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Tramp
- Suzuki, will you marry me?
- Posts: 2828
- Joined: Fri Jul 25, 2008 10:09 pm
- Location: Rotherham - South Yorkshire
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by Tramp » Mon Nov 12, 2012 1:17 pm
ScottieJ wrote:Edweird wrote:
What's involved in a LiPo conversion? I don't really know much about them. Don't fast chargers shorten the life of the battery?
Buying a lipo and lipo charger
and a lipo sock to charge the battery in. yes they are volatile but it's very rare for them to actually explode.
You need to check that your ESC is lipo compatible too, as lipo compatible esc offer voltage cut off protection to stop you over discharging your lipo battery pack, the alternative to this is a lipo low voltage alarm which sets a buzzer off when you need to charge your pack
Some battery trivia for you
Nimh & nicd are made up of 1.2v cells, generally 1:10 scale use stick packs of 6 cells which make volts 7.2v, lipos use cells of 3.7v, a traditional stick pack will be made of x2 cells which give 7.4v, in lipos the amount of cells is given in the S number ie 2s for a 7.4v 2 cell pack, the mah is your capacity, ie how many amps you can get out of it before its discharged (so the higher the longer your run time) then there is the C number which tells you what percentage of the battery capacity can be used instantly, people call it punch but it just means that if you have a fast motor that the battery can give up its power instantly, but it depends on your mah rating, cheaper batteries have a lower c value, I have a 30c lipo which works well in a 1:10 care running a 13t brushed motor
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Edweird
- Suzuki, will you marry me?
- Posts: 2531
- Joined: Sat Jan 23, 2010 11:04 pm
- Location: Brigg, North Lincolnshire
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by Edweird » Mon Nov 12, 2012 4:42 pm
Yeah, I understand about the capacity of batteries, speaking of which, Scott, that LiPo on eBay is only 460mAh. My NiMH ones for my MLST2 are 1100mAh. What's going on there?
The standard ESC on my Losi MLST2 seems to have a low voltage cut off. After you've been running it for about 15/20 minutes it will just stop dead and it has a little red light that blinks. I wouldn't be surprised if, as they are both 1:18, that the MRC and MLST2 shared their ESC and other bits.
If I was going to do a battery conversion I would probably change the battery connector on the car to a Tamiya one, as they are pretty much THE standard in the UK. It would make getting batteries much cheaper.
There's three ways of doing things:
The right way,
The wrong way
And my way, which is like the wrong way but faster.
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ScottieJ
- The Boss
- Posts: 11620
- Joined: Tue Apr 15, 2008 12:13 pm
- Location: Chippenham, wiltshire
Post
by ScottieJ » Mon Nov 12, 2012 4:52 pm
Size
I could run a bigger ah battery but wanted something tiny, it's smaller than a matchbox.
Mines mostly used as a crawler, and there isn't much room for all the electrics
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They are so cheap and quick to charge that it doesn't bother me. Also remember these spend most of there time going slow so don't drain that battery very fast
I use deans for all my rc cars. Tamiya ones always used to melt together I found.
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Edweird
- Suzuki, will you marry me?
- Posts: 2531
- Joined: Sat Jan 23, 2010 11:04 pm
- Location: Brigg, North Lincolnshire
Post
by Edweird » Mon Nov 12, 2012 5:58 pm
Slightly daft question, but do you think your Losi SJ can do 7mph Luke?
There's three ways of doing things:
The right way,
The wrong way
And my way, which is like the wrong way but faster.
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Tramp
- Suzuki, will you marry me?
- Posts: 2828
- Joined: Fri Jul 25, 2008 10:09 pm
- Location: Rotherham - South Yorkshire
Post
by Tramp » Mon Nov 12, 2012 7:13 pm
No way, I'd estimate 2-3mph at most, its really slow!
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ScottieJ
- The Boss
- Posts: 11620
- Joined: Tue Apr 15, 2008 12:13 pm
- Location: Chippenham, wiltshire
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by ScottieJ » Mon Nov 12, 2012 7:59 pm
Here you go Ed this how's how little space I have for all the electrics on the original chassis. hence why it's a bit of a rats nest. There's a receiver, external bec, low voltage buzzer and speed controller all squeezed in around the transmission. I didn't want any of it on the suspension links like some people do.
This little battery does last around 25mins, maybe more I haven't actually timed it to see though.
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Tramp
- Suzuki, will you marry me?
- Posts: 2828
- Joined: Fri Jul 25, 2008 10:09 pm
- Location: Rotherham - South Yorkshire
Post
by Tramp » Tue Nov 13, 2012 7:32 am
Edweird wrote:
The standard ESC on my Losi MLST2 seems to have a low voltage cut off. After you've been running it for about 15/20 minutes it will just stop dead and it has a little red light that blinks. I wouldn't be surprised if, as they are both 1:18, that the MRC and MLST2 shared their ESC and other bits.
If I was going to do a battery conversion I would probably change the battery connector on the car to a Tamiya one, as they are pretty much THE standard in the UK. It would make getting batteries much cheaper.
Yeah it will have a battery volts cut off (My MRC ESC does too) but it will be set for nimh batteries which has the cut off lower than lipos (if the lipos discharge that much they become permenantly damged) I've had a look at the esc's for both and they are different but only slightly I imagine the MLST2 will handle more current as its controlling the power for two motors (it also has the wiring to accomodate two motors) wheras the MRC one only has to operate one 280 sized motor
Tamiya plugs are easy to get hold of and are guud in there own way (ie compatibility) but what I don't like is how the male centers can move out of line and stop the plug going together, also they don't always make a fantastic connection, like scottie on all my 1:10 cars I've fitted deans ultra T's because they are just better, in my MRC I've left it the standard connection so I don't have to cut up my ESC power cable to fit new leads
I don't physically know how big your MLST2 is but I imagine if its 1:18 the suzuki body will sit on it quite comfortably, I also think you could get softer springs if you wanted better articulation to make it look more 'real life' but it certainly doesn't have to be fantastic as SJ's arent great!
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Edweird
- Suzuki, will you marry me?
- Posts: 2531
- Joined: Sat Jan 23, 2010 11:04 pm
- Location: Brigg, North Lincolnshire
Post
by Edweird » Tue Nov 13, 2012 1:11 pm
Tramp wrote:I don't physically know how big your MLST2 is but I imagine if its 1:18 the suzuki body will sit on it quite comfortably, I also think you could get softer springs if you wanted better articulation to make it look more 'real life' but it certainly doesn't have to be fantastic as SJ's arent great!
The trouble with the MLST2 is that it's got fully independent front and rear, like a Freelanderp.
My reason for asking about speed was that scale wise 7mph would be equal to 70. I could maybe put a bigger pinion gear on if I wanted.
Hopefully I should be able to get this done within the next year or so, because my insurance for next year is looking like it's going to drop from £2000 to about £600. I'm going to talk to 2gether and see if they can hook me up.
There's three ways of doing things:
The right way,
The wrong way
And my way, which is like the wrong way but faster.