48 volt golf cart, bms died on the road

[L0veless]

My 48 volt golf cart died on the road yesterday, I have no idea what happened, powering along nicely drawing 55amps just stopped no power.
checked the Battery on my phone (through Bluetooth) nothing out of the normal, temp was OK (31c) cells were still at 52.4 total volts. no cells high or low all withing .002
All connections were tight. this is a home built 105ah 16s battery with a 250amp Daly BMS. this build is about 5 months old and has not had any issues. could not find anything out of the ordinary from my phones settings. Friend towed me home, hit it with the charger and fired right up. took it out today no issues.
all I can think of is for what every reason the BMS just shut down. The Bluetooth was working, I had spark on the battery. just nothing coming through the BMS.
is there anyway to "wake " up the BMS with out another power source? or any ideas on what might of happened.
Now I'm nervous about taking it out for fear of just quitting again.

 

[sunshine_eggo]

Very sorry. sounds like yet another DALY failure. There seems to be a lot of those over the last several months.

Shorting P- to B- wakes up old ones. No idea if that works on newer ones.

 

[L0veless]

I will make up a jumper cable to keep with me,

Thank you

 

[Capt Bill]

Here's a $40 48 Volt 7 Amp LiFePO4 ...Back Up Battery Charger
https://www.amazon.com/dp/B0BX777PJP?ref=ppx_yo2ov_dt_b_product_details&th=1

Says it has Multiple Protection System. It was the cheapest bet that got my attention after reviewing many options. I am testing it out right now as I write, on a new set of 16 LiFePO4 x 305 Ah for my first ever DIY 48 volt LiFePO4 Battery, on its' first time ever battery charging cycle. My Start Battery Voltage was 52.6 volts. Then ... w little Charger Hooked up to 120vac; I measured 52.7 volts at battery, and measured 7.5 Amps via my DMM Clamp. 2 hours later was 53.2 volts. I am testing the charger now, so if bricks, I can easily return it for a refund. Currently, I am happy I ordered it :+)

Note: I am currently charging without a BMS because I am at a low tier of battery voltage, and charging at such a low amperage, and I want to tet this charger. I will check each cells battery voltage later today. I want see how high the battery voltage gets late this afternoon. My JK BMS is getting hooked up after this test, ... for when I will be testing the BMS, & charging via my new EG4 3000 All In One that says I charge at 50 Amp from 120 vac. I may hook it up through a 120vac 30 amp breaker like the manual recommends, or might try 20 amp breaker and cord/ to see it it trips. Great Options :+)

When near my full charge, I will then rearrange my cells in parallel for my Top Balance Charge.

I wanted a small backup charger for my first ever 48v system ... as easy way to bring battery voltage up a little bit, ... fo if this battery bank's voltage ever dropped down low enough by accident, for a BMS or All In One ... low voltage protection cut off. IMO: This was $40 well spent. If it bricks, I come back and report.

 

[Solar Guppy]

Golf carts are not a good fit with typical general purpose BMS's, the reason is peak current usually far exceeds what general BMS can handle.

Even the most basic stock EZGO will pull 150 amps and modified carts can easily pull 400 amps. I have an Altrax 400 amp controller in my customized cart and I've programed it to pull no more than 200 amps ( battery side ), using a pair of the Raptor 60 amp BigBattery Golf cart batteries.

 

[Capt Bill]

Re: modified carts can easily pull 400 amp

I have three Chargery BMS for my 4 LV2424 on a 24 v Battery set up. ... that have 300 amp shunts. Think they have same in their 48 volt options (though lost popularity as JK and others developed active balancing options. Wonder what handles 400 amps? Let us know when if you find one.

 

[Solar Guppy]

@Capt Bill , Not sure where the second quote came from but I have never owned 24V batteries or LV2424 inverters

 

[Capt Bill]

@Capt Bill , Not sure where the second quote came from but I have never owned 24V batteries or LV2424 inverters

I got you are on 48 volts, and seemed to be wondering about (maybe) pulling up to 400 amps (I could imagine that for a 48 v E vehicle) ... In wondering what BMS might handle 400amps, ... I was just saying I have note the Chargery BMS lines carry shunts (require of their type of BMS) in the 300 Amp category. I have not yet seen the BMS that handles 400 amp (but not look for that either). Be Interested in waht you find in that arena, if that is what you are looking for.

 

[Solar Guppy]

No, my EZGO is 36V highly modified running an Altrax 400 amp controller. Batteries are a pair of BigBattery Raptors which can each handle 300 amps for 6 seconds, 115 amps continuous.

Since series wound motors act as an inductor, the current at the battery is less than what the motor sees when at partial pwm. Current draw is the highest near zero rpm and I have programmed the controller to limit to 200 amps, which still provides the maximum the motor pulls from a dead start.

Using a generic BMS meant for storage systems is the wrong tool for the job with golf carts and if you search sites like buggies gone wild yuo can learn what others are doing / recommending.