I've ordered some LiPo's to experiment

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I've ordered some LiPo's to experiment

Postby schoey » Wed Oct 22, 2014 8:47 pm

So I thought I'd start the ball rolling with the LiPo experimentation, I've ordered a 2S LiPo and a buck regulator. At this stage it probably won't fit 'under the hood' but some double sided tape will sort that out.

Anyone here that this isn't gibberish to? Anyone played with buck regulators (dc-dc converter)? It would be good to bounce ideas around. At this stage I've made the assumption that the 3 cell AAA's are in series therefore 4.5V, I'll hook the 7.4V LiPo to the buck regulator and dial it into 4.5V, do some heat stress tests and see if I can wind it up a touch, then see what kind of run time is achievable, then re-order LiPo to fit in battery bay if correct form factor and size is available. Hopefully heading towards longer or the same at least run times, quicker charging, and the ability to bump up the volts.

Depending on interest (and my success)I'm happy to go into more detail. I'll test on one of my cars and when I'm sure I won't fry it I'll share the set up.
Can't wait for my Pro Racing Set Ultimate + Pro-Racing Track Upgrade...

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Re: I've ordered some LiPo's to experiment

Postby martin » Fri Oct 24, 2014 3:05 am

I like that idea (had to look buck regulator first though). Question: will that just supply 4.5V until the Lipo's are dead? in other words no warning of low battery and car might stop on the track? A buck with a lipo battery level LED status would be nice.
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Re: I've ordered some LiPo's to experiment

Postby schoey » Fri Oct 24, 2014 6:44 am

martin wrote:Question: will that just supply 4.5V until the Lipo's are dead?.... A buck with a lipo battery level LED status would be nice.


Yes, but you tend to just use lipos differently (or I do at least), they don't mind being constantly topped up and don't like to be stored full/empty so you get used to just using them to the halfway point, the packs are relatively cheap so if I'm flying my quad copter I just go outside with 3 in my pocket and one in the quad normally that's plenty of flying time but if you're really keen you just come back in and rotate them through the charger. With Real FX I'd suggest just one on the charger one in the car should do and you just change after 'x' number of laps, the less you have taken out of a pack the quicker it tops up anyway.

With different current draws you soon work out how many packs you need ie higher current draw set ups need more packs in rotating to allow for the charging cycle.

This all may be a bit of a waste as I trust that the stock set up works, it's just hard to get my head around as in RC cars/planes alkaline was replaced 15? years ago by NiCD and improved soon after with NiMH, and these days no one even bothers with anything but LiPo.
Can't wait for my Pro Racing Set Ultimate + Pro-Racing Track Upgrade...

Yep 2 x flyovers :-) !!!
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Re: I've ordered some LiPo's to experiment

Postby dvs-626 » Thu Oct 30, 2014 3:03 pm

Id be interested to see how you go with this.
I don't mind tinkering with stuff as well, although i can never guarantee they come out of it working :D
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Re: I've ordered some LiPo's to experiment

Postby Pyrofer » Wed Dec 10, 2014 11:47 pm

I was also thinking of using LiPo cells. Any decent cell has a battery protection circuit so the biggest worry is going flat during a race, which to be honest isn't the end of the world.
Most Dc2Dc buck regulators do either 3.3v or 5v, so would need a custom circuit or a mod to an existing one unless the car runs fine on 5v. I doubt that, but the guys that made them could comment?

I have my cars now, Not had a chance to play yet though.
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Re: I've ordered some LiPo's to experiment

Postby Racingben » Sun Dec 14, 2014 11:00 pm

I've thought about it but to be honest can't see the point. You could modify the battery bay and fit in a 250-300 mah lipo but for pennies you can buy 900 mah LSD - low self discharge NIMH from hobbyking. I was thinking about running a single cell lipo

There's not a lot of spare space by the looks of it so a 2 cell will have to be very low capacity!
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Re: I've ordered some LiPo's to experiment

Postby Racingben » Sun Dec 14, 2014 11:01 pm

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Re: I've ordered some LiPo's to experiment

Postby schoey » Sun Dec 14, 2014 11:32 pm




These are the rechargables I have and recommend to others, what I hope to gain out of the lipos is a solid 4.5V (or possibly even over, if it can handle it) via 2 cells and a regulator rather than 3.6V max out of the rechargables. My starting point won't fit in the battery bay and may be a bit ugly but that's cool, I don't mind running without a body shell with the battery/regulator velcro'd on top.

I should have mine delivered in the next day or two so I'll post results and see if there is any real difference in speed.
Can't wait for my Pro Racing Set Ultimate + Pro-Racing Track Upgrade...

Yep 2 x flyovers :-) !!!
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AAA Li-Ion 3.6v 500mAh in parallel

Postby DanBriggs » Fri Nov 06, 2015 3:55 am

Would modifying the battery compartment to connect these AAA Li-Ion batteries in parallel work?( http://www.all-battery.com/aaa1000mahte ... ttery.aspx )
Would a further mod to allow the batteries to be charged in the car be feasible or should I just do a nightly swap with the cells in a charger?
Or should I just get these 1000mAh NiMHs (http://www.batteryjunction.com/aaa10hicanir.html) ? It seems I can get 50% more run time just by adding simple jumpers to ues the Li-Ions in parallel.
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Re: I've ordered some LiPo's to experiment

Postby DanBriggs » Fri Nov 06, 2015 4:03 am

Whoops, had the wrong link for the AAA Li-Ions. This is the right link, http://www.batteryjunction.com/10440.html
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