State of the art and trends in energy storage

[Roberto Gava]

Let's talk about the actual state of the art in our energy storage systems.

Here I put a little questions to discuss about.

¿Fast charging LiPo's? ¿Are they the best solution for today? ¿Future?

I found this ones to be the ones with faster charging speed. ¿Do you saw anyones faster?

¿LiFePo?

I also saw this ones with interesting format and weight.

¿What about Ultacapacitors?

[Tim Mackey]

The 5C fast charge LiPos ( Tipple loong max ) are popular here in the UK - I have several and find them excellent.

Genuine A123 cells ( LiFe PO4 ) are chargeable at 5C also, and capable of 100A currnet discharge rates. Excellent cells and tough as nails.

However, I HAVE tried the others you linked to ( I call them softpack LiFes) and was not impressed but that was few years back and things may have improved. 

Ultra capacitors? No expereinece so cant comment.

[Roberto Gava]

Timbo, or other mod.

I don't know why, but this thread is duplicated.

Can the answers of the two threads be merged and delete one of the copies?

Sorry if I made a mistake.

[Frank Skilbeck]

I have one of the 3,000 mah 4s tipples from GC, they are doing the 3S a bit cheaper http://www.giantcod.co.uk/loong-tipple-2300-3s1p-30c40c-lipo-battery-p-404359.html.

 

I haven't tried charging at above 1c yet but they do have very good discharge capabilities.

 

I also have a 4s LiFe from Puffin Models and thats been very good also. 

[David Ashby - Moderator]

Done Roberto

[Roberto Gava]

Interesting.

So I asume that fast chargin LiPo's are actual state of the art.

Maybe LiFe is comming, but not as strong as LiPo's in the past.

I've been involved in research about electric cars and for that reason I learned some about ultracapacitors.

It's my personal oppinion that they have a very interesting set of characteristics for us.

Charge and discharge rates are almost unlimited. Being a phisical energy storage, they don't suffer loss of capacity with cycles. The only drawback is that they don't keep the charge for a long time, but it isn't for us. We can only charge them just before to flight.

Thanks David  

[Danny Fenton]

Hi Roberto, another interesting subject. And close to my heart but i am an avid A123 user, so am biased.

I guess it depends IMO what your priorities are for the cells, but for me at the moment there are only two runners, LiFe and LiPo.

(Ultracapacitors are being used in the supercomputers the company I work for has developed, but I have yet to get my hands on one.

 

1.    Fast charge time.

               Lipo now do fast charge eqivalent to A123.

 

2.   High discharge.

               No difference really.

 

3.   Safety

               A123 are safer hands down.

 

4.   Price

               Lipo in the short term, A123 in the long term

 

5.   In plane charging.

               A123 can be left in, and charged in (safely), the airframe

 

6.   Longevity

               A123 easily holds capacity over the life of the cells, and last longer

 

7.   Ease of use

               A123 again wins because they cannot catch fire if overcharged, and can survive being fully discharged.

 

8.   Weight

               A lipo is lighter than the same size A123 pack, however if you only discharge the LiPo to 75% capacity to give the pack some life then the eguivalent LiPo needs to be of 25% greater capacity to be equal. The weight then starts to get very close.

 

9.   Pack size versatility

               LiPo wins easily there seem to be an infinite range of cell sizes available. Currently the 2300 A123 is the only real candidate (I know the 1100 exists)

 

Cheers

Danny

[Tom Foreman]

I would also add phyisical size to that list and the need to run an extra A123 cell compared to lipo because of the lower cell voltage 2.75v compared to 3.5v under load. I find A123 good for sports and scale models and Lipo better for EDF, electric gliders and high performance. Thats not to say you cannot use either for all of the above just my personal experience I know how  much Danny likes his A123's

 

Tom

[Danny Fenton]

 

 

[Roberto Gava]

Danny, good point on A123

Does anyone else have something to say about our batteries?

Some inovative way?

 

[Keith England 1]

Actually - if you want to talk state of the art and the future of our energy storage needs the area with the greatest - as yet sadly unfulfilled potential is methanol fuel cells. One or two of the mobile manufacturers are talking of having them ready "soon" with the methanol in little cartridges like the ink for fountain pens - so never have a flat battery on your mobile just slip another cartridge in when it gets low. These however are low power usage and are able to absorb enough oxygen from the air without difficulty.

 

Now extrapolate this to the huge portable power tool industry. The one big drawback currently for tradesmen is sites without electricity, so powering their tools with a refill of methanol would be a boon. However at the powers they need air would have to be forced through the fuel cell with a fan to get enough oxygen quickly enough.

 

Having a ready airflow for a fuel cell is not a problem to us so look at the possibilities. You turn up at the field with a gallon of methanol, fuel your 'plane up and go flying. When you want another flight, you fuel up again and fly again - sound familiar? The only difference is its with electric motors, no oil, and not too much noise.

Thanks to Giant Cod I'm already flying 2KW set-ups for less than the cost of a Saito 125 – including 2 sets of batteries - I just need to not have to lug the car battery to the field and find that my 10 cell packs flatten it half way through the afternoon!

Edited By Keith England 1 on 05/04/2010 19:23:32

[Danny Fenton]

Keith that is a problem we are all facing, its looking a bit sily that we are pursuing quiet flight to then lug a generator to the field to cope with the charging.

 

I did read of another technology on the way I think it was Lithium Sulphur, so far its not there the charge cycles are too low, and they don't last, but watch this space.

 

Lithium Sulphur

Edited By Danny Fenton on 05/04/2010 22:11:11

[Roberto Gava]

Posted by Danny Fenton on 05/04/2010 19:50:35:

Keith that is a problem we are all facing, its looking a bit sily that we are pursuing quiet flight to then lug a generator to the field to cope with the charging.

....

 This is off-topic, but I was thinking to propose to my club to install a windmill to generate power over the whole week, store it in big batteries and use it when we go to the field to charge batteries, to plug our flight boxes for IC powered planes.

I think it is not a big investment for a club and we can presume of using really clean energy.

[Roberto Gava]

No more to say about batteries or fuel cells?

Just to ask, once I saw in an Spanish forum a video of some flexible LiPo's.

Is it true or is fake?

For me is hard to believe on it.

Edited By Roberto Gava on 07/04/2010 20:32:44

[Vecchio Austriaco]

Not a highly sophisticated comment - stick to LIPOs of well known brands, as for instance Hyperion or other well known brands. So far I did not have any dead cells or strong asymmetry with those. Most of the new good brands allow high charging rates - practically all of them 2c, some of them 5c. Important is not to discharge them below 10% of their initial capacity as then single cells may start to suffer. Also I store all my LIPOs at 60% capacity during the week (as recommended by all producers).

 

Flexible LIPOs: Never saw them, but I could believe it is possible to make them. Only I don't see any advantage - as the current ones are much less stable as for instance NiMh or ABC -  crashing a plane can easily destroy a LIPO by cracking the aluminium cover during the impact. I could think a flexible LIPO is even more delicate to such treatment. (I know - we don't fly to crash - but sometimes things are happening) 

VA

Edited By Vecchio Austriaco on 07/04/2010 22:02:05

[Vecchio Austriaco]

Obviously I was to unpatient with my ADSL connection so I pressed enter twice.

If one of the admins has time please delete this duplicate post.

Thanks

VA

Edited By Vecchio Austriaco on 07/04/2010 22:00:31