Hello All

Sorry if this question was already raised!

As you all know Lego Rechargeable Battery for ev3 is expensive.

May I ask you if anyone tried to use 6 Li-Po 1.5v rechargeable batteries there instead of regular lithium Batteries?

Ni-MH  are all 1.2v , and will not work as needed but maybe 1.5 li-po would be Ok ?

Brand, let say : ZNTER

They can be found on ebay for $40 for 6 batteries ...

http://www.ebay.com/itm/6pcs-ZNTER-1-5V-AAA-400mAh-LiPo-rechargeable-lithium-battery-USB-charging-line-/272099707530?hash=item3f5a680a8a:g:RQ8AAOSwX~dWkQt-

or

http://www.bestbuy.com/site/eco-cell-usb-cell-rechargeable-aa-batteries-4-pack-white-green/4471800.p?skuId=4471800

Thank you !!!

Edited August 2, 20177 yr by Serg

3 hours ago, Serg said:

Ni-MH  are all 1.2v , and will not work as needed but maybe 1.5 li-po would be Ok ?

Befor talking about the lipo, nimh is also okay and this is the reason why:

when we say a nimh cell is 1.2v, it means it is 1.2v on the everage.

If you look at the discharge rate curve of both alkarine 1.5v cell and nimh 1.2v cell, actually the 1.2v nimh cell is usually at the higher votage than the other.

you can take a look at the curves here

And I can't understand how they made a 1.5v lipo cell. But I still suggest to use nimh cells as they are more stable and easy to deal with than the lipo cells.

If you would use nimh cells, I suggest eneloop nimh.

By the way, zn mno2 means alkarine.(at the discharge curve)

Edited August 3, 20177 yr by move5
changed graph to curve

There is probably a step down voltage converter inside the AA battery shaped 1.5V LiPo module to drop the voltage down to 1.5V. 

In my opinion I would just buy Amazon Basics Batteries or Eneloops, They will be a bit cheaper, not from a no-name brand, and I use them and they work with Ev3 just fine.

https://www.amazon.com/AmazonBasics-Rechargeable-Batteries-8-Pack-Pre-charged/dp/B01FJAL4PK/ref=sr_1_1?ie=UTF8&qid=1501721996&sr=8-1&keywords=amazon%2Bbasics%2Bbatteries%2Brecharge%2BAA&th=1

https://www.amazon.com/Panasonic-BK-3MCCA8BA-Pre-Charged-Rechargeable-Batteries/dp/B00JHKSN5I/ref=sr_1_1?s=electronics&ie=UTF8&qid=1501722086&sr=1-1&keywords=eneloop+aa

 

 

P.S. These are AAA's not double A's: http://www.ebay.com/itm/6pcs-ZNTER-1-5V-AAA-400mAh-LiPo-rechargeable-lithium-battery-USB-charging-line-/272099707530?hash=item3f5a680a8a:g:RQ8AAOSwX~dWkQt-

I use Panasonic Pro Eneloops, they work great, and because of the high captivity, they last for ages!

In fact, I ONLY use Eneloops for EV3, as well as for all my other Lego - I have had bad experiences with alkaline and cheap NI-MH (including one that exploded while charging!).

First link you gave for those AA 1.5 LiPo batteries states that "Maximum output current: Less than 1A". That's not good If you plan to use the several of the large EV3 motors at the same time.

Also 400 mAh capacity is very low, your robots will have short autonomy. And you still have to take batteries out to recharge (or at least open the robot and plug 6 USB cables on it) - why don't you just use common NiMH batteries? The total voltage isn't so important.

So, I guess no one has tried them yet? I hear the lipos are very good and they maintain a 1.5 volt output during their life span before recharging, which is better than any alkaline or 1.2 volt rechargable. They are also much lighter. I've been looking at the kentli batteries, they look like good rechargable lipos. But they are expensive so I haven't tried them yet. 

No offense but I would stay with the LEGO solution. They might be more expensive than a typical Chinese option, but they are very robust and you don't want your brick to be destroyed.

6 hours ago, MajorAlvega said:

Also 400 mAh capacity is very low, your robots will have short autonomy.

I agree, the Eneloops I use have 2500mAh captivity - more than 6x more than those lipos!

6 hours ago, allanp said:

which is better than any alkaline or 1.2 volt rechargable.

Well, not really... take the Eneloop pro for example - even if you charge them twice a week, they will still last 5 years. (they can be charged 500+ times)

7 hours ago, allanp said:

But they are expensive so I haven't tried them yet. 

Yes, and that also applies to Eneloops, but it's not much compared to the EV3 set...

 

I guess I should add a link to the Eneloops after all the talk about them! 

Here they are: Eneloop (standard), Eneloop Pro, Wiki page