Who's in to electric RC cars?

Mark A · 7 Feb 2012 at 17:39

Hmmm, I have that exact same charger and it charges my Vapex 7.4 and 8.4 3700mah batteries up ok.

Bear in mind that they're stated as being 3700 but are more than likely less than that anyway.

Sounds like either the charger of batteries are faulty.

Luke · 7 Feb 2012 at 17:45

Building Candy said:
A rule of thimb is to charge at 1 x the capacity, so your 3700's at 3.7 or thereabouts, between 3 and 4 amps is fine..

On the NX85 you linked to would that be best to run at 3.5a or 5a given my batteries are 3700mah?

Luke · 7 Feb 2012 at 17:46

Mark A said:
Hmmm, I have that exact same charger and it charges my Vapex 7.4 and 8.4 3700mah batteries up ok.

Bear in mind that they're stated as being 3700 but are more than likely less than that anyway.

Sounds like either the charger of batteries are faulty.

Do you mean the same as my charger or the same as the one buildingcandy linked to?

Mark A · 7 Feb 2012 at 17:47

I'd check the cells are not faulty before you buy a new charger. I have the same cells and charger as you and they work fine.

Then again its a pretty old charger now and seems to have been discontinued so probably not a bad idea to get a new one.

Luke said:
Do you mean the same as my charger or the same as the one buildingcandy linked to?

Same as you, the ACX1. I'll check it again but I think it takes a few hours and the light goes green and the packs seem fully charged.

Luke · 7 Feb 2012 at 17:49

Hmm..... I've only just bought the charger, it was end of line so was cheap but new.
Any way to check if it is the cells? They also are new, but I can't return them as I've cut the tamiya plugs off and have soldered new Deans plugs on.

rhysduck · 7 Feb 2012 at 18:22

SciNeT said:
What's the CEN ATX, that an off-road buggy? I have a number of CEN spares plus an HPI FLUX Brushless ESC that might suit it.

Yeah an Off Road Buggy here. It's IC but thanks anyway... I wish I could get it up and running, it's never ran under my ownership

Mark A said:
Has anyone ever built their own RC car from scratch? Looks like it would be fairly easy to do. Obviously would need to buy the shocks and wheels and maybe a few other bits that would be hard to make.

http://imageshack.us/photo/my-images/4/dsc00090df.jpg/ (wont let me insert it as a pic)

(Car on the left)
http://www.rccars.com/forums/showthread.php?t=5000&page=1

Building Candy · 7 Feb 2012 at 18:29

Luke said:
Hmm..... I've only just bought the charger, it was end of line so was cheap but new.
Any way to check if it is the cells? They also are new, but I can't return them as I've cut the tamiya plugs off and have soldered new Deans plugs on.

Dont worry, they wont be "faulty" well highly unlikely anyway.

Your charger will do fine , stick them on at 3 amps they should be done just after an hour

Mark A said:
Bear in mind that they're stated as being 3700 but are more than likely less than that anyway.

again not true, a lot of nimh will be at thier rated capacity or higher, if you get a decent charger you'll see exactly what the charger is putting in the batteries.

Luke · 7 Feb 2012 at 18:46

Building Candy said:
Your charger will do fine , stick them on at 3 amps they should be done just after an hour

And therein lies the problem. I charge them and they don't seem to take a charge.

Mark A · 7 Feb 2012 at 18:46

Building Candy said:
Dont worry, they wont be "faulty" well highly unlikely anyway.

Your charger will do fine , stick them on at 3 amps they should be done just after an hour

again not true, a lot of nimh will be at thier rated capacity or higher, if you get a decent charger you'll see exactly what the charger is putting in the batteries.

Did you even read his post? He has had the cells on charge overnight and they only have a partial charge. So something obviously isn't right. AFAIK there is no way to change the charge rate on the ACX1.

