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Author Topic: 4.35 Volts per cell batteries  (Read 1746 times)

Offline Matt Piatkowski

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4.35 Volts per cell batteries
« on: October 18, 2017, 03:37:17 AM »
Hello,
http://www.store.revolectrix.com/Products/Blend435-PLATINUM-Label-40C-GoPACKS show batteries that, according to the manufacturer, can be charged to 4.35 Volts/cell. Normal chargers (charging max. to 4.2 Volts/cell) cannot be used for such batteries - a special charger from revoletrix.com is needed.

The batteries are suspiciously cheap: Revolectrix 2530mAh 6S LiPO - Blend435 Platinum Label 40C GoPACKS is only $48.62 (Excl. GST).
Please note that this price seems to be in the Canadian dollars as the GST is mentioned. I feel flattered that the Singapore based warehouse uses the currency of my adopted country but, again, why are these batteries so cheap?

The opinions of the R/C community range from "fantastic!" to "another hoax" and "the marketing ploy to sell these new expensive chargers...".
Some R/C people say that such batteries will last only a short time, will swell after small number of flights, are dangerous and so on.

Please share your comments and opinions with me.

Best Regards,
M




Offline Matt Piatkowski

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Re: 4.35 Volts per cell batteries
« Reply #1 on: October 18, 2017, 07:34:46 AM »
Hi Motorman,
Why do I need all that?
Because I am the guy who likes to know.

Remember the story of the PC?
People were asking the same question you have just asked.

Best Regards,
M

Offline Russell Bond

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Re: 4.35 Volts per cell batteries
« Reply #2 on: October 18, 2017, 04:52:57 PM »
Revolectrix batteries are very, very good!
I have some that are 4 years old and work perfectly.
A lot of good chargers can charge to 4.3 volts, you have to go into settings to change it. (My iCharger does)
Bandolero

Offline Igor Burger

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Re: 4.35 Volts per cell batteries
« Reply #3 on: October 19, 2017, 02:24:02 AM »
Well I use cheaper batteries from HK (zippy compact or turnigy ) with good result, so it is not cheapest battery. I do not see reason why it should not work. We do not need any special batteries.

Regarding charger - you can use also normal charger, or charger which goes to 4.3V like Russell wrote, but you get little less capacity. The only difference to normal cells is, that the chemistry allows higher charge voltage (difference between discharged and charged) and that will give little more capacity from the same amount of material, so they can be little lighter.

That also tells its disadvantage - for good efficiency I prefer power source with constant voltage, not battery which changes voltage during dischargeing. But it is very small difference, it will work well I think. 

Offline Christoph Holtermann

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Re: 4.35 Volts per cell batteries
« Reply #4 on: October 19, 2017, 05:55:15 AM »
Hi Matt,
as you know many factors influence your battery choice.
The criteria I look at are:

- Battery dimensions: The shorter, the better for me. A short battery such like the Revolectrix (4 inches in this casee) but also the ThunderPower can be moved inside the battery compartment to slightly adjust CG. With the longer ones it is difficult or impossible.

- Battery weight: I have compared batteries with up to 60 grams difference in weight (6 cell battery) and flying indeed is different. My plane has some slight tendency to stalling in warm weather and calm air and if I can save some grams I do it. The 350 grams of this Revolectrix seem light. If you can make use of its capacity then do it. If for instance you use less than 80% of your battery capacity for a normal flight then why have additional capacity if it isn't needed?

- Convenience:I also fly two high voltage batteries, the rest is with normal 4.2V cells. I always need 100% concentration to change the charger setting from 4.3V  back to 4.2V to charge my standard type batteries. During the heat of a competition I don't want to have these setting changes in my charger to avoid the risk of over-charging the standard-cell batteries. Some battery testers also get mad when checking a fully charegd HV-type LiPo. Mine always warns me with "over-voltage". Also inconvenient if you check this prior to a competition flight and spectators around you ask you questions what problem there is with my battery. At least it distracts me  :)

But like Igor says: Why shouldn't they work? Even if you don't yet have a high voltage charger you still can use your normal charger at the expense of some unused capacity. I guess you would lose some 150 mAh if you charge them up to 4.2V/cell only.

Christoph

Offline Vitalis Pilkionis

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Re: 4.35 Volts per cell batteries
« Reply #5 on: October 20, 2017, 08:44:16 AM »
This year I used these lipos from HK in configuration 2 x 3S:

https://hobbyking.com/en_us/turnigy-2700mah-3s-20c-lipo-pack-suitable-for-quanum-nova-phantom-qr-x350.html?wrh_pdp=3

They are good batteries overall, but extremely sensitive to discharge level.
Low voltage cut-off at 3.2V is way too low for them - internal resistance rise tremendously and after few flights you get them useless.
Set an LVC in your esc at 3.4V-3.5V or adjust power consumption so that after a flight voltage would stay at ~3.7V and then these lipos will serve you well.
I also doubt about C rating of them, cause they heat up quite strongly, so good ventilation is a must.

Offline Matt Piatkowski

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Re: 4.35 Volts per cell batteries
« Reply #6 on: October 21, 2017, 09:05:09 AM »
Hi Christoph,
Hi Igor,
Good idea with charging 4.35 V/ cell batteries using standard charger that goes to 4.2 V/cell or setting the max. voltage on your HV charger to 4.1-4.15V.      4.2 / 4.35 = 96.6%. Not going to max 4.35 V/cell should extend the HV battery life a bit.

Everybody,
I have received the confirmation directly from Revoletrix, that the 435 Blend batteries, for example:

PN: B435 YS2530-6S-XP
Revolectrix 2530mAh 6S LiPO - Blend435 Platinum Label 40C GoPACKS
Blend435: GRAPHENE OXIDE SPECIAL EDITION
Price: $48.62 USD (Excl:GST)

are being re-designed. They are currently out of stock but suppose to be available again in December 2017.
Revoletrix claims that these re-designed batteries will have better longevity - up to 100 cycles.

Regards,
M

"A day without learning at least one new thing is wasted"

 

Offline NED-088

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Re: 4.35 Volts per cell batteries
« Reply #7 on: October 26, 2017, 04:15:58 PM »
I never charged them over 4.2 V per cell and always put them in storage condition of 3,8 V per cell. Mine never were below 3,7 Volt at the end of the flight.
I've been flying these 3200MAh 4S batteries and while the first batch I had - 30C Black label- took me through 2015 without any signs of deterioration, they died during the first training in 2016, only weeks before the W.Ch.
My next batch -40C Platinum label- has been used during 2016 and 2017 and so far, still OK.

My main reason for using them is weight, these 4S packs are only 275 grams. No way I could get my CG right with any other batteries, besides, I wouldn't like any higher wingloading either.

Problem with the RC driven development is that batteries for a given capacity are getting heavier all the time.
Revolectrix is the pleasant exception here. Hopefully their 'redesigning' is not making them useless to me.
'If you think there's something about my English, you're right. I'm Dutch... '
But I DO play Stunt and I DO fly Bluegrass.


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