help needed in determining materials list

Question

Hello. I am very new to hardware development and am in need of some professional help determining what parts I need to accomplish my goal. I am looking to build a power management system for use inside a car. The system will be used to manage power to a Raspberry Pi. Attached is an accurate (yet I'm sure very crude...please pardon my ignorance) representation of what I'm trying to accomplish. The goal of this is to maintain a constant stream of clean power to the RasPi while the vehicle is in operation. Could I get some guidance on what materials I need in order to make this a success?

shabaz · Answer

I didn't understand the exact requirement, did you intend the RPI to gracefully power off when the vehicle is not in operation?

If so, there are alternate ways that do not require the LiPo and step-up DC-DC converter - the sleepy pi would then likely meet the need.

autodeskguest · Answer

On 06/11/14 22:09, shabaz wrote: Regarding " however, I really need to be able to fend off the spikes, brownouts, and sustained voltage craziness in the vehicle. " You'd have to do that with any circuit intended for a vehicle, it is not eliminated using a LiPo - you have merely moved the problem to the input of the LiPo charger circuitry. Vehicle electrical systems are a horrid environment, but just throwing a LiPo at it isn't the solution. By the way, 17V (the max input rating for the Sleepy Pi board) is quite low for vehicle use, Low but probably just about tolerable, as long as it's the max steady voltage. There will be momentary spikes above that. Mind you, I once encountered a (very expensive, German made) explicitly automotive piece of development kit that would fry a tantalum if subjected to over 16V for a fraction of a second. so perhaps you may want to use a linear regulator (e.g. a 10V linear regulator like a LM7810) preceeding it. I'd go with a series resistor and MOV rather than a (potentially equally sensitive) linear regulator It wouldn't consume enough current in shutdown to worry about in a vehicle (about 6mA with typical linear regulators). Most OEMs now consider 6mA an unacceptably high quiescent current for (an individual piece of) automotive electronics.