Battery question

[wickedgmc]

I am getting ready to buy new Lipo batts and had a few questions first.

1. These will be used in my Jolly Cat with a Hydra 240 and a KB 8 or 11

2. Do I want to run in parallel ore series, and why?

thanks guys

do I want to buy 6s, 5s or 3s not sure which ones I want and what mah, I have my own ideas but am looking for suggestions

[NorthernBoater]

If you go with the KB 8 I would go 4s. This would put you in the mid 40s. If you go with the KB 11 I would go with 6s. Runng them in parrallel will cause less wear and tear on the batteries becasue there will be less current draw from each pack.

If you choose to go 1p instead of 2p going with an even number of cells will be easier to balance. You will be able to put half the cells on one side and the other half on the other side. If you parrallel them as an example you would want to put one 4s pack on one side and another 4s pack on the other side.

[SJFE]

Alot depends on your set up. We need to know how what you expect to get in refernce to speed & run time. Then we can help ya out a little better :)

[Fluid]

In addition to what is in SJFE's post, when choosing pack capacity you have to consider the amp draw of your setup, it is not just more runtime that you get with more capacity. If you want to draw high amps - which with a CC-240 I assume you do - then you will want a minimum of 5000 mAh capacity. You can get that with either a 1P 5000 mAh pack, or a 2P 2500 mAh pack. With 25C cells that means you can draw 125 amps continuous safely (as long as the cells do not get overheated on a hot day).

You can obtain the voltage you need with either 4S or with two 2S packs. Here are you options for 5000 mAh and 4S to the ESC:

1 pack - 4S1P 5000 mAh
2 packs in parallel - 4S1P 2500 mAh
2 packs in series - 2S1P 5000 mAh
2 packs in series - 2S2P 2500 mAh

Obviously the last three will give you more flexibility in achieving the correct CG.


.

[SJFE]

Mr Fluid fills in the blanks as always...lol. FYI I have the Jolly as every one knows. I will be running 2 packs in series - 2S1P 5000 mAh configuration on the KB8XL. As advised by Mr Smock :). I am also saving my pennies.... . Neu power is NOT cheap.

[wickedgmc]

I am looking for a few different things, first as far as speed I would like high 40's to mid 50's.

Run time would be good, however I would not expect to run this boat for a long time at higher speeds.

I ordered a pair of 6s and a pair of 4s both with 6000mah and that should give me some things to play with. The Hydra has a max of 6s input so I am limited there to cell count. I will not be running any nimh batteries as all I have are 14 total of those, 2 7 cell packs

[SJFE]

I have 3 sets of fresh 8cell IB3600 packs. I have been topping off every 10 to 14 days since I bought them in march. I expect to be using them for quite some time. I will be replacing them with the lipos starting this fall. My lipo safe, charging/ storage/ transport box it all most finished. That is what really holding me up from crossing over @ the moment.

[wickedgmc]

yea the 3600's were great batteries considering the crap they try to sell as batteries now. I had 4 sets of 4200's when on road started this season they were all junk after 3 Friday night rounds. Wasted 200 in my opinion after that I went and got a pair of Orion 3200 lipos and have never had a problem since. The 2 packs I have right now are still in good shape but there are only 14 of them, they are fun in my Supervee.....

How did the KB motor mount up in your Jolly? Did it bolt right in or did you need to modify the mount? Once Steven gets back from vacation he will be sending me an invoice so I will then have my Jolly at least paid for :)

[Rctothend]

Looking to cross over to the Lipo side myself, mainly for the same
reason that the new Nimh cells have gotten alot of bad reviews and Lipo is
gonna be the future like it or not. Anyway where do you guys get your
Lipo's, I would be using them for 1/10 scale cars (7.4v), An E-maxx
(14.8) and of course boats (14.8). Would be nice to have a few 7.4v packs
to use one at a time in the cars as well as using 2 at a time in the
boats to get the proper balance and voltage. I have a castle system for
the cars and plan on a Hydra 120 for the boats, so I'm prepared for
the voltage cut off. Other question, when the esc cuts out when the
Lipo's are almost discharged does this leave the boat stranded or does the
voltage come back a little like a Nimh after you let it rest a second
to let it get back to shore or do you just have to realize that the pack
is dumping and get it in before it does? Also what charger do you guys
recommend, any help would really be appreciated.
Thanks.....Greg......

[SJFE]

Greg my cut off blips power on and off in order to get me back to shore. You should always have a back up plan for retrieval.

[NorthernBoater]

I just bought some balancers from http://www.rclipos.com/ , I ordered them on Sunday night and received them on Wednesday. They seem to be a decent site but it is hard to say from one purchase. Everyone recommends either Poly Rc, Thunder Power or PolyQuest.

[Rctothend]

Thanks for the replies! Ill check out the sites.

[SJFE]

I have a question. My balancer has a tap for s4. Now I have a set of s4 1p packs. Since there is a cell in parallel do I charge it with the s4 tap adaptor ???? If not I think I'm hosed and need a new balancer

[Rex R]

if you are referring to a 14.8v pack setup (4s1p), then what you have is 4 cells in series. methinks I would use the s4 tap.

[SJFE]

That is what I had hoped. I got confused beause if the 5th cell. Yes they are 14.8 3300mah 25c packs I just score from the Doozman on a trade.

[wickedgmc]

SJFE the other way a lot of people balance there cells is to charge them at a very low setting, and they swear by it. Myself I still use a balancer for mine, thats just me. I did however run the last charge at way less then 1c

[SJFE]

Hey ya know I knew that but didnt think it applied to the lipos. I do that to my nimh packs to balance them also. Thanks for the heads up :).