What batteries are people using?

Dave Pickett · Post by **Dave Pickett** » 08 May 2011, 12:18

And how long do they last?

I currently am planning on using a 1300 mah Lipo at 78 grams, or if weight in an issue a 900 mah lipo at 50 grams. I may or may not use a voltage reducer (the rx and eurgle winch are rated for this voltage and I suspect the steering servo will survive!)

What is everyone else using and how long do they last?

Hiljoball · Post by **Hiljoball** » 08 May 2011, 18:06

I have just started to use liops for both TX and Rx and am delighted with the results. The Tx can go a whole weekend at a regatta on one battery. No knowing how good they were, I bought three Rx and two Tx batteries so I have lots of capacity at an event.

Just take the usual precaution about keeping the batteries dry, and follow the charging instructions carefully, especially the safety aspects. ( I remove from boat and charge in a tin box away from flamables on a concrete floor)

I have an RMG which likes the voltage and amperage, and has a voltage regulator that feeds the Rx and servo a steady 5 volts.

John

chris sullivan · Post by **chris sullivan** » 08 May 2011, 18:27

Lipo - 7.4v./2100mah by venom, I think I got mine from Tower hobbies
stats - 2s2p cells
3.2 oz/90.7g
50x30x31mm
sully

Bruce Andersen · Post by **Bruce Andersen** » 08 May 2011, 22:22

LiPo's by MaxAmps in boat & transmitter

Peter Allen · Post by **Peter Allen** » 15 May 2011, 03:45

900mah LiPo gives 4hrs+ sailing time.Boat uses 185mah per hr at flat out no1 rig weather using a RMG.How do i know i installed a watt meter.Modern LiPo's can be charged at 5C that's 12min provided you have a proper balance charger,do it all wrong and you'll watch your boat or worst yet your house burn down.The flame produced from a LiPo fire can melt aluminum,they're not toys but if used correctly they are the buisness.A123 or known as LiFeP04 batts have fairly similar propertys without the hazard,weigh slightly more and 3.3v per cell.Using LiPo batts in a Tx is not great voltage is a bit high,some have had probs by what i've read,however some of the new hi end radios are LiPo compatible.Cheers

Peter Allen · Post by **Peter Allen** » 15 May 2011, 04:14

Dave,a 2s LiPo 8.4v will smoke a 6v rudder servo and the short will be going back to the batt not good ,there are Hi Voltage servos available BUT EXPENSIVE.

Dave Pickett · Post by **Dave Pickett** » 15 May 2011, 08:13

Helpful stuff, thanks Peter. OK I'll use the voltage regulator I bought for the rx and rudder servo but run the winch direct, as it is designed for the higher voltage................

Good warning on the lipos, have seen the videos of them catching fire, but I have also heard of someone loosing sight in one eye after an nimh cell exploded, we do need to use common sense with all types of battery. Have jsut ordered some 2300 mah lipos (92 grams) seems I could actually use the 900s I have when I need to keep the weight right down.

Peter Allen · Post by **Peter Allen** » 15 May 2011, 13:03

As far as the Tx goes,i've read that most 8 cell module based radios actually use 5v to operate so the higher voltage is dissapated in heat,hence we see radios with 4 cells.So you can see where a lipo at 12.6v could be a bit much,however an A123 3 cell batt is the ticket.Several people use LiPo with a diode to drop the voltage.

Bruce Andersen · Post by **Bruce Andersen** » 17 May 2011, 02:03

Folks using RMG winches are in luck inasmuch as they have an internal voltage regulator that outputs 5 volts, pretty much regardless of the input voltage (4.8 to 7.2 volts). As long as you run power to the winch and allow it's output to power the Rx and the rudder servo, you're OK. I've been running LiPo's (2s2p configuration) with an RMG for 3 years now without a single rudder servo problem (except when it turns my boat the wrong way - I'd like to blame the servo but it's usually a loose nut on the transmitter).

