Last night I had the good fortune of speaking with the owner of Troy Built Models. The topic of discussion was Lithium Ion/Lithium Polymer batteries. Basically the reason that the conversation got started was that I brought some one of his foam airplanes as a birthday gift for my son. It is powered with a 2 cell lithium polymer battery and when I brought it I asked if I needed a special charger and he said I could use the duralite lithium ion charger that I already have for my jets. I was a little concerned since the battery did not have the charge safe circuit built into the back but he told me not to worry that the charge safe circuit was built into the charger also. This put my mind to ease quite a bit and we continued talking when I asked if he also sold the Li-Ion packs as well and he said yes. He sells either 2200 Mah 2 cell packs or 4400 4 cell packs. I said great how much are they and he said his two cell pack was 25.00 and his 4 cell pack was 50.00. He told me the cells that he used and where he got them from so that I could research it. He also stated that with the charge safe circuit built into my Duralites Plus charger I could use it to charge these batteries.

Well I did some investigating last night and on the internet and found the cells that he was using on the net. Out of curiousity, I cut the shrink wrap off one of my old duralite packs and opened up my charger and he was 100% correct the charge safe circuitry is in both the charger and the battery and the cells are identical. Made by the same company and the same stock number as what duralites plus uses. I placed an order for one of his batteries and should have it in the next couple of days to test with the ECU of my RAM 500, if it works out well I will continue to buy my batteries from this company for half the cost of what duralites plus is selling them for.

This is not a plug for this company but information that I wanted to share with everyone. Why continue paying twice as much for our RX and ECU batteries when you can get the same product from another supplier for less.

I will post how my test goes with the ECU Battery that I ordered, should be very interesting.

Patrick.

Patrick,

Looking forward in hearing about your test results using these batteries for the Ram 500 ECU.

Steven T

Just one point. The reason the charge-safe circuitry is in the battery pack is to protect the cells if the pack should be connected to an improper charger. Like one set to charge nicads instead of lithium. That is the true protection.

I had a quick look at a new product from FMA (www.fmadirect.com look under chargers) called a "Safety Guard" which attaches to our normal constant current style charger outputs and adapts these chargers for use with Li-poly batteries. I assume it limits the voltage into the packs somehow... The only drawback is that you have to have one each for 2, 3, or 4 cell Lithium packs. I guess you also need to remember to have it attached to the charger, which is no more demanding than remembering to use the Lithium charger for Lithium batteries! With these Li-poly cells now coming out in 8 to 12 C discharge rates (higher soon too) they are quite capable of handling our highest current demands when the starter and glow are both energized. There is a significant weight reduction, so these cells should soon become the standard for most RC uses. I still worry about charging them inside the plane though, and I put them into a metal can outside the plane for that extra measure of safety.

Len

Tony,
Powerflite does not use the charge safe circuit in the battery, but just in their charger and you have not heard of anyone having any serious issues with their batteries. I know the old saying, "Build a better mouse trap and you just get a smarter mouse", well with these batteries build a better way to protect the end user and you will get an end user who will still screw it up. Trust me someone will end up charging through the black lead on a duralite instead of the yellow one. You can't idiot proof everything.


Patrick.

On my Duralites you cannot charge through the black lead. Don't ask me how, I just know if I hook it up to the charger through the black lead the light won't come on. I hear what you're saying, I'm just telling you why DuraLite also puts the circuitry in the pack. I do believe that with all the recent attention to lithium charging issues, you will see more lithium packs do the same.

That's interesting.....wonder why? Your black charging jack isn't going thru the regulator, I presume, as some of the regulators on the market are diode protected from reverse current flow......if not, then there must be something like a separate diode blocking it which would be unusual.....

Gonna have to see if my Duralite ECU pack will charge thru the big 14 ga leads....never thought about that.....this is my first Duralite pack......always used Powerflites before, disconnecting the battery from the ECU and charging that way.....

If it doesn't, I may have to add an extension to the charging lead as the Duralite on the KingCat is way up front, and I was planning to charge thru the lead end near the ECU......

Tom

Just answered my own question....one one of the frames of the Duralite website, a statement is made that the black lead is reverse protected to prevent hooking up an "inappropriate charger"....learn something new everyday.....

So probably if you add all that proprietary protection stuff to the Troy-Built packs, gonna come out priced close to the Duralites....

I still like the double safety net (actually triple with the black lead blocked as well) in the charger and the bats which is why I have switched to 4000 maH Duralites from Powerflite.......that way I can comfortably leave the house or go to sleep with the bats in the plane in my garage on the floor, rather than having to stuff them in a sheet rock lined box in my fireplace.....I never have charged the R/C liths unattended in the house and don't plan to.....even in my workshop, way to many flammables close by....

Tom

Tom,
If you are that concerned about the batteries doing something strange while you sleep just buy the new safeguard circuit from FMA and put it in line with the lead from the charger. The circuit will prevent the overcharging of the battery just like the circuit in the duralite pack. 40.00 for a TBM pack plus 12.95 for each charge lead. even if you bought one for each charge lead you would still come out lower than half the cost of a duralite. This is just my opinion. The only time the charge safe circuit is in use is when charging not when actually using the battery.

Don't want to offend anyone but if I am correct the charge safe circuit is just in between the pack and the charger. Why wouldn't the FMA circuit soldered into the charge lead serve the same function?

Patrick.

Patrick:

As long as the in-line overvoltage limiter from FMA monitors each cell in addition to the entire pack to aid in preventing un-balancing the pack during repetitive charge cycles, you have a point.....it would be cheaper.....

The good old free market.....competition always produces more favorable pricing......

Tom

Patrick,

How did your test with these Li-Ion packs work with the Ram500?

Thanks,
Steven