Batteries?

[bigu2fan]

I have a vintage Sand Scorcher with a Tamiya stock 540 motor. I'm using a Futaba MC230CR ESC.

My question is, what kind of 6 cell batteries should I use? I have seen a number of different types for sale, i.e. 7.2 volt 6-cell 2400mAh, Sanyo RC1500 6-Cell Flat Battery Pack, 6 Cell 1800 mAh Flat Battery , 6 cell, 3000mAh Nickel Metal Hydride Battery Pack. The list goes on and on.

Which voltage/mAh pack(s) can I use safely in my Scorcher? What did Tamiya recommend, and what will give the longest run times without damaging/stressing the gears and ESC? Thanks in advance for any help you can give.

--Will

willgreenlee@yahoo.com

[DJTheo]

The problem is that none of current 7.2V packs fit in the SS radio box, as it was designed for 6V or 7.2V hump back, that is a battery with the 6th cell on the top. The only one I know that fits is the special one sold with the Six Wheeler re-release, or better solder your own pack.

The higher the amperehours (capacity) the longer running time you have, the stress depends on the voltage, so I would choose a nice 3000-3300 mAh NiMH for LONG running times...

[bigu2fan]

Thanks for your response. I'm running my Scorcher without the radio box, so I don't have to worry about the hump back battery packs. I'm using a CRP or MRP (can't remember the proper name) chassis, which is wider at the rear than the standard Scorcher chassis.

Are you saying that as long as the voltage remains 7.2, I can use as high a mAh pack as I'd like? If so, do I have to adjust the quick/trickle charging time? Is the mAh number basically an indicator of the length of running time (assuming the voltage remains 7.2).

--Will

willgreenlee@yahoo.com

[mr_lister999.]

quote:Are you saying that as long as the voltage remains 7.2, I can use as high a mAh pack as I'd like?

id="quote">id="quote">

yup, thats right!

Don't forget to keep an eye on motor temperature though. The car was never designed with more than a 1200 pack in mind. should be fine with the standard motor but its worth a couple of checks on the 1st few runs.

quote:? If so, do I have to adjust the quick/trickle charging time?)

id="quote">id="quote">

i take it that you have a clockwork charger that has a dial that you select charger time? If you buy a ni-cd battery then just up the time accordingly. eg if 30 mins gives you a charged 1200 pack then a 2400 pack will take 60 minutes.

If you want a 3000maH or above pack get a reasonable peak charger as you must not over charge these or let them get HOT during charging. I don't know about slow charging these 3000mah plus packs as they are metal hydride cells and so are diffent from the normal ni-cd's and i am not up to date on the latest charging techniques of these.

quote: Is the mAh number basically an indicator of the length of running time (assuming the voltage remains 7.2).

id="quote">id="quote">

yup again. They are all proportional. a 2400 pack will last twice as long as a 1200 pack assuming all conditions are identical.

hope this is of help to you.

[snollan]

With my dealings with the fast electric boat guys. Like it's been mentioned her before a 2400 will last longer than a 1200. However the 1200 will "dump" fast thus the motor will run a little faster than a 2400. I found this to be true -BUT- the speed gained is so small compared to the ammount of run time lost. If you ever get a chance Moltech had some 2500 which are good cheep stick packs.

I pick up my loose cells from here:

http://www.battlepack.com/loosecells.asp

[bigu2fan]

Thanks very much for all the info!

I'm currently using a 1700mah battery pack that I bought at the local hobby shop. I don't think my charger can handle the Nickel Metal Hydride packs. I've been charging the 1700 pack for 15 minutes on my charger, which as you surmised is the "twist the dial to 15 minutes" variety. Should I be charging this 1700 pack for longer than 15 minutes? Also, what battery do you guys run in your vintage Scorchers/Rough Riders/Champs?

--Will

willgreenlee@yahoo.com

[stulec52]

Sean,

what you say is kinda true... BUT, if you only want to run for 5 minutes at a time, for racing maybe... then with the extra capacity you can gear a motor much higher for much faster speeds!!