Barry Fox CAN262 · Post by **Barry Fox CAN262** » 17 May 2011, 05:56

If you are using Nimh cells in your Tx and it is of the variety that uses 8 cells then the nominal voltage for those packs is 9.6 V. However that is just above the threshold where most of these radios start to alarm that they are getting low (usually around 9 V). A good 8 cell pack of Nimh come off the charger well over 12 V and settle into the 11 V range and then 10 V range for most of a good long sailing day. The same kind of voltage applies for the NiCd pack that comes with most of these radios except they are such small capacity as to be useless for much more than an hour and bit.

So, a 3s Lipo peaked at 12.6 V is really not much different, it just has a much better discharge profile and will last a long, long time. I've used them in my radios for a couple of years now and the only downside is that I no longer have an excuse to stop sailing and take a break.

Peter Allen · Post by **Peter Allen** » 17 May 2011, 12:15

Barry i can't agree there on those voltages.Fully charged NiMh come off the charger at 11.5v and are at under 11v in short order,i've never seen a pack at over 12v.That LiPo will stay over 12v for a considerable amount of time,the LiPo has fantastic run time without question but you need to install a diode to lower the voltage a bit,or get the LiFe batts thier voltage is spot on as is .HiTec Spektrum JR service depts all have bullitins on Tx LiPo use.

Barry Fox CAN262 · Post by **Barry Fox CAN262** » 17 May 2011, 19:14

I can only tell you that my Nimh routinely came off the charger peaked well over 12V. They do drop off into the 11 range quite quickly though. If you used fresh alkaline batteries you would have right around 12 V when they were completely new but those also drop off soon.

I'm happy.

Bruce Andersen · Post by **Bruce Andersen** » 19 May 2011, 01:33

I agree with Barry - my Tx packs come off fully charged at 12+ volts and by the end of a 2 day regatta are usually around 9.8 volts. You do have to take care not to let them discharge below their critical value or they're dead and cannot be charged.

Peter Allen · Post by **Peter Allen** » 19 May 2011, 16:24

Bruce are you reffering to LiPo's 12.6v is normal end voltage after charging ,where Barry is refering to Nimh,i have charged over the years using hi quality delta peak chargers to cheap wall warts and never seen 12+v out of a NiMh pack best i've seen is 11.6 or so,if Barry says so it must be so.In any case i now use LiPo's with a diode to drop the voltage to 11.5v at full charge,the LiFe batts are spot on with the voltage without having to do that diode thing,but i'd already bought the LiPo and it works great.
Also of interest is the new wave of batt chargers,I have both the I Charger B106 $80 available online in the US and Turnigy Accucell 6 $30 from Hobby King in HK,both charge any chemistry batts including your car and fit in the palm of your hand and run on 110-220-12v,they are equally accurate at thier job but i recon the I Charger probably has better quality electronics inside and might last longer.These chargers have multiple menues within the LiPo menu,the information these things provide for the money is incredible.

Bruce Andersen · Post by **Bruce Andersen** » 21 May 2011, 05:48

yes, I'm running all LiPo's and the values refer to them not NiMH batteries

Dave Pickett · Post by **Dave Pickett** » 09 Jul 2012, 10:59

Have found some LIFE battery packs that look totally suitable and I can use them without a voltage regulator - worth a look:

http://www.vapextech.co.uk/acatalog/cop ... eries.html

The 1600 mah @ 68 grams looks a decent weight/price/capacity ratio............

Peter Allen · Post by **Peter Allen** » 09 Jul 2012, 12:53

That's a good choise not quite as much volts as a lipo 6.6 opposed to 7.4, but a more docile chemistry with fast charging capability,however i doubt thier claim that this battery weighs 68 grams a 2s 1600mah lipo is around 97g and LiFe's are a bit heavier so i would expect them to weigh 110-115g nearly doubble thier claim.My advise to you would be buy the 1000mah x 2,the primary reason for using these chemistries are weight and volts with the bonus of fast charging.Storage charging is not nearly as critical as it is with a lipo so it's a good compromize,you'll need to get yourself a decent balance charger these batteries are also great for the Tx.

