Lipo battery question, 20c enough?

[marko500]

I'm looking at getting 4 Lipo batteries, 2 5000mah 2s 20c, 2 5000mah 3s 20c, this way I could use them in my SV and my cat. It would leave me the option to run several different configurations. My question is will 20c batteries be enough for a Bittburger cat, Hacker 8xl motor, Etti 150 esc,x447 prop, 1.3, 1.2, 1.1 to 1 gear ratios. Used just for fun running. I'm sure I forgot something if so just let me know. I don't want to waste money on somethting that won't work, so I would really appreciate any and all help. Thanks

[Eodman]

While I'm not an expert by any means ... from what I've read you will be much better off with a higher "C " rating especially with boats!

They are more money but well worth the investment! There are some good vendors here with good pricing ... not sure if RC Lipo is a perferred vendor but he has great pricing call him and tell him your a boat guy ...... he likes us!!!

I picked up a set of the new Marine power 2s and they pack a punch!

[NorthernBoater]

The 20c packs will be suitable for a SV27 but not much more. For an 8XL you will either need 4s2p rated at 20C or 4s1p rated at 30C.

[line6]

The 20c packs will be suitable for a SV27 but not much more. For an 8XL you will either need 4s2p rated at 20C or 4s1p rated at 30C.


:iagree:

[domwilson]

How big is your cat? The basic starting point for lipos is 20c. But that does depend on the hull size and te lipos. I have seen as well as myself, run 4000 10c lipos in a sv27 and 3700 20c in a 30" cat. Get the biggest you can afford and start from there.

[NorthernBoater]

It is a good idea to allow yourself 25-50 amps of headroom with you battery capacity. You need to error on the higher side if you buy lower quality packs.

[marko500]

My cat is a Bittburger, it's about 34" long. Does the gear drive trans lower the amp draw of the motor? The info I had on the motor says it has a 60 amp current, is this correct ? Another option I have is go with 5s2p at 20c (5000mah per pack), would this be an option? I've always wanted to name one of my boats (full size or RC) "Misappropriated Funds" my wife has no idea how much money has been dumped into them over the years!

[yurkanip]

I would use this rule of thumb when choosing a lipo. to see what sort of amps the battery in THEORY it should be able to deliver use this formula.
for example: 20c lipo, that is 3000mah. to see the amps it should be able to deliver take the 20 multiplied by 3000, then divide by 1000. This will give the amps it SHOULD deliver. Again, I say should, because not all lipos that are labeled will delvier as such. Most ebay cheap lipos, will burst in minutes if you draw more than 40 amps. Zippy lipos in my experience are the best bang for the buch, from hobbycity. particularly the zippy-h.


another eample of this. I use zippy-h 20c, 5000mah lipos in my fastest hull, a 34" rigger. Use the formula as stated:
20*5000/1000= 100 amps. I have never pulled more than about 70 on mine and I run (2) 3s lipos in series as a 6s in a 60 mph rigger.

Hope this helps., in choosing a lipo...it really is not as mysterious as some may make it out to be..just to be safe...never choose less than a 20c, 4000mah lipo for a boat. Higher mah, is always better, or even going 2p is a good thing, as stated by other members.

[kevinlew211]

of course 5000 20c lipo will handle your setup, unless you are using some cheap lipo and their rate is not acurated :smile:

[detox]

I think large voltage drop is the number one killer of esc's. So to safeguard against it would be safe to use lots of mah rating in high powered setups. The chart listed in link below is for lipos with atleast 20c rating.
http://www.castlecreations.com/support/documents/neumotors-castle_boat_apps.pdf

..........

[detox]

My question is will 20c batteries be enough for a Bittburger cat, Hacker 8xl motor, Etti 150 esc,x447 prop, 1.3, 1.2, 1.1 to 1 gear ratios. Used just for fun running. Thanks

I would invest in two 4s1p 4300mah packs with atleast 20c rating for that setup. Two of these wired parallel (4s2p 86,000mah) would be safe for sport running and racing. You could also use both of them in the SV27 and UL-1 wired parallel (4s2p) for loooong run times. Of course you could use just one 4s1p pack in the low amp draw SV27 and UL-1 boat, but with shorter run time.

These 20c lipos will work, but something with a higher discharge rating of 20c would be even better.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXWUA2&P=7



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[marko500]

I would really like to thank everyone for the help and Lipo lessons. I've now narrowed down my choices to either 2 5000mah 20c 5s packs to be run parallel in the cat or 2 5000mah 20c 4s packs hooked up parallel for both SV and cat. If I get the 5s packs first they will go in the cat and soon I will get the 4s also for both boats (already have Nimh packs we use in the SV) The cat moves ok on 14.4 v but should be alot of fun on the 5s packs. What do you guys think does this sound like a decent plan? Again thanks for the help I've learned alot in the last 2 days!

[Flying Scotsman]

of course 5000 20c lipo will handle your setup, unless you are using some cheap lipo and their rate is not acurated :smile:

Kevin, on the button. Do not believe what you see for some manufacturers

Douggie

[NorthernBoater]

5s is to much for a 8XL.

[Tony]

I'm trying to decide which Zippy lipos to get as well.

2x 2s1p 4000mAh 25C , or 2x 2s1p 5000mAh 20C. Both will give me 100amp .
I will run these lipos in series.

My boat is a 32" cat, motor is a 9XL Feigao, ETTI 125 esc, Octura X642 prop.

So, what do you guys think of the lipos batt? will it be enough for this setup?

My other batt option is 2x 3s1p 5000mAh 20C. However, the reason i want to stay within 2s1p batt is because i have another boat running with 2s pack only.

[marko500]

Is 5s too much for a 8xl? The specs I got from the Hacker website says 1973 Kv, 4-5 Lipo, 60 amp operating current,1700 watts peak. I sure don't want to burn anything up,yet. This is also running a FD turbo Trans if that makes any difference. I don't know enough about this to be doubting anybody I'm just confused.

[Flying Scotsman]

If you run the Transmission on a 1.3 gear ratio you will reduce the amp load on the motor with the same prop running direct. If you have not bought the motor I would use this Product ID: fei-580-L
Feigao 580L "Long" Sized Brushless Motor
And run it direct on the cat
I prefer to run large low rpm/volt motors and use higher voltage within the limits of the motor to obtain what I desire in large hulls for sport boating. My 2 cents

Douggie

[6S HYDRO]

I would invest in two 4s1p 4300mah packs with atleast 20c rating for that setup. Two of these wired parallel (4s2p 86,000mah) would be safe for sport running and racing. You could also use both of them in the SV27 and UL-1 wired parallel (4s2p) for loooong run times. Of course you could use just one 4s1p pack in the low amp draw SV27 and UL-1 boat, but with shorter run time.

These 20c lipos will work, but something with a higher discharge rating of 20c would be even better.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXWUA2&P=7



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86,000 MAH WHOA :sarcasm1:

[Flying Scotsman]

86,000 MAH WHOA :sarcasm1:

There is no call for that, we all make mistakes when we type :thumbsdown:


Douggie