Using NiMH Rechargeable in Futaba 3GR-2.4GHz?
 

Hi,

Rather than buying the expensive and low capacity NiCad recommended by Futaba I thought I'd try to use some NiMh ones instead and just use the charging jack.

Unfortunately my charger just shows "open" when I try to charge them via the socket on the radio.

Is there something else I should be doing, or is this not possible at all?

The batteries I have are the Duracell Accu Supreme at 2450mAh

Steve

When the transmitter is on it disables the charging socket, so make sure it's turned off when your trying to charge it.

If your already doing that then make sure your lead is ok, and is polarised correctly.

The only other thing I can think of...I had the 3pm (wheel version of the 3gr) and had some weirdness with this to begin with...one thing being that the hole in the case stopped the plug on the lead I had from making a connection properly. The hole was smaller than the body of the plug itself, and the socket was mounted quite far into the outer case. It felt like it was mating fully but was actually being held out of the socket just enough to stop it connecting properly. So I fettled the plug and the hole a little to make sure it was going all the way in and connecting properly.

I'm not sure what the socket/case is like on a 3gr, but could be worth a look?

you need a long reach charge plug not a short one

Isn't that always the way :eh?:

Any idea where I can get one?

Steve

maplins of course

Looked at Maplins on-line but couldn't seem to find a long reach one, so I've now ordered one from eBay for £1.29 delivered.

Thanks for the help.

Steve

Well, fitted the long reach plug, and it still doesn't work as the charger just shows open.

The lead and charger works fine with my Futaba T9C Super so that's all OK.

Anybody any ideas?

Thanks,

Steve

using gp2700 nimh in my 3vc with no problems at all, have you taken the pack out of the transmitter and charged it on a regular charger to check it is ok? if you havent charged it since buying it the pack voltage may be too low for the tx charger to register its existance

Try these for your tx. They act like lipo with very slow discharge if left for 1 year they will stil have 70% left in them. £9.99 del bargin.
http://cgi.ebay.co.uk/8x-AA-2100mAh-...item35a8fe12e1

http://cgi.ebay.co.uk/TX-Pack-9-6v-N...item35a21667ba

When you say you are using GP2700, are they in a pack format, or just individual cells you've put in? Maybe the 3VC is different to the 3GR?

Not too keen on trying other batteries at the moment as I'll probably just get the same result.

Batteries are currently at 9.9v, so don't see a problem there. Even if they were very low my charger would just read out "low voltage" anyway rather than "open".

Think I'm going to have open up the Tx....

Steve

It looks like I've been using the wrong 5.5mm DC plug.

Didn't know there were two sizes of ID, 2.5mm and 2.1mm

So I've ordered a long reach 2.1mm one now.

Just been lucky with all the other sockets I suppose.

Steve

at least you know what the problem is, its annoying if you cant find it. the cells i am using are made up into a pack and covered with heatshrink, just like any pack you would buy from a shop, albiet soldered rather than welded like commercial ones. looked at the low discharge rate nimh cells also as suggested by bodgit, unfortunately the uniross ones i tried dropped in voltage quite a lot after a couple of minutes use and recovered again after a short break, not ideal really although other makes may well be better.

Oh well, got to think again.

The smaller ID doesn't fit, so the original plug must be the right size, unless they do a 2.3mm ID!!!

Steve

Just charge them out of the radio?

Haven't got anything to hold them while charging...

It's not a Tx pack of 8, they are just 8 individual cells.

Steve

If you have nothing to charge them in then the best and cheapest option would be to buy the set I advised you of earlier in the thread
http://cgi.ebay.co.uk/TX-Pack-9-6v-N...item35a21667ba

If push comes to shove I might well go the pack route.

I'm using Instants in my other Tx.

It's just that I don't fancy having to keep on plugging and unplugging the battery pack when there should be a perfectly usable charging socket.

Steve

i see if i have one in the shop today and check that one for you to see if it your charger or the radio charging socket that works or not

Well, thank you very much.....

Steve

I have the older red vapextech cells in my 3gr, have had for the past 18 months & regularly used....excellent!
I should have had shares in Duracell the AA'S i was going through!!

Do you charge them with the standard Futaba charger, or with a smart charger?

I've just seen in the 3GR instructions, "The transmitter charging circuit is equipped with an over current protection circuit. If the battery is charged with a quick charger for other than digital proportional R/C sets, it may not be fully charged.

Just wondered if my problem was with using a peak detect charger rather than a Futaba slow one.

Steve

right i have checked the one i have here the plug is a 2.5 internal size and i have tried to charge it on 7 different chargers and they all charge it with no problems here so i guess it either your charger does not like it or you got a bad connection inside the tx or try swopping the black and red wires around the postive is the inner part of the plug if thats any help see if that works

will not make any difference quick or slow the quick charger will or should be set at 1 amp and no more to charge the tx

Thanks for that, it must be the Tx as I've tried two different chargers, both of which work fine with my Futaba TC9 Super.

Oh well.

Steve

Have you tried a continuity meter between the charger socket and the plug which the batteries plug into. Maybe a wire broke.

I actually just made a plug to short circuit the socket, and with a multimeter across the two pins that the battery plugs into, nothing.

So I looked at the socket, and I've took some photos to post, but I can't now get my camera to download :(

From what I can see though there is absolutely no connection from the -ve side of the socket to anything!

I'll try to get the photos up.

Steve

Well here goes

http://i108.photobucket.com/albums/n...n/IMG_1504.jpg

http://i108.photobucket.com/albums/n...n/IMG_1506.jpg

Top photo, the centre +ve goes to the two at the back, and you can trace the circuit to the +ve pin. The -ve hasn't got any tracks leading from it.

Bottom photo, again, it doesn't seem to go anywhere!

Steve

just make a connection from the 2 pin plug to the socket jobs done then

This just gets stranger, checked again with the multimeter and there is a circuit from the -ve pin to the -ve socket even though I can't see one. What there isn't is a circuit from the +ve pin to the centre +ve of the socket, so I've just soldered a wire to form one, and now it charges OK.

Wonder if the diode has blown as there is definitely something called D2 in the +ve circuit.

Steve

I've always charged my TC9 at 1/10, or 2.4 amps, so I should really only charge at 1 amp, probably due to the very small cross section of the internal wiring?

Steve

Just goes to show how confused I can get!

Just tried the charger again and got an open circuit. :o

Now I've found out that it's nothing to do with the radio, but the intermediate plug between the charger and the Tx, all it needed was not to be fully plugged in, and I mean by fully that means it almost needs to be held together.

No idea why, as I have just checked the plug and it's all OK, but I changed it anyway, and the new one works fine.

So the wire has come out of the radio, and it still works.

Thanks for all your help, and at least I found out the problem, even though I still do not know what is wrong with the plug...

Steve