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I have been charging my 9XR Lipo by using a 12V 1.5A power supply and find that very convenient. I know my battery won't be fully charged, but I get more than two days flying out of it so I'm hoping for a long life for it. I bought a Pro two months ago, but if I ever get it I would like to use the same protected battery. I'm a bit worried after reading the below ( about the 300 mA maximum...) in the hardware manual. Should I be?

The Turnigy 9XR Safety Protected 11.1v (3s) 2200mAh 1.5C Transmitter Pack
This is the battery sold by HobbyKing specifically for the 9XR series of radios. It is a low cost, low
discharge rate Lithium Polymer battery which includes a regulator that is claimed to allow it to be
charged at a low rate while still in the transmitter. The charger used must deliver less than 0.3
Amps (300 mA) at 12 volts. If the battery is almost fully discharged and a typical 150 mA charger is
used, charging may take about 24 hours. The charger jack has the centre pin positive. This is the
same as Futaba chargers but opposite JR and Spektrum chargers.
Note that the 9XR radio has a 0.3Amp fuse in the charging circuit to protect the transmitter and
battery. This will burn out if subjected to a higher current and is difficult to change

You should really remove the battery and charger it with a proper Lipo battery charger. Even one of those 5 dollar Lipo chargers from HK would be fine.

Do you remove the lipo from your cell phone before charging?
This battery has the same protection. All I worry about is the fuse...

Wimh wrote:Do you remove the lipo from your cell phone before charging?
This battery has the same protection.

The phone contains a proper lipo charger though, the protection on the battery is only there as last resort should the charger fail and is supposed to never be needed.

You're sending unregulated current into the battery and relying on the protection that doesn't actually limit that to save you from some fireworks. Your call.

BTW, yes the fuse will blow if you use anything but a supply that is current-limited to less than 300mA, ie what is talked about to safely recharge the battery as per your quote above.

Sent via mobile

As far as I know the phone has a charger and also the battery is only one cell. It doesn't need to be balanced. the pack you want to charge, does..

ooops, Kilrah was faster.. And explained it better too

Fuse is 2A these days.....

Is that on all production units?
What is the rating of diode D3 in the charge circuit?

Mike.

The diode is rated at 3A

Thanks, no problem for me then. I will try not to get into a discussion about what a "proper" lipo charger is and why this specific battery balances itself when charging "my way". I will try to see what happens with current and voltage.( FWIW , my friend has not "balance charged" any of his lipo's since he started using them several years ago. He does not overcharge or overdischarge them and all his packs are still perfectly balanced. I DO balance my power packs on almost every charge though)

At the end of the day we all do it the way WE think is correct

A friend from my club also did it the way he thought he was the right one until he nearly burnt his house down a couple months ago

João

Ummm... yeah.

LiPo batteries MUST be charged with a proper Delta-peak battery charger DESIGNED for LiPos to be charged safely. Multi-cell packs MUST be be balance-charged to be charged safely. Anything else is a recipe for a chemical fire that burns almost as hot as magnesium.

This is NOT a matter of opinion. It is established fact, outlined by every manufacturer of Lithium chemistry power cells in the world.

Trickle-charging ANY Lithium technology battery is just b!tch-slapping Murphy and BEGGING him to make an example of you in a fashion suitable for the Darwin Awards.


mnem

jhsa wrote:.. until he nearly burnt his house down a couple months ago

João

So charging it outside of the TX will not burn my house , while charging it inside the TX will?

mnementh wrote:.

LiPo batteries MUST be charged with a proper Delta-peak battery charger...

delta-peak, right.....

NOT delta-peak, that is for NiCd and NiMh!
LiPos need a constant-current/constant-voltage charger that limits the maximum voltage.

Mike.

Wimh wrote:

jhsa wrote:.. until he nearly burnt his house down a couple months ago

João

So charging it outside of the TX will not burn my house , while charging it inside the TX will?

No, but using a proper balance charger, and put the battery inside a LiPo bag while charging, will probably reduce the chances of burning your house down.
If you insist in living the battery inside the radio, then get a balance cable extension, and put the complete radio inside the LiPo bag..

João

No one system will please everyone but the 9XR/overcharge protected Lipo seems the worst of all. That said, there don't seem to be a lot of reports of fires with that battery/charger setup. Apparently it works and isn't as dangerous as it would seem.

(I use a LiFE battery and charge it outside the TX on a proper charger)

MikeB wrote:NOT delta-peak, that is for NiCd and NiMh!
LiPos need a constant-current/constant-voltage charger that limits the maximum voltage.

Mike.

Actually, modern LiPo chargers DO monitor Delta-Peak of individual cells, but not voltage, rather current instead up to the limit voltage. This is spot a cell that has developed a high internal resistance and keep from over-charging that weak cell and causing a fire. Many now also charge intermittently; periodically stopping the charge current, monitoring the voltage drop, then charging again. Based on the discharge curve, they will adjust the charge current in the last stages of charging.

As this technology matures, we're learning new stuff about how best to manage it. When we first started using LiPos in high demand applications, the recommended management was to never let them sit discharged, but to charge them again as soon as they cooled down to maintain peak capacity. This was based on experience gathered using the technology in relatively low-demand applications; which real-world usage has proven is not exactly applicable.

Now we've learned that approx 55-60% charge is best for storage of more than a few hours; this is why modern chargers all have a "Storage charge" mode. Best practice now is to charge to a storage charge as soon as they cool down, then charge to full capacity just before use. Understand that this refers to main high-current power packs for electric craft, not the low-demand packs we use for TX and receivers. They still seem to serve well if kept fully charged unless being stored for long periods.

As I've stated elsewhere; Li-ion technology is MUCH higher maintenance than Lead-Acid and Ni-XX technology. LiPo and LiFe batteries simply will not put up with abuse like those older technologies will and they become dangerous when abused. THAT is why it's important to charge on a charger designed to charge them.

It's funny having this discussion on a forum devoted to Radio transmitters; it's only because it is now such common practice to plug in "any old 3S pack we might have lying around". The truth is, ordinary 18650 Li-Ion cells as commonly used in laptops are the PERFECT power source for them; they are inherently safer than any polymer cell which is what we want in the TX we hold in our hands, and if bought in commercial quantities, also about as cheap as you can get, except of course for busting up discarded laptop batteries. If I were going to build a pack for mine, it would be a couple UNPROTECTED 18650 2500mAh cells with a balance connector on it; which is what I made for and still use on my ground transmitters. Why UNPROTECTED? Because I'd rather eat the battery in my TX than have the protection circuit in one of the cells shut off my radio mid-flight because I forgot to charge it.


mnem
*Unregulated*

And that already happened. Not the person forgetting to charge, but the protection circuit went bad on him... while flying.. result, a nice crash..

João