15 replies to this topic

[Omar (OZ)]

I have a "Well.... technically...."(maybe?) question. I know I need 7.5V to 12V to power the netduino.If Voltage = Current * Resistance isnt there a way to increase the volts of a battery? (I have a 6V-650mA battery) so I can power my netduino with it?.

[CwbhX]

Correct me if I am wrong, but what about internal resistance?

[Omar (OZ)]

Correct me if I am wrong, but what about internal resistance?

ummmm didnt think about that.... I dont really know. I guess what I'm asking is what can I do to get a battery with high amps and at least 9V... cuz they sell them for RC model airplanes, but those are crazy expensive

[Chris Seto]

You can step the voltage all you want, but it will come as a cost of current. 6V probably would power the Netduino, not 100% on that though, I haven't looked at the schematics yet.

[dab]

ummmm didnt think about that.... I dont really know. I guess what I'm asking is what can I do to get a battery with high amps and at least 9V... cuz they sell them for RC model airplanes, but those are crazy expensive

Well, you could put two of the 6V batteries in series to get 12V.

With a regulator, it's fairly easy to *decrease* the voltage. But, in general, it's not easy to increase the voltage of a DC source.

Increasing the voltage generally involves converting DC to AC (or a DC square wave), passing it through a step-up transformer, and converting back to DC.

But if you do that, then the current will decrease proportionally with the voltage increase (actually, you'll lose even more current due to losses in the transformer, etc.).

[CwbhX]

What is the Amperes needed to power the NetDuino Plus? I might have a battery. I was doing research earlier this summer for a solar lighting project, so I might be able to take from that to NetDuino. P.S. Just found my NetDuino Plus packed away with a lot of papers from MakerFaire 2010, the packers didn't do a good job at taking care of it, yet it seems to work .

[klotz]

You can step the voltage all you want, but it will come as a cost of current. 6V probably would power the Netduino, not 100% on that though, I haven't looked at the schematics yet.

I have run the Netduino, and Parallax boe bot chassis on 4 AA batterys. ( 4 x 1.5 = 6Vdc)
I have been using the same batteries for over a week and had several test runs of the chassis. So I would say, 6VDC will just make it.
Remember you lose about 0.6-1.0 volts to a regulator and the Netduino wants a solid 3.3 Vdc for main power and 5Vdc +- 10% so your can get by.

[CwbhX]

Well, in the meantime I found this: http://www.newegg.co...7-874-_-Product I think the Amp hours are a bit high?

EDIT Perhaps this is closer :/ http://www.newegg.co...4-416-_-Product

I like Li-ion

[CwbhX]

Well, USB is 5v and has say 600mA?

[Mark H]

How about something like this? $4.95 -1000mah 2S lipo (7.4v nominal) - should run the netduino for about 10hrs.

Or... $12.15 -2350mAh 2S - should run a netduino for more like 24hrs.




No need to spend crazy amounts of money when you have hobbyking to look to

[CwbhX]

Nice find! I haven't heard of the website before; is it reliable? I might purchase on of these, or go with a solar approach.

[Chris Seto]

Yep, plenty of people use Hobbyking/hobbycity. They have a US warehouse now, too.

[Mark H]

I've been using hobbyking for about 6 years. Their products are excellent, the service is exceptional, the price is second to none.

[Crispin]

Well, in the meantime I found this: http://www.newegg.co...7-874-_-Product I think the Amp hours are a bit high?

EDIT Perhaps this is closer :/ http://www.newegg.co...4-416-_-Product

I like Li-ion

Both of those are ok - the netduino will pull what ever current it requires providing the batteries can supply it. Batteries and PSUs do not _push_ current or amps, they only have the capacity to supply what is required.

[kettch]

How about something like this? $4.95 -1000mah 2S lipo (7.4v nominal) - should run the netduino for about 10hrs.

Or... $12.15 -2350mAh 2S - should run a netduino for more like 24hrs.




No need to spend crazy amounts of money when you have hobbyking to look to

I thought of LiPo batteries, but you have to be careful not to drain them below about 3.0 V, or you risk damage to the cell. I suppose it's possible to build something to measure voltage?

[Chris Seto]

It's very easy to monitor current/voltage. There are plenty of modules out there for UAV use, or you could make your own circuit. You could also mod a low voltage Lipo alarm to allow the Netduino to poll battery status.