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Old Aug 30, 2012, 11:03 PM
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What type of battery?

New to RC sailing I'm wondering what type of batteries might perform best in a 1m Soling? There are 2 servos requiring 6V. On race days the boats are about 3 or 4 hours on the water. For reference, 4 AA Alkyd batteries work well but may not last 4 hours. 5 AA NiMH will work but is that the best for the job?
What about Lipo?
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Old Aug 30, 2012, 11:45 PM
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Chicago , Illinois
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Hi Mark
I sail in the Soling class also.my boat was bought used, and I got a old 1600mAh
NiCad 6 volt pack in the deal. (wow, that was 4 years ago)anyway, while the
pack does still work, I really don't trust it since I don't know it's charging history.
point is, I found a sale on some 2200mAh 6 volt NiMH packs - and I invested in
what I think is a decent charger. have never ever come close to using up the
charge on he 2200 pack -more then enough power.I wouldn't go LOWER than
1500/1600mAh because of the big sail arm winch.
if you PM me I can say privately where I got the battery packs, and can
recommend a couple of chargers.
from lipos, i don't know.
Allan
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Old Aug 31, 2012, 12:13 AM
Did you check the FAQ already?
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For a big boat like this I would suggest a AA 6 volt Eneloop pack or similar cell, like the Hobby King "LSD". Low self discharge, so your boat is always ready to sail, and good power. Eneloops AA are about 2000 mAh, the HK LSD is about 2400 mAh.
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Old Aug 31, 2012, 07:46 AM
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Always remember:
Regardless of the class, you never want to add anything you don't HAVE to add.
The key here is to use the HIGHEST voltage your servos will allow, and the LOWEST capacity you can get away with.





I am using a 1650mAh nimh pack on my BIGGER boats than the S1M. (EC-12) A fully charged 1650mah pack lasts all day in regattas. Morning session and afternoon session.
And that's running 3 "servos" ( An RMG winch, HS-645MG Jib Tweaker, and HS-311 Rudder Servo)
If we're sailing in heavy air... I'll pop a fresh one in at lunch just to be safe.


I hear good things about the eneloop batteries, but I haven't tried them. A regular nimh pack is lasing a long time with constant sailing on them. Then I replace them before they have an opportunity to die during a regatta.
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Old Aug 31, 2012, 08:07 AM
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I have been running Lipo's for about 5 years now. Size depends on the boat and power usage. I have figured out what each boat uses and change them before there is any chance of going dead. When using a RMG winch, there is no need for a voltage regulator as it is built into the winch. On other boats I either use high voltage servos or a regulator. Now that you can get Lipo's from hobby king for $6 to $8 they make a great choice.
A couple boats battery usage for reference RG 65 swing rig, half day 400 mah, star 45 with rmg half day 600mah, rg 65 conventional rig GWS winch, half day 900 mah. half a day is 3 hours or so. The real beauty of lipos is at the big regatta you can take two pack and charge them in less than 2 hours at night.
They do take more care in the fact that you can not run them all the way down, but reasonable care avoids that problem.
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Old Aug 31, 2012, 08:08 AM
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If the rule allows, you can try 4x NiZn rechargeable AA batteries. NiZn battery has higher voltage at 1.6v, so four of them is 6.4v and they hold the voltage flat. At hobbyking.com, it sells at <1.5$/cell.

Or my favorite is a 2s LiFe pack. These are two cells (3.3v x 2) at 6.6v. You can find 1800 or 2100mAh <$10 at hobbyking as well. Or course you pay shipping.

I favor these two options than LiPo because of safety concern.
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Old Aug 31, 2012, 09:22 AM
Guz
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Or my favorite is a 2s LiFe pack.
+1

These are awesome Rx batteries. When I get done sailing, I come home, charge them up, and put them back in the boat. They hold a charge with minimal self decay so I'm always ready.

You DO need a smart charger though. If I'm in the field, I do a high amp (max C) charge in a few minutes. But at home I do a low amp, balance charge to keep them in tiptop condition.
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Old Aug 31, 2012, 12:11 PM
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Originally Posted by Guz View Post
+1

These are awesome Rx batteries. When I get done sailing, I come home, charge them up, and put them back in the boat. They hold a charge with minimal self decay so I'm always ready.

You DO need a smart charger though. If I'm in the field, I do a high amp (max C) charge in a few minutes. But at home I do a low amp, balance charge to keep them in tiptop condition.
More on the LiFe packs please.... .for those that don't know too much about them.
First, isn't a 2s liFe pack 7.4v?