Luke · 7 Feb 2012 at 18:49

No, the ACX1 is fixed at 3A.
Given the 3000mah battery takes a full charge but the 3700mah batteries don't I am left assuming it is the batteries.
I've resoldered Deans connectors onto all three batteries and am confident of my joints, so I'm then looking to the cells.

Building Candy · 7 Feb 2012 at 18:51

if its charging at 3 amps it'll be done in about 1 hour 15 mins or there abouts, the cells will get warm as they charge, when they "peak" (voltage stops increasing and starts to drop off) the charger should stop, if it doesnt they will get hot. If the cells are getting hot they are charging, if not you have a charger issue!

Luke · 7 Feb 2012 at 18:56

The cells are getting hot.

Building Candy · 7 Feb 2012 at 19:31

Luke said:
The cells are getting hot.

then they are charging just fine, dont let them charge for more than an hour and 20 or you'll kill them eventually.

That charger your using isnt the best it has to be said. Years ago the nicad used to peak really sharp but now the NIMH have quite a shallow peak and some chargers dont always spot the "peak" this leads them to keep charging hence them going from warm to hot, if they are hot they are charged.

Mark A · 7 Feb 2012 at 19:34

Yeah mine get very hot. I think I might have mto replace it at some point.

rhysduck said:
http://imageshack.us/photo/my-images/4/dsc00090df.jpg/ (wont let me insert it as a pic)

(Car on the left)
http://www.rccars.com/forums/showthread.php?t=5000&page=1

That looks awesome! Will have a proper read through the thread later.

wazza300 · 7 Feb 2012 at 19:37

I still have my original tamiya lunch box,came out mid to late 80's and recently been re launched

Building Candy · 7 Feb 2012 at 19:38

Mark A said:
Yeah mine get very hot. I think I might have mto replace it at some point.

If they get very hot its because they are charged, it wont do them any good. Some chargers have a thermal probe that acts as a secondary monitor incase the voltage peak is missed. Not normally needed as a decent charger will spot it, but its always good to keep an idea in your head of how long its going to take to charge so you can check them 10 mins or so after that to make sure its peaked off or they are not hot. Thats why I say its good to charge at the capacity, so a 4000mah at 4 amps will take 1 hour plus a bit as they normally take a bit more than stated.

SciNeT · 8 Feb 2012 at 15:01

rhysduck said:
Yeah an Off Road Buggy here. It's IC but thanks anyway... I wish I could get it up and running, it's never ran under my ownership

Ahh, a Fun Factor, had one of those, what's up with it? Won't start? Or parts missing?

Edit, got this now, very similar 1/10th IC off roader

http://www.morso5.fsnet.co.uk/img/NMT_Racer3.jpg

http://www.morso5.fsnet.co.uk/img/NMT_Racer.jpg

Luke · 8 Feb 2012 at 15:22

Well I've just bough an NX85 charger and it is no better. I have tried discharging the batteries fully but still get no improved runtime.
they charge for approx 20 minutes at 5A or 35 minutes at 2A so if my maths is right it's putting in between 1100mA and 1700mA before they peak and stop charging.

I've contacted the eBay seller (which seems to be the manufacturer) but as I've replaced the connectors don't think I'll be able to return them. Looks like I'm stuck with paperweights

.

SciNeT · 8 Feb 2012 at 15:27

Batteries sound faulty unfortunately.. What make are they?

Building Candy · 8 Feb 2012 at 15:31

Luke said:
Well I've just bough an NX85 charger and it is no better. I have tried discharging the batteries fully but still get no improved runtime.
they charge for approx 20 minutes at 5A or 35 minutes at 2A so if my maths is right it's putting in between 1100mA and 1700mA before they peak and stop charging.

I've contacted the eBay seller (which seems to be the manufacturer) but as I've replaced the connectors don't think I'll be able to return them. Looks like I'm stuck with paperweights .

How odd, if you want to email me direct (my website www.ukmonsters.co.uk) you can post them to me and i'll check them and try them on my charger then send them back, at least you'll know one way or another.