RXV dropping below 44V and stuttering while under accelerating

[Sville_RXV]

Hey ya'll.

I have a 48V RXV that I converted to lithium. It has 4x12V 100AH EnjoyBot batteries, 2 gauge wiring, Navitas 600A controller, and an Enjoybot battery monitor.

It ran fine for about 6 months but now it drops to 44V and stutters very aggressively. I believe the stuttering is actually the controller hitting a low voltage cutoff but I'm struggling to figure out why it's dropping the way it is. I have attached a Voltage vs Amp draw graph that Navitas sent me.

Anyone able to give me some advice on what to check?

[ojo]

12V Lithium in series are NOT recommended as they run out of balance over the time. You have to single charge them, easiest with an 4-channel charger ( 4x 12v ), but they're expensive.

[Capt. Lenny]

Originally Posted by Sville_RXV

Hey ya'll.

I have a 48V RXV that I converted to lithium. It has 4x12V 100AH EnjoyBot batteries, 2 gauge wiring, Navitas 600A controller, and an Enjoybot battery monitor.

It ran fine for about 6 months but now it drops to 44V and stutters very aggressively. I believe the stuttering is actually the controller hitting a low voltage cutoff but I'm struggling to figure out why it's dropping the way it is. I have attached a Voltage vs Amp draw graph that Navitas sent me.

Anyone able to give me some advice on what to check?

Sorry about the problem you're having. I 2nd what Ojo says. you should have visited this site before you made the decision on 4x12's.

[Sville_RXV]

I actually did visit this site and saw what people were warning against. I reached out to EnjoyBot and they told me it wouldn't be an issue and since it was several hundred dollars cheaper, I went the series route.

I did charge them individually but I'm not 100% sure if the charger worked well. They are all sitting at the same voltage now and all act the same when accelerating.

[Capt. Lenny]

Have you tried contacting EnjoyBot and telling them you're having problems? What's the warranty?

[Sville_RXV]

Unfortunately, I bought from their Amazon store which seems to be different so they won't offer help since they don't have an order number from their website. I have reached out to the Amazon store and they offered me little help other than telling me that the cart is modified and unless I put it back to stock and retest, they can't help me.

[Capt. Lenny]

Well, so much for the warranty and Amazon. But you said you reached out to EnjoyBot and they said it wouldn’t be a problem?

[Sville_RXV]

Yeah it's been a real pain to get help. I did reach out to EnjoyBot's customer service on the website before ordering off Amazon. Do you have any ideas of how to test for a bad cell in one of the batteries or a faulty BMS? They all act the same with voltage drop, regen, capacity, etc.

[TheCartBoy]

Is there a Bluetooth app or anything to know what the BMS is doing?

[Sville_RXV]

Nope. These were the last produced without Bluetooth. Probably another reason they had such a good sale going.