Lithium Conversion 48 volt system

[gman@engineer.com]

hopefully the pictures uploaded this time. I am thinking that one of the Anderson connectors has come loose and at times the system runs of one battery. I am securing the connectors better. I am also trying to reduce the length of the wire to the buss bar to reduce resistance. The wires that came with the system are a foot or two too long.

[PingEye3]

Originally Posted by WalterM6

Is the item I circled in blue your contactor/solenoid for your cart? If it is it's too small for an electric cart.

I have a 2014 Star Cart, 2 seater, street legal with VIN number on the cart. It has the same 400A Curtis controller as the City Cart (the six passenger version of Star Cart) and the same solenoid from the factory. Still working fine. Mine is a project cart but it runs fine.

I was shocked when I first saw the solenoid, but if it ain't broke, it don't need fixin'.

[gman@engineer.com]

Originally Posted by PingEye3

I have a 2014 Star Cart, 2 seater, street legal with VIN number on the cart. It has the same 400A Curtis controller as the City Cart (the six passenger version of Star Cart) and the same solenoid from the factory. Still working fine. Mine is a project cart but it runs fine.

I was shocked when I first saw the solenoid, but if it ain't broke, it don't need fixin'.

Your Orion Jr 2 BMS costs as much as my battery. Is it worth it. If I try to connect both 48 volt battery packs together they will weigh 140 lbs, but I can use one BMS. Not sure I want to try that, but replacing the BMS would be nice (I think).

[ryanfoster34]

Jumping in on this because I talked with Fred yesterday at TechDirect and although he sells the prefab boxes, he almost seemed to want me to to buy the 2 groups of modules (in 7 series) and get parts. Maybe the BMS they include (60AH peak for each box) really isn't enough.

I have a completely stock 2014 CC Precedent with original batteries that are at their end... but want to make sure I could use an Alltrax controller later if I want. The whole point of my upgrade to lithium is longevity and no acid. I'll be super frustrated to do this and realize I need to change something up in a couple years.

Also, has anyone thought about taking a pack like this one (which runs 104v @ 6kw) and stepping down voltage to 52 or so? In theory you'd get double the AH rating, right?

[gman@engineer.com]

Fred is who I talked too. I shortened the wires they sent and upgraded from 10 gauge to 6 and 4 gauge wires. The latter going from the controller to a buss bar. I had to purchase a buss bar and change out the ends to the cable. The Anderson plugs they provide and the way they are mounted inside the box, will allow them to creep out of the black box while driving, so I secured them. When one plug comes out, the battery runs on one box and at half the amps, typically cutting the vehicle/battery off. The units tend to discharge a volt or two during the first 48 hours, staying around 56 volts. I am still testing them out, but I did make a 10 minute run with lights on and at 25 mph successfully. There are active BMS units out on the market that I am looking to swap the existing BMS with. I hesitated taking the units apart thinking I would send them back, but with a 20 percent stocking fee and paying shipping, I elected to work with them. If these are G2 leaf batteries as advertised, the costs are about right for the system, and modifications with a new active BMS and protection board would fix the problem. Unfortunately by the time you mount the system (purchasing the additional equipment and making wire modifications) and test it out you are past the 30 day warranty period anyway.

Look at the Graphene batteries (pretty cool) and check out the active BMS.

[Sergio]

I don't know of anyone in this site using an "active" BMS or any reason to use one.

Once the batteries are balanced they will stay balanced, any variations due to possible age differences will be minute and easily corrected by any BMS.

You are using the word "buss-bar" in a way that is not consistent on how it is used in Lithium setups.

The word buss-bar as I used in previous posts in your thread refers to the internal connections between the lithium modules.

The issue with the TechDirect pre-packaged setup is that they use a printed circuit board to carry the 100+ amps between the cell modules.

They also pass all of that current through their BMS printed circuit board, which generates a lot of heat in the FETs.

The G2 Leaf modules themselves are fine as I use them as well and my single 7 module setup and it does not have any shutdown issues since the current goes from the modules directly to the cart solenoid.

[kraftzion]

I am new here, but in the middle of swapping 2 of the 7 module packs from tech direct into a 2004 club car precedent. I bought the modules and the boxes but told them they were nuts when they recommended 60 amp bms's. Upon relentless questioning they stated that Nissan rated the modules at 130 amps( but they would get hot). I ordered and am awaiting 2 100 amp continuous, 200 watt peak bms's off ebay. My cart pulled 220 amps when stomped on, 47 amps at 18mph with 4 12 volt lead acid batterys.

[gman@engineer.com]

Originally Posted by kraftzion

I am new here, but in the middle of swapping 2 of the 7 module packs from tech direct into a 2004 club car precedent. I bought the modules and the boxes but told them they were nuts when they recommended 60 amp bms's. Upon relentless questioning they stated that Nissan rated the modules at 130 amps( but they would get hot). I ordered and am awaiting 2 100 amp continuous, 200 watt peak bms's off ebay. My cart pulled 220 amps when stomped on, 47 amps at 18mph with 4 12 volt lead acid batterys.

That sound about right, the service tech indicated the heat would kill them, but I am not sure I believe them as you only hit 200 amps for a very short period. The leaf batteries were know to get hot, but that may be G1, I paid extra and G2. What kind of BMS did you get, active or passive. What was the manufacture and why.

[molfpedal]

If you use Sergio’s relay setup you don’t have to worry about the discharge current destroying the BMS. I used it and the BMS will still protect the pack and the controller using the external relays with HV and LV settings. Here is the link to his thread!

http://www.buggiesgonewild.com/showthread.php?t=160302

Read his explanation and you will understand.
Good luck.

[kraftzion]

I got the g2 batteries too. I had signed up bgw a long time ago for a different buggy, forgot my password and could not get the link sent to reset it. So I was following Sergios build but the charger wasnt available, the bms people were out to lunch and i couldnt get on to ask amy questions.So i read what i could and took a shot at it. For better or worse this is the bms 's that I have coming, and the charger I bought.
http://www.ebay.com/itm/113948956720
http://www.ebay.com/itm/143140955383