|
Title: Help me with lead acid batteries. Post by: coeprobotics on April 23, 2010, 09:31:21 AM Hi,
I'm doing a qaudrotor project for which I'm using 4 Emax CF2812 motors with 7*6 Propellers. It draws 10 A current to provide 200 g thrust. As i'm doing it on prototype basis, I'm doing a WIRED version. So I can provide the supply through any ground based power source. I tried : 1. Laboratory Power Supply (NO sufficient current) 2. SMPS (Voltage drops) 3. LEAD ACID BATTERY (10Ah) --- > this proved satisfactory but for 1 motor voltage drops down in 1 min. 4. LEAD ACID (60Ah) ---> this can provide 10 A for 5 min w/o dropping voltage but for 1 motor. So I'm a bit worried if i use 4 motors it won't stand longer... About using Lipo--> I'm unsure about the performance and price is also high... So can u suggest if I can use lead acid or is there any other power source for WIRED prototype... Title: Re: Help me with lead acid batteries. Post by: anwar on April 23, 2010, 03:30:09 PM There is a reason why lipos are preferred for such applications, their high discharge capability. And your setup is complicated by the fact that there are 4 motors to deal with.
Is there no way you can go for lipos ? They have become somewhat affordable lately. I assume you are talking about 10A for each motor, and not 10A in total. Lead acid batteries tend to have the AH at the good price, but do not work well when it comes to continuously providing high current (high discharge). Title: Re: Help me with lead acid batteries. Post by: ankur on April 23, 2010, 07:44:03 PM firstly i think u should use lipo batteries as said by Mr.Anwar..
and abt the cost pat.. i dont think its too expensive-as the 60Ah battery costs no less than rs5000 in which 4 lipos to power individual motor of ur quadrotor can bought... u can easily experiment with nicd/nimh batteries of different sizes but the best will be lipos.. some links to lipos u can chose whatsoer u wish according to ur requirements...... http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6518&Product_Name=ZIPPY_Flightmax_2200mAh_3S1P_15C http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6540&Product_Name=ZIPPY_Flightmax_2200mAh_2S1P_20C http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6472&Product_Name=Zippy_Flightmax_1000mAh_2S1P_15C http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6293&Product_Name=ZIPPY_Flightmax_1800mAh_3S1P_20C Title: Re: Help me with lead acid batteries. Post by: coeprobotics on April 23, 2010, 11:19:03 PM Sir problem with lipos is
1. its high cost i.e. around 5000-8000 Rs 2. they are very delicate to handle, i.e. if there is any wrong connection by chance, my lead acid battery can survive but lipos can't. 3. I don't have lipo charger etc. so i would have to buy that. 4. I have 65Ah lead acid battery with me. but still i'm 50 - 50 about lead acid and lipo.... Title: Re: Help me with lead acid batteries. Post by: izmile on April 24, 2010, 12:10:28 AM If you are looking for an appropriate outboard power source then I have a suggestion:
Use a 400W - 500W PC ATX SMPS. The modern P4 SMPS have a +12V supply for the processor which could supply +12V at about 15A continuous and probably about 25A peak. Visiting an old computer junk yard would be good idea. Look for the specification on the SMPS before you buy any. -Ismail Title: Re: Help me with lead acid batteries. Post by: sunk? on April 24, 2010, 03:26:21 AM hi mate
regards to lead acid battery.......... high discharge batteries are as used in wheelchairs etc they usualy come in 10/12/14/ ah and about the size of motorcycle batts..........6 or 12volt if it is the same motor that keeps cutting, check the 'low power cutoff' setting for the esc on that motor regards don Title: Re: Help me with lead acid batteries. Post by: akky on June 24, 2010, 01:19:52 AM Ankur i advise u to use 8 2100 mah uniross AA batteries arrange them in packs of 4 celll ..make 2 such packs..u get 4 AA battery case so go for it..u will get a good amount of power :thumbsup:
Title: Re: Help me with lead acid batteries. Post by: Rao on June 24, 2010, 03:04:27 AM Ordinary AA sized Ni-Cd/Ni-mH batteries could not provide 10Amp or more amp current. For such high discharge currents, high discharge capable and bigger size batteries like A and Sub-C size are more suitable. Also 4 cell battery packs/4.8 volts could be too low to power the mentioned motors.
Title: Re: Help me with lead acid batteries. Post by: vinay on June 24, 2010, 09:30:52 AM 4. LEAD ACID (60Ah) ---> this can provide 10 A for 5 min w/o dropping voltage but for 1 motor. Either you are measuring wrong or the battery is old and dead. I can fly a HK450 Heli for hours in 60 ah 12V(if it was possible :D). In fact, I get 8+ mins of flight on a 2.2 ah 12 v lipo. And I am speaking of motor consuming 200 to 300 watts at FFF. Title: Re: Help me with lead acid batteries. Post by: akky on June 25, 2010, 01:17:25 AM the four 2100x4 mah 6 volts battery pack is good from school projects...but not for rc....for rc lipos have no competitor....they are the best
|