LiFePO4 Help Needed

Nah, its easy. Stick to the basics and you will be fine.

You can get whatever (lifepo4 compatible) charger you want, and based on the system you want to run, you just need ANY (4) cells, 3.2V, prismatic (preferably), 40AH cells.
That will get you through a full day of battle at nats.

Mike has more experience with the other brands but I don't think it really matters if they are thunder sky, powersonic (batteryspace), Calb, or GBE (?).

 

Brand names are kinda like buying a car; they all do the same thing with minor differences. heh.

Thundersky (yellow) cells tend to be the lightest and most durable brand. Unfortunatly, they are very difficult to get right now due to some sort of brand name litigation going on in China.

CALB (blue) cells are slightly heavier than Thundersky, slightly smaller, and has very good amp draw ratings. Downside is one thousand less cycles of life than the Thunderskys.

GBE (greenish) is the newest brand out and fall someplace in between Thundersky and CALB cells in all catagories. The 20ah cells in the Erin have perfomed well so far without any trouble other than a couple cells bloating slightly (normal for prismatic types and doesn't prevent the cell from delivering power).

 

Okay, so I could use this charger for charging 2 of the CALB at 6+ volts and 20 amphr enough to run a cruiser on for 2 sorties/1 battle?

http://www.hobbypeople.net/index.php/propeak-sigma-ii-lipo-ac-dc-charger-110vac-leads.html

 

OH, Thanks
Skippy

 

What kind of cruiser would hold two 20AH prismatic cells? You may want to look at smaller cells. For simplicity I run 6v nimh 4.5ah packs in my Gloire.

 

As far as the charger it would work but its seems to be about the same as the one from Strike.

 

Somebody said something about blue cell and I was thinking about these, http://www.ebay.com/itm/230686164817?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 not the 20Ah square ones. Anyway would the charger work with these cells 38120S Cylinder, 2 would equal 20AH and wolud be 6.4 volts.
Right????

 

And would only weigh about 1.5 LBS.

 

Those are 10ah cells at 3.2v each. That means you would have 10ah at 6.4v with 2 cells. You would need 4 cells for 20ah. I recently bought some from http://stores.headway-headquarters.com/StoreFront.bok and had a smooth/ quick transaction. They were also very well packed for shipping.
Das Butts

 

I am fairly certain that any computer charger, like the unit Strike carries, or Hyperion (like I have), or any other charger where you can program the amount of voltage.. will work with any Lifepo4 cells / pack. You just need to know the voltage cut-offs to program in.

The more simple 'smart' chargers like the ones I got from Batteryspace have a built in cut-off so you have to be sure your cells can be charged to its pre-programmed cut-off. In this case it is 3.6. My yellow 20ah cells an be charged up to 3.65 so I am ok with those.

 

Skippy, which cruiser are you setting up with these cells?

 

A DKM Lutzow, a Mogami and maybe the Battle Cruiser SMS Derfflinger.

 

Okay Guys,
I hope every buddy had a very Merry Christmas yesterday and that you got all the toys you wanted. I got a Sigma II EQ Intelligent Battery Charger and while looking throgh the instructions I ran across a section that said Charging the "LEAD-SULPHURIC BACID"BATTERY. iS this the same as the SLA "Sealed Lead Acid Battery?
This seems like a dumb question but I just want to be sure before doing anything stuiped,
TIA, Skippy

 

Yes it is the same as a sla battery.
Ron Hunt

 

I'm also looking at buying LiFEPO4 batteries. I'm going to be using them in a convoy ship just to try the water out. My first question is what kind of AH should I be looking at? Secondly, I would have thought just building a pack and then using a charger to charge the whole pack at one time is the way to go, but it seems like several of you guys charge individual cells? I'm also confused as to which chargers will work with LiFEPO4. When looking at Hobby King they just all seem to say LiPO and I know that there is a difference concerning voltages and such. I just don't want to waste $200-$400 trying to figure out how it all work like I did when I first started using NiMH. That is a whole sad story in itself.

 

Many chargers have a LiFe setting also. The reason for charging individual cells is two-fold. One, if you do not, you should balance charge them and/or put cell protectors in the pack is my understanding. Second, if you use the large cylindrical cells like these: http://www.batteryspace.com/lifepo438120pmsizecell32v10ah100asurgerate32whwith6mscrewterminal-unapproved.aspx you can put one on each side down in bilge curves and have 6+ v for 10Ah. However for my Lib, I just use SLAs, as they are cheap and I need the ballast.

Cheers,

 

Yo Ralph,
As an early adopter of LifePO4 let me say this, for a convoy just stick to nimh. Its stupid simple and at Bob's advice bought some built 4.5ah packs from battery space for 30 each. 1 pack will run a convoy ship for over an hour.. maybe even more. I share them with my cruiser. For that I dont have to worry about balancing or needing a high end charger. Most likely you already have a nimh charger... so why fight it.
I think LifePO4 is great when you need higher energy density like in the 20ah and 40ah cells but doesnt always make sense for others since you need a compatible charger for Life. So if you have a nimh charge already then I suggest you stick with nimh for a convoy ship.
Hope you are doing well.

Johnny

 

well that's the thing, while I do have a NiMH charger, it is in California in a storage locker and I don't remember which storage bin it went into...That is why I was thinking of trying LiFEPO4. And this way I'll have experience with them when I get around to revamping current ships which are also in the above mentioned storage locker somewhere. I wasn't there when the moving people unloaded into the storage locker, and I just have this funny feeling it is in the very back....

 

I have not used the larger cylindrical cells but prefer the smallest pack I can get. I did by some M or F cells ( I dont remember which) and they were smaller. It turns out that, much like anything else they sell, all of the cells are not of equal capacity in the same type/size of cell.

I made two packs and had one cell that was not good in that it had super high internal resistance and didnt want to charge as quickly as the other pack. I also had to make a pack out of multiple cells to get above 6v and added a balancing plug and used a balancing charger. The larger cells are easier to wire as single cells which allow you to charge them individually.

A pack will require a balancing lead and smart charger and is a bit of a hassle to charge. I think 5 or 6 amps should be plenty for most cruisers depending on how much damage you tend to take.