Basic Nissan Leaf 7 module Lithium setup with Generic Chinese BMS

[GolfCardMods]

Awesome info here. Props to the OP for getting this one started.

[Volt_Ampere]

It is critical to get the pack in good balance at the high end of their voltage range before doing a full charge. A good BMS will save you $$ in the long run by making your batteries last longer.

[DaveTM]

Since the LV appears to be 2.5V per cell....go less than that and trash your battery.....you are just above "the wire".

I can't speak to the charger as others with more experience will, but if you disconnect the pack from any external sources, the cell charges should remain the same for the time period you are talking about.

[Murby]

Originally Posted by yensidcamper

I got the pack to charge back up. Stopped at 55v to hopefully not over charge any single module.

I am going to order another Cheap BMS unless I can stomach buying a better one. I paid $450 for the leaf cells hard to just justify a very expensive BMS. Any suggestions on a moderately priced BMS?


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Your perspective is wrong. You're building a battery bank and you're looking at it like you're purchasing lithium ion cells and adding a BMS. This is not the perspective you seek.

The way you should be looking at it is: "I'm purchasing the BMS, which lithium cells do I want to add to it"


Truth be told, you got lucky that the BMS drained your cells. Imagine what would have happened if it failed to protect a cell from high voltage? Not only would use lose your battery, you could lose your golf cart and whatever structure it is parked in.

You can screw around with LiFePo4 cells.. all they do is smoke when things go wrong. But when lithium ion goes rouge, really bad things can happen.

As DaveTM said, the cost of a good rifle isn't in the rifle, its in the scope. Funny thing, it also applies to photography. As they say "$500 Camera bodies come and go, but the $1500 lenses you buy will be with you forever"

[fstop]

Where is Sergio?

Hope all is well with him. Miss his insight and experience around here...

[fstop]

Originally Posted by fstop

Where is Sergio?

Hope all is well with him. Miss his insight and experience around here...

Anyone?

[Bobbob]

fstop I am also worried about him he seemed to have just dropped off the face of the earth. Hope he is ok wish he would just pop in and say “ HI”.


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[harrybel2769]

Hi all, I have a 14s2p Leaf module I'm putting in a resistor cart with the 5 solenoids. Would the relay setup in the first post work with this? And would I connect my key switch in series to one of the K2 terminals?

[jhornbr225]

I previously ordered all the parts to do this, but the more I look at it, the more I'm convinced that I didn't do the right thing by ordering ALL the parts.

I'm not going to have a built in charger like Sergio, which, according to how I'm looking at the circuit, I won't need Z1, D2, K2 or K3.

I believe it's the BMS that directly cuts charging when any cell's voltage goes over the max. All that K2, K3 and their associated circuitry does, as far as I can tell, is protect from excessive current flowing when the charger first gets power. They also keep the charger from seeing the battery voltage all the time, and prevent the small constant drain on the battery by the light in the charger.

K1 and D1 are responsible for acting like the keyswitch shutting off if any cell goes undervoltage. I think that's the only part of the circuit I'll need.

Can anyone confirm or deny my suspicions?

[WalterM6]

I just built my pack and that's all I did. When the BMS interrupts the 48v to the power supply a relay drops out and opens pin 10 (tan wire) on the controller.