I am seeing vague references to 6 volt batteries in the posts from racing sailors. This voltage clue indicates the skipper is using Lithium “Energizer” cells, which deliver 6 volts in the AA format. I am curious, how many of the top skippers are using “Energizers”? Please contribute to this unofficial poll, I am sure the new comers would want to know.
What else would anyone use? They’ not actually all that expensive masured in terms of pounds per Watt hour (at prsent anything is expensive measured in dollars, unless you hppen to be paid in euros).
I don’t know about top skippers, but I’m using them. Same pack I made at the end of April, is still going strong.
For a development class the idea of restricting batteries to a narrow type seems very undevelopmental.
How about just using a minimum weight for battery, holder and plug?
My personal feeling is that ANY restriction (even weight) is against the spirit of development.
If it fits in the box etc. it should be a footy.
(grumble, mumble, etc.)
Pete
I don’t have any experience with Lithium batteries and have many questions.
-
Can the batteries be charged while connected in series (i.e. 6 volts)? A must for me.
-
What charger (model, source, url) would you buy for 6 volt charging?
-
I have heard that there is potential for explosion. Under what cnditions?
-
I have been making my own packs from NiMh AA’S. Can the Li batteries be soldered to make serial connections?
-
What is the weight difference (Ni-Mh vs Li)?
-
Where to buy Li AA batteries?
-
It sounds like most skippers use LIthium. Were all the boat weights listed in issue #152 using Li?
-
List of URL’s for background reading?
Maybe a good summary would be helpful to many readers. It may be time for me to change.
Thanks, Frank
ffastffrank - I suggest that you explore this thread from the beginning and you will get a sense of the different points of view about Lithium “Energizer” batteries. But to answer most of you questions right now, Energizer AA cells are not rechargable. Depending on how long your sailing sessions are they will last for four to six sailing sessions. Four cells deliver six volts as opposed to 4.8 for you NIMH, NiCAD, or regular AA alkaline cells. They cut battery weight by a third. But they are expensive. Read my earlier posts on this thread for more on a cost comparison.
I think we need to back up a bit and take it steady.
Neil - the 6V does indeed indicate 1.5V per cell.
There are several battery chemistries which produce 1.5v
The most common and relevant in this case are Manganese alkali (duracells)and disposable Lithium.
So if the 6V data is true, that’s probaby what is being used.
Fwiw I use both of these - The Lithium Energiser cells cost me about 7.00pounds, and have lasted since last Christmas, but mainly I use disposable 1.5V AA cells bought in large packs from B&Q. I would use disposable lithiums if money were not an object since they are the lightest.
Ffastffrank
<<I don’t have any experience with Lithium batteries and have many questions.
-
Can the batteries be charged while connected in series (i.e. 6 volts)? A must for me.
-
What charger (model, source, url) would you buy for 6 volt charging?
-
I have heard that there is potential for explosion. Under what cnditions?
-
I have been making my own packs from NiMh AA’S. Can the Li batteries be soldered to make serial connections?
-
What is the weight difference (Ni-Mh vs Li)?
-
Where to buy Li AA batteries?
-
It sounds like most skippers use LIthium. Were all the boat weights listed in issue #152 using Li?
-
List of URL’s for background reading?>>
1 and 2 - not rechargable, not relevant
3. Not possible, no danger of explosion
4. Yes, see Brett’s post
5, I think its 4gms per cell saving, but check the Energiser website
http://data.energizer.com/PDFs/l91.pdf
6 in the Uk - any good chemist or camera store
7. I would think that the first 8 boats at Birkenhead used Lithium - hence the weights are inclusive of that (but bear in mind if it comes off the batteries it goes back on the bulb!)
8 start with the ref above - there isn’t much more to digest
Hope this helps,
andrew
I see that the Argos BOGOF offer is repeated. This gives UK residents 4 AA energiser Lithiums for 7.00 pounds
http://www.argos.co.uk/static/Product/partNumber/9803954.htm. only for another 3 days!
andrew
deleted - hit post again
Thanks for the quick and good feedback. A set for those special regattas makes sense? Maybe I can get my modified B-2 to under 1 pound, currently 16.1 oz. Sail light, sail fast generally speaking and my B-2 has changable ballast.
I have a friend that won last Spring’s Daytona Footy event and he mentioned having to be careful charging these batteries. I am now wondering if we are talking about the same thing? Are Lithium and Lithium Poly (LiPo) different batteries?
from the web:
Lithium Battery Breakthrough - Lipo BatteriesCharging LiPo batteries requires a very different charge method than other types of cells. It’s imperative to use a charger designed specifically for LiPo …
www.rchobbies.org/lithium_battery_breakthrough.htm
Never to old to learn, but time is running short. Frank
Yes, they are different. See this article and the chemistry of a lot of Lithium batteries:
The only kind that are usable for footy racing are the disposable AA lithium cells, and afaik the only world manufacturer is Energiser.
