Battery Upgrades?
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PandaBear.
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October 20, 2003 at 2:06 am #11421
I already know changing a battery can give you better run time. But will certin batteries increase the amount of current being drawn by the motor (ie. make the car go faster)?
If so what batteries have people used to get good results?
SMP -
October 20, 2003 at 2:06 pm #27885
SMP, the way to increase the current going to the motor is to increase the voltage, that is what doing a dual cell mod is all about, the increase of the voltage to the motor.
But, (theres is always a downside), the extra weight of the second cell stops the car handling as good as it did as a single cell car.Another option is a Lithium polymer cell, these are light as a single cell, and are 3.7volts (roughly 150mAH) so its like having a triple cell car in the weight of a single cell. BUT (and this is a big downside), you need an expensive charger to recharge it as the LiPo cells are VERY sensitive, and if you charge them wrong they go into a coma and never return. And at around AU$12 each for a cell it can get expensive to kill these.
Another option, (the best option so far) is to FET mod the cars electronics. This allows more current to flow to the motor without the need for the second cell, and it can still be charged on the original controller.
Just while we are on batteries, did you know that the controller only puts about ONE TENTH of full charge in to the cell in a BCG. So much better run times can be achieved by charging multiple times. Each charge delivers a little less than the charge before it, but theses cars can be charged up to 8 times, easily. Or the ultimate is using a delta peak charger to completly fill the cell to 100% full.
A full (original) 50mAH cell will run for about 20 minutes, so there is really no point changing the cell to a larger one if you arent filling the one you have in the car anyway.So there you go.
:)uAEdited by – micro_Amps on 20 October 2003 10:08:50
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October 20, 2003 at 3:03 pm #27895
“the ultimate is using a delta peak charger to completly fill the cell to 100% full”
where can i get one of those chargers?
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October 20, 2003 at 4:40 pm #27898
Most hobby shops sell delta peak chargers, just be sure to mention the small size of the cell you want to charge, some chargers only charge larger cells.
Also try Jaycar and Dick Smith Electronics, (if you are in Australia) they also sell similar chargers.
:)uA -
October 20, 2003 at 9:19 pm #27900
You are a wealth of information Micro.
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October 20, 2003 at 11:00 pm #39118Quote:Most hobby shops sell delta peak chargers, just be sure to mention the small size of the cell you want to charge, some chargers only charge larger cells.
yup!
Most hobby chargers will only do minimum 4 cell packs, and
some that can do single cells with adjustable current will
only go as low as 500mA.0.5A is probably a bit high for your little bitty 150mAh cell. :dead:
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October 21, 2003 at 2:45 am #27236
If you are fairly electronically advanced you can make you own delta V charger for real cheap (i spent about $AU10 on parts). This can be fully customised to work with 1 to 26 cells and charging current for C/4 to 4C. I have set mine to switch off at -5mV and it works fine for these small cells. It does not get false reading from the car circuitry as it supplies the circuitry as well at the batt. Use the MAX712 or MAX713 chips. They will GIVE you 2 sample chips for NOTHING. thats right, nothing. you don’t pay shipping or anything. The chips retail for around $25ea on rs components and that excludes GST. Just an idea for the techies out there.
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October 21, 2003 at 2:45 am #27538
If you are fairly electronically advanced you can make you own delta V charger for real cheap (i spent about $AU10 on parts). This can be fully customised to work with 1 to 26 cells and charging current for C/4 to 4C. I have set mine to switch off at -5mV and it works fine for these small cells. It does not get false reading from the car circuitry as it supplies the circuitry as well at the batt. Use the MAX712 or MAX713 chips. They will GIVE you 2 sample chips for NOTHING. thats right, nothing. you don’t pay shipping or anything. The chips retail for around $25ea on rs components and that excludes GST. Just an idea for the techies out there.
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October 21, 2003 at 2:51 am #27237
Ads, I’m so with you there dude. Hell I’ve just gone and bought probably the same components from dickies. Hope to have it up and running soon.
ph2t.
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October 21, 2003 at 2:51 am #27539
Ads, I’m so with you there dude. Hell I’ve just gone and bought probably the same components from dickies. Hope to have it up and running soon.
ph2t.
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October 21, 2003 at 5:00 am #27243
Good stuff guys, could be marketing oportunity in that for you. I’m sure plenty of people would like a BCG charger that delta peaks.
:)uA -
October 21, 2003 at 5:00 am #27545
Good stuff guys, could be marketing oportunity in that for you. I’m sure plenty of people would like a BCG charger that delta peaks.
:)uA -
October 21, 2003 at 11:58 am #28670
can someone make me one? i’m in the USA.
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October 21, 2003 at 12:03 pm #39115
one thing I didn’t say was where to get the free ones…duh. you get the 2 free samples from http://www.maxim-ic.com they are the manufacturer. I am thinking about getting there LiPo chip so I can do the 3.7v mod.
ph2t, can you get the delta v chips from dicko’s or are you just talking the circuit components??
