Charging LiFe 6.4 volt battery.
 

Several transmitters have batteries, LiFe 6.4 volts and 1400 mah's. Chargers show charges for 6.6 volt batteries. So how do you charge the 6.4 volt battery out side of your transmitter with a regular charger? Thanks.

I'm not sure I fully understand the question. But LiFe batteries charge to 7.2 V for a 2 cell pack, not 6.4 or 6.6. 6.6 is the normal working voltage for LiFe though. Configure the charger for normal LiFe batteries at the appropriate current and cell count for the particular battery and let the charger do its job. It isn't usually necessary to remove LiFe batteries from the transmitter / airplane for charging as would be common practice with LiPo batteries.

Lipos were easy for me. a two cell pack was 7.4 volts. Full charge was 8.4 volts. The packs are labeled 7.4 volts not 8.4 volts. So now I have a transmitter battery that is labeled 6.4 volts.
I notice LiFe batteries that are used in planes to power receivers are usually labeled 6.6 volts.

So my charger can charge Li-Fe batteries. I see the first setting for a 2s battery. Screen shows (2s 6.6 volts), I scroll to the next setting it shows (3s 9.9 volts), next is a (4s 13.2 volts)
I am allowed to change the cell count of the battery I am charging and the charging mah's. As I increase the cell count the voltage goes up by multiples of 3.3.

My concern arose when I see I have a battery that is labeled as a 6.4 volt battery. I see no charge settings for a 6.4 volt battery. Each cell would be at 3,2 volts. I then wondered if I should just go ahead and use the 2s 6.6volt setting on my charger. It is a 1400 mah battery. I did not want to ruin the battery.

JR and Hitec use the same type battery in the transmitters. I have a JR transmitter. The Hitec battery is cheaper around $20.00 and I bought one to check it out, I just wanted to charge it up with my regular charger.

Just noticed my 6.4 volt transmitter pack charged in the transmitter to 7.2 volts.

You're just dealing with a labeling issue. 6.4, 6.6, etc are nominal voltages or the usual working voltage of the battery under load. I don't know where the 6.4 came from as I have never seen that voltage used when referencing LiFe batteries. Anyway, to make a long story shorter, 7.2V is the correct charging voltage for any (2) cell LiFe battery I have been exposed to or know of. Thats why your charger charged to that voltage. After you remove the battery from the charger, after a bit of time, the voltage will settle down around the 6.6V range +/- a bit. Sounds to me like you're on track with the charger setup.

Maybe the company that makes the transmitters wanted you to buy their replacement batteries labeled 6.4 volts at a higher cost of course for guys thinking that is what they must use. I see now that a 2s battery commonly labeled 6.6 volts would do the job safely and be bought for a much lower price.

Thanks so much for your help.

Maybe it is just me but I always want to have the battery being charged to have a balance connector and a charger that makes sure that all cells are balanced at the end of charge. This is hard to do without removing the battery from the transmitter for charging as you do not have access to each individual cell in the battery.

You are correct, Rodney. I feel the same way about batteries.

JR's transmitter has the charger built in the transmitter. I see no extra balance leads. Maybe they are built in??The Hitec battery looks like any 2s battery. I don't see any extra lump or bump under the wrap. It also has no balance leads.The charger is the wall type. I have no idea if they are being balanced charging inside the transmitter. I usually charge inside the transmitter but wanted to charge this one up with a charger as it did not have the JR plug for it. Upset a bit because the DSMSS transmitters have a different white plug that they had in their DSMX transmitters. The JR transmitter batteries are over $50.00. I bet a cheaper 2s Li-Fe would give me good service and be a good backup battery even without the balancing. Would not bet on that though. So I save $16.00, maybe it is not worth all the effort finding the right JR plug , which I have not so far and messing with soldering.

When Li-ons first came out there were no balance possibilities and they usually lasted 3-4 years. Wonder if a balanced Li-on battery would last longer. Don't get me wrong I believe in balancing batteries.

Just wanted to ask about LiFe batteries for the rx and tx. My son who has JR equipment and myself with Futaba have been out of the hobby for a few years and he wants to replace our old batteries with LiFe for longer run times with our aircraft. I just need to know if they will perform as he thinks and do we need to purchase chargers for LiFe batteries only? Thanks Sunny_B