Do most builders/users not use inverter precharge?

[Tomthumb62]

Positive or negative.
It doesn't matter.

Thanks, that’s what I thought. Must’ve been user error then, low light with wrong eyeglasses on, lol.

 

[Ellcon123]

Thanks. This is what I’ll do next time as I seem to fudge it up using a regular 60W lightbulb.

Also, I’ve seen most videos doing the pre charge on the negative battery cable. Does it matter? I’ve been doing it on the positive cable and maybe that’s why I’m getting such a big spark even though I’m using resistor of a lightbulb.

Good practice to connect -ve last, especially in a vehicle. Chassis is generally ground so accidently dropping the -ve does nothing.

 

[sunsurfer]

Thanks. This is what I’ll do next time as I seem to fudge it up using a regular 60W lightbulb.

Also, I’ve seen most videos doing the pre charge on the negative battery cable. Does it matter? I’ve been doing it on the positive cable and maybe that’s why I’m getting such a big spark even though I’m using resistor of a lightbulb.

I'm wondering if the bulb impedance is to low. They also have less resistance during warm up of the filament. I would get a small automotive bulb and stack them in series to get the correct voltage. So for 48v, put 4 12v in series perhaps?

 

[Tomthumb62]

I'm wondering if the bulb impedance is to low. They also have less resistance during warm up of the filament. I would get a small automotive bulb and stack them in series to get the correct voltage. So for 48v, put 4 12v in series perhaps?

I don't think it matters. I've seen plenty of videos of people using a regular 60W 120V incandescent lightbulb as a pre-charge resistor for 12v, 24v and 48v inverters. I think I was just doing something wrong. On my old 2000W inverter, this method worked and the first time I did it for the new 1000W Victron it worked (both 12v inverters) but the 2-3 times after that I think I may have not had the correct contacts of the bulb to the battery+cable and simply was creating a circuit through the metal side of the bulb base, bypassing the circuit of the bulb internals/filament. I was pretty tired and my hands might have fumbled. Glad it wasn't a 48V system.

 

[BroomJM]

Below is a picture of a 24v (2P-2S) system I just set up. Note that the battery switch is in the "OFF" position. I have not yet wired the solar or AC, incoming or outgoing. I am not sure it's safe to turn the battery switch to the "ON" position before precharging the capacitors.

I have a 100W, 10 ohm resistor. With the battery switch still in the "OFF" position, can I run a small jumper wire from either bus bar, through the resistor, to the corresponding post on the inverter, to precharge the capacitors? Would it be smarter/easier to leave the battery switch off, connect the incoming AC line (and/or solar?) and then turn on the inverter? Once it's been running for 30 seconds or so, then turn the battery switch to "ON", because the caps should be charged by then?

Sorry I'm such a n00b on this stuff. :-/

 

[SamDeleted]

I use a pencil

 

[SamDeleted]

Below is a picture of a 24v (2P-2S) system I just set up. Note that the battery switch is in the "OFF" position. I have not yet wired the solar or AC, incoming or outgoing. I am not sure it's safe to turn the battery switch to the "ON" position before precharging the capacitors.

I have a 100W, 10 ohm resistor. With the battery switch still in the "OFF" position, can I run a small jumper wire from either bus bar, through the resistor, to the corresponding post on the inverter, to precharge the capacitors? Would it be smarter/easier to leave the battery switch off, connect the incoming AC line (and/or solar?) and then turn on the inverter? Once it's been running for 30 seconds or so, then turn the battery switch to "ON", because the caps should be charged by then?

Sorry I'm such a n00b on this stuff. :-/

View attachment 159718

Broom are they lithium batteries or lead acid(flooded or gel) ?

You don't have to worry so much about precharge with lead acid

 

[BroomJM]

Broom are they lithium batteries or lead acid(flooded or gel) ?

You don't have to worry so much about precharge with lead acid

They are two sets of 12v, 100AH, LiFePO4 batteries. One is a set of Power Queen batteries and the other two are 4S packs I built a year or two ago, but with no more than maybe 25 cycles on them.

 

[sunshine_eggo]

I have a 100W, 10 ohm resistor. With the battery switch still in the "OFF" position, can I run a small jumper wire from either bus bar, through the resistor, to the corresponding post on the inverter, to precharge the capacitors?

Yes. Once you have nearly full battery voltage at the inverter terminals, the caps are charged, and you can power on the main switch.

 

[HarryN]

You could always pre-charge with a small solar panel and no controller.

Added - some (not all) controllers will run and charge up the inverter caps from 0 volts just fine, but others will not turn on.

 

[K8MEJ]

Hi Bob - you have been to my shop - and my typical customer is not a power engineer. Some are EEs but really none power engineers. Some are full time users, some occasional.

They all have a manual that they don't bring with them on their vacation - neither the printed nor e version.

But they do have my cell phone number to help them through whatever is going on, so I design in a "plan", "back up plan", and a "secondary back up plan" to minimize the number of times that they have to call me.

The other thing that they have in common is that they know how to fix a windows computer by re-starting it and that is what the breakers allow them to do either on their own or on the phone with me. It is all there and tolerant of small errors because that is what people do.

You have to decide on your own if you will be the only one running your power system, or if others will also be using it when you are not there and don't have your knowledge to overcome challenges that happen at inconvenient times.

Harry

OMG. Are you business spirit animal?! ? I need to create a video I can give to each and call it "What to Do Now Because You Weren't Paying Attention the First Time"

 

[sunsurfer]

OMG. Are you business spirit animal?! ? I need to create a video I can give to each and call it "What to Do Now Because You Weren't Paying Attention the First Time"

I would be scared to be an independent installer for this exact reason. Fear of being married to every system. I've had a few people ask me to build them systems and I politely say I will just give what advise I can. I love helping where I can but I don't have enough time for my own problems as it is.

 

[HarryN]

OMG. Are you business spirit animal?! ? I need to create a video I can give to each and call it "What to Do Now Because You Weren't Paying Attention the First Time"

No - but I am originally from Ohio and am married to a woman from Missouri , so that might explain part of it.