Battery power problems

[flippy]

Samsung 29E 18650 2850mAh 2.75A Battery, https://www.imrbatteries.com/samsung-29e-18650-2850mah-2-75a-flat-top-battery/
Do you use this battery yourself? I thought I would be better off with a higher capacity cells. The pack will be a 10S 10P in size, for 36VOLT 500 WATT motor with a 20 amp controller.

i have 450 of them in one scooter and 680 in my "faster" scooter and another 3000 or so on the shelf.

higher capacity means shorter lifespan. anything above 2.9Ah wears out a LOT faster.

 

[stevecahill]

higher capacity means shorter lifespan. anything above 2.9Ah wears out a LOT faster.

Was unaware of having higher capacity means shorter lifespan. When you say shorter lifespan what is your criteria of a shorten lifespan?

I am planing to only charging these batteries no more than 3.9 - 4 volts per cell to extend life. Additionally I have room on this E-bike build for only 100 cells so 10P 10S will allow 100 cells, giving the bike a 28.5Ah pack with the Samsung 29E's. The build is for a senior citizen, so this does not need to be a 2000 watt build, only 500 watt.

Having that many Samsung 29E 18650 2850mAh batteries is proof of the reliability of these cells.

Thank you for that useful information, look forward to your follow-up reply.

 

[flippy]

high capacity cells suck at delivering high currents, that is just inherent to the capacity>internal resistance ratio. for the same load the lower capacity cell with last longer.
charge up to 4.05~4.1V on a bike/vechicle. there is nothing to gain by going lower unless you want to the battery out outlast the car/bike.

a 10S10P setup with 29E's will be able to devilver 500W comfortably for years. i expect to see a faster loss in capacity with bigger cells. they tend to wear out faster as they have more trouble delivering power with less cells.

 

[stevecahill]

Thank you!

 

[stevecahill]

Flippy, Thank you for your advice. A couple more questions before I place my 29E battery order.

1. What charger would you advise, for 10S-10P pack?
2. What BMS with balancing would you recommend and who would be the preferred vendor?

I finally found a e-bike kit that has all the components that I want in kit so I do not have to wrangle out the wires if I were to purchase the components separately. Happens to be a 36Volt, 750Watt motor, with a
>. Driver: brushless controller
>>. MOSFET: 12 PCS
>>. With LCD: YES
>>. Rated Voltage: DC 36 Volts
>>. Min. Voltage: DC 30 ± 0.5 V
>>. Rated power: 750 Watts
>>. Casing material: aluminium
>>. Maximum Current: 26 A ± 1 Amps
>>. Thermal: aluminum shell and the substrate
>>. 3 phase 120° brushless motor
>>. Operating Conditions: -20~45 °C
>>. Waterproof design
>>. Size: 171 mm L × 82 mm W × 42 mm H

 

[flippy]

Flippy, Thank you for your advice. A couple more questions before I place my 29E battery order.

1. What charger would you advise, for 10S-10P pack?
2. What BMS with balancing would you recommend and who would be the preferred vendor?

mean well HRP-300-48 should be plenty and will never break. just set the top voltage and you are done.
should charge the pack in 3 hours from dead.

bms:
https://www.aliexpress.com/store/product/Smart-Display-300A-8-24S-Cells-Lithium-Battery-Protection-Board-Balance-BMS-Coulomb-Meter-Lithium-iron/2856009_32827394534.html

i would also order the LCD, you can hook it up to the pluse signal from the controller so it can calaculate the remaning range and stuff.

 

[stevecahill]

Nice BMS, above my pay grade for setting up at the moment. I like the BT functionality. Will have to find a YouTube video for this.

It appears the LCD display comes with the BMS @ https://www.aliexpress.com/item/Sma...pm=a2g0s.13010208.99999999.259.7eb23c000GfXvT

The E-Bike kit I will be ordering has a KT LCD-3. Looks like I might have multiple displays. Now to figure out where to physical put all of these displays.

 

[stevecahill]

Flippy, where do you source your Samsung 29E 18650"s from?

 

[flippy]

Nice BMS, above my pay grade for setting up at the moment. I like the BT functionality. Will have to find a YouTube video for this.

It appears the LCD display comes with the BMS @ https://www.aliexpress.com/item/Sma...pm=a2g0s.13010208.99999999.259.7eb23c000GfXvT

The E-Bike kit I will be ordering has a KT LCD-3. Looks like I might have multiple displays. Now to figure out where to physical put all of these displays.

No, it does not come with a screen. Its a separate 20$ option.

Flippy, where do you source your Samsung 29E 18650"s from?

Nkon

Note that i dont have any shipping issues as i live 30min from them.

 

[stevecahill]

Flippy, Question, you mentioned that the MW Mean Well HRP-300-48 48V 7A 300W Single Output with PFC Function Power Supply would be good to charge a 36volt 10s 10p pack, will that not be too high voltage @ 48 volts? Or will the smart Bluetooth BMS manage the output to the batteries for charging?

Thank you.

 

[flippy]

No, you SET the voltage on the charger. The bms is only there to PROTECT the battery. Its the job of the charger to shut off at the proper voltage you have set. Only if there is a problem the bms will intervene.

 

[stevecahill]

I was not aware that the MW Mean Well HRP-300-48 48V 7A 300W Single Output with PFC Function Power Supply was adjustable.

Does this power supply have a adjustment for voltage before I purchase?

Thank you.

 

[amberwolf]

His point was not whether that specific PSU has adjustments. His point was that the BMS does NOT, and that any adjustments must be done on the PSU (or charger).

You can look at the Meanwell website for that PSU's specifications to see if it has adjustments or not.

 

[stevecahill]

He recommended this power supply in a earlier post above.

 

[amberwolf]

Ah, sorry, I missed that. I do still think that his point was as I noted above.


And I still would recommend verifying the specifications of the PSU on the meanwell site.


(same for any other PSU; I'd check with the manufacturer to make sure it's specifications are correct for your use before buying)

 

[stevecahill]

I did buy this power supply and await its arrival. https://lunacycle.com/luna-charger-36v-advanced-300w-ebike-charger/

Also waiting for this BMS @ https://www.aliexpress.com/item/8S-to-24S-2018-new-DIY-Lifepo4-li-ion-50A-80A-100A-110A-120A-smart-bms/32847165991.html?spm=a2g0s.9042311.0.0.28044c4d6djyLg

Thank you for your support.