60.html
How will we ensure 25 minutes out of this set-up?
If we fall short by even 20 seconds we are disqualified!
"I know it takes a lot of energy to get the prop started"
Not really, especially considering the high torque of electric motors on start up.
It takes considerable more power at speed, ~8 - 10 knots ( ~4.5 m/s ).
Yes, you hit the nail on the head there.
They require documentation of battery specs.
Max 180 Watt-hours
Not sure which Turnigy 4000 you meant.
This one: https://hobbyking.com/en_us/turnigy-bat ... xt-60.html
How will we ensure 25 minutes out of this set-up?
If we fall short by even 20 seconds we are disqualified!
"I know it takes a lot of energy to get the prop started"
Not really, especially considering the high torque of electric motors on start up.
It takes considerable more power at speed, ~8 - 10 knots ( ~4.5 m/s ).
- DrkAngel
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Re: Battery Advice Needed For Middle School Competition
Not sure on the 4Ah RC LiPo.
1. Median C rate, (20-30C for better consistency-reliability)
2. good brand name. Ask others about "good brand name".
Watt meter has watt function.
... think I figured this for you already ...
Keep throttle positioned for determined watt usage (400W?) battery output.
1. Median C rate, (20-30C for better consistency-reliability)
2. good brand name. Ask others about "good brand name".
Watt meter has watt function.
... think I figured this for you already ...
Important to test drive before actual race.DrkAngel wrote:2. Watt-watt Hour meters are fairly accurate and inexpensive. If a throttle is used, maximum safe battery output can be regulated fairly precisely!
180wh x 60/25 min = 432w
Should maintain 400w+ battery output for 25 minutes
Keep throttle positioned for determined watt usage (400W?) battery output.
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
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Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
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Re: Battery Advice Needed For Middle School Competition
Ah, yes indeed, you did show me that, thank you and my apologies for overlooking it.
I've just read through the thread a few times and believe I'm getting a firm grasp on reality, finally.
So, 25C constant with 50C burst isn't okay?
You pick one.
I've just read through the thread a few times and believe I'm getting a firm grasp on reality, finally.
So, 25C constant with 50C burst isn't okay?
You pick one.

- DrkAngel
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Re: Battery Advice Needed For Middle School Competition
Either look good!
If budget allows, might recommend 2 sets of batteries or at least 1 spare, in case of accident or failure?
Graphene is newer tech with greater reputed lifespan.
If budget allows, might recommend 2 sets of batteries or at least 1 spare, in case of accident or failure?
Graphene is newer tech with greater reputed lifespan.
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
EBike Toolbox - Bargains! $
Endless Sphere Wiki
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
EBike Toolbox - Bargains! $
Endless Sphere Wiki
Re: Battery Advice Needed For Middle School Competition
Yes, we are advised to have a second battery in case of poor weather and the solar-only heats will run on battery instead.
But I thought you didn't like the first one, the HobbyKing R/C one.
Graphene you say. Perhaps that has something to do with the differing three letter abbreviation associated with the different lipo listings.
Come on, stick your neck out and recommend one... please.
Or your two top picks, then you're not on the hook.
Is the heavier battery, of the same rating, the better way to go?
Thanks again.
But I thought you didn't like the first one, the HobbyKing R/C one.
Graphene you say. Perhaps that has something to do with the differing three letter abbreviation associated with the different lipo listings.
Come on, stick your neck out and recommend one... please.
Or your two top picks, then you're not on the hook.
Is the heavier battery, of the same rating, the better way to go?
Thanks again.
- DrkAngel
- 10 GW
- Posts: 4583
- Joined: Dec 15, 2010 11:14 am
- Location: Upstate-Western-Southern Tier NY. USA
Re: Battery Advice Needed For Middle School Competition
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
EBike Toolbox - Bargains! $
Endless Sphere Wiki
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
EBike Toolbox - Bargains! $
Endless Sphere Wiki
Re: Battery Advice Needed For Middle School Competition
Lol, ok, graphene it is... even though it's lighter.
Re: Battery Advice Needed For Middle School Competition
With them RC lipo its just like lego, you plug whatever you want together, making sure to pay very very very very close attention to what you are doing. Buying or making a parallel adapter, I used a 5.5mm connector with 10awg that split into six 4mm 12 or 14awg wire, then I bought some 5.5mm bullets and some wire to solder the main wire. Its pretty simple to learn. Then you got to take care in charging and discharging. One day I will buy LiPo again.
