Failed Lithium project

[Sergio]

WalterM6 please read my posts, the non existing relay in that drawing that you are describing is not anywhere or mentioned in a drawing footnote.

Your understating is also incorrect, as shown there is nothing other than the charger (-) connected to the BMS C- (switched) - connection.

You do have to add a small relay with the negative of the relay coil connected to the same terminal block as the charger -.

If You use a relay like the T9AP1D52-48 relay, You should also add a 600Ω x 1 watt metal film resistor in series with the relay coil to keep the relay from prolonged operatinon near the top of its overvoltage rating.

The positive for the relay coil can be connected to the same terminal block where the KSI input for the converter is located.

Also, since You would be switching the relay coil with the BMS FETs, it is absolutely necessary to use a flyback diode in parallel with the relay coil, with the striped side (cathode) of the relay towards the KSI connection.

You now have a "dry switch" (Isolated On/Off) that can disconnect any signal in case a single Cell goes under voltage while driving or overvoltage during a Regenerative brake event.

Hopefully this will give one idea on how to complete that drawing in order to provide full protection to your lithium pack.

[hiway44]

Hi all, I'm stil working on my pack and waiting for my busbars to arrive. The pack that I have installed is working out OK. I have not charged the pack, but one time for about 10 minutes. I have put only about 3 miles on the car since I installed the lithium pack. The difference between the lead acid batteries is huge! I have been able to reach higher rpms 5800 and voltage has never dipped below 49. That is a big difference with the lead acid batteries I would be pushing 42 and 43 volts.
I recently purchased a volt meter that has 3 wires. Red , white and black. What is the correct connection to the key switch? Diagram? No direction came with the meter. Black to neg. 48 volts, red to 48 volt, white to key?

[DaveTM]

When my voltage drops to 50V at rest, it's time to charge the pack. The "start" of the Leaf knee voltage drop is at 49V (14 x 3.5VPC) and believe me.....that knee drops fast on a golf cart!!!

I've stranded my cart on two occasions just taking a ride "out back over the hill". Then it's up to the house.....fire up the lawn tractor and haul the Honda generator down to run for 3 or 4 hours.

It's really not something you wanna do.

[WalterM6]

I was out yesterday trying to establish a benchmark for my batteries. I picked the steepest hill in the neighbor. With a fully charged pack the voltage dropped to 51 volts. That will be my reference if I suspect a battery problem in the future.

[hiway44]

Busbars arrived today, but were the wrong thickness. I have to send them back. I made the order wrong. I received 1/4 thickness bars instead of 1/8. Another week of waiting to get both packs done. While waiting I'm going to cut some 110 copper tubing and experiment with it underneath the PC Board of the pack that I currently have installed. Not really sure if it matters because I have had no issues with the PC Board. I have gotten the amps up to 284 and 310 amps on quick takeoff. I have checked and don't see any signs of burnt material.

Drilling through 1/4 busbars with a cordless drill would take to long. It was my error.
.

[DaveTM]

Originally Posted by hiway44

Drilling through 1/4 busbars with a cordless drill would take to long. It was my error.
.

About ten years ago I purchased a Ryobi bench top drill press. Under $100 brand new and I've beat that drill press like a rented mule and it still works great today.

Pick up the Ryobi press and a cheap drill press vise and you're in business!!

[hiway44]

Battery Charger died. I was sent a Delta ESR-48/30D with my twin pack of batteries from Big Battery. I called them and they are sending me out a newer type of charger.

Just curious what charger are you guys using, is it adjustable and does it have an auto shut off. I may be willing to make an investment in something new if I'm not satisfied with my replacement charger when/if it comes.

The problem with the Delta ESR-48/30D is it won't get any voltage. Connected it to a volt meter reading -.003. I had it set to 57.8 volts.

[DaveTM]

My charger. It's CanBus and I can program it. OTOH.I set it up at the start and never made any changes after that. https://www.elconchargers.com/catalo...0/10295151.htm

[yensidcamper]

I used the same one Sergio recommended. It shuts off at set voltage and output voltage can be regulated. Came in 10 days even though Amazon said a month when I ordered.

[hiway44]

Big Battery sent me out a new charger. Its the same one Sergio has, but its 15amps. I curious to see if the votage was lowered. If not Im going to open it and put it 56.7. Fexex showing it will arrive on Wed. July 29. I currently have 54 volts showing. Have to ride slow until then.