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October 21, 2003 at 1:26 pm #27165
nah dude, I got ’em from maxim as well :approve:.
I got 4 of each 712 and 713. 2 in the DIP package and 2 in the SMT package.
Hey Ads, I just wanna say welcome to the forums and it’s good to have another techo!
Lets start a new thread on this charger man, I gots some development questions for you.
ph2t.
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October 21, 2003 at 1:26 pm #27467
nah dude, I got ’em from maxim as well :approve:.
I got 4 of each 712 and 713. 2 in the DIP package and 2 in the SMT package.
Hey Ads, I just wanna say welcome to the forums and it’s good to have another techo!
Lets start a new thread on this charger man, I gots some development questions for you.
ph2t.
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October 21, 2003 at 2:18 pm #27168
uA, which Li batts you using and from where?
ph2t, sure thing dude, just hope I can help as i am only new the whole Bit thing! I really want to get a nice developed Li charger and possibly a microcontrolled multichem charger:shock:
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October 21, 2003 at 2:18 pm #27470
uA, which Li batts you using and from where?
ph2t, sure thing dude, just hope I can help as i am only new the whole Bit thing! I really want to get a nice developed Li charger and possibly a microcontrolled multichem charger:shock:
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October 21, 2003 at 3:58 pm #27091
Ads, I’m using the 145mAH LiPos that Tiny RC are selling, at about US$6.95 (i think) the price is not bad. Also their postage is flat rate per package.
I have also bought from Plantraco for some larger cells (550mAH) but they are more expensive. The TinyRC LiPos are from plantraco anyway, but they sell cheaper than Plantraco does.
:)uA -
October 22, 2003 at 12:50 pm #26796
I’d like to see the schematic, the design, and the finished product of a charger that can provide a timed charge to perfectly charge 4 (or with the new SBCGs up to 10) BCGs at once. Just put the cars on, press a button to start the charge, and take the cars off once the light goes off to say they’re all ready to go.
This way all people having a race would have fair and equitable starting point, so it’s be down to drivers skill, car tuning, and perhaps little differences in motor quality (assuming they’re all rated the same).
I could work it out if I had the time, but I don’t.
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October 22, 2003 at 1:34 pm #26801
Davef, this charger IC can do that. I will start a new thread for development shortly. :approve:
ph2t.
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October 22, 2003 at 2:09 pm #26803
Dave, the trouble with going to lots of cars on the one charger is the AC/DC transformer. Unless you are happy to put them on for a couple of hours (which most of us are too impatient to do) you will need a pretty big trans. For instance, you want to charge 4 150mAh bats in 30mins you will need a trans capable of at least 1.6A. For 10 cars thats at least 4A! Allowing for some losses!
As for a timed charge, my first Bit CharGer was a timed current reg with LED countdown timer. This is a very simple circuit and I will post a pic later when I get home. Might be more what you want for same charge in many cars.
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October 22, 2003 at 2:32 pm #26805
Hey Ads, I believe it could still be done man. The circuit allows for batteries to be put in series and the delta-peak changes to account for that. From what I got from the datasheets anyway. The issues are that all the car’s batts would need the same mAh rating and you need to be able to switch the IC’s sensing to account for 2, 3, 4 cells/cars and so on.
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October 22, 2003 at 3:59 pm #26671
Yes you are right. The fact that they all need to be the same is the problem. I know my racing buddies all have different setups so I was only thinking parallel charge. sorry for any confusion.
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October 22, 2003 at 5:34 pm #26676
That’s cool.
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October 22, 2003 at 6:57 pm #26679
As promised, my first current reg charger.
Presetable countdown timer (via DIP’s), charge/discharge switch, variable current, ammeter, auto off with buzzer and indicator light. Has cooling fan as I only used small heat sinks.
This is NOT the delta V charger but a simple timed current regulator!
p.s. Thank you uA for you FET mod site (as you can see this lxx is FET modded). Wouldn’t have done it without your explanation.
Cheers – Ads
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October 22, 2003 at 7:18 pm #26689
Wow dude, that’s freakin mad!:p
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October 22, 2003 at 8:00 pm #27989
That is the coolist thing ever Ads. You have a huge market just waiting for somebody to start selling those things…
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October 22, 2003 at 9:08 pm #26644
At about $AU35 to $40 (without meter which costs an extra $28) it is not the cheapest thing. I am going to make a few for some mates who just want a set charging rate for like $15. I am keen to get my Li cells and make up a similar charger with the MAX chips. I am going to need some help since there is like 3 types of Li cells!
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October 23, 2003 at 5:11 am #26670
No problem Ads, always happy to help, nice work on the charger too BTW.
LiPo / LiIons come in 3.6 and 3.7 volt cells. The most important part is to have the charging settings correct. Constant current up to 4.2v and hold at 4.2 until charging current reduces to zero.
Maximum recommended charging current is 1C, but I have seen 2C with out problems, ANY heat when charging is over charging, so reduce current.
A good LiPo/NiMH/NiCd combo charger is a real asset.
You probably know all this stuff anyway
:)uA
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