RXV HV/LV BMS Shutdowns

[MrBritGolfFan]

Originally Posted by molfpedal

It has for me. I had a loose connector on my charger interlock wire and it tripped the circuit. My cart coasted to a normal stop, found the bad connection and took off. I didn’t get the bullet connector all the way together when I put it together, sod it vibrated loose.
I will try to get some good pics of the circuit for you. What controller was is in your cart before the Navitas?

Molfpedal, i had a curtis 235 amp. I still have it too.

I am struggling to understand the k3 relay. I get the need for it, but the 120 VAC label is throwing me off? I am not currently sending 120 v to the cart, so im not following this one? Cab you help?

[molfpedal]

Originally Posted by MrBritGolfFan

Molfpedal, i had a curtis 235 amp. I still have it too.

I am struggling to understand the k3 relay. I get the need for it, but the 120 VAC label is throwing me off? I am not currently sending 120 v to the cart, so im not following this one? Cab you help?

The 120 volts is from the charger port. I have an onboard charger, so I took out eh regular EZGO port and put in a 120v plug that is connected to the charger. So, I plug an extension into that to turn on the charger. When the K3 gets 120v on the coil it opens the NC contact which is connected to 1 side of the K1 coil so it cannot be driven while hooked up.
In your case, if you are still using the built in charger port then you can probably eliminate that relay and connect the P1 + directly to the coil of the K1 relay. This would be your HV/LV trigger. As long as there is power on the C- side of the BMS it keeps the K1 circuit closed and the accelerator works. If there is a problem it opens and the cart just stops like you let off the accelerator. I prefer this to the locked brake without it.

[MrBritGolfFan]

Originally Posted by molfpedal

The 120 volts is from the charger port. I have an onboard charger, so I took out eh regular EZGO port and put in a 120v plug that is connected to the charger. So, I plug an extension into that to turn on the charger. When the K3 gets 120v on the coil it opens the NC contact which is connected to 1 side of the K1 coil so it cannot be driven while hooked up.
In your case, if you are still using the built in charger port then you can probably eliminate that relay and connect the P1 + directly to the coil of the K1 relay. This would be your HV/LV trigger. As long as there is power on the C- side of the BMS it keeps the K1 circuit closed and the accelerator works. If there is a problem it opens and the cart just stops like you let off the accelerator. I prefer this to the locked brake without it.

Molfpedal, like this?

EZGO RXV HVLV Wiring_Diagram No Onboard Charger.jpg

[Sergio]

If You are going to use the BMS to directly control charging HV & LV cutoff, go ahead and also eliminate K2 and anything connected to it.

The charger positive will go directly to pack positive.

The charger negative will go to the BMS OUT (C-) terminal so it can disable the charging in case of LV or HV.

You will only use K1 and D1 in this case.

[MrBritGolfFan]

Originally Posted by Sergio

If You are going to use the BMS to directly control charging HV & LV cutoff, go ahead and also eliminate K2 and anything connected to it.

The charger positive will go directly to pack positive.

The charger negative will go to the BMS OUT (C-) terminal so it can disable the charging in case of LV or HV.

You will only use K1 and D1 in this case.

Thanks Sergio. I did see another post (it may have been yours) where someone had used an ANT BMS 300A, which then allowed them more amps through the BMS. I am worried that i might pull too many Amps through the BMS and blow the BMS up.

Here is the BMS in use, rated at 130A, although i already measured over 250A with my meter on the negative battery cable:

inside.jpg

What i dont know is the C rating for my cells that are being used in the battery. here is some info on the inside the of the pack:

Batteries inside.jpg

I would be interested in bypassing the BMS for when the cart is being used and only use it during charging. Is that what you have done?

[Sergio]

I would hope any lithium battery sold for motive application would be able to handle the quick peak current during acceleration.

You can set your Controller "Max Battery Amps" or similar to 200 amps.

The Controller "Max Armature Amps" can be whatever your motor can handle, 400 amps to start.

To by-pass the BMS during discharge:

Run a new 4ga red cable directly to the pack positive battery terminal, add an inline 300 amp fuse for protection.

You will also need a new 4ga black cable directly connected to the pack negative battery terminal.

The negative wire coming from the P1 (12v led or resistor equivalent) goes to one of those BMS C- solder pads where the Anderson connector black wire is also connected.

That will allow the BMS to control the charging using the existing Anderson connector and provide LV & HV cell protection during discharge by disabling the K1 relay.

[molfpedal]

Originally Posted by MrBritGolfFan

Molfpedal, like this?

Attachment 206230

Sorry I didn’t go into enough detail about the relays. Listen to Sergio. He is the one who came up with the relay setup. I just modified for my situation.


Sent from my iPhone using Tapatalk

[MrBritGolfFan]

Originally Posted by molfpedal

Sorry I didn’t go into enough detail about the relays. Listen to Sergio. He is the one who came up with the relay setup. I just modified for my situation.


Sent from my iPhone using Tapatalk

no worries, thank you molfpedal!

[MrBritGolfFan]

Originally Posted by Sergio

I would hope any lithium battery sold for motive application would be able to handle the quick peak current during acceleration.

You can set your Controller "Max Battery Amps" or similar to 200 amps.

The Controller "Max Armature Amps" can be whatever your motor can handle, 400 amps to start.

To by-pass the BMS during discharge:

Run a new 4ga red cable directly to the pack positive battery terminal, add an inline 300 amp fuse for protection.

You will also need a new 4ga black cable directly connected to the pack negative battery terminal.

The negative wire coming from the P1 (12v led or resistor equivalent) goes to one of those BMS C- solder pads where the Anderson connector black wire is also connected.

That will allow the BMS to control the charging using the existing Anderson connector and provide LV & HV cell protection during discharge by disabling the K1 relay.

Thank you Sergio!

I cannot recall the history of the batteries, but i feel like i remember reading they were used in hospital equipment, i could be wrong though and i will check with BigBattery dot com to see if they know.

I'll draw up what i think you are suggesting and make sure its correct, i really really appreciate your help and molfpedal too, awesome forum!

[MrBritGolfFan]

Originally Posted by Sergio

I would hope any lithium battery sold for motive application would be able to handle the quick peak current during acceleration.

You can set your Controller "Max Battery Amps" or similar to 200 amps.

The Controller "Max Armature Amps" can be whatever your motor can handle, 400 amps to start.

To by-pass the BMS during discharge:

Run a new 4ga red cable directly to the pack positive battery terminal, add an inline 300 amp fuse for protection.

You will also need a new 4ga black cable directly connected to the pack negative battery terminal.

The negative wire coming from the P1 (12v led or resistor equivalent) goes to one of those BMS C- solder pads where the Anderson connector black wire is also connected.

That will allow the BMS to control the charging using the existing Anderson connector and provide LV & HV cell protection during discharge by disabling the K1 relay.

Sergio, like this?

new diagram.jpg