Re: Battery Advice Needed For Middle School Competition
Did you mean it takes a lot to get the motor going?999zip999 wrote:I know it takes a lot of energy to get the prop started
So what is the amp draw of the controller and add a few ? So 12s 2p of Samsung 25r cells 25amp cell. Price is going down. Maybe 3.75- 4.00 usd each.
I've been told we may have a problem when running on panels only getting the motor turning due to it's high start-up draw. The panels may drop below the min voltage cut off in the controller.
Re: Battery Advice Needed For Middle School Competition
DrkAngel,
I noticed the upper limit on the motor controller is 42.5 +/- 0.5 Volts.
Is this going to be a problem at 44.4V?
This is printed on the controller, the spec sheet differs, same for LVC.
I noticed the upper limit on the motor controller is 42.5 +/- 0.5 Volts.
Is this going to be a problem at 44.4V?
This is printed on the controller, the spec sheet differs, same for LVC.
- DrkAngel
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Re: Battery Advice Needed For Middle School Competition
.
... Edited!
Better contact seller to confirm!
States 36-48V capable! ... ?
Very often 36V controllers have no HVC (High Voltage Cutoff) 42.5V might be hypothetical?
42.5V upper limit would be bad for 44.4V or from panels!
~31V LVC with 44.4V ≥ 50.4V charged capability required.
... Edited!
Better contact seller to confirm!
States 36-48V capable! ... ?
Very often 36V controllers have no HVC (High Voltage Cutoff) 42.5V might be hypothetical?
42.5V upper limit would be bad for 44.4V or from panels!
~31V LVC with 44.4V ≥ 50.4V charged capability required.
Last edited by DrkAngel on Nov 18, 2017 9:42 am, edited 3 times in total.
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
EBike Toolbox - Bargains! $
Endless Sphere Wiki
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
EBike Toolbox - Bargains! $
Endless Sphere Wiki
Re: Battery Advice Needed For Middle School Competition
42 volt is 10s fully charged.
Ok srill guessing 42v fully charged x 42,000mah equals 176 wh ?
Ok srill guessing 42v fully charged x 42,000mah equals 176 wh ?
- DrkAngel
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Re: Battery Advice Needed For Middle School Competition
Volts x Amps = Watts
Volts x Amp hours= Watt hours
V x Ah = Wh
"V" (Volts) is based on the average discharge voltage during a full discharge.
EG. 4.2V >> 3.2V MFG rated @ 3.7V
Wh is based on Ah x V averaged
Wh is rated at mfg rating of average voltage at modest discharge rate 11.1V (3x cell 3.7V) x mfg rated mAh (4000mAh) = 44.4Wh
(12s) 44.4V x 4Ah = 177.6Wh (180Wh limit)
edited previous post ... clarified expanded.
Volts x Amp hours= Watt hours
V x Ah = Wh
"V" (Volts) is based on the average discharge voltage during a full discharge.
EG. 4.2V >> 3.2V MFG rated @ 3.7V
Wh is based on Ah x V averaged
Wh is rated at mfg rating of average voltage at modest discharge rate 11.1V (3x cell 3.7V) x mfg rated mAh (4000mAh) = 44.4Wh
(12s) 44.4V x 4Ah = 177.6Wh (180Wh limit)
edited previous post ... clarified expanded.
Last edited by DrkAngel on Nov 19, 2017 2:40 pm, edited 1 time in total.
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
EBike Toolbox - Bargains! $
Endless Sphere Wiki
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
EBike Toolbox - Bargains! $
Endless Sphere Wiki
Re: Battery Advice Needed For Middle School Competition
Aren't we stuck at 42.5 volts because the upper limit of his controller or 10s ?
Re: Battery Advice Needed For Middle School Competition
Can we pick the direction of rotation on this motor or is it predetermined?
We are proposing to thread an aluminum tube onto the shaft threads of the motor.
If it turns counterclockwise, it will tend to unscrew our propeller shaft!
We are proposing to thread an aluminum tube onto the shaft threads of the motor.
If it turns counterclockwise, it will tend to unscrew our propeller shaft!
- DrkAngel
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- Joined: Dec 15, 2010 11:14 am
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Re: Battery Advice Needed For Middle School Competition
Youtube search shows motor turns clockwise, facing gear.
BM1418ZXF(BLDC)
Brushless motors, typically, are not reversible, without special controller.
BM1418ZXF(BLDC)
Brushless motors, typically, are not reversible, without special controller.
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
EBike Toolbox - Bargains! $
Endless Sphere Wiki
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.
I enjoy enlightening ... and enlivening the spirit of the innovators.
New & Improved - Acronym Definitions
Index - Homemade Battery Packs - Updated - November 2015
EBike Toolbox - Bargains! $
Endless Sphere Wiki