Probably best off getting a nice matched pack of 2400's especially now that the top boys are onto 3300's the 24's a bit cheaper nowadays.

[TWO STAR]

i dont want to confuse you but what type of 1700 cells are you charging?,are they a sce ,scr or scrc type?.i use allot of 1700mah

batteries,in your staement you said your charging a 1700 mah battery pack for 15 min......do you know what your charger is putting out for amperage?,or is it just a timer?.if your charger is putting out 4-4.5

amps it should take about 17 -22 minutes to charge a pack.with a proper charger you can take a 1700 scr pack and get about 1900mah

@9.3 volts out of it.(powerflex charging).

[WillyChang]

General rule of thumb is that your battery pack will usually be "comfortably warm" to the touch when its finished charging. It should feel like the firstaid heatpacks from the pharmacy - nice cosy warm, not hot enough to burn. (The thermometer says 40-45degC.)

If its still "room temperature" then its nowhere near fully charged. You can afford to give it another turn, but keep watch on the temp especially towards the end.

If its "too hot to touch" (60degC+) then its definitely overcharged. Not good for cell longetivity!

[bigu2fan]

I'm using a Dynamite Mega 1 AC/DC charger. I almost exclusively charge by plugging it into my house outlet. The battery is nearly always just room temperature, as opposed to slightly warm to the touch, when it's finished 15 minutes of quick charging.

There is no indication on the battery pack about what type of cells they are, i.e. sce ,scr or scrc. There is no indication as to what the charger is "putting out for amperage." The manual does state that "The trickle charge rate is 100mAh."

--Will

willgreenlee@yahoo.com

[TWO STAR]

i think your doing the right thing...i wouldnt risk lenthening

your charge time...with no amperage readouts from the charger..if you wish you could buy or borrow a buddies ammeter(inductive pick up will work too)and try to get an amperage reading from your charger

if your really worried or curious....I know asroflight does sell a rc

modellers ammeter and its fairly cheap and very accurate.

[bigu2fan]

TWOSTAR:

Thanks for the help! I should have added that once I pulled out the manual it stated that 1500-1700 batteries should be charged 20 minutes. 1200-1400 batteries, if I remember correctly, should be charged 15 minutes. I guess it would have helped if I had read the manual :-). Chalk one up to my own ignorance. Thanks to all for the helpful insight and general knowledge on batteries. Now I know a lot more so I can make informed battery purchases in the future.

--Will

willgreenlee@yahoo.com

[DJTheo]

Yes, it was suspicious that your cells didn't get warm after charging, an indication that your batt isn't still full, which is bad as they have memory effects and need after special treatment to (and if) reach their old, full, capacity.

quote:if your charger is putting out 4-4.5

amps it should take about 17 -22 minutes to charge a pack

---

id="quote">id="quote">

A general rule of thumb, is charging time in mins = battery Ahs (for example 1.7)*60/chargers output in Amps * loss factor

Loss factor is 1.2-1.4 is because not all the charger energy is stored in the battery but some is lost as heat.

quote:However the 1200 will "dump" fast thus the motor will run a little faster than a 2400.

id="quote">id="quote">

This depends on the internal resistance of the cell (SCR, SCs, NimH have all different charcteristics)and its treatment (matching etc.) and not on its capacity, generally NiCds have more "boom" then NiMHs.

[nmunn]

does anyone no were to get the batterys at a good price i think they are type-c batterys in uk

[DJTheo]

Almost every local, online or ebay RC store has C-cells, just look and compare.

Cheers

[jimbo858]

sorry, but... I've got a noob question for everyone. is there generally a size difference between NiMh and NiCd battery packs? I just got some 7.2v 3300Mah NiMh batteries from Ebay and they're too big for my Tamiya trucks?

[mr_pushrod]

Size does often go up ever so slightly with capacity. I would try trimming the plastic endcaps and re-heatshrinking so they are a little thinner.

[nmunn]

found this link for bats what you rekon?

http://search.stores.ebay.co.uk/search/sea...1&submit=Search