# 6s 5000mAh b grade battery $32



## Brandon (Jul 6, 2011)

I was digging through some lipo batteries for a friend and noticed these:

http://hobbyking.com/hobbyking/store/__28552__B_Grade_5000mAh_6S_30C_Lipoly_Battery.html

Since loco's don't pull a hundred amps like some plains do, these packs should last longer in trains, even though they're b grade lipo's.


----------



## SD90WLMT (Feb 16, 2010)

That width is a tight fit inside a narrow hood loco..
50mm = 1.97"

In side ....average..2.00" plastic varies...
Any other build combinations??

D


----------



## Totalwrecker (Feb 26, 2009)

Says only good for 60 cycles chg/dischg
Plus they tend to get Puffy.... oh boy!


----------



## Greg Elmassian (Jan 3, 2008)

60 High rate charge / discharge cycles.... we don't normally do high discharge or charge. Might be worth a try if it is not a "zero clearance" fit.

Greg


----------



## Paul Burch (Jan 2, 2008)

PCB protection????


----------



## SD90WLMT (Feb 16, 2010)

Paul....lipos have internal circuitry to limit and control both charging and discharging rates...

Typical uses in model aircraft drain batteries at a high rate...
We do not come close to this discharge rate using them in our locos..which implies they should not get "cut off" during operation, tho I know some have experienced this..

Dirk


----------



## SD90WLMT (Feb 16, 2010)

......was down pondering... ( I'm awaiting parts ..so all I can do till they get here ) 
My SD70 is in pieces currently.....

I grabbed a small steel ruler...the i.d. of the hood in several locations is 2 1/8"....

This could provide at most 1/16" clearance on each side wall to the battery in discussion here..
Question is..how much poof or puff occurs in the battery...
But ...if this is a Lipo..it is made from many C type cells....they should not puff at all....
Solid sealed batteries do the puffing ..don't they??

D


----------



## K27_463 (Jan 2, 2008)

I have a few customers that years ago insisted on using lipos, rather than lithium -ion. Even bought the little voltage monitors available for a few bucks to aid in operations. All have gone back to ion away from lipos. The lipo circuitry does not cut the battery off before it reaches the point of no return.If discharged completely, they do not come back. It is not my experience that lipos have any protection in them as mentioned above. Plane and race car guys do not want or need the extra weight and protection. So, A lipo can go over charge and under charger very easily. I have many lipos here around my shop, there is nothing inside except the cells. now, lithium ion do indeed have a protection board, and that is what makes them suitable for our train use. If a lipo cut off as suggested, that would be very bad for airplane guys. They will go until dead, though the discharge curve drop off is very fast, it is not abrupt like a li-ion with pcb. You can use lipo just fine, just know you will be replacing them often and they will present a hassle factor. is it worth it for the cost involved? You decide.
jonathan
www.rctrains.com
25 years of battery rc in the garden


----------



## Brandon (Jul 6, 2011)

Many LiPo batteries do have pcb's that make sure the voltage per cell does not go below a set value. In my planes, many ESC's and BEC's allow you to set the voltage. 2.6v, 2.7v, 2.8v and some get even more precise or allow you to set any range digitally with software. Li-Ion are definitely worth considering since we don't care about weight or high amp discharge in trains. One thing though I will mention is it's far easier to remove a dead cell when there's 4-6 in a li-po back vs 1 of 15 in many of the li-ion packs that get the same mAh ratings due to the need to parallel cells in Li-Ion packs.


----------



## Greg Elmassian (Jan 3, 2008)

There's actually very little difference between li-poly and li-ion... the biggest difference is that li-ion is normally in a metal cylinder, and li-poly is normally in a flexible bag or plastic enclosure. We don't need flexible enclosures, and they don't puff unless there is a problem.

Safety is the main reason li-po is not popular recently, too easy to puncture or damage and have a bad experience, the metal housings of the li-ion is much safer.

Greg


----------

