2017 Precedent i2 - Dakota Lithium

[BlackHornet]

Hey guys, long time member.....with a very long hiatus.

A lot has changed since playing around with these carts and I have a few questions in regards to Lithium battery packs.

I now have a 2017 Precedent that the first part of the serial is: JE1704.

So, from what I decoded, it is a 2017 that came with the i2 rapid charger.

All accessories, to my knowledge, are wired to a separate 12v battery on its own circuit.

Thats the background of the cart^^

Now, on to my question(s):

The trojans decided not to work anymore and so I just installed 4-12v 100ah Dakota Lithium batteries.

I get 51volts when looking at the pack...remember these are brand new.

I am currently charging them with a Dakota Lithium 48v/8amp charger....this is where one of my questions comes into play. With the charger plugged in, I am only seeing 53v, shouldnt I be seeing closer to 58v?
I have another Dakota Lithium charger to use later (4 bank, 12v/15amp charger) that I will install onboard later.

My next question is, I did a quick function test of the cart at 53v...I can ease onto the throttle and its fine, but if I stomp on the throttle, it "dies" and wont do anything. No reverse buzzer, nothing. I plug the battery pack back in, I get the buzzer back and can ease the cart forward. Is that the factory BMS shutting everything down because of the rapid current draw that these lithiums are allowing to flow?

If it is the factory BMS....what can be done?

Thanks!!

It feels good to be back!

[CP241]

Couple things. First, it will climb gradually as it charges. It won’t reach 56 or 58 or whatever Dakota specs their batteries at until it’s nearly done charging. What you’re seeing is normal.

Second, skip that 8 amp charger and use the 4x15. Amp hours go both ways. Both for discharge and recharge. If they’re at 0% and they’re 100aH batteries it’s gonna take 12-13 hours to charge them to 100.

At 51v they’re very very low, likely for shipping purposes. Put them on the charger and leave them there until it’s fully charged. If you disconnect the charger within a few hours it should settle to around 53v. Lithium does not discharge like lead acid. It can still read 52-53v and be 80% SOC. When it starts dipping below 52v into the 51’s you better be heading home.

That said, with 51v as your static reading, it makes sense it would cut off when you floor it. You’re tripping the Dakota BMS. (There is no factory BMS, each battery has its own built into it from Dakota). At this point I don’t think it is due to over current as much as it is low state of charge. Charge them all the way up and I think all your issues will “fix” themselves.

[BlackHornet]

Originally Posted by CP241

Couple things. First, it will climb gradually as it charges. It won’t reach 56 or 58 or whatever Dakota specs their batteries at until it’s nearly done charging. What you’re seeing is normal.

Second, skip that 8 amp charger and use the 4x15. Amp hours go both ways. Both for discharge and recharge. If they’re at 0% and they’re 100aH batteries it’s gonna take 12-13 hours to charge them to 100.

At 51v they’re very very low, likely for shipping purposes. Put them on the charger and leave them there until it’s fully charged. If you disconnect the charger within a few hours it should settle to around 53v. Lithium does not discharge like lead acid. It can still read 52-53v and be 80% SOC. When it starts dipping below 52v into the 51’s you better be heading home.

That said, with 51v as your static reading, it makes sense it would cut off when you floor it. You’re tripping the Dakota BMS. (There is no factory BMS, each battery has its own built into it from Dakota). At this point I don’t think it is due to over current as much as it is low state of charge. Charge them all the way up and I think all your issues will “fix” themselves.

That is good to hear that the charger will ramp up the voltage towards the end, as long as everything is ok with the charger.

So, the 8amp charger is only being used because using the 15amp charger is going to be a little more involved and the cart is needing to be used as a shuttle.....now. Once that is done, I will be using the 15amp.

Yes, the pack was at 51v because of shipping, thats why I made sure to say that they were brand new. That coupled with the charger only reading 52-53v, I figured would just give the whole story. The charger has now been on the cart all night, so when I get a chance, I will go check voltage here soon.

As far as the cart shutting off when requesting some power, I was hoping that it was due to the low voltage and the nature of Lithium.

Thank you for the reply!!

As I am typing this, the charger has been on for almost 12 hours. I will report back!

[BlackHornet]

ok, update:

charger said full charge. Battery pack was at 57.4v

I pull out of the garage, easing onto the throttle...no issues.

I mash the throttle, the cart loses power.
I hit the reverse switch, no buzzer, no power.
I push the cart back into the garage and check the voltage of the pack: 0.4v

I plug the charger back in, it reads 54v and I tap the reverse switch and it buzzes.


Any ideas on what could be putting the cart into what appears to be "shut down mode"?

Thanks!

[LJC2001]

Wow, this sounds serious. Have you contacted Dakota? I'm following your thread. I'm ready for new batteries and do not know what to buy.

[Fairtax4me]

The cart isn't shutting down. The batteries are. This is the common problem carts face when matched with batteries that can't provide enough amperage and the BMS in the battery shuts down to keep the battery from going into thermal runaway.
The answer is likely going to be sending those batteries back to Dakota. Not every lithium battery is going to work in a golf cart, because they just don't have the discharge capacity to make the cart work.

[CP241]

As FT said the BMS in the Dakota batteries is what’s shutting the cart down.

I don’t think that a stock motor/controller should shut down the pack, unless one or more of the batteries or BMS is defective. Is the cart stock or upgraded motor and controller?

[BlackHornet]

All, thanks for the replies.

I have already reached out to Dakota because I was thinking that the BMS is causing an issue. I called them first thing after I tested the cart today and the recording said to leave a message because everyone is busy. I also sent them an email.

The cart motor/controller is 100% factory.

[jasonojordan]

I would not think that a stock motor and controller could demand enough to trip the factory bms on these batteries...something seems off.

[CP241]

Originally Posted by jasonojordan

I would not think that a stock motor and controller could demand enough to trip the factory bms on these batteries...something seems off.