Lipo suggestions

On 16 Jan 2007 01:01:19 -0800, I said, "Pick a card, any card" and "Steve" instead replied:

Don't put them in the vacuum cleaner. That would be lipo suction.

Ba-dump!

-- Ray

Steve, Let me suggest you go ahead and goto 20c batteries. I currently have only one battery that is not a 20c "thunder1320". I am very hard on batteries most of them didn't even sorvive a month. But since my first

20c they have takin a beating but I can say they are all still working. Even the 1200 that went into the street at around 60mph! Ok so they don't look the best and people always say things about the safety of them. wellof the 1.. !! Which I still use and the day that the safety charger no longer detects a 3 cell 1200 20c enerland then I will despose of it properly.

Well hope it helps Ricky

Ps. you shouldn't need to change any of the chargers

Steve wrote:

I have found that almost all brands are reliable at 8C discharge rates.

I have read data and seen tests that indicate that almost none are reliable and have long life at the manufactures/vendors CLAIMED rates.

In short, get a pack big enough to run at no more than 8C flat out, and inmost sport applications flying at half throttle you will get about 30 minutes total pack time, which means you will be unlikely to ever run the packs flat, and this, together with the modest demands you are placing on them, will mean that they don't pop burn up and die, don't need 'balancing' and will last a couple of years (200+ cycles) too.

One accepts that if you have a requirement for ultra high power density

- competition or EDF or some forms of extreme 3D, you may need to run batteries harder than that. Well read the reports and get the best. And accept the need for balancing, and a short service life, and the expense.

I'm using and am happy with CommonSenseRC lipos. Look to

for info.

I find it just as cheap or cheaper to buy them through my local hobby shop.

OS

"Steve" wrote in news:1168938079.345866.252090 @q2g2000cwa.googlegroups.com:

I strongly concur with the other poster who recommended Common Sense. Their prices are good, they ship very quickly, the packs are well-built and well-labeled, and I believe that they're more honest about their pack performance than some other vendors. For instance, I suspect that their "8C" packs would be considered "12C" by many companies.

The downside is that they're slightly heavier than a lot of brands (maybe

10%?) and don't come with PowerPole connectors.

Aside from CommonSense, I've been happy with my Tanic and Thunder Power packs, though I haven't done a lot of cycles on the Thunder Powers. Flew the heck out of my Tanics, though.

FWIW, neither the Tanics nor the Thunder Power packs came with PowerPoles, either.

and CommonSenseRC prices and warranty.

OS

>

Steve,

Your LiPoly chargers will charge ANY LiPoly pack on the market. The charge requirements are the same because the chemistry is the same.

Now, you're blaming the brand for your battery problems. That may not necessarily be the case. To have so many problems with packs would indicate a problem in how they're being used, not a problem with any particular brand. It is very unusual to have that many failures, even with a mediochre brand of battery. Electrifly packs are not low-quality packs by any stretch.

I would propose to you that if you went out and picked up more 10C rated packs, you would have just as many problems, no matter what brand you chose. Why? I'm betting that you are pushing the battery packs too hard and don't even know it.

Do the packs come out of the plane HOT? You're pushing them too hard. Are you carefully choosing your packs based on the anticipated or better yet measured current draw from the motor? If not, you're probably pushing your packs too hard. Are you zooming around at full throttle for the entire flight? You're probably pushing your packs too hard. Are you using a Whattmeter to check your systems to make sure that they're operating within the limits of motor, ESC, battery? If not, you're probably pushing the packs too hard.

I use them in a plane that does mostly aerial video (Magister). My typical flight is very slow back and forth passes. I installed an Eagle Tree micrologger on the plane in search of my problem and never got over 35 amps (and that was at take-off). I was using 4 3S 1500 mah Electrifly batteries in parallel, then tried again with 5 in parallel. With the 4 in parallel this is just over 5C.

I had 1 Electrifly battery that wouldn't charge straight out of the box. As soon as I hooked it up to the charger I got the "no battery" error. I had another one that charged once and never again, the second time I tried to charge it it went for about 10 minutes then gave the same "no battery" error. I was using the Electrifly quad charger both times, usually charging them about 1/2 C. I sent them both back to Electrifly with a note about what was going and they sent me 2 new ones.

I had a smaller one (910 mah I think) that was sitting on a shelf and hadn't been used in at least 2 months. Then 1 cell swelled up one day.

On the other hand, I've had 3 Polyquest batteries that haven't even hinted at a problem in the 2 years I've been using them.

Maybe I'm just unlucky with batteries or maybe something else is going on. I asked here a couple months back about the battery fialure problem and was never able to come up with a cause.

I guess my next step is to make up soem adaptors to put my WhattsUp meter on the batteries when I charge them and see if I can tell what's going on.

Thanks, Steve

I have heard numerous reports like yours regarding Electrflt batteries and also the motors and speed controls from them.

I have had good luck with LiPos form Kokam and Common Sense RC. I use

2,000 mah, 10C batteries where other folks use 1500, 15 or 20 Cs. They cost less and don't weigh all that much more.

CR

Steve wrote:

You must be the only person then..

Overrated and overpriced. They do work at 1/3 to 1/2 advertised ratings reasonably reliably I'll grant you..

In some cases they weigh *less*.

Always look at what the watts per pound of the battery pack is..after derating the manufactures wilder delusions to something approaching common sense.

Usually the lower rated batteries of higher capacity will weigh no more, cost no more and give you longer flights.

I haven't used common sense, but have heard good things.

I'm glad someone is getting decent service from Kokam. Other than a couple guys at the field that are running them at NO more than 1/3 or 1/2 of their advertised rating , they have pretty much been junk...and they are as expensive as Thunder Power.

I bought 10 Kokam packs , 5 1500 3 cell and 5 1500 2 cell. In less than a year of light usage , they have all bit the dust. A couple swelled up and burned , 2 burned while charging and the others lost capacity to the point they were worthless.

I've checked many of the other guys Kokams and when they got close to half of their rated continuous capacity , the voltage dropped to the floor. Checked many of the cheap batteries also with the same results. I'm sure there are other good Lipos out there , but so far Thunder Power is the only brand I've tested that actually came VERY close to their claim. I have loaned my Thunder Power packs to a few of the guys who have some of the cheap packs and they couldn't believe the difference.

Again , I will say that if you don't load the packs to any more than

1/3 to 1/2 of their capacity and then use only 70-80% of that before you land then they will probably do the job. Given this , you could buy a smaller and lighter Thunder Power for less money , ie: Thunder Power 1320 mah vs Kokam 2000 and get very close to the same performance.

Ken

and Common Sense RC. I use

A thourughly good summation of 'Kook-Ems' as they are known. The brand purveyed by the 'Dark Smerf' himself*

*anag.

On Wed, 24 Jan 2007 02:40:50 +0000, The Natural Philosopher wrote:>>

Thanks TNP :-)

Ken

They are known as Hokum for a reason.

Out of 5 Polyquest batteries (various capacities) purchased in the last year, 1 is still working, and it's only good for a five minute flight. All were always charged at slightly over .5C with a balancer, and used under

10C. Thunder Power is the only brand I've gotten decent life from.