bafflerback

My Feedback: (6)

I've just converted my DX 8 to Lipo batteries. The problem is when you connect the charger the batteries charge at an extremely slow rate. I can charge all my flight batteries in about 2 hours. In that time the transmitter will only go up about 2 tenths of a volt. Do any of you guys charge your lipo transmitter batteries overnight? I've have 2 flight batteries go off charging so I don't leave them alone, but that is a high rate of charge. I guess I'm just concerned.

Bob

RCKen

My Feedback: (9)

You can't charge a lipo battery in the transmitter. If you have retrofitted your transmitter with a Li-Po battery you will need to remove the battery in order to charge it. Once you have the battery out of the radio you can setup and do a proper balance charge which will allow you charge the battery at 1C and have it charged in one hour. The charging system on transmitters are designed for charging a Ni-Cad or Ni-mh batteries, which have different charging characteristics than a Li-Po battery does. In addition, if you charge a Li-Po battery improperly you can run the risk of the battery starting a fire. 

countilaw

Here is a picture, that I obtained from another site, illustrating the dangers of unattended LiPo battery charging.

It's a very good idea NOT to charge a LiPo battery while inside your transmitter. It's NOT a very good idea to charge LiPo batteries outside of a fire proof container.

Frank

flyinwalenda

My Feedback: (5)

How are you connecting the charger and what charger are you connecting ?

As stated you can't charge through the transmitter like you did for NiCd or NiMh packs. If you have a charger that charges and balances lipos through the balance plug then you can charge it that way. If your charger requires both the balance plug and the output leads to be connected to the charger then you need to remove it and connect it up to the charger that way.

I've had LiPo's in my transmitters for 5 years and I remove the cover, connect a cellpro4 via the balance plug and charge it . If you take care of the batteries, maintain them, charge them properly and monitor them(keep an eye on them) you shouldn't have any problems.

bafflerback

My Feedback: (6)

I'm afraid I wasn't very clear. You can buy a Lipo battery from Spektrum for the DX8. You install the battery and then go into the programming and tell it you installed the Lipo. It will configure the radio charger to now charge the Lipo and turn it off when it is done. There are no balance leads. The battery is made for the transmitter. My son's QQ DX18 came from Horizon with the Lipo batteries installed. They tell you to charge the battery until the charge indicator on the transmitter goes out. Still don't like the idea of charging it unattended.

flyinwalenda

My Feedback: (5)

Well yes that was as clear as mud !
I just read about that lipo and it's designed with a balance board inside the pack and it's not designed to be charged by a normal lipo-type charger . As you say it is specially made to be slow charged through the transmitter after the transmitter is programmed to lipo. You will need to keep the charger on for a very long time to fully charge and balance the pack. You are charging it with the wallwart charger so it's going to take maybe 20 hours to complete. Because the battery is specially made it can't be charged outside the radio.

bafflerback

My Feedback: (6)

I understand that. My question is about leaving it unattended. Like plugging it in and going to bed.

TEBerg

My Feedback: (1)

I have used amo cans for some battery charging - you can probably find a can that you can stand your TX up inside and it will provide some proteciton. Besides that, you could always charg it in the tile shower - Just make sure the wife knows not to turn on the water[:@]

600Bob

Yes I charge mine overnight on a stand near my bed.

JohnBuckner

My Feedback: (1)

Wow, charging a Lipo in your sleep by your bed, what a Horrific thought and a terrifying way to go!

AMA 74894

My Feedback: (1)

oh, My........
Never Never NEVER EVER EVER EVER EVER Charge a Lipo Battery Unattended.
(I don't even go to the store if I've got a lipo charging...)
my head is absolutely reeling at the thought.
this would be akin to leaving your live cut Christmas tree (dry, with no water) decked out with 25 stands of (old school incandescent, HOT) lights
on all night while you go to bed. WILL it catch fire? probably not the first night... but the statistics suggest that it WILL happen eventually.
never ever ever ever EVER put a lipo battery on charge and then go to sleep!
(no disrespect meant to 600bob BUT....)
I have a DX8 that I've installed a lipo in and I LOVE it, however it's not the Spektrum brand, so it does have a normal balance charging plug.
I remove it from the TX to charge with my normal balance charger.

600Bob

So are Lipos so unstable that charging at 0.1c is a fire hazard?

AMA 74894

My Feedback: (1)

I know that personally, I would not bet my life (or that of my wife, kids, dog etc) that the charger isn't going to malfunction.

Chucksolo69

I charge the lipo pack (GForce 2750 mah) for my DX7s when I get home from work and while I am watching TV. I usually get home at 4 PM and go to bed around 10-10:30 and it is usually done by the time I go to bed. Incidently, I have only charged it 3 times in about 2.5 months.

JohnBuckner

My Feedback: (1)

Here is a fun one cause I was almost a victim! And the battery was not even being charged all that was done was it was just plugged in.

I have no idea why the three foot flames, erupted with a rather big Bang and I don,t really care. The probelms is I was sitting in my wheelchair with a gallion container in my lap refueling my gasser on a starting station just eight feet away. Fortunately one of the guys who was on their feet grabbed my fire extinguisher that I keep close by when flying gas. Now imagine this was next to your bed and being charged!

So 600Bob I don,t care how low a rate you use, Sooner or later you are gonna screw it up somehow on the progaming or the chargers themselves are gonna go south and that certainly also happens. Ever wonder why all the warnings on every single lipo battery sold here in the US unless its direct from Hong Kong (I suppose they have plenty of replacement people there). That warning is very, very real. I don,t mean to sound harsh but I would prefer to see you continue posting rather than reading about the burning bed incident


John

600Bob

Perhaps Horizon Hobby should sell a Lipo charging bag big enough to hold the DX8 since you have to charge the Lipo inside the TX?

AMA 74894

My Feedback: (1)

absolutely john, and my comments were not meant to be disrespectful in any way...
I've simply seen too many pieces of equipment fail to trust them not to kill me in my sleep :-)
I get the point about needing a lipo sack for the whole tx too!
I like spektrum stuff, its what I use. Id first check what their suggestion is.

JohnBuckner

My Feedback: (1)

Absolutely Jim I was also just trying to help convince Bob. Now Bob that charge bag big enough for the Tx Line is hilarious had me doubled up. So with your permission I wanna use that one at the field

John

Jetdesign

My Feedback: (8)

I would buy a new battery for $15 that I could charge with my regular lipo charger, charge the thing in 20min like you should be able to, and chalk it up as a learning lesson.

600Bob

Actually I wasn't trying to be funny because the Lipo for the TX is made to charge inside the TX. To charge it outside you would have to make a proprietary charge lead like inside the TX. Then I'm assuming that the TX charger applies the same voltage to the batteries built in circuit board that a standard charger would i.e that it is only a balace board and not also a regulator.

I wonder how long it will be before Horizon Hobby has to defend themselves against lawsuits for burned up houses?

AMA 74894

My Feedback: (1)

I completey get it bob, there must be a rhyme or reason for that charger to work that way...

Minnreefer

I may be stupid, but if it was me, I would at least charge the tx in an extra large lipo sack (if possible) or in something that can't/ won't catch fire and would help provide some protection if it exploded, like a large pot with sand on the bottom.

Jon

600Bob

I charged it for the first time since the initial charging when I bought the battery.  It took about 19 hrs. to go from 7.3v to full charge, for a 4000mah battery that is a very low c rate.  I charged it on the washing machine, I could put it in the oven that would stand some heat  

JollyPopper

My Feedback: (6)

Charge it in your BBQ grill.