LifePO4 golf battery

[NCPW]

I've peaked at 417 amps with mine. 150 amps just wouldn't cut it for me.

[sloppydogdrool]

So yeah I don't claim to be an electrician. It's my understanding the Trojan Batteris that everyone uses are only 250amps max. The curtis controller is 400 amp. You hear people saying they draw over 400 amp. So how can you draw more amps than a battery can put out? My understanding is also the way the batteries are wired in series the Voltage increases but not the amps? So I am a bit confused.

[Volt_Ampere]

Max current rating on a battery isn't how much it can put out but how much you should safely draw from it. You can pull 1000 amps easily from a FLA battery. Same goes for motors. You can exceed the current rating and it will overheat and fail.

[MrBritGolfFan]

Hi everyone, i actually purchased this 42.9v battery from bigbattery.com (BB) back on 26th May for my 2014 Ezgo RXV which has a Navitas 600 AMP controller (put in last summer). I have already converted my cart to road legal, and have the tag/ insurance etc. We use the cart mainly to go to our local town and back, which is about 1 mile away with our 3 small kids (in Florida).

I had been looking for the right lithium conversion solution for almost a year. I had come to the conclusion i would just build my own if i could get hold of the right cells at the right price. Then i came across this BigBattery Golf Cart solution. TechDirect were also offering the item on Ebay - BigBattery were just faster at replying on email and phone calls so they won the business from me.

i spoke with Ed at BB who was very helpful. The order took about 9 days to arrive, via freight on large pallet. They apparently test every cell before shipping, which i think is pretty good. If you search on YT for Will Prowse he has had a few BB batteries. Some have been great, the last one he got sent the soldering was not so great. But Will did say he was pleased with how they certify/ inspect their cells before shipping. Will also load tests the batteries (there is a solar version for off grid applications, same battery different casing, and he was getting just over 80% capacity, which is what they state) all good!

These are A123 NEC batteries, and the unit is very well made. When it arrived i took the battery housing apart to inspect all the wiring, and make sure all the connections and solder was good. It was pretty decent, i didnt have to change anything. The 150A BMS worried me, but i spoke to Ed just before they shipped the battery and he said he would work with me to fix it if the BMS needed upgrading to a larger peak rating, or he would return the whole unit if need be.

Warranty Wise - Ed said that any issues in the first year and they will solve it, his word was strong enough, and he assured me they will fix what needs to be fixed.

LiFePO4 Charger is not included, they say you can use your own, but thats incorrect, since LiFePO4 needs to be charged a different way to Lead (as many of you know i suspect). I have a delatq charger, i spoke to them through their website and they were great at getting back to me and advising that my deltaq charger will not work.

Bigbattery and TechDirect are not the same company (BB informs me this) however they buy from similar sources and therefore offer similar products.

My 42.9v battery stated it had a 150 AMP, however if you do some more digging on these batteries (TechDirect had some more stats) they claim the peak or surge is 300 Amps.

I fitted mine into my RXV (had to cut a small piece of the original tray out to fit) and tested with a fluke amp meter, and i was pulling 258 amps and no cutting out. I had my thermometer sensor on the battery too, and again on the BMS and no issues so far.

I ended up buying a charger from Enay through TechDirect. They made sure the charger was rated to 47v and supplied a SB175 connector with lead, and it was a 15AMP charger too. The charger cost me $130. I then purchased a watt meter from amazon, made some new leads inline with the watt meter so i can measure what charge amount i end up needing to put in.

I contacted Navitas and got the dealer login (dont know why i never did that before).

Performance - works great, really much faster acceleration, and quick to 30mph. I am not looking for speed, 25/27 is enough for me, i just want hassle free batteries (no watering!!!). My cart is not lifted (i read over the years thats not ideal for RXV, but someone please tell me if thats wrong). I do have 20" wheels on.

OK NOW FOR THE ISSUES!

NAVITAS...... This unit is not lithium ready, and is expecting a lead acid 48v system. The Navitas system cuts out around 41.5-41.9V so as to protect your lead batteries, the controller shuts down. And for RXV that means it stops, and in the middle of the road!

The first day i installed the battery, i took it out at 42.4v. I got just about 1 mile and it stopped in the middle of the road. I couldnt get it shifted. Luckily we were right outside a restaurant so the missus ran home, got the charger and extension lead, we sat for 90 mins charging it, and we got home.

Spoke to Navitas who suggested some ideas. One was to switch to 36v mode, which i nearly tried, but didnt want to do anything that might toast it before being told by them etc. Anyway, this was apparently going to work great, and i was super excited.

It did work great...but then the resistor behind the controller went bright red. I believe this is because the Navitas system now thinks i have a 36v lead battery and its reading it as a full battery, so it starts dumping regenerative charge to the resistor coils, and its just too much. We are talking 500F + too much!

