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What are the benefits of going Lipo vs Nimhs?

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Old 09-01-2008, 01:59 PM
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mtdoramike
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Default What are the benefits of going Lipo vs Nimhs?

What are the benefits for switching from nimhs to lipos? Have you found any?
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Old 09-01-2008, 10:46 PM
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Default RE: What are the benefits of going Lipo vs Nimhs?

Lipos have more or less revolutionized electric flight.

The biggest benefit is that lipos weigh about one-third as much as NiMH for the same capacity. This is another way of saying lipos have about three times the power density of NiMH. This means you can:

1 ) add a lot of flight time without increasing the weight of the plane, or

2) keep the battery capacity the same but your plane will be much lighter and therefore performance will improve, or

3) get BOTH better flight time AND better performance by switching from NiMH to a lipo with a somewhat larger capacity.

The downside? You need a charger designed for lipos, and you must take care not to overcharge or over-discharge lipos. Lipos can't withstand the same type of abuse that NiMH can.

- Jeff
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Old 09-03-2008, 05:43 PM
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Arkitexas
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Default RE: What are the benefits of going Lipo vs Nimhs?

The other downside of Lipos is the cost. Lipos are twice (+-) the cost of a NiMh of the same mAh. Still, Lipos are the best in the long run.

Rick
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Old 09-03-2008, 08:51 PM
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Default RE: What are the benefits of going Lipo vs Nimhs?

ORIGINAL: Arkitexas

The other downside of Lipos is the cost. Lipos are twice (+-) the cost of a NiMh of the same mAh. Still, Lipos are the best in the long run.

Rick
Depends on what & where you buy.

This 3S 2000 mAh 8C lipo pack
http://www.commonsenserc.com/product...products_id=48

is less expensive than this 2000 nimh pack:
http://www3.towerhobbies.com/cgi-bin...?&I=LXGBM9&P=7
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Old 09-03-2008, 11:39 PM
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Default RE: What are the benefits of going Lipo vs Nimhs?

Depends on what & where you buy.

This 3S 2000 mAh 8C lipo pack
http://www.commonsenserc.com/product...products_id=48

is less expensive than this 2000 nimh pack:
http://www3.towerhobbies.com/cgi-bin...?&I=LXGBM9&P=7
OK, for an apples to apples comparison price both cell types from the same supplier. Besides, the Nimh can deliver 10c to 12c. Pick a 12c Lipo.

Rick
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Old 09-04-2008, 04:11 AM
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Default RE: What are the benefits of going Lipo vs Nimhs?

and with Lipos, you can do like we do: after a long day a flying and its time to fire up the grill, we simply grab one of our beat up lipos and toss it in the barbeque pit. a few good bashes with a rock the size of a bowling ball, and "Voila" we have fire. a BB-gun does the trick every once in a while, but since we are so safety consciouse, we limit the BB gun shooting - we wouldn't want someone to lose an eye and miss a beautiful BBQ.

Kurt
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Old 09-04-2008, 09:39 AM
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Default RE: What are the benefits of going Lipo vs Nimhs?

On a practical note, the self discharge rate for lipos is very low. You can charge a lipo and even if you don't use it for a few days, it will hold its charge just fine. No need to "top off" just before flying. You can charge them whenever convenient, then grab them and go fly days later.

- Jeff
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Old 09-04-2008, 09:44 AM
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Default RE: What are the benefits of going Lipo vs Nimhs?


ORIGINAL: mtdoramike

What are the benefits for switching from nimhs to lipos? Have you found any?
With lipos it's much easier to fly with higher voltages. The higher the voltage, the less current you need for the same power output. This improves efficiency and battery longevity. It will also allow you to use less expensive, lower-C batteries.
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Old 07-11-2010, 09:21 PM
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Default RE: What are the benefits of going Lipo vs Nimhs?

li-po batterys suck, as far as i am conserned. they cost to much, must be balanced, are delecate,don't last one fourth as long as nimh type. i've had plenty over the last two years and don't have any left to use. they stop working at any time. you can't fix them like nimh or ni-cad packs when a cell goes bad. they can ballon up, they can catch fire or explode too. i'm not saying there no good, but have more disavantages than nimh. they are lite in weight, put out high amp rates and are ok, but you pay for it. drawing high amps kills there life to half. i got tired of them after awhile. you pay good money for these , and they should last much longer. of course money is short these days and it doesn't help things either. just seems a 50.00-60.00 li-po should give you a year of no trouble flying twice a week. no way they do IMHO.............RON
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Old 07-14-2010, 12:56 PM
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Default RE: What are the benefits of going Lipo vs Nimhs?