Peter Allen · Post by **Peter Allen** » 09 Jul 2012, 13:38

One thing of concern is the 6.6 voltage is nominal these batts will come off the charger fully charged at about 7.2 volts and quickly drop a bit,they are a bit different in having a very flat discharge curve meaning they they will drop from full charge voltage and run at that voltage the whole way though and then suddenly drop off again at the end and you're out of juice.For 90% you will be over 6v so i'd still do some homework if your gear can handle the slightly higher volts.Some radio gear will and some won't especially the older stuff .If using a RMG winch you have no problem if you are not i'd go and ask the aircraft guys on another forum i believe quite a few of them have this setup.

Peter Allen · Post by **Peter Allen** » 12 Jul 2012, 19:11

I did ask the question and yes the aircraft guys are using them directly to power the Rx and servos with no problems.

Dave Pickett · Post by **Dave Pickett** » 13 Jul 2012, 10:38

Thanks Peter, definately going this route, more usable voltage and more stable chemistry. Once I get the batteries I will post up the weights.....................

Gyula · Post by **Gyula** » 14 Jul 2012, 16:20

I use pack of 5 Eneloop 2000 in the boat, never could run them flat in a day of sailing. I also tried to use eneloop 800 in pack of 5 in a Marblehead, where weight saving is an issue, and it was OK with RMG winch, but I always had a charged spare pack, just in case....

Peter Allen · Post by **Peter Allen** » 16 Jul 2012, 18:23

Nothing wrong with endloop low self discharge batts probably the best brand in NiMh,just that 5 cells are 6v and nowhere near the 9v spec an RMG can take so 6 cell pack is better 7.2v,i feel better having a 125g extra in lead in the bottom of the boat 45g-170g ,while the RMG winch on a 2s lipo and 55mm spiral drum is probably as fast as a servo arm winch and the charge time is 20 mins,matter of choise absolutley nothing wrong whatsoever with using NiMh batts.Peter

Dave Pickett · Post by **Dave Pickett** » 18 Jul 2012, 14:46

The LIFE batteries have arrived, the 1000 mah weighs 49 grams, the 1600, 76 grams...........

Peter Allen · Post by **Peter Allen** » 18 Jul 2012, 16:03

Very good i'm suprized,my 850mah lipos weigh 45g.What charger are you using do you have a balance charger for the LiFe chemistry?

Dave Pickett · Post by **Dave Pickett** » 18 Jul 2012, 20:02

Peter,

I am using this one:

http://www.ebay.co.uk/itm/iMAX-B6-Li-Po ... 1e70245f9b

and yes it will balance charge LiFE batteries as well as Lipo and nimh etc......

Barry Fox CAN262 · Post by **Barry Fox CAN262** » 18 Jul 2012, 23:44

My guess is the weight is per cell???

Peter Allen · Post by **Peter Allen** » 19 Jul 2012, 00:40

Yea i'm scratching my head also,when i look up lipos on HK a Turnigy 20C 1000mah is 62g and the 20C 1600 mah are 97g,LiFe's are supposed to weigh a bit more but Dave said he's weighed them 49g-76g both lighter.

Barry Fox CAN262 · Post by **Barry Fox CAN262** » 19 Jul 2012, 05:40

HK shows a 2 cell 2300 mah LiFe at 165 gms assembled, wire and connector so that is right back in 5 cell Nimh range and about the same voltage on average. Maybe a better discharge profile and better shelf life/less voltage drop off charge.

Dave Pickett · Post by **Dave Pickett** » 19 Jul 2012, 17:09

Guys,

To confirm for total clarity

the 1000 mah 2s LI FE battery weighs 49 grams, the 1600 2s comes in as stated at 76 grams.

I think these are a good option, personally I use Lipo without concern, the fires etc that you see on youtube are caused by deliberate abuse. We must be aware that all cells carry risks, there is a case of a young lady who lost sight in one eye when nimh cells blew up.

These LI FE cells appear to be a good combination of stable chemistry and workable voltage, combined with low weight.

Barry Fox CAN262 · Post by **Barry Fox CAN262** » 19 Jul 2012, 21:56

Thanks for the update Dave. It looks like the weight varies a lot by capacity so that is an interesting thing to keep in mind.

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