These are radically different from any of the rechargable Lithium chemistries - some of which have special need for love and care.
As a disposable cell they have so much capacity that there would be no need to keep them for high days and holidays (and regattas) - one of the plus points is plumbing them in and forgetting them:D
The data sheets seem to indicate how you would detect approaching the end of the capacity.
Our current requirements are tiny and even common-or-garden alkaline cells last for a long while.
andrew
I’m a newbie, but I’m with PeteSchug -restrictions on weight, sails, and batteries are NOT conducive to a developmental class. I’m in favor of putting the batteries in the keel where their weight would do most good. Throw out ALL the restrictions except dimensions - if it fits in the box it’s a Footy… and let the best design and the best skipper win – glynn
When you vote on the Rule changes, the first page of this thread shows how the poll was split. Paul
Gentlemen and ladies, I do believe that there are more than 64 registered Footy owners out there somewhere. There are 65 total votes in the poll above. Two of them are mine, one on the rig issue and one on the battery issue. If that is typical then there are only 32 respondents to this snap poll. This is hardly a representative sample of our membership. I encourage everyone consider the issues carefully and thoughtfully, and to cast a ballot in the Footy Rules referendum.
Why bother to keep the dimensions if we’re going to toss out all the other rules? After all, a 12" long boat is pretty restrictive, and as far as development goes you can only do so much. Same for that stubby shallow keel. Let’s see some REAL development like in the M-50/800 & 1 Meters.
Bill
Bill,
You want real development like in the M Class and One Meters then a good place to start is to vote to omit the battery designation from rule C.2. Neither of these classes you site enshrine carrying extra and unnecessary internal ballast in their rules. Being able to choose the r/c gear and battery types is a given in these classes. Footies would gain a performance boost from eliminating 50 to 70 grams of extra battery weight or moving that weight to the keel bulb were it would improve righting moment, making the Footy less tender.
Hi Neil,
Sorry if my sarcasm confuses anyone. My point is that the Footy is presently the best bang for the least bucks, and is a good place for those that want to design and/or build their own boat & still be reasonably competitive. Part of this is due to the restrictions the rules place on batteries and radios. At the other end of the spectrum are the Marblehead class and the One Meter, where to be competitive you must have the highest tech boat at the highest costs (have you priced a Skalpel lately?). One of the reasons there are so many different versions of the One Meter is an attempt to keep older boats viable when newer more expensive ones come out. We DON’T need this to happen in the Footy class.
Bill
Bill,
You are mistaken in the notion that any of the Footy Class rules will dissuade the professional boat builders from entering the market. Right now the market is small, but the number of Footies being made and the numbers of people making them is growing fast. My hunch is that we will soon reach the numbers that will become tempting.
One other thing has to fall into place as well. Right now Footy development is all over the place. Once things settle down a bit and one general hull type becomes the norm then you will see an influx of high quality, professionally designed and built Footies supplant home built ones because some guys don’t have the craftsmanship skills that others do. They will buy the professionally built boats to be competitive. Thats just the way r/c yacht classes develop. Right now we are all doing the R&D with our home built boats.
The other repercussion of the advancement of a class is the addition of new restrictions and ever more picky definitions of the existing rules. I have been sailing model sailboats long enough to remember when M Class (then called Marblehead) were strip planked in mahogany. The Marblehead rule was 3/4s of a type written page in those days. Today I can hardly translate some of the minutia or fathom why it was necessary to include them. The rules for the IOM class print out to 9 pages. My preference is to eliminate restrictions, particularly ones that harm performance unnecessarily. Thats why I advocate omitting the 4 AA battery designation from rule C.2. It is the right way to help all Footies attain better upwind performance.
Niel,
While you may be correct, as soon as Footy racing becomes more about racing your wallet than the toy boat you build, I will be outta here, like so many others in the two classes I mentioned in my previous post. While I can afford to go out and buy an expensive boat if I want to, the key point here is that I DON’T want to! One of the things I like most about the Footy, is the creativity involved in building one. The guys who want to buy their trophies via expensive, custom built toys, have lots of other places to play than in the Footy class. As for pointing, I think the relationship of the sail’s center of area to the boat’s center of lateral resistance is more important to a boat’s pointing ability than what kind of batteries you use.
Regards,
Bill