Interface between LiFePO4 and Ezee controller

LogRaam

10 mW
Joined
Oct 23, 2008
Messages
29
Location
Quebec, Canada
Ok.. I’m a nearly perfect newbie in electronics and electricity setup and I purchased 2 LiFePO4 packs that I must rewire... DOH!!

The good news is that I just receive them today! Straight from Hong Kong!
And the other good news is that YOU can help me out with the wires issue.

Let me show you...

First of all, I have a Ezee motor hub kit with a Ezee controller. The Ezee controller has typical Anderson power connector. I use a “ductapped” 48v/8Ah NiCAD pack as below:

lapipaabh.jpg


The pack have 2 connectors; 1 Anderson connector to draw power from the pack

mapibaabh.jpg


And a XLR for recharging

mapicaabh.jpg


Now, here is the LiFePO4 48v/20Ah from M. Xie:

mapieaabh.jpg


The pack has only a 3-pin connector.

mapiiaabh.jpg


The kit include a XLR plug

mapijaabh.jpg

mapikaabh.jpg


And a cable interface from 3-pin connector to XLR connector

mapilaabh.jpg


This cable interface let me connect the LiFePO4 pack into the charger

mapinaabh.jpg


Ok.. My first question is: “Can I build an interface cable from 3-pin connector to Anderson power connector to connect the LiFePO4 into Ezee controller?”

My second question is: “The LiFePO4 only have 1 wire.. if I understand, I can draw power from the pack AND recharge the pack from the same cable?” Hey! stop laughing.. ;)

Thanks guys,
 
yes, you charge through the same plug you discharge through. do not use the nicad charger, use a lifepo4 charger capapble of putting out 59V.

you got 2 ebay specials from a mr xie?

do you know if it even has a BMS? or what kinda cells?
 
I bought directly from M. Xie's Company.

2 LiFePO4 58.4v/6A chargers + 2 LiFePO4 48v/20Ah + taxes + air shipping + customs = 1650.00$ CAD (~1200.00$ USD). Straight from Hong Kong.

Each 48v/20Ah LiFePO4 cost me 502.00$ USD. Each charger at 29.00$ USD. All new.

Both LiFePO4 have a BMS.

I don't have wrapping stuf so I didn't check out which batteries are in use inside.

Ok, if I setup an interface cable with 1 Anderson and 1 3-pin connector to plug between the 3-pin from LiFePO and Anderson from Ezee controller, this should work eh? Right?
 
Oh, I forgot.. M. Xie is the owner of Ecity Power.. Check out his website at: http://www.ecitypower.com/index.php?page=1
 
so these are prismatic cells inside the tape? the 3 pin plug is built that way to maintain the polarity i expect. you can use any connectors you wish, and you can put the xlr plug in parallel with the leads.
 
LiFePO4 have cylindrical cells packed together.

Here's what I'll do:

1) Replace the 3-pin connector from battery pack with a Anderson connector;
2) Replace the 3-pin connector from "XLR to 3-pin" cable with Anderson to get a "XLR to Anderson" setup;

This way, I'll be able to connect the battery pack to the Anderson connector from the controller. And I'll be able to connect the XLR from the charger to the pack.

Before I cut my wires, is there an advantage to stay with the 3-pin connectors? Am I right to think Anderson connectors are the way to go?
 
Andersons are perfect for both charge and discharge wires, just arrange the blocks so you canot accidentally plug the controller into the charge port...loll. ( I color code my voltages with andersons )

Just make tripple sure you get the polarity right !!!

And remember to cut 1 wire at a time when working on batteries ! :mrgreen:
 
Thanks YPedal..
But I wonder.. My LiFePO4 pack have a single wire with 3-pin connector. The same wire is used for charging and discharging the pack. From your reply, you seems to refer to a different wire for charging than discharging using Anderson.. Do you mean I can't use a single wired pack using Anderson for both charges and discharges ?
 
2 or 3 pin connector makes no difference.. just match the + and - accordingly. some packs like nimh have a temp wire on the 3rd pin. no such thing with lithium.

Looks like your pack has only 1 + and - lead.. for both charge and discharge.. some BMS's are like that.. so no worries.. all good !
 
Don't forget to check the polarity with a meter... color codes are not always the same from country to country.
 
you can install the andersons to connect to the controller and solder the leads for the chargin XLR plug on the leads behind the andersons so you could even leave the pack installed on the bike and not disconnect to charge.

put a switch in the wire that delivers the controller current, and then you can turn off the controller but leave the pack charging and still hooked up. but include a fuse or inline circuit breaker in the positive lead from the battery, just in case.
 
Update. I got an interface plug with 1 XLR at one end and 1 Anderson at the other end. I connected the XLR on the battery, and after I connected the Anderson to the controller's... but when the 2 Andersons make contact, it just spark with a flash of light.. and the 2 connectors got welded together!! I can’t remove them anymore. Anyone have experience with such an issue? :?

LogRaam
 
Do you have a switch between the battery and controller? Most controlrs have a large capacitor which charges up when the battery is connected- This can cause a small arc that might weld Anderson connectors together. If you can use the system (controller gets power, motor works, etc) then all is probably fine, but you may have to cut the 'welded' connectors out and replace them. It is convenient to have a separate charging and discharging connector on the battery so you can charge while the pack is on the bike if you wish.

Placing a switch between the (+) battery wire and controller lets you power the system on and off, and connect/disconnect the batt without seeing sparks. The switch should have contacts that can take at least 30A or more. I have a DC circuit breaker (40A) on the (+) battery wire and an inline fuse on the (-) wire of my aging SLA pack because I have had surprise sparks from the charger connecter bumping into an exposed battery terminal (which is very exciting, not in a good way!).

Just be sure the polarity is right when you connect things up- a cheap multimeter is worth the investment. Some controllers do not tolerate reverse polarity. You will have a great system once it is up and running- have fun!
 
**UPDATE**

Hi folks,
‘Have plugged the LiFePO4 48V 20Ah on the Ezee kit (front hub + Ezee controller). Everything seems to work well for at least 1 month, and then I ride the bike under rain… To protect the controller I placed a waterproof hood on top of the Ezee controller; bad idea I mean. I completely cooked the resistors in the controller, busted the throttle and disabled a hall sensor in the front motor hub. After only ~6 month my Ezee kit was completely disabled.
Fortunately, I met DoctorBass at his home and he agreed to help me building a new eBike. My father always told me to have a good “doctor” in my contacts.
Thanks Doc! ‘Hope you’ll be able to turn my Surly into an electric monster! ;)
 
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