Going "Lipo!"

[gil]

No, I'm not going to the clinic to lose weight!  :o

I decided to try Lipo chemistry batteries for my MTR and K1. So I ordered a charger and three 3S 1050mA/H battery packs from http://hobbyking.com, as well as some connectors. About $47; more than I anticipated, but with these and my AA cells, I should have enough power storage for a month of daily use! The charger uses 12V input so I might be able to use my solar panel with it, or any 12V battery for that matter.

Anybody else using Lipo batteries? I am curious as to how well they will perform and will post an update after I test them.

Stay tuned  ;)

Gil.

[Joe]

Hello Gil

I have used Lipo's in my R/C rigs. The power drain curve is more stable than the NIMH's, the battery packs weigh less than the same size NIMH and have more capacity. Caution does need to be taken when charging and using these batteries.

Charging:

Have battery in a Lipo safety charge sack    http://www.venom-group.com/Battery-Safety-Charge-Sack-Large.html

Have a bucket with sand by charging station to extinguish any possible fire or chemical fire extinguisher.

Follow charge amperage recommended by manufacture of battery, this is the charge rates for the Venom batteries I use.

Do not charge at over 1C current. C= battery pack mah capacity
÷ 1000. Divide the battery mah capacity by 1000 to determine
the proper charge rate. Example: 1200mah ÷ 1000 = 1.20 Amps
Charge Rate for Venom Power LiFe Battery Packs, example:
a. 800mah Capacity = 0.80 Amps
b. 1200mah Capacity = 1.20 Amps
c. 2000mah Capacity = 2.00 Amps

The video is old and quality is pore but the content is good and shows what could happen when charging the same risk is involved when using them at least in R/C's they don't take shock from crashes to well I have seen one truck and two planes burn after crashing with lipo's in them.

http://www.youtube.com/watch?v=z3o_2mwRPdw

Store the batteries in a cool place and inside the charge sack. I only use my Lipo's when racing if I am booney bashing or offroad coarse I use NIMH's.

I have thought about trying to use my NIMH's with the RockMite.

73

Joe

[gil]

Great info Joe, thank you!
That video is pretty sobering...
I will thus avoid charging those batteries on my bedroom wood floor while sleeping!

Gil.

[KK0G]

They have awesome potential but the charging difficulties that Joe mentioned is the main reason I've shied away from them.

I use four different battery types for my QRP rigs:

SLA
Advantages: Low cost, fair storage capacity and dirt simple charging.
Disadvantages: WEIGHT - they are full of lead after all.


These stay in the shack and are what I power my rigs with for normal daily use.


Alkaline
Advantages: Low initial cost but of course they're disposable so cost will add up over time, massive storage capacity, lightweight, low self discharge rate.
Disadvantages: Non-rechargeable, voltage drops fast as discharged.


I cut costs on these buy buying AA cells in bulk at Costco. I also have some 6V lantern batteries wired in series to make a 12V battery with truly MASSIVE storage capacity for my KX1's 31mA current draw.


NiMH
Advantages: Relatively low cost, relatively simple recharging, voltage remains high with a flat discharge curve.
Disadvantages: lower storage capacity and lower charged voltage than alkaline's.


I'm using these less than I used to mainly due to the lower capacity.


Energizer Ultimate Lithium
Advantages: Extremely light weight, higher voltage than alkaline's, good capacity.
Disadvantages: Very expensive in comparison to the other types.


Because of their higher voltage, putting a set of these in my KX1 doubles the RF output power compared to a set of alkaline's. Their high cost is offset by the fact I only need six of them at a time and I use them pretty infrequently - only when portable.

[gil]

Hi Chris,

I haven't used internal batteries for my KX3 yet, but would probably use alkalines since I haven't even taken it out yet, so it is pretty infrequent, to say the least.. I could use those 3S Lipo packs with it too I guess.. or maybe a 4S pack with three diodes in series to drop the voltage until the battery goes down a bit (KX3 max is 15V).

Do not charge at over 1C current. C= battery pack mah capacity

Hum, that charger I ordered has a max of 5A but is presumably "automatic." I don't know how it could determine battery capacity though..:

The iMAX B6 Compact Balance Charger makes charging of your Lipoly batteries easier than ever before. With no current limits or cell counts to set, you simply connect your battery to the B6 and it starts charging automatically. The charge current is variable, determined by the capacity and charge state of your battery. The max charging current is 5A (up to 50W).

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=41635

Gil.

[Joe]

Do not charge at over 1C current. C= battery pack mah capacity

Hum, that charger I ordered has a max of 5A but is presumably "automatic." I don't know how it could determine battery capacity though..:

The iMAX B6 Compact Balance Charger makes charging of your Lipoly batteries easier than ever before. With no current limits or cell counts to set, you simply connect your battery to the B6 and it starts charging automatically. The charge current is variable, determined by the capacity and charge state of your battery. The max charging current is 5A (up to 50W).

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=41635

Gil.
[/quote]

Hello Gil

That is a automatic charger, it bases charge rate on where the balancer lead is plugged into the charger. And as it charges it pickups the cell voltage and adjust amperage accordingly.

