S800, total weight 7kg, should I still use maxamps?

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PeterLester

Member
5C is the charge rate..... they are likely 40C discharge rate as indicated in posting #11. You can run eCalc for Multicopters for a wide range of battery scenarios to gain perspective as to finding the sweet spot for optimum flight time with the intended payload....... with exponential counterforces such as gravity and temperature working against us, the laws of diminishing returns kicks in very quickly.....pay another $100 for one more battery and only gain 30 seconds more flight time!!!!!

Sometimes its just better to settle on 2 separate flights, each @ 7 minutes with half battery capacity than to try to get past 10 minutes with all batteries on board.....

Personally, I am holding out for a tokamak cold fusion electrical generator as an ultra light, nearly infinite source of electrical energy for MRs!!! :shame:



flyingbiscuit said:
I am beginning to think the Max Amps may be a big problem with my machine, I would have never gotten into them if I had known there constant C rating, they wre extremely expensive batteries, not sure what I can do about it now.
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flyingbiscuit

Member
Yes cold fusion thats the answer ! :)
, although like others have noted the Maxamps are actually 5C constant discharge, 40C is the burst. They didn't state that anywhere on their site when I bought them, and probably still don't, but they confirmed it to a user who had bought a large quantity
 

D

Digitech

Member
just dont use them , after a short while they will start do have a lot of cell difference in voltage and the Resistance will rise and rise.
the C rating is bull**** , they will tell you different fact is the C rating they tell you is not the one you will have...
its more like 4C
your voltage is starting to drop , that is what causes your S800 to act funny.
we used to be a dealer for Maxamps , however in case of problems they will dump you.
we got 25 packs left 11000 5S , anyone interested i am asking 100 euro,s for them BRANDNEW boxed.
just dont use more then 40 amps discharge, they will crap out on you.



here is the email from Dear Josch:


Sandor,

Choosing the best battery for a given application is not always easy. Sometimes, much testing has to be done beyond just crunching numbers and hoping it is going to work. I’ll try and explain what I mean by that below.

We base our packs off of its max burst capability and not the constant C rating many other companies use. The reason for this is that in our main market, RC cars, the burst rating capabilities are far more important than the constant. I know this can be confusing when comparing packs, which is why I always recommend testing a pack first before ordering large quantities. A solid constant amp draw for our 11000Mah packs would be around 5C. This pack is designed for a low continuous amp draw whereas our higher rated packs can handle more power and hold much higher voltage under load.


sofar the TRUE 40C :)
 

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Chris98

Member
Thunder power is the key the same batteries on the draganflyer x8 they just came out with a g8 battery that 65 c. 6 cell
 



K

ksrimoungchanh

Member
@saidquad,

I have been using 2x8000mah (nanotechs).. though they are less expensive, I made a habit of using 6s2p on evey flight... I had a few times that battery packs goes weird on me.

I am over weight for sure, but because I have those 8000mah and don't want to fly single packs, I am going to plan to remove my retracts, and trim more excess wires..

I will keep on using 6s2p for the life of my multi-rotor flying... I will end up with something like 2x6000mah or 2x5000mah going forward when time to order more packs.

KS
 


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fj_montilla

Member
saidquad said:
This was my solution
http://www.maxamps.com/proddetail.php?prod=Lipo-10900-222-Pack&cat=363
They work great with full loaded S800. I am waiting to receive EVO arms and damping plate for IMU V2 to do the final test. So far I am happy that new packs handle the 7kg S800 without being warm and the IR looks stable.
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Can you share some your charge settings? I recently got a maxamps 10900mah and so far I'm a believer. The few flights I've had have been enjoyable to say the least. Not fully loaded yet, will test this weekend.
I use a Hyperion charger, with plenty of possible settings.
 

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flyingbiscuit

Member
fj_montilla said:
Can you share some your charge settings? I recently got a maxamps 10900mah and so far I'm a believer. The few flights I've had have been enjoyable to say the least. Not fully loaded yet, will test this weekend.
I use a Hyperion charger, with plenty of possible settings.
Click to expand...

