Toddler Board Power Question

NWCCTV

Does anyone know what the absolute maximum voltage is that can be applied to the Toddler Control Board without frying anything? 6V just does not seem to cut it for the most basic walking tasks and I want to use a couple of my 3,7V batteries to give it more oomph!!!

Publison

While the onboard regulator will take more voltage, (data sheet states up to 60 volts), the servos run from raw VIN. I would be afraid to run them at more than 6 volts. Most specs for GWS servo say 4.5 to 6.0 volts.

NWCCTV

I am using 4 Ea. rechargeable AA batteries. It seems that this is an issue or my rechargeable batteries are bad and are not putting out enough amperage. I connected a 5V 500ma Wall Wart and everything works just fine. When using the batteries, even at full charge and each running about 1.6V, the Toddler acts really weird and when just trying to center the Servos it seems to run for about a minute before stopping at center. If I power cycle it repeats this even if the servos are already centered.

Publison

NiMH and NiCad are only 1.2 volt per cell. That only gives you 4.8 to start out with.

I have been using the NiZn (1.6 volt) cells with very good results:

http://www.amazon.com/s/?ie=UTF8&keywords=ni-zn+batteries&tag=googhydr-20&index=aps&hvadid=27170773083&hvpos=1t2&hvexid=&hvnetw=g&hvrand=10887913300365098693&hvpone=&hvptwo=&hvqmt=b&hvdev=c&ref=pd_sl_7y52n6tmo5_b

You may want to look at a 5 cell battery pack:

http://www.parallax.com/product/753-00007

Not sure how that fits the Toddler.

NWCCTV

Thanks @Publison. I will have to order some and give them a try. In the mean time I can use my Wall Wart!!!

Publison

Just make sure you get the correct charger with the batteries. The NiZn can not be charged with a NiCAD or NiMH charger.

erco

Andy: Are you running your 4.8 volts of NiMH batteries through an onboard regulator? That would drop voltage even more and be a showstopper.

I like Jim's suggestion of NiZn batteries, but I have not tried them myself. Likewise, his suggestion to add a 5th NiMH cell has merit.

Lately all my small bots have run directly off of a 3.7V LiPo or Li-Ion cell (servos get 3.7V direct) and I use a dollar USB 5V booster for electronics & sensors. Works perfect on small bots, but Toddler servos may pull more current than this setup can deliver.

Ironically, I'm building interesting new bots weekly, more than ever, but they are now for work, not hobby and I'm not free to share.

Edit: If you're VERY careful you could try running one 14500 (AA-sized) Li-Ion cell with one, or possibly two NiMH cells to get around 6V, but per Jim, servos can get damaged much above 6V. That's a bit half arsed though, not a good long term solution.