What battery to use for portable RPi?

Question

I was planning on making an RPi robot, wireless, of course, and i was wondering what type of battery or battery pack to use (size, voltage, amperage, etc). It would also be helpful to know if i should wire it directly to a male micro usb cable to plug directly into the Pi, or with a female micro usb jack to plug another cable into. If you could give any sugestions as to how to recharge the battery pack, or simply use regular AA batteries, it would be greatly appreciated.

ipv1 · Answer

Ah Excellent Idea. Here is my answer:

Option 1: Get a 2200mAh battery pack that is a good option for the RPI B+ itself. Make sure you power the motors from a different battery though since motor starts can cause problems with the regulation when drawing high currents.

Option 2: With the RPI B+ you can buy the LiPo Rider Pro which can be used to charge the LiPo battery as well as supply the high currents to the RPi. Again separate batteries for the motor.

Option 3: IF you can use a bigger battery, Get a 12V lead acid battery along with a LM2596 switching regulator to get 5V from the 12V battery. In this case you may use the lead acid battery for the motor as well.

I use the lipo rider pro since I can charge the LiPo while it powers the RPi B+

Hope that helps

Former Member · Answer

For situations that require absolute safety I would go for stacking the ultra flat Prologium LCB batteries.

http://www.prologium.com/Performance.aspx?02F0EA87FB60FF526BD81D51338B43D5

I saw their demo in 2012 at a Battery fair in Tokyo. They showed that these batteries can be cut with a scissor or thrown in the fire and nothing dangerous happened with it.

These batteries also bring the possibility of shaping and curving although not recommended. The flat squares can find an easy home in your robot suit or become the suit

The slightly thicker Pouch types are more powerful so lets try one 12V configuration, assuming we can take care of the Motor noise with a TVS Diode clamping at 15V :

Using PLCB 140210 type of battery with these specs:

Dimensions (mm): 140x210

Weight (g): 145

Nominal Voltage (V) 3.75

Nominal Capacity (mAh): 4970

Arrange 2 sets of 4 in serial, in parallel mode results in:

VDC range (V) 12~15

Nominal Capacity (mAh): 9940

Total weight(g): 1160

Recommended max discharge rate 0.2C will be about 2A.

toxxn · Answer

Lucky enough for projects like this there are a wide variety of different types of batteries one could use, Lipo, Li-ion, ni-cd, etc, or you could even go with a 5v 4x AA battery pack.

Any hobbyist battery of 4.5-5v with at least 1000mA or higher would be my choice. They are generally small, rechargeable, decently priced, and if you need more amperage, you have that option as they come in a variety. As for size of the battery, that depends on your project and how much space you want to allocate for the battery. As mentioned however, hobbyist batteries are generally quite small and lightweight as they are used in electronics such as RC cars, boats, planes, etc.

You can power the Pi directly using the provided GPIO pins on the board using one of these batteries. I wouldn't alter the battery in any way to adjust how you want to power the Pi as some of these batteries such as Lithium Ion can be very dangerous if misused. If you did not want to use the GPIO's, you could simply just get a connector that fits to the battery and solder on a micro USB.

Just a a word of caution with li-ion batteries, only charge them with the correct method of charging. Otherwise you could create a recipe for disaster as Li-ion's if not charged properly, overcharged, or misused can create quite a powerful chemical reaction that may result in a fire and/or the battery to explode. I tend to stay away from lithium batteries.

Former Member · Answer

Something I have that is long lasting for a four wheel rover is a RC Lipo Battery (11.1V/2600mAh). Works for the motors and I add a 5V/1.5A regulator bypass for the RasPi. Lasts for days and the battery charges in 2hrs. Works as well for the BeagleBone Black.

toxxn · Answer

This is also a great option. Using a Step-Down Module (Buck Converter) you could use a larger voltage battery and increase the mAh drastically.

I have a KIS3R33S USB DC 7V-24V to 5V 3A Step-Down module that I used in a custom Pi power supply I made.

I recycled an old Bose wall wart that is 12v 1800mA for my custom power supply which allows me to power a small tft lcd (Car reverse monitor) at the same time, while the step-down module allows me to step the 12v down to 5v for the Pi. 2 in 1 power supply. This also leaves me open for a larger voltage battery or a car charger using the same power supply.

dougw · Answer

Generally DC-DC converters are much more efficient than linear regulators. They are also usually more complex and more expensive, but the costs keep coming down. On the drawback side, they can be significantly more noisy, larger and more failure prone.