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Need advice for LiFePo4 battery cells


#1

Hello everybody…
Earlyer this year I purcased 4 LiFePo4 battery cells, each 3.3V and with a capasity on 10Ah, seriel connected should make 13.2 volt giving some hours with radio operation on low power (5-10watt output).

The problem is I don’d have any charger ment for this cells.
I did a search on Ebay.com for LiFePo4 charger but came up with a big mountain of results.

Could anyone advise me to a good charger, maybe on Ebay.
I have read that the best way to charge this LiFePo4 cells is to charge them single (one by one)= long time with only one charger.

I will be very happy for any advise and assistance regarding this subject.

Best 73s LA3DNA Leif


#2

In reply to all: I have no information for Leif, but I will be watching this thread with interest as I have two 7Ah SLABs which have nearly come to the end of their life. Do I buy a new SLAB at about £20, or go for less weighty LiPos - more expensive - and with added expense for a suitable charger (and the firebrick surround for safe charging)?

Reference to information about LiPos, cell sizes, charging balancers, anything would be usefull.

The life of a SLAB appears to be about 3 years, given that the charging voltage, limited by the need to avoid gassing, prevents the full charge that can given to a vented battery. How long will LiPos last in the amateur radio environment (I usually transmitt at 20W)?

Regards, Dave, G6DTN


#3

In reply to M0DFA:

I went to the local Heli Store and asked them for Lipos and a reasonable charger. I payed around €100.- and went went out with two Lipos and a Hyperion EOS 0403i DC

No problems since then, neither with the lipos nor the charger, couldnt be happier.
Look at http://dl4maq.wordpress.com/2011/05/02/weightwatching-tut-not/

72, Jo
dj3cq


#4

In reply to M0DFA:

Hi Dave

Most of your questions have been answered in previous threads here. You may find a bit of digging gives you the answers.

73

Richard
G3CWI


#5

From my earlier post

"I bought my Lipo from the link below for $48.57US & postage.

http://www.hobbyking.com/hobbyking/store/__11939__Turnigy_nano_tech_6000mah_3S_25_50C_Lipo_Pack.html

I have bought many items from them before and they are most reliable with reasonably prompt postage. They have standard postage/weight rates and it is therefore sometimes cheaper to combine postage or buy more than one item.
The batteries are 3S, 11.1 V although this is the quoted discharge voltage. They charge to 4.2v each cell giving 12.6V. They are very heavy duty for their size giving 25C continuous or a 50C burst - not that a SOTA op would ever need it hi hi."

They also do chargers at a very reasonable rate.

Regards
Dave


#6

In reply to LA3DNA:
Hello Leif,

I purchased this

http://www.lightningrc.co.uk/index.php?main_page=product_info&cPath=11&products_id=312

last year for my LiPo battery. It charges most battery types and it works well.

73
Roger MW0IDX


#7

Some more here

http://www.hobbyking.com/hobbyking/store/_216__408__Battery_Chargers_Acc-Battery_Chargers.html


#8

Hi Leif
You must make sure the charger you get can charge LiFePo cells - they are a different chemistry from LiPo cells and require different charging voltages!

Without looking at the manual, I think the Turnigy Accucel charger from HobbyKing can charge up to 6 LiFePo cells, but I am not sure if it can charge 10 Ah cells.

The recommendation to charge cells one-by-one is probably to avoid cell voltage balance problems. A balancing charger (such as the Accucel) ensures the series connected cells in a battery are automatically charged to the same voltage (when they are at the same voltage, the cells in the battery are known as ‘balanced’).

However, if a single cell charger could provide four times the charge current that one cell needs, you could charge four cells in parallel and they would all charge to the same voltage (and so be balanced).

You do not need a balancing charger to charge a LiFePo (or LiPo) battery, but a regular balancing charge helps prolong battery life.

If you are using individual cells, rather than a battery with an built-in balance connector, and want to use the balance facility of a charger; you will need to provide a balance connector. A Google search should provide the details you need, if not contact me through this list.

73

Stuart, G8JMS


#9

In reply to LA3DNA:
Hi,

IMHO the best, and cheapest charger you can buy for this LiFePo4 batteries(and many other types) is the IMAX B6. There are tons of them selling on Ebay, and yes, are LiFePo4 ready.

I am charging my entire 4,4Ah 13,2V (4S) LiFePo4 pack with it OK, not the individual elements one by one.

Best 73, EA4MZ Moises “Mo”