glider battery duration problems

On Monday, October 7, 2013 7:19:32 PM UTC-7, son_of_flubber wrote:
On Monday, October 7, 2013 7:25:28 PM UTC-4, Evan Ludeman wrote:

I made some notes in the process of educating myself on LFP batteries last Winter. I've tried to condense them here into something semi-useful.



Oh man. Flying around with two or three cheap plastic buckets filled with hydrochloric acid and lead seems the way go for now (unless you really really need the power capacity).

Just received my order of the LiFePO4 battery. The first thing on the box in large print; "LITHIUM BATTERIES- FORBIDDEN FOR TRANSPORT ABOARD AIRCRAFT AND VESSEL"
Hmmmm......?

Just received my order of the LiFePO4 battery. The first thing on the box in large print; "LITHIUM BATTERIES- FORBIDDEN FOR TRANSPORT ABOARD AIRCRAFT AND VESSEL"

Hmmmm......?


Where did you order them from?

On Tuesday, October 8, 2013 11:33:56 AM UTC-4, 6PK wrote:
On Monday, October 7, 2013 7:19:32 PM UTC-7, son_of_flubber wrote: On Monday, October 7, 2013 7:25:28 PM UTC-4, Evan Ludeman wrote: I made some notes in the process of educating myself on LFP batteries last Winter. I've tried to condense them here into something semi-useful. Oh man.. Flying around with two or three cheap plastic buckets filled with hydrochloric acid and lead seems the way go for now (unless you really really need the power capacity). Just received my order of the LiFePO4 battery. The first thing on the box in large print; "LITHIUM BATTERIES- FORBIDDEN FOR TRANSPORT ABOARD AIRCRAFT AND VESSEL" Hmmmm......?

I got an ELT with the same warning on the outside of the box due to the lithium battery used in the remote display.
Go figure.
UH

It's that pesky "Hazardous Cargo" thing. Same thing goes for dry ice, hair
spray, and oxygen generators stacked on top of magnesium wheels in the cargo
compartment.

I'm seriously considering a 12v 6Ah LiFePO4 pack (or two) wrapped in (gasp)
shrink wrap for my tail compartment. But they will be fitted inside of a
carbon case.


"6PK" wrote in message
...
On Monday, October 7, 2013 7:19:32 PM UTC-7, son_of_flubber wrote:
On Monday, October 7, 2013 7:25:28 PM UTC-4, Evan Ludeman wrote:

I made some notes in the process of educating myself on LFP batteries
last Winter. I've tried to condense them here into something
semi-useful.



Oh man. Flying around with two or three cheap plastic buckets filled with
hydrochloric acid and lead seems the way go for now (unless you really
really need the power capacity).

Just received my order of the LiFePO4 battery. The first thing on the box
in large print; "LITHIUM BATTERIES- FORBIDDEN FOR TRANSPORT ABOARD
AIRCRAFT AND VESSEL"
Hmmmm......?

Dan Marotta wrote, On 10/8/2013 9:40 AM:
It's that pesky "Hazardous Cargo" thing. Same thing goes for dry ice,
hair spray, and oxygen generators stacked on top of magnesium wheels in
the cargo compartment.

I'm seriously considering a 12v 6Ah LiFePO4 pack (or two) wrapped in
(gasp) shrink wrap for my tail compartment. But they will be fitted
inside of a carbon case.

I think you should consider these batteries instead.

http://www.starkpower.com/

They do allow parallel connection, come with what appears to be a
substantial case, a complete BMS, make a clear distinction between their
starter and energy storage batteries, offer compatible chargers, and the
prices seem reasonable.

I have no direct knowledge about the company or the batteries, but it is
the best website I've seen for the kind of batteries we are interested
in. There is more detailed information about the batteries, and that
gives me more confidence than the rather sparse websites K2 and the
others have.

They also offer more choices in sizes and amp hours, and can be
purchased off the Amazon website (same price, though).

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

son_of_flubber wrote, On 10/7/2013 8:10 AM:
Please correct me if I got this wrong:

1.LiFePO4 with BMS are less likely to self-ignite compared to other
lithium based batteries (or LiFEPO4 without BMS). But LiFePO4 still
contain lithium and will make an intense and difficult to extinguish
fire should they inadvertently ignite.

2.If an undamaged LiFePO4 battery self-ignites, it is most likely to
occur during charging due to a malfunctioning charger or BMS. The
battery overheats to the point of ignition due to internal resistance
to the current applied by the battery charger.