For those using a RMG winch for their sail controll, the new ones atleast will handle up to 9volts Max! so the sail winch is not to worry about,
But Most people's servos are rated at 6v, so they need to either use a regulator for the servos, or upgrade their servos.
(you can run them at a higher voltage, but of course it's not reccomended long-Term)

I would think a 7.4v pack, with a RMG, and a Rudder servo rated to handle 7.4v would be a GREAT combo.
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Old Aug 31, 2012, 04:46 PM
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2S LiFe: off charger 7.2v; nominal range 6.6 - 6 volt; never exceed 5.6 volt.
Some receivers and most servos will not handle off charger voltage. Add 2-3 power diodes in series to reduce voltage.
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Old Aug 31, 2012, 05:02 PM
Guz
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The last time I checked, all the servo and Rx mfgs. said that 2S LiFe are just fine with the majority their servos, even fresh off the charger (there are always exceptions ex: Hyperion Atlas DS-09).

Where-as they state that 2s LiPo is to much, unless you use their high voltage servo's, or put an inline voltage regulator.

But when-in-doubt, just go the the manufacturer's web site and verify the specs.
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Old Sep 01, 2012, 02:08 AM
Did you check the FAQ already?
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If you need to spare weight, LiFe is a nice option, these cells can take more abuse than a LiPo, and their voltage is lower, so it's less likely that the voltage will fry your electronics. LiFe is especially suitable as TX battery, a 3S pack is around 10 volts, nicely close to a 8 cell NiMh pack, that is often used for a TX.

One thing though, storing a LiPo for a longer time will affect it's capacity. And the lost capacity can't be regained. Not sure if LiFe chemistry is also affected by this, if so, you would have to discharge the cells to storage. Also beware that not every LiPo capable charger can charge LiFe cells. It needs to have a special LiFe program, don't be tempted to try these on the LiPo charge program...

As far as I know, Eneloops, so the Low-Self-Discharge NiMh type, don't lose their capacity when stored fully charged. In fact, that is their main advantage, even after a year in storage still 85% of the charged energy is still present, and the batteries can still accept a full charge, no permanent capacity loss.
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Old Sep 01, 2012, 07:57 AM
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Find out what your boat draws and size accordingly - I run 350mAh 2s LiPo in my Micro Magic and 700mAh in my Victoria (regulated to 6V where required). Charge takes 15min and I can sail all day.

I run 2s LiPo direct to a HS 5646 waterproof for my sails on the Vic and could not be happier. Great speed and power. "HV" is the future...
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Old Sep 01, 2012, 09:20 AM
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Originally Posted by SoloProFan View Post
One thing though, storing a LiPo for a longer time will affect it's capacity. And the lost capacity can't be regained. Not sure if LiFe chemistry is also affected by this, if so, you would have to discharge the cells to storage. Also beware that not every LiPo capable charger can charge LiFe cells. It needs to have a special LiFe program, don't be tempted to try these on the LiPo charge program.
Really only an issue if you store Lipo's at full charge. I simply run them part way down then store. I have packs that are 4 or 5 years old. Yes they have higher IR and slightly less capacity, but all batteries age. From my experience Lipos age better than the high capacity NIMH cells. Now that they are so cheap, <$10/pack why not just buy a pack or two every couple of years.

My experience with Life cells is watching guys run them as RX packs in RC cars. They seem to go through a lot of them, so I am not convinced they are as durable. I would run some sort of voltage regulation on either Life or Lipo so the voltage difference is not an issue for me.
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Old Sep 01, 2012, 09:49 AM
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LiFe is a good choise,but i would not leave them stored at a fully charged state even though it is not as critical as a lipo to do so and decent charger has a storage mode.Lots of people are running these straight off the charger,thier peak charged voltage drops off rapidly to 3.3 per cell and run a very flat discharge curve,fast charging capable and light weight.The genuine A123 are said to be the best EP Buddy.com
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Old Sep 01, 2012, 11:00 AM
Did you check the FAQ already?
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Originally Posted by slotracer577 View Post
Really only an issue if you store Lipo's at full charge. I simply run them part way down then store. I have packs that are 4 or 5 years old. Yes they have higher IR and slightly less capacity, but all batteries age. From my experience Lipos age better than the high capacity NIMH cells. Now that they are so cheap, <$10/pack why not just buy a pack or two every couple of years.

My experience with Life cells is watching guys run them as RX packs in RC cars. They seem to go through a lot of them, so I am not convinced they are as durable. I would run some sort of voltage regulation on either Life or Lipo so the voltage difference is not an issue for me.
When taking proper care, like using storage mode, there is indeed no problem using lipos. High capacity NiMh do lose their capacity over time, as you rightly mentioned. Even when new, they hardly reach their rated capacity, is my experience. However, this is not true for the Low Self Discharge type. While you can get high capacity AA cells up to 2600 mAh or even higher, the Eneloops are only 2000 mAh max and tend to stay close to that value.

As for the fast fading LiFe cells, do those car drivers have any low voltage protection active? LiFe cells tend to be quite rugged, but can be destroyed when abused. Also their are LiFe cells in various grades of quality, ranging from total crap to excellent.
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