Re: R/C dumb. Could use some help

pkrankow Mon Dec 11, 2017 8:37 pm

Cribbs74 wrote:https://www.venompower.com/products/venom-2-4-cell-ac-dc-dual-lipo-battery-balance-charger

Does this one look right?

That will get the job done. I presume it runs on a wall wart and includes battery clips for the field from the description.

Phil

roddie Mon Dec 11, 2017 9:08 pm

Cribbs74 wrote:I decided on these.

https://www.venompower.com/products/venom-10c-2s-850mah-6-6v-life-tx-rx-transmitter-and-receiver-battery-2-packs-1

Now can someone tell me what charger I can get to charge them? From the same website... I have been looking for the last 40 mins

Ron, have you purchased a radio-system yet? I ask because I had concern about the LiFe cell's voltage being 6.6V. I'd previously asked about that "here" on the forum.. because receivers have "traditionally" had an input-voltage of 4.8 to 6.0VDC. I had concern that the .6V over-current might be enough to "fry" the electronics in the receiver.

Whilst doing some recent research (yesterday..) I noticed that that the "Futaba" receivers (in particular..) are now rated for up to 7.4VDC. It's "speculative" whether my fears were warranted.. but the fact that Futaba's receivers will now handle a higher voltage is likely the result of modern battery-technology. It may be wise to purchase a "receiver" that is rated for 7.4VDC.. just to be safe.

Any charger designed to charge LiFe batteries should work for you.

**Cribbs74** Mon Dec 11, 2017 9:24 pm

I have a brand new 2.4 Spektrum radio that has sat unused for the past 6 or so yrs. It doesn’t require a battery pack to operate. I also have a spektrum receiver . No idea what it’s designed for voltage wise. I assumed the 6.6V was what I needed as that’s what was suggested here.

NEW222 Mon Dec 11, 2017 9:29 pm

Do not buy the charger you have listed. That one specifies LiPO batteries. No mention of LiFe batteries. Just give me a minute.

NEW222 Mon Dec 11, 2017 9:37 pm

This would be the one I would recommend from the site:
https://www.venompower.com/products/venom-lipo-and-nimh-ac-sport-balance-charger-1

This looks to be easy to use, charges many types of batteries, but the only thing is that it is AC only. So, if this is a big deal to you, then please disregard this one.

The one you linked to earlier says LiPo in the ad, but in the instructions it makes mention only once of LiFe. I cannot say for sure, but that fact alone would make me shy away from it. That is, however, just my opinion.

NEW222 Mon Dec 11, 2017 9:45 pm

Cribbs74 wrote:I have a brand new 2.4 Spektrum radio that has sat unused for the past 6 or so yrs. It doesn’t require a battery pack to operate. I also have a spektrum receiver . No idea what it’s designed for voltage wise. I assumed the 6.6V was what I needed as that’s what was suggested here.

No worries. Spektrum receivers, and their 'fruity' copies are designed to operate from 3.5V - 9.6V. I have used, and still do, a 2s 7.4V LiPo battery plugged directly into any of my 2.4 gig receivers. No problems at all. The LiFe were designed as a safer alternative for all. As I do not have LiFe batteries, I have not used them on an older receiver myself, BUT, a friend at work uses them now exclusively on his older Futaba 72mHz receivers and radios and has had no problems.

pkrankow Mon Dec 11, 2017 9:48 pm

Blasted chemistry. Yes, different types of battery take different charge rates and voltages. It is very important to get this right.

Phil

Mark Boesen Mon Dec 11, 2017 9:48 pm

2300mAh 4.8v NiMH (note the mAh)
https://hobbyking.com/en_us/turnigy-receiver-pack-2300mah-4-8v-nimh-1.html?countrycode=US&gclid=CjwKCAiA9rjRBRAeEiwA2SV4ZWHv579uKzvKgcyaRv0P07qvm1o_tX1Xu5dYX1I4lf42Wci0MSv1zxoCT9AQAvD_BwE&gclsrc=aw.ds

or go to walmart/ Menards and and build your own.
https://www.walmart.com/ip/Duracell-Rechargeable-NiMH-AA-Batteries-4-Count/26120755

This charger will do everything you need, shipped from USA
https://www.ebay.com/itm/iMax-B6AC-1s-6s-Lithium-Polymer-LiPo-Battery-Charger-NEW-FREE-SHIPPING-USA-Stock/172427947983?epid=1438037386&hash=item282581afcf:g:-N8AAOSw1NFaDgN9