3.If a LiFePO4 battery is charged while it is in a battery box, it
may reach a higher temperature due to a reduced ability to dissipate
heat to the surrounding environment. If it is a hot day or if the
glider is in the sun, the charging battery will reach a higher
temperature.

4.BMS have a fail-safe method of monitoring battery temperature. The
BMS will suspend or reduce charging current should the battery
temperature exceed a safe level.

5.The BMS makes charging a LiFePO4 battery, without removing it from
the battery box in the glider, a safe operation. Manufacturers
anticipate this scenario.

6.If I have a 5 AMP master fuse at my LiFePO4 battery terminals and I
have a partial short that draws 4.5 AMPs. The BMS will detect any
dangerous temperature rise and disconnect the circuit.

7.If the BMS is damaged in an accident, mishandling, or by
age-related component failure, all bets are off. A LiFePO4 battery
with a damaged BMS will be obviously "dead".

I don't know enough about LiFe batteries to give you good answers, but
this website is the best I've found of the consumer suppliers:

http://www.starkpower.com/index.php

Note that they clearly separate their "starter" batteries from their
"energy storage" batteries. Here is the link to their instructions:

http://www.starkpower.com/2013test/U...al_Warrany.pdf

This page has the details for their energy storage batteries.

http://www.starkpower.com/spnews/energystoragebatt/

I notice they use some very pessimistic values for lead acid batteries
in their comparison table with LiFe batteries, in addition to using
"flooded" batteries instead SLA batteries for the comparison.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

On Tuesday, October 8, 2013 8:55:56 AM UTC-7, wrote:
Just received my order of the LiFePO4 battery. The first thing on the box in large print; "LITHIUM BATTERIES- FORBIDDEN FOR TRANSPORT ABOARD AIRCRAFT AND VESSEL"



Hmmmm......?





Where did you order them from?

Bioenno Power

Thanks, but I couldn't find any on that site which will work in my tail
application. The tail battery box (removeable) measures 22 11/16 L x 1
7/16 inchesW x 3 H. It holds three of these wired in parallel:
http://www.batteriesplus.com/product...erker/12V.aspx.

I'm going to hold off for a while with LiFePO4 batteries. I began to
suspect my master switch as my problem and replaced it today with a much
more robust switch. We'll see how that works out.


"Eric Greenwell" wrote in message
...
Dan Marotta wrote, On 10/8/2013 9:40 AM:
It's that pesky "Hazardous Cargo" thing. Same thing goes for dry ice,
hair spray, and oxygen generators stacked on top of magnesium wheels in
the cargo compartment.

I'm seriously considering a 12v 6Ah LiFePO4 pack (or two) wrapped in
(gasp) shrink wrap for my tail compartment. But they will be fitted
inside of a carbon case.

I think you should consider these batteries instead.

http://www.starkpower.com/

They do allow parallel connection, come with what appears to be a
substantial case, a complete BMS, make a clear distinction between their
starter and energy storage batteries, offer compatible chargers, and the
prices seem reasonable.

I have no direct knowledge about the company or the batteries, but it is
the best website I've seen for the kind of batteries we are interested in.
There is more detailed information about the batteries, and that gives me
more confidence than the rather sparse websites K2 and the others have.

They also offer more choices in sizes and amp hours, and can be purchased
off the Amazon website (same price, though).

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email
me)

I hesitate to enter this conversation, however, some of you may want to know we have been selling Lithium Iron Phosphate (LiFePO4) batteries with great success and no complaints. One word of caution is you need to use a special, inexpensive battery charger for this type of battery.

See www.eglider.org

Tom Knauff

On 8/10/2013 04:17, son_of_flubber wrote:

The internal "completely discharged" capacity of a Shorai LFX is 1/3
the rated "PBeq" capacity. For example, the LFX18 12V series have 6Ah
cells internally. But the cells are capable of 80% discharge without
damage and while retaining more cranking ability. As such, the USABLE
capacity(or "reserve capacity") of an LFX18 12V battery is on or very
near par with 18AHr-rated lead acid batteries, while providing
superior cranking performance and a vast reduction in weight. The
Shorai PBeq AHr (lead-acid equivalent) rating system therefore allows
users to compare a very different technology from lead-acid, but on a
close apples-to-apples basis when making a choice.

So they say. In the famous words of Miss Mandy Rice-Davies "They would
say that wouldn't they".

BTW - how big is "vast"?

GC