I don't know any guys flying electrics with NiMH or NiCd packs anymore. Power to weight ratio sucks with them.

If you're going to fly electric, go with brushless/LiPo power systems, otherwise you're better off just sticking with nitro IMO.

I've also got LiPo packs in my transmitters, and LiFePO4 packs in my nitros for the RX packs. The weight isn't as big of an issue in these applications, but the low self discharge rate of the LiPo and LiFePO4 packs means my TX and planes are always charged and ready to go no matter how long they've been sitting. The fast recharge rate also means I can charge them much faster than the NiMH packs.

HobbyKing sells LiPo packs for about 1/2 what most US based stores sell them for (including shipping).
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Old 08-01-2010, 11:57 PM
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Default RE: What are the benefits of going Lipo vs Nimhs?

IMHO with the drop in the cost of Lipo's, it's the only way to go. If NiMH or NiCd are so good, why are brushed only included with the cheaper trainers. Just about everything now is brushless. I've been buying 2200 MAH 3cell 25c rated batteries for less than 20 bucks.
My lipos give me about 100 flights before they start to go bad. There is no way for my FW190, EDFs, or my hotliner to perform the same way on NiMH or NiCd as it does on Lipos. NiMH or NiCd are fine for TX and RX usage.
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Old 08-02-2010, 10:14 AM
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Default RE: What are the benefits of going Lipo vs Nimhs?

There is no requirement that brushless motors use only lipo batteries. Or that brushed motors can't use lipos.

Now it just so happens that lipos became widely available at about the same time as the prices for brushless motors started to fall. It was a "perfect storm" for our hobby that gave electric flight a huge boost.

So while it may seem as though brushless and lipos must be used together, you could use one without the other if you want to. I'm not sure why you would, but you could!

- Jeff
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Old 08-03-2010, 10:43 AM
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Default RE: What are the benefits of going Lipo vs Nimhs?

If you do used a brushed ESC with a LiPo, just be sure it has the proper LVC (low voltage cutoff) for the LiPo. Many of the older brushed ESCs have only NiMH/NiCd LVC levels.

I started using 2S LiPo packs in my brushed surface vehicles, and those ESCs don't have the proper cutoff voltage, so I purchased some 2S LiPo low voltage alarms to let me know when they are getting close to the min voltage. With an aircraft, this type of alarm may not do the job, though (too far to see or hear).
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Old 08-04-2010, 01:47 PM
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Default RE: What are the benefits of going Lipo vs Nimhs?


ORIGINAL: Arkitexas

The other downside of Lipos is the cost. Lipos are twice (+-) the cost of a NiMh of the same mAh. Still, Lipos are the best in the long run.

Rick
I don't think the cost issue is really there anymore. You can find expensve NiMh and you can find cheap lipos.

On a $$ per mah, lipos are the winner.

On a weight basis, lipos are the winner

So, weight and capacity are the key advantages.

If you BADLYabuse lipos they can be dangerous, but you have to really badly abuse them.

I have phased out almost all of my NiMh and NiCd packs.I only useNiXX packs for my receiver packs in my gliders and I am starting to move those over to Lipos too.
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Old 11-07-2010, 09:54 AM
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Default RE: What are the benefits of going Lipo vs Nimhs?

VS

This is not meant as an off-the-cuff, smart-ass reply. It is fairly accurate.

Lipos:
cost more
lighter
much more powerful/faster
more fragile
require better fuel (different charger)


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