TOPIC:

I just tried a 1S Lipo battery in a vintage Holiday Buggy with a 540 Motor with mixed results ... on carpet or concrete it's not too bad, a scale crusing speed you could drive around all day at not crash (or not do any damage when you do) - I'm not sure exactly how fast, I'd guess at least 5mph but a lot less than 10mph.

On grass though, it was completely hopeless, slowing to a halt in about 3 metres with the motor stalled. It could well be better with an ESC (rather than a heavily worn wirewound MSC) but I wouldn't guarantee it.

I wouldn't say Lipo-ising 6v packs with a 1S cell was a complete waste of time, but I don't have a regular need to drive old cars very slowly on a smooth surface...

Is there room to get 2-off 1S in there, wired in parallel? - the extra "available" current might help? - wattage doesn't necessarily need to be made up with volts, but it's also likely the varistor MSC & 27t motor are restricting the flow of beans

HI!... Why go with a 1S set-up? They make small enough 2S set-ups that are 1800- 2400mAh's that would easily fit. Or you could go with a Life style battery . They are closer to 6volts if that's what you want.

I'm guessing it's a quest for scale speed without loss of guts, without having to modify the car, & have a modern-spec battery that looks like a vintage original. I'm sure there's a reason for going 1s rather than 2s.

Only problem I foresee could be low voltage radio problems/shutdown if someone decided to use it in a BEC setup

Non-existant user wrote:

HI!... Why go with a 1S set-up? They make small enough 2S set-ups that are 1800- 2400mAh's that would easily fit. Or you could go with a Life style battery . They are closer to 6volts if that's what you want.

eddrick wrote:

I'm guessing it's a quest for scale speed without loss of guts, without having to modify the car, & have a modern-spec battery that looks like a vintage original. I'm sure there's a reason for going 1s rather than 2s.
...

Well it did turn out to be a mistake - but I still don't think my reasoning was that flawed, well, most of it ...

- Lots of people have reported how much faster a car goes with a 2S Lipo than a 6 cell Ni-Cd/NiMH; much faster than the 0.2V increase in nominal voltage would suggest;

- If you're putting a 6v sized pack in a car, then you're expectingly to go slowly - and if a 2S pack is faster than a 7.2v Ni-Cd, it's going to be too fast for a speed equivalent to using 6v;

- The only lower voltage Lipo choice is 1S ... I knew they are being used in 1/12 indoor racing, but it didn't occur to me - although in hindsight it probably should have done - that it would be inadequate in a bigger, heavier car, off road

- I did look at "LiFe" batteries (at least through Hobbyking's UK warehouse), but although the tiddlers are comparable in price, they all are described as RX (or sometimes TX) packs & the cables/connectors are inedaquate for a drive battery; better appointed "LiFe" packs are far too long to fit inside the Tamiya cases




I'm not convinced about trying two 1S cells in parallel, the units I have are 2200mAh, 20C packs - so theoretically deliver up to 44A - so I don't think the Amperage can really be the problem, the fuse would have gone or the wiring melted if the motor was pulling that much



Overall, I still don't look at it as a failure - the 2S hump packs have worked out quite well

Not really clued-up on LiPos, the only experience I've really had with them is that you have to buy 8x duff ones before you score one good enough to make the heli fly, & that they improve drastically after the first couple of charge/discharge cycles.

All I can tell you about LiFe is that old laptop batteries use them, you can't buy the separate laptop battery cells privately to repair the packs & that whoever came up with LiFe as an abbreviation for Lithium-Ion, needs a good kicking. I suspect their capacity to size/weight ratio &/or discharge rate might be less than LiPo, I can't think of another reason why laptop manufacturers ditched them in favour of LiPo. On the upside, they seem to have a longer less fragile life, & aftermarket ones usually work before you've sent them back 8 times.

I still say go overboard & stick one of them fuel cells in there!

Oh & I was so affected by the iPhone battery experience, I almost forgot - aftermarket LiPos for iphones are also a minefield to be avoided

HI!... The reason a 7.4 volt LiPo seems way faster than a 7.2 volt NiMh is that when a 7.4 volt LiPo is fully charged it actually reads 8.42 volts. At least all my LiPo's do on my charger and on a volt meter. I have like 20 of them.

Non-existant user wrote:

HI!... The reason a 7.4 volt LiPo seems way faster than a 7.2 volt NiMh is that when a 7.4 volt LiPo is fully charged it actually reads 8.42 volts. At least all my LiPo's do on my charger and on a volt meter. I have like 20 of them.

That's not it all - a fully charged 7.2v NiMH pack delivers a similar figure:

Look that Jonny you can be interested.
www.ebay.fr/itm...43b9148966