The 10900mah maxamps is a far better battery, I get at least 2 minutes longer flight than the 11000mah, I am actually happy with maxamps now, and i wasn't with the 110000. The 10900mah is only 80g heavier than the 11000mah and worth every penny if you are flying a heavy s800
 

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deluge2

Member
Anyone care to comment on the pros and cons of running a single higher capacity, vs. 2 batteries with equal ratings but half the capacity. For example MaxAmps has similar rated 10900 ($430) vs. 2 x 5450s ($250 ea).

Is there any validity to the notion that the added wt and cost due to dual packaging and wiring, is offset by the added security that if one battery 'fails' the other remains to increase chances of safe landing. Other potential benefits include parallel charging.

Just curious regarding what experience teaches on this,
Steve
 

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ProPilotWannaBe

Member
I personally go with dual packs and it just gives me a little warm fuzzy thinking one can backup the other... but that may not totally be the case. A true "short" in either will cause the fail. But if it's just a bad cell, then the other battery will carry the system until you land. I know there is a user on this forum (forget who) that also states that by putting two in parallel you are lowering your total Internal Resistence which lessens your loaded voltage.
 

Benjamin Kenobi

Benjamin Kenobi

Easy? You call that easy?
I like two in parallel for the same reason. But that's really because I can't afford MaxAmps! I would get them if I could. Ben@YonderBlue uses em so can't be all bad...
 

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deluge2

Member
ProPilotWannaBe said:
I personally go with dual packs and it just gives me a little warm fuzzy thinking one can backup the other... but that may not totally be the case. A true "short" in either will cause the fail. But if it's just a bad cell, then the other battery will carry the system until you land. I know there is a user on this forum (forget who) that also states that by putting two in parallel you are lowering your total Internal Resistence which lessens your loaded voltage.
Click to expand...

Benjamin Kenobi said:
I like two in parallel for the same reason. But that's really because I can't afford MaxAmps! I would get them if I could. Ben@YonderBlue uses em so can't be all bad...
Click to expand...

Thanks to you both for your comments.

I'm not sure about the internal resistance point, since the actual composition of the large pack would probably be the same two smaller pacs just internally placed in parallel (to make a 10Ah 6s2p from two 5Ah 6s1p cells). Maybe there are larger internal connectors that are used in combining the cells.

In looking at MaxAmps (as an example that appears to provide reliable size and wt data) two choices with the same specs (C rating) are:

1 x 6s 10900 mAh battery (137 x 45 x 103 mm, 1371 g) for $430, or

2 x 6s 5450 mAh batteries (each 137 x 45 x 52 mm, 693 g) for $250 each

I was pleasantly surprised by the very low size and weight penalties associated with the dual battery approach (have to add in the wt of the y-connector). Now if only there were a way to lower the price...

Steve
 

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jhardway

Member
Battery experiences:

NanoTech I had three of them, although they work well they start puffing up pretty quickly. The harder you make the draw the sooner they will start to puff up. I got about 50 uses out of them then I stopped using them mainly because the puff tension on the battery is making me nervous. Right now I am flying on gens ace and so far everything is looking good. They may a little heavier then the nano tech but I feel they are much better designed and that in it self makes the difference. Example they wrap them in a shield under the shrink wrap, that held keep them from puffing up and also from damage if they get banged.

I also have a 10900 Max amp and so far that is working pretty good. Between the two the gens amp are half the price then the max amps but in that case with the larger copter you will have to fly it in tandem but so far I am pretty much getting the same result. In both cases I am flying them on an HL Tarot Octo with 4014 330KV motors. It weights just under 7KG or just around 15lbs on takeoff.

With each set up a 10 min flight time as my come down period. That allows me about 1:45 in reserve before hitting my second must come down threshold. or about a 1:15 before hitting the 80% use. it allows me to extend my flight time a little if needed but it also keeps the battery in a good range for helping with its health.

At the end of the day I am pretty happy with that so far.
 

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