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-   -   Advantage of running 5 cells (http://www.oople.com/forums/showthread.php?t=5507)

delanobe 24-09-2007 12:41 PM

Advantage of running 5 cells
 
The title says it all :wtf:

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 24-09-2007 01:01 PM

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 24-09-2007 01:23 PM

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?? :wtf:

josh_smaxx 24-09-2007 03:01 PM

Are you allowed to run 5 cells in BRCA events?

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

notlawnomis 24-09-2007 03:18 PM

Duration, depending on the track of course??

delanobe 24-09-2007 03:19 PM

For the Belgian / Netherland championship it's allowed.

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

Thanks

tc2k 24-09-2007 03:20 PM

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

delanobe 24-09-2007 03:21 PM

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 24-09-2007 03:23 PM

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

PaulRotheram 24-09-2007 03:25 PM

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

jimmy 24-09-2007 03:27 PM

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

Northy 24-09-2007 03:31 PM

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

David Church 24-09-2007 03:40 PM

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 24-09-2007 04:46 PM

Quote:

Originally Posted by delanobe (Post 61535)
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 24-09-2007 09:56 PM

what about the guys running smaller motor wires?
 
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 24-09-2007 11:08 PM

Quote:

Originally Posted by tc2k (Post 61534)
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 25-09-2007 07:17 AM

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 25-09-2007 07:34 AM

Quote:

Originally Posted by josh_smaxx (Post 61524)
Are you allowed to run 5 cells in BRCA events?

not for 12th scale that's 4 cell only :D

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

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 25-09-2007 11:37 AM

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 25-09-2007 11:39 AM

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

No problems if you do that.


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