Advantage of running 5 cells

[delanobe]

The title says it all

At our club a lot of guys are running 5 cells instead of 6 with a 5.5, 4.5 or 3.5 brushless and are very quick!

What are the advantages or negatives of this combo?

Less weight is a big + but what else??

Thanks

[Southwell]

Less voltage is the main advantage, it helps on tracks with low grip.
In 4wd most people run 5.5's and in 2wd 6.5's. 4.5 and 3.5 are way too fast for most tracks.

[delanobe]

Just did the calculation compared with 6 cells.

If you use 5 cells with a 4.5 it has a bit more watts than a 5.5 with 6 cells and 70gr less weight. Only good things?

Am I missing something negative with the 5 cells??

[josh_smaxx]

Are you allowed to run 5 cells in BRCA events?

If yes then i cant see any negative with running them.

[notlawnomis]

Duration, depending on the track of course??

[delanobe]

For the Belgian / Netherland championship it's allowed.

Isn't it allowed in the UK or for the European championship??

Thanks

[tc2k]

Actually, I heard somewhere that less cells mean less current draw so longer duration

[delanobe]

I "think" the duration is exactly the same cause it's still 4200mah.

The only difference is that we are not running on 7.2V but on 6V. This "should be compensated by running a 4.5 instead of a 5.5.

[Kopite]

Has anyone tried 5 cells and a 4.5 in off road?

[PaulRotheram]

Think you'l be the first to try this weekend stan hahaaaa

[jimmy]

I think Craig Drescher ran 5 cells and 4.5 in his AE B44 at the World Championships.

[Northy]

I ran 5 cells at Bury National this last year in 2wd.....

[David Church]

Craig did run 5 cell at the worlds. In fact, people have been doing it for a while. This was in his 4wd.

[super__dan]

Originally Posted by delanobe

I "think" the duration is exactly the same cause it's still 4200mah.

The only difference is that we are not running on 7.2V but on 6V. This "should be compensated by running a 4.5 instead of a 5.5.

Duration should be the same, but usually 5 cells and faster motor is slightly less punchy that normal 6 cell so people throttle jam a little more which leads to less duration.

I tried 5 cells without changing anything else at all last year and it was quite good, something I said I'd use in the wet in 2wd, but never did though, just used old cells instead

[dancoog]

can anyone fill me in on this?
5 cell brushless, smaller wires?
seems a lot of new things were tried at the worlds.
any feedback on things to come or what works?

[terry.sc]

Originally Posted by tc2k

Actually, I heard somewhere that less cells mean less current draw so longer duration

Depends. For the same motor running on 5 cells instead of 6 means less current draw so more duration, but the lower voltage means less speed as well. So you bolt in a faster motor to get the speed back and so reduce the duration.

At the 2005 Worlds Neil Cragg ran 5 cells to win the finals. The low grip surface meant drivers were using fairly mild motors and he qualified using 6 cells and a 14x2 motor, which was changed to 5 cells and a 12x2 motor for the finals. It was smoother but Neil didn't notice the difference between the two different setups.

[mark christopher]

no matter what the capacity will still be 4200 on a ib4200 cell irispective of the amount of cells in the pack when in series configuration,
as a lower wind motor is used to maintain the speed, if anything it smooths the power making the car more drivable and reduces weight

[Chequered Flag Racing]

Originally Posted by josh_smaxx

Are you allowed to run 5 cells in BRCA events?

not for 12th scale that's 4 cell only

but as this is forum is 1/10th Off-Road based, the BRCA section rules say,

25. BATTERIES
25.1 Cars will be driven by a maximum of six
rechargeable cells, which cannot be replaced
after a race has started.

25.2

The description, specification and types of

rechargeable batteries approved for use in Off-
Road Sanctioned events can be found in the
section entitled ‘BRCA Electric Board’ (EB).
25.3

Cells can only be used if they are included

on the BRCA (EB) homologation list at the time
of the event.
25.4

Entrants must be prepared to open packs

on demand of the race Scrutineer to demonstrate

the eligibility of the rechargeable batteries.

[DaveG28]

This has me intrigued, as someone running a 4wd thats nearly 200g over the weight limit!

So a 5 cell will have same duration but less speed, which can be got round by having a faster motor (which will lower duration again!)? Does anyone know how that balance ends up, eg net win or loss!?

On a techy note, how do the chargers cope with 5 cells, does the voltage change throw them out of whack? ie I have an orion advantage charger!?

Dave

[delanobe]

For the charger you must select 5 cells in the set up instead of 6.

No problems if you do that.