Spektrum DX8 Transmitter Battery Failure

[Marc]

This was only the third or fourth time I've charged this transmitter. Plugged it in lastnight just before bed and pulled it off about an hour ago. About 8 hours. I haven't done any searching on the web yet to see if this is a common failure or not. And I have no idea what Spektrum might do about it yet. The transmitter doesn't seemed harmed since I turned it on before I realized what happened. It had enough juice to complain about the battery being very low. I was charging it with the supplied wall charger.

 

[Tony]

They should replace that as long as you went by the manual on charging. but I think they will replace that battery. just looks like that one got hella hot like the delta peak didn't kick in.

 

[RCD]

My DX8 charges in 4 hours, so maybe you over charged it.

 

[Lee]

Very interesting Marc. I did the initial charge of 10/12 hrs as specified in the manual. When i switch it on it was only half charged??? I will keep an eye on it.

 

[Tony]

two people both having issues charging nimh in the dx8... I would check for a recall soon. One thing you can do is to charge it on the actual charger. It will set the delta peak, and once it does, it will shut off. Should be good to go for a day or two of flying.

 

[Marc]

The wall unit is only capable of 200mAh output which I think is considered a trickle charge for a 2000mAh battery. The battery was almost dead when I plugged it in lastnight so 8x200 = 1600mAh. It really shouldn't have overheated like this, I'm waiting on a call back from Horizon now, will let you know what they say.

 

[Marc]

Just got off the phone with Horizon. They are going to send a new battery pack out free of charge.

I have found several posts in other forums where people have had overheating problems charging the NiMh batteries in the transmitter. So if you have a DX8 beware! Some guys have purchased an additional battery cover and fitted a charging jack onto the cover that bypasses the internal charger of the system so you can use your charger of choice. I may end up doing that, I don't want to risk a fire.

I also have a handmade LiPo pack with cells the right size I can use. Just need to solder on the tx battery lead.

 

[Tony]

If you are wanting to use a 2s or bigger, make sure to use a BEC to lower the voltage. Max of 6 volts (on the DX6i), and with teh rechargables, it's running at 4.8. But I agree I would start charging with teh real charger and not the one it came iwth.

 

[Marc]

The DX8 is designed from the factory to run on a 2s LiPo as well no voltage regulator required as far as I can tell. There is even a setting in the main menu to select the low voltage warning for LiPo vice NiMh.

Homemade pack installed, it powers up, and I'm headed out to test it.

I was reading somewhere that when a LiPo is installed the charging circuitry works a bit differently and will actually shut off the charger once 8.4 volts is reached. I dunno, but I won't charge it unattended that's for sure.

 

[Tony]

If that's the fact, then you can't beat that. Let us know how it goes.

 

[Marc]

Well after 6 hours with the lipo battery in the transmitter and the provided wall charger the charging indicator has turned off. Throughout the charge I monitored the battery temp and it never increased over room temp. I'll let you guys know how it goes on the next charge, but this seems to be the way to go. Don't know what the cost difference between the nimh vice the lipo, but I think this is how this xmitter should have come.

Sent from my BlackBerry 9650 using Tapatalk

 

[Tony]

Size for size (physical size, not mah), the lipo can hold more mah. Thus should allow you to fly longer.

 

[Marc]

Ok, so final update to this thread. I have had several recharges with the DX8 and lipo battery. Each time the transmitter turns off when the charge is complete and the battery never gets over room temp. I received the replacement NiMh battery from Specktrum and plugged her back in to test. After three hours the battery was already warm to the touch. I didn't read its temp, but I don't plan on charging the NiMh pack in the transmitter again, just not worth the risk to me. I'll find another use for the pack and charge it with my external Ni-Cad/Ni-Mh charger.

 

[Tony]

Glad teh lipo is working for you. I would have made them send you a new case since yours was damaged by the other battery lol. But that's just me lol.