As far as your Spectrum Rx, 4 AA Duracell or NiMh will last a long, long time. The Rx, if you're not using a motor/ESC you only need juice for servos, 4.8-6.6v will work, some say the higher voltage is tuff on the servos, they do move quicker. When running a ESC/motor with 7.4 (2 cel) or 11.1 (3 cel) battery pack the ESC reduces the voltage going to the servos.

ian1954 Wed Dec 13, 2017 8:25 am

Hi Ron,

DO NOT PLUG THE RECEIVER AND SERVOS INTO A 2S Lipo battery

They will fry. Most of us who fly electric forget that the ESC unit that powers the electric motor has a built in voltage regulator to bring the voltage down to 5 volts for the receiver. The receiver is plugged into this - not directly to the battery.

To connect a 2S lipo to a receiver the voltage has to be limited to 5v.

These units are readily available and can be used to step down lipo batteries from 2S to 6S.

https://www.banggood.com/5V-3A-UBEC-Support-2-6S-Lipo-Battery-Fully-Shielded-Anti-interference-Voltage-Stabilizer-p-1033112.html?gmcCountry=GB¤cy=GBP&createTmp=1&utm_source=googleshopping&utm_medium=cpc_ods&utm_content=heath&utm_campaign=pla-airplane-gb-pc&gclid=EAIaIQobChMImbXGyJaH2AIVYRbTCh2DwA4REAQYASABEgL7hvD_BwE&cur_warehouse=CN

**Cribbs74** Wed Dec 13, 2017 10:56 pm

I am not going to swear, but I am about fed up. If the dang stuff needs to run on 5V then why make 6.6 packs.... Mad

KariFS Wed Dec 13, 2017 11:50 pm

Ron, most, if not all, battery chemistries that have lithium in them, have a voltage of 3.7V per cell. So the voltage of just about any Lithium pack is a multiple of 3.7V. The number in front of the "S" tells you how many times you need to multiply the 3.7. This is a pita if you have older equipment requiring 6 volts.

EDIT: Lithium-iron cells have 3.3 volts, not 3.7. Sorry.

Lead batteries have 2V cell voltage, that's why we have 2V glow plugs in bigger glow engines Smile

Traditional dry cells are 1.5V, rechargeable Nickel cells 1.2V and so on, pack voltages are obviously multiples of cell voltages.

If you are using the packs just for powering the RC equipment, and your plane is of a reasonable size, I recommend an NiMH pack of 4.8 or 6 Volts and use a voltage limiter if necessary.

LiPo packs are light, powerful and very good for high power applications but on the other hand require a special charger and very special care. And there is the higher risk of fire too. I just recently found out they need to be stored not full, but in a special "storage charge" which is not empty, nor full, and they need to be "topped up" before use. Makes "ex tempore" usage just about impossible.

NEW222 Thu Dec 14, 2017 1:27 am

Kari, you are correct about the storage charge on a lipo battery. The average well used is 3.85V per cell, and this is why I recently bought my iMax charger, because it has the storage function.

Oldenginerod Thu Dec 14, 2017 5:58 am

Well all this back and forth talk has sealed my fate. I can easily calculate nitro & oil content, and know what size/power engine I have. I can easily make up a 1.5 V glow starter battery pack using cheap off-the-shelf Duracells. I can easily control a plane within a controlled hemisphere with two flying lines and know 100% that I actually have control, not just assume that an invisible radio signal is going to do everything that I want to do in safety.

It's I/C & C/L all the way for me.

ian1954 Thu Dec 14, 2017 10:09 am

Cribbs74 wrote:I am not going to swear, but I am about fed up. If the dang stuff needs to run on 5V then why make 6.6 packs....

!

I understand the frustration with this. I looked at a few sites for receiver packs - most of which recommend 2S lipos but only a few mention BECs and that is in small print.

I know that some receivers will happily take 6v but not all servos are happy at this voltage.

I should also mention that a lipo cell has a nominal voltage of 3.7v but on full charge - this is 4.2v! A fully charged 2S lipo is 8.4v!

I always play safe and use a BEC set to 5v.

roddie Thu Dec 14, 2017 10:59 am

Hi Ron..

Have you lost your mind yet? Take a look at this YouTube vid from RC Model Reviews. This fella (Bruce) gets on my nerves a bit.. Laughing

but there's some good information that might help you. The final segment of the vid covers the LiFe batteries.. but it's worth watching the whole thing.

getback Fri Dec 15, 2017 8:22 am

Man what a pile of info. Blows my mind , but once you get it sorted out then you know what to stay with , keep it as simple as possible is what i try and do Very Happy

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