Geoff Blamey Posted November 24, 2016 Share Posted November 24, 2016 Hi all, I'm new to RC and keen as mustard. I already have several models and a DX9. As I'm also a motorhomer and wanting to take my models away on my travels I want to be able to charge everything from the vehicle 12volts. I can do all my batteries via my Overlander VSP, but what about my DX9? I know it has a built-in charger. The mains adapter output is 12 volts at 0.5amps. I have a ciggy lighter adaptor that outputs 1amp, would I be safe to use that direct to the charging port on the Tx? Or do I need some other method? My MH doesn't have an inverter so no mains voltage unless I go to a campsite. I don't really want to have to remove the battery pack from the Tx each time and risk wear and tear on the connector. Thanks for any advice. Quote Link to comment Share on other sites More sharing options...
Former Member Posted November 25, 2016 Share Posted November 25, 2016 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted November 25, 2016 Share Posted November 25, 2016 Just your 0.5A Tx would be OK on the cigarette lighter Geoff, but in plain sight, and don't be tempted to later put in your 6s 5000s.? If you look at your car wiring diagram, you will find it was fused approx 10A, but they were thinking this was just for a lighter Edited By Denis Watkins on 25/11/2016 07:07:17 Quote Link to comment Share on other sites More sharing options...
Geoff Blamey Posted November 25, 2016 Author Share Posted November 25, 2016 Thanks for the replies and the welcome. Just to clarify, the DX9 has a 2000mAh 2S Li-Ion. The manual states 'The DX9 has an internal charger designed to charge the included 2-cell Li-Ion battery at a charge rate of 200mAh. The charge port is not polarity-dependent.' The 12volt supply I mentioned is not just a lead with a ciggy plug on, it has a gubbins inside and a label saying 'output up to 1amp'. It's one of those things where you can turn a wee adjuster to give different voltages on the output. I did find some info by Googling and there were comments (in USA) that you could charge a DX8 by just connecting a 12volt supply. However, I preferred to find definitive info from someone who actually does it. With motorhoming being popular in the UK, I hoped to find someone who already does what I'm wanting to do. Thanks again. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted November 25, 2016 Share Posted November 25, 2016 Am understanding you now Geoff, and you are still OK to use the 12v available. The limiting factor is the home wiring, but is in the 10A ballpark. Your gismo will handle 1A, and your Tx only requires 0.2A. And yes, I do charge at the field from my car but not left unattended. Edited By Denis Watkins on 25/11/2016 07:43:47 Quote Link to comment Share on other sites More sharing options...
Hamish Posted November 25, 2016 Share Posted November 25, 2016 When in MH I use a small inverter and the normal chargers. I connect the lipo charger direct to battery using crocs. Tx battery does not need charged on a daily basis unless it has severly heavy use Quote Link to comment Share on other sites More sharing options...
Geoff Blamey Posted November 25, 2016 Author Share Posted November 25, 2016 Thanks, guys, that's reassuring. I go off in the MH for weeks at a time, so the Tx will need charging at some stage. Vehicle voltage can be a bit variable unless the engine is off, but I have solar panels as well, so I'd need to remember to isolate whatever battery I'm charging the Tx from. I wouldn't want to put 14.5volts into the Tx. I might need to modify the wiring a little but I wanted to avoid using an inverter if possible. It might be safer for me to fit an inverter but every time you add something into the circuit there are losses, and because I tend to wildcamp a lot of the time, I need to be as efficient on power as possible. Quote Link to comment Share on other sites More sharing options...
Hamish Posted November 25, 2016 Share Posted November 25, 2016 I would be very reluctant to connect my tx directly to the vehicle/leisure battery. I remove lipo from my tx and charge through a normal lipo charger which is able to tolerate variations in input voltages. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted November 25, 2016 Share Posted November 25, 2016 I don't want to cause more work Geoff, or go beyond your scope and have wires dangling everywhere but a 12v Voltage Regulator Chip costs 50p, and has an overload cut out, gives 12v 1.5A from variable input, and would ensure that only the prescribed voltage arrived at your charger. You have task of soldering this 3 legged IC onto a mount for wireing and placing in a small project box. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted November 25, 2016 Share Posted November 25, 2016 Quote Link to comment Share on other sites More sharing options...
David Tayler Posted November 25, 2016 Share Posted November 25, 2016 The regulator chip sounds fine but what about the drop-out voltage? As the tx has a built in charger and the current demand is low why noy just charge the Tx battery when the engine of the motor home is not running? Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted November 25, 2016 Share Posted November 25, 2016 Agreed David, that is the simplest solution, it is just that Hamish sewed the seed of reluctance to connect his Tx directly to a battery, and I just offered up a regulator as a safety valve Quote Link to comment Share on other sites More sharing options...
Hamish Posted November 25, 2016 Share Posted November 25, 2016 And what voltage will the MH battery be at when you have just stopped the engine? High enough to blow your tx. Do not think it's a good idea to directly attach a tx o an unregulated supply but you can tale a chance. Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted November 25, 2016 Share Posted November 25, 2016 The Dx9 has a built in charging circuit so probably has an inbuilt regulator like the one above. But rather than take a chance why don't you call Horizon or post on RC Groups where Andy Kunz from Spektrum would probably advise. Quote Link to comment Share on other sites More sharing options...
Former Member Posted November 25, 2016 Share Posted November 25, 2016 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Geoff Blamey Posted November 25, 2016 Author Share Posted November 25, 2016 All good advice, thanks very much. I will indeed contact Horizon. Why didn't I think of that? Just passed my A test this morning despite gusty winds here in Devon, so I'm on a high atm. Yay! Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted November 25, 2016 Share Posted November 25, 2016 Geoff, no need the Spektrum engineer on RC groups has alrady said any power supply upto 15v is fine. Congratulations btw Quote Link to comment Share on other sites More sharing options...
Geoff Blamey Posted November 25, 2016 Author Share Posted November 25, 2016 That's brilliant, thanks a lot, Frank. Quote Link to comment Share on other sites More sharing options...
Geoff Blamey Posted November 25, 2016 Author Share Posted November 25, 2016 I've now found the DX9 thread on RCGroups (that'll keep me off street corners for a while reading that lot!) This RC business is a steep learning curve for an old noob like me. Thanks again for the helpful advice and pointers, much appreciated. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted November 25, 2016 Share Posted November 25, 2016 I have a recollection that I've seen advice from one manufacturer not to use in car charging with the engine running due to the possibilities of voltage spikes damaging the inbuilt charging circuit. Edited By Martin Harris on 25/11/2016 17:23:51 Quote Link to comment Share on other sites More sharing options...
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