1. Because now you know your power supply can offer way too little current for those hungry motors, that’s the reason for such a big voltage drop. Change the power supply and probably it will all work fine.
2. You can add as many caps in parallel as you like, but look at the voltage rating, should be at least double the battery voltage. Also, the breadboard contacts may be a current limiting factor.
5. The USB should power just the Arduino and what ever you have plugged on the 5V or 3.3V pins. Vin pin should not have any power on it, but perhaps it may have some leakage from the voltage regulator.
Yeah, I was ready to suggest you try another battery because I felt yours may not supply enough, but 330mA I wouldn’t have thought eighter. At least you’ve learned some things…
Good thing - my rc car bot is working and I thank you all for your help. It even got IR remote control now, how cool is that :P Bad thing though - my power supply only gives 1A current and the car cant rotate. Therefore I decided to buy a good 4,5Ah NiMh accumulator. But I dont know what charger to buy. The cheapest one is 10$ and looks like this:
And has following properties:
Charge current/ Charge time pro 100 mAh for 7.2V
180mA / 45 min
I did the math: 4,5/0,1*45 = 2025 minutes. 2025 / 60 = 33.75h. Okeeey, 33h charge time? Really?
Another cheapest charger comes for 50+$ and is a digital thingy with nice features, but is kinda expensive:
This one has 0,6A charge current, which should charge my 4,5Ah battery in 10h. It also got car terminal and many nice features such as overcharge protection, bad cells detection etc. Both cant LiPo though.
What is nice about that charger is that it can charge from 0.3A up to 3A. I mean what, can you really charge a 3Ah battery in just an hour? it can also do LiPo but only up to 3,7V ones. It also has same overcharge protection which is really cool. What I dont understand is that here: http://www.rcmarket.org/Power-Peak-A4-EQ-LCD-230V-12V.html it says the output voltage is 16V. Can I charge 7,2V accu with that? It also says:
Charge current with cell count (12 V operation):
2S = 3 A
3S = 3 - 2.4 A
4S = 2.2 - 1.8 A
So 1S is one cell or how? My 4,5Ah battery is 6 cells. And I guess no 3A charging for that
So what charger would you recommend? I would go with the last one, if it can really do 3A charging. Also what is your experience with chargers? Should I invest 50+$ for a really nice charger? Be cause 33h charge time is simply unacceptable, if I did the math right.
Hmm, if you look at the foto, the motor also has two small ceramic caps. Arent they supposed to filter tha noise out? I mean why additional choke coils?
Does anyone know the discharge current of NiMH? Wiki says NimH cells give 1,15V at 2A current. Thats only 6,9V out of 7,2V for a 6 cell. I need 10A of current. Are only LiPos the way to go? I was thinking about this NiMh race pack:
Discharge current: The recommended discharge current of the NiMH is considerably less than that of the NICAD. For best results, manufacturers recommend a load current of 0.2C to 0.5C (one-fifth to one-half of the rated capacity, see 3.1 C-Rate). This shortcoming may not be critical if the required load current is low. For applications requiring high power or a pulsed load, such as on GSM digital cellular phones, portable transceivers and power tools, the more rugged NICAD is the recommended choice.
LiPos also have a discharge rate, something like 10C, 15C, 20C… So a 2S 1000mAh 10C is exactly what are you looking for, but it is always better to get a more powerful one. I suggest this one:
Yea, I’ve been reading for more then an hour abour Lipo, Nimh etc and LiPo is the way to go. The 1.3Ah is undoubtely cheap but will last at 5A current for only 15 min. But those prices are sick. In germany I have 20,00€ for 2500mAh which is 29$.
Turnes out bananaking has a warehouse in Germany, iam so happy now It has same 4000 mAh for 26USD. I dont know if dealextreme ships to Germany and what wait time and price they have. Since bananaking has warehouse in Germany it should be much faster and cheaper. Soon my robot will have 72W power and be unstoppable
It can charge 4-8 NiMH cells. It can also charge 1-4 LiPO cells. In the second picture in the link you provided it shows an 11.1V lipo charging:
Yes, an NiMH 3000maH battery will charge in around an hour at 3A.
The "S" ratings apply to the Lipos, not the NiMHs. It is short for "series" ie 1S = 1 x 3.7V cell, 2S = 2 x, etc. "P" stands for "parallel" if you ever run across it.
The amount of current used to charge with (and hence the charge time) is only manually adjustable for NiMH batteries on that charger. LiPOs are done with an automatic CC-CV setup using 0.3A to 3A.
Also, between those chargers, I'd get the last one. It has flexibility between battery chemistries, and as you noted, the first one will take fooooooorehhhhhhvah.
Yea, I also love the last one. The NiMh are out of question now as I need up to 10A of current and NiMh fail to provide it. So LiPos all they way. I was first startled from the prices you get in germany but seeing that banaking has 5400 for 18€ Iam in heaven now.