Joe

[gil]

Extraordinary coincidence: This morning I started shaving with my beard trimmer when the battery went down. I had just charged it... It had been doing this lately, and I knew the battery wasn't holding a charge anymore. I had shaved a third of my face, so I really couldn't go anywhere like that :o I opened up the device and there was one AA cell in it. Since I had a couple spare NiMH cell, I decided to swap. I soldered the leads to the new battery and inserted it. I don't know if it was from the heat of soldering or there was a short, but the battery started hissing and smoking. I immediately cut the wire, but it still was going off! Finally it stopped. There was no flames, but the smell was aweful. I tried with the last cell I had but only solder the positive lead this time and inserted the battery. I then connected the negative wire. All seemed well. The trimmer worked and I finished shaving!

Gil.

[KK0G]

Extraordinary coincidence: This morning I started shaving with my beard trimmer when the battery went down. I had just charged it... It had been doing this lately, and I knew the battery wasn't holding a charge anymore. I had shaved a third of my face, so I really couldn't go anywhere like that :o I opened up the device and there was one AA cell in it. Since I had a couple spare NiMH cell, I decided to swap. I soldered the leads to the new battery and inserted it. I don't know if it was from the heat of soldering or there was a short, but the battery started hissing and smoking. I immediately cut the wire, but it still was going off! Finally it stopped. There was no flames, but the smell was aweful. I tried with the last cell I had but only solder the positive lead this time and inserted the battery. I then connected the negative wire. All seemed well. The trimmer worked and I finished shaving!

Gil.

It was most likely caused by the heat applied from the soldering iron................ been there done that, have the scar on my shack desk to remind me not to do it again. 8)

[gil]

I finally got my three Lipo packs yesterday with the charger from Hobby King. It's been long enough! They came already charged at 11.77V. Perfect for my MTR. I proceeded to test power output and got 5.6W on 40m and 4.2W on 20m, 11.7V on receive load. They are very small but should last a long time.

I can't find a good answer as to the minimum discharge voltage. I see anything between 2.5 and 3.7V per cell! So, I will set myself a lower limit of 9V total voltage (hopefully 3V per cell) on light receive current load. The MTR has a voltmeter built-in, so that will be easy to monitor. If anyone has any suggestion, I am listening..

I suspect that after recharging, the battery voltage will be slightly higher than 11.8V. I may have to use a diode to lower it by 0.6V.

I'll try those little 1050mAh packs with my KX3 as well, just out of curiosity.

Gil.

[KK0G]

Boy that was pretty fast shipping!! 8)


Let us know how they work out.

[Archangel320420]

WOW! What great information! Thanks to so much to all.

[gil]

I destroyed my first LIPO pack!  :o

Ray and I were chatting away KX1-to-MTR and I let the battery drain down to 5V. The MTR to it's credit kept on chugging away happily and the propagation must have been good because Ray heard me just fine, although I was QRPP (much less than 1W) at that point. LIPO cells get damaged below 3V, I ran them down to 1.7. My charger refuses to charge it now. $6 lesson learned: Monitor your LIPO voltage frequently.

Gil.

[RadioRay]

And I thought that we were just loosing the band, and here you are using fractional Wattage!  Naturally, this occurred after I have done a KX1 mod, installing laptop speaker into the front panel, but did not have my earphones wired in yet, the grandson was visiting (loud), the washing machine was chugging along, the sun was in my eyes, the DOG ate it, copy was all uphill with the wind SAND blowing in my eyes the entire time!

Oh how I suffered - such PAIN you would never know...   ??? ::) :o ...... ;)

Seriously though, it really is amazing what a small amount of power from Gil's TINY MTR with a 'dead' battery to a very basic wire antenna can do on HF radio in CW. Small wonder that CW was the MAIN radio communication method for special operations for a generation and the back-up after that: low burden & high reliability. 



de RadioRay ..._ ._

[gil]

Back to the soldering iron tonight to make connectors for the MTR and Lipo packs (two left  ::)). The one on the bottom has a diode in it (1N4004) to drop the voltage a bit since charged, the packs show 12.6V. 0.6 too much for the MTR. I am sure it would be fine but why risk it... I love the little guy and I'll be damned if I fry it. I used a thicker wire on the Lipo connector (forgot the type) and thinner for the plug that goes in the MTR. All inside heat-shrink tubing.

I first thought that my charger wasn't working but discovered that both connectors are used to charge the Lipo packs. The balance plug is only for monitoring. I need to be careful in the future about monitoring voltage and stop using them when they reach 9V. Fortunately both my MTR and KX3 have a built-in voltmeter. I just need to remember to check ::) I think I'm going to order a 4Ah pack to use with the KX3 and if needed that would probably power the MTR for a month of casual use! I have a spare charger on the way ($9), just in case.. I want to try using a solar panel with it and see if it works.

The Lipos are finicky to use because of the voltage monitoring requirement and they can blow-up while charging :o However recharging is very quick. They are also light and small. With my AA cells and these batteries I am all set.

By the way, DO NOT buy "Ansmann" cells. Out of eight I bought, six were bad. The Eneloops seem to be the best ones. The GoalZero cells work fine as well.

Ya'll have a good night :)

Gil.

[cockpitbob]

I second Eneloops for NiMH.  I've never tried LiPo and probably won't given that I like my batteries like my women; low maintenance, loaded with energy and durable. ::)