Tom Thomas Posted November 4, 2017 Share Posted November 4, 2017 Hi chaps, I wish to partially discharge my 4.6v square rx battery for the winter I charged it for my wildthing maiden and its only had about 20 mins use, the instructions advised keeping about a third charge in it for long periods of storage and I'm not likely to use it again till spring. I soldered an old torch halogen bulb to a servo extension lead and its very bright, (the battery in the pics is an old one and not the same make which I forget, that is in the wildthing). I then tried an old car headlight bulb to see if it would light, it does but I'm worried the current drain may be too much and damage the battery? I ask because I wondered if the car bulb would safely drain it quicker than the torch bulb . Advice appreciated Edited By Tom Thomas on 04/11/2017 02:40:25 Edited By Tom Thomas on 04/11/2017 02:42:52 Quote Link to comment Share on other sites More sharing options...
JohnP25 Posted November 4, 2017 Share Posted November 4, 2017 If you left it alone, it would self discharge over a period. First time I've read about discharging a Ni-Mh for storage. Quote Link to comment Share on other sites More sharing options...
Mike Stevens Posted November 4, 2017 Share Posted November 4, 2017 What is a headlamp bulb - 55watts? - I am sure that Nimh would stand that sort of current pull or alternatively why not leave your Tx on for a couple of hours and discharge its that way?? Edited By Mike Stevens on 04/11/2017 07:08:19 Quote Link to comment Share on other sites More sharing options...
Jon H Posted November 4, 2017 Share Posted November 4, 2017 i wouldn't discharge a nimh for storage. As John says most will self discharge and your eneloop is designed to hold charge for longer storage. Al I do with mine is give them a charge, then a full discharge/recharge cycle before the new season. Any that don't make the grade get ditched . Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted November 4, 2017 Share Posted November 4, 2017 ‘New Season’ Jon? I thought you were an all weather, no season type flying guy? Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted November 4, 2017 Share Posted November 4, 2017 I just leave them fully charged and if I remember   take them out of model and keep in a dry place. When usage starts again I give them a even charge and test them on load for ten minutes or so . If ok re-charge them and they are ready to go. Always check the leads and plugs regularly and especially after a lay up. If in any doubt about cells or leads replace with new. Edited By Engine Doctor on 04/11/2017 10:05:30 Quote Link to comment Share on other sites More sharing options...
Jon H Posted November 4, 2017 Share Posted November 4, 2017 Posted by Ron Gray on 04/11/2017 09:44:09: ‘New Season’ Jon? I thought you were an all weather, no season type flying guy? I am, but not all of my models are. Once you have rebuilt mud filled retracts a few times, or nearly lost a finger to frostbite trying to assemble a biplane held together by 14 screws you soon realise which models in the fleet are all weather and which aren't Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted November 4, 2017 Share Posted November 4, 2017 The important thing is to remove it from the model and store it in dry conditions - especially if there's any chance of exposure to damp air. Black wire corrosion will spread through the negative side of wiring and switches - even as far as the receiver in extreme situations. Most switches only switch the positive side... not too clever when you think about it! Quote Link to comment Share on other sites More sharing options...
Tom Thomas Posted November 4, 2017 Author Share Posted November 4, 2017 Thanks for the replies I can't remember the make and it's buried deep in the wildthing nose. It's not eneloop though. Why the instructions said not to keep it fully charged I don't know then? Thanks again! Quote Link to comment Share on other sites More sharing options...
Plummet Posted November 4, 2017 Share Posted November 4, 2017 Do you have a multimeter? If so, try to measure the resistance of your bulb. You can work out the maximum current that will be drawn from the battery by that bulb by (dear old) ohms law. If ... R is the resistance of the bulb in ohms. V is the voltage of the battery in volts then Current = V / R Now if the bulb draws enough current to get hot and to glow, then it will increase in resistance, and so the current drawn will drop. However the maximum current can be determined, so you can avoid drawing more that the maximum rated current of the battery. Plummet Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted November 4, 2017 Share Posted November 4, 2017 ...or set it on Amps and measure the current. Quote Link to comment Share on other sites More sharing options...
Plummet Posted November 4, 2017 Share Posted November 4, 2017 Posted by Martin Harris on 04/11/2017 21:15:25: ...or set it on Amps and measure the current. If your multimeter can survive high currents without destroying itself or blowing a fuse. Plummet Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted November 4, 2017 Share Posted November 4, 2017 I wouldn't be expecting anywhere near a 10 Amp discharge?!? Most multimeters these days have this capability - even cheapies...in round numbers even a 55W headlight bulb takes less than 5A at 12V so there's little chance of pulling more than a couple of amps from a receiver pack... Quote Link to comment Share on other sites More sharing options...
Tom Thomas Posted November 4, 2017 Author Share Posted November 4, 2017 This the bulb info Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted November 5, 2017 Share Posted November 5, 2017 If you don't know the capacity of the battery, I'd recommend playing safe and using an indicator lamp (21W) - IF you still insist on discharging it. NiCds were supposed to be stored long term at 1v per cell but I've never seen similar advice for NiMHs - in fact several manufacturers state that charge state is unimportant and simply recommend a yearly charge to prevent separator deterioration and leakage. Avoiding high storage temperature (not normally a problem in a UK winter) is a good thing though, as is avoiding high humidity. Quote Link to comment Share on other sites More sharing options...
Tom Thomas Posted November 5, 2017 Author Share Posted November 5, 2017 Thanks Martin, I'm going to take advice and leave it alone, but I will bring the model into the house for the winter to avoid the humidity and damp. Again many many thanks for the advice chaps Quote Link to comment Share on other sites More sharing options...
Tom Thomas Posted November 5, 2017 Author Share Posted November 5, 2017 Just looked the battery up it an EnErG Pro by J Perkins Features Battery Lead - Silicone Fut./JR heavy duty Capacity - 2100mAh Cells - 4 (4.8v) Continuous Discharge - ENERG-PRO AA SQUARE RECEIVER PACK (NiMH) Maximum Charge -210mah Size - 50 x 30 x 30mm Weight - 122g Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted November 5, 2017 Share Posted November 5, 2017 Is it a lead silicone or a NiMh? Never come across a lead silicone battery . Or is that a description of the battery lead. Looked up lead-silicone battery and they do exist for use on electric bikes . Edited By Engine Doctor on 05/11/2017 09:23:46 Quote Link to comment Share on other sites More sharing options...
JohnP25 Posted November 5, 2017 Share Posted November 5, 2017 I read it as the battery lead is heavy duty silicone insulation with a Futaba / JR plug. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted November 5, 2017 Share Posted November 5, 2017 Interesting - the advice from J.Perkins in this guide to Energ Pro packs states, "Never leave you battery in a fully discharged state." As NiMH cells self discharge quite significantly in storage, it's probably reasonable to expect them to be fully discharged after a few months of storage from the 1/3 charge state mentioned in the OP. There's no mention there of storing at 1/3 capacity as far as can see. However, the distributor's advice seems a bit muddled - it states that because these cells have a high discharge rate, they should be charge/discharge cycled every 3 months in storage - which would, by my interpretation, mean storing them fully discharged... Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted November 5, 2017 Share Posted November 5, 2017 You all know that these packs discharge themselves and get damaged when left for months Check them monthly, and at least charge them, or at best cycle the packs monthly Quote Link to comment Share on other sites More sharing options...
Former Member Posted November 5, 2017 Share Posted November 5, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Tom Thomas Posted November 5, 2017 Author Share Posted November 5, 2017 I wish I could find the instructions that came with it, knowing me I've read them all wrong....... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.