[ArieKanarie]

Hello,

I have a question regarding reconnecting the battery pack after maintenance.
When I reconnect the last pair of connectors I'm assuming there could be a big spark.
I've read about pre-charging the capacitors, how would I do such a thing?
Would this be needed for attaching the main voltage leads or will this be taken care of after the fact in the contactor box when turning the ignition?

Because the car is second hand and there are no obvious markings of what parts are used (nothing to be found online either) I have no clue which parts are in the car.

I hope someone could guide me a little bit

 

[piotrsko]

Depending what connector you attach. Battery to controller with automatic precharge, no spark. Controller to motor, off condition, no spark. Battery segment to battery segment possibly depending on imbalance. My sub packs are independently fused, so I pull a fuse, charge one half, then charge the other half so my sparks are about 2-3 volts and no big deal.

 

[ArieKanarie]

It's the connector from the battery pack to the controller. I am not sure if there is a precharge in there, I will check this week.

I'm talking about these connectors;

 

[DMPstar]

A quick and fairly reliable way to determine if you may have a spark is to measure DC Voltage between the points you are connecting. As mentioned above, a few volts may not be a big deal, but if you see something close to battery Voltage, best to precharge it with a light bulb or resistor rated for the voltage present.
Also it is probably good to investigate what parts are in your car... I am actually in the same boat with my used EV project lol, so just a mild suggestion.

 

[ArieKanarie]

While the battery was disconnected I dared to open the HV box. I found a lot of contactors in there.

If I remove the fuse then I can safely attach the battery right? Then check both bolts with a multimeter and when there's no voltage I can safely put the fuse back.

Is the resistor in the middle used for precharge?

 

[cricketo]

It's impossible to tell what it's used for for certain given the wiring isn't visible, but it's very likely that it is a precharge resistor. I've seen a couple of different ways of how precharge resistor is used - across the main power contactor (doesn't look like it's connected there) and via a dedicated precharge circuit. It's possible one of those smaller contactors is what plugs it into the circuit when precharge is activated.

 

[DMPstar]

Those 3 contactors in a row look a little overkill for the wire gauge used, or the wires are a bit small for the load. Likely the contactors are oversized for reliability.
Any idea yet of what some of your main components are? Like controller, DCDC, etc?
What maintenance were you performing?

 

[ArieKanarie]

Those 3 contactors in a row look a little overkill for the wire gauge used, or the wires are a bit small for the load. Likely the contactors are oversized for reliability.
Any idea yet of what some of your main components are? Like controller, DCDC, etc?
What maintenance were you performing?

I truly have no clue, except for the charger which is a TCCharger 1.5kW. The components in this build are not or barely labeled, I can't find any info on them.

I'm replacing 3 dead cells and 13 cells that have a reduced capacity.

 

[piotrsko]

150 ohms is typical precharge, 75 watts is a bit overkill but it probably wont fail. Tyco contactors. High amperage shunt for current. Somebody spent some money putting that together instead if typical amazon cheapo schlock.

 

[ArieKanarie]

150 ohms is typical precharge, 75 watts is a bit overkill but it probably wont fail. Tyco contactors. High amperage shunt for current. Somebody spent some money putting that together instead if typical amazon cheapo schlock.

That is great to hear!
It's a conversion that was done in China, it's a Zotye 5008EV.
Glad that it seems to be built well.

 

[DMPstar]

Looks like they didn't want the headache of warranty claims if they were to use underspec parts

 

[evric]

Those 3 contactors in a row look a little overkill ...

The small contactors could be for switch items like, precharge circuit, DC-DC converter or heater.

 

[DMPstar]

The small contactors could be for switch items like, precharge circuit, DC-DC converter or heater.

Yep for sure, just could possibly have been smaller. They look like 200A or maybe 100A rated, Precharge and DC-DC are usually a lot less than 100A.
All good though to have comfort in overspec.

 

[summetj]

It sure looks like a commercial battery pack, which almost certainly has a precharage solution and contactors inside. (For example, on a Nissan Leaf, the high voltage is disconnected from the rest of the car (by contactors inside the battery) until the 12v system tells it to "connect" (at which point the precharge system does it's thing and then the full connection is made). From your photos it looks like your battery has a very similar setup, so the HV connectors should be at zero volts until the rest of the car talks (over the data connector) to the battery and tells it to connect up.

 

[DMPstar]

Still check with a Volt meter between the open connection to be sure.

 

[piotrsko]

Also act like it is live until.proven otherwise. One handed preferably with gloves.