Spoke to Navitas again, and they said they would code lithium into their firmware within 7-10 days but that was about 5 weeks ago. I keep checking in with them but i keep getting pushed down the road. I really hope they can solve it, as this is one hell of a great solution. I will upload pictures ones i post this tonight/ tomorrow.

I do have my old curtis controller and i wanted to ask y'all if that would have the same issues as the navitas? or is there a way to program the old controller with the parameters of the new battery?

Some photos:

How it arrives:
arrived.jpg

The Connections and BMS
inside.jpg

On the pallet
on pallet.jpg

In the RXV - excuse all the messy wires
messy.jpg

Navitas Hot Coils
hot.jpg

[MrBritGolfFan]

The Amp pull:
amp pull.jpg

This was going slow to max speed, at slow acceleration and fast acceleration.

I also had the navitas max pull AMPS to 150 and 200 and tried at 100. Only setting to 100 seemed to change anything, at 150 it still pulled the above.

ALSO - i just checked my log and i have two more examples where my amps pulled over 317 amps with no cut out.

Now some photos i just took of the charger:

D3218545-2419-46D8-8736-6506A0B2BBB5.jpg

7E307FBD-AA36-46DB-8B3F-61F16EE6AD9F.jpg

4B862509-B133-431E-8808-43FAAFFD225C.jpg

F0F16480-0B7C-407D-A155-510C60DB7E13.jpg

I added an accessory 12v AGM battery when i first converted to road legal, so I wouldn’t put drain on the 48v system, or have to get a transformer. This Duracell is 35ah, and runs the led lights (front, rear), horn etc, plus it also runs an led multi light system under the cart i added too. I am about to add an LED light bar, so i might switch out this 12v AGM for a self made 12v 100ah LiFePO4. Hence the mess still on top of the bigbattery. Also i added a fuse box for any accessories i add along with relay for main power on for the 12v. OTT i know, but when its all back in the right place it looks clean.

[NCPW]

Do a forum search for BobBoyce.


I think he'll tell you that you wasted money on that Navatis controller compared to the stock Curtis. He can unlock some magic with he's special programming and you'll see plenty of folks that are super satisfied with the results.

[MrBritGolfFan]

Originally Posted by NCPW

Do a forum search for BobBoyce.


I think he'll tell you that you wasted money on that Navatis controller compared to the stock Curtis. He can unlock some magic with he's special programming and you'll see plenty of folks that are super satisfied with the results.

Will do thanks.

I really like the navitas controller, for me having the ability to adjust on the fly different variables through the 3 knob remote is great, along with the app that really allows me to tinker a bit.

Right now, i'll taker whatever controller will work for me, as i cant use the cart at all.

[davidgolfer]

Originally Posted by MrBritGolfFan

The Amp pull:
Attachment 205875

This was going slow to max speed, at slow acceleration and fast acceleration.

I also had the navitas max pull AMPS to 150 and 200 and tried at 100. Only setting to 100 seemed to change anything, at 150 it still pulled the above.

ALSO - i just checked my log and i have two more examples where my amps pulled over 317 amps with no cut out.

Now some photos i just took of the charger:

Attachment 205876

Attachment 205877

Attachment 205878

Attachment 205879

I added an accessory 12v AGM battery when i first converted to road legal, so I wouldn’t put drain on the 48v system, or have to get a transformer. This Duracell is 35ah, and runs the led lights (front, rear), horn etc, plus it also runs an led multi light system under the cart i added too. I am about to add an LED light bar, so i might switch out this 12v AGM for a self made 12v 100ah LiFePO4. Hence the mess still on top of the bigbattery. Also i added a fuse box for any accessories i add along with relay for main power on for the 12v. OTT i know, but when its all back in the right place it looks clean.

Interested to hear what the actual run time per charge on one of these batteries is. The price is good just would like to hear more real world experience on mileage per charge.

[MrBritGolfFan]

Originally Posted by davidgolfer

Interested to hear what the actual run time per charge on one of these batteries is. The price is good just would like to hear more real world experience on mileage per charge.

once i get the software update from navitas, or switch back to curtis controller (if that can be re-programmed) i will post the results.

I dont want to drive it anywhere with fear of it cutting out and me being stuck. RXV wheels lock up, and then i cannot get into TOW mode. I did read online (probably in these forums) that with an RXV you can switch wires 1/2 and 3/4 around (which are under the cover above the controller) and that is supposed to unlock the motor break - i have not tried that yet...

[JBERGER]

I'm just trying to follow along, you bought a 42V battery pack for a 48V cart?
And you are waiting on Navitas to write some code to work with a 42V pack because the 36V setting triggers overload?

It seems like it would be easier to buy a pack that matches the cart's rating.
Even if you get the navitas code for 42v, wouldn't that make the cart inefficient and possibly damaged in the conversion from DC to AC for the motor?