Pre-Charge Switch

[chrisski]

Turns out if you want to add a resistor to precharge your caps in your system, much easier when it is first installed.

In my install, Turns out the Perko switch

won't able to be wired where I want it because of my installation

Because of the stud patten on the back of the Perko

once secured would cause the wire going to the rest of the system to go up without a way to route to the busbar underneath it without totally redoing the powerboard. Not an easy task. I now will use thisBlue Sea Switch which is similar:

with a bolt pattern like this:
Just unsure what the alternator field disconnect does if wires are not hooked.

 

[FilterGuy]

Turns out if you want to add a resistor to precharge your caps in your system, much easier when it is first installed.

In my install, Turns out the Perko switchView attachment 83571

won't able to be wired where I want it because of my installationView attachment 83575

Because of the stud patten on the back of the PerkoView attachment 83576

once secured would cause the wire going to the rest of the system to go up without a way to route to the busbar underneath it without totally redoing the powerboard. Not an easy task. I now will use thisBlue Sea Switch which is similar:

View attachment 83577with a bolt pattern like this: View attachment 83578
Just unsure what the alternator field disconnect does if wires are not hooked.

Keep in mind that all 4 side skirts on the perko are removable. The picture in the resource shows one of the 4 skirts removed... but the others can be removed as well. Consequently the perko may still work for you.

Just unsure what the alternator field disconnect does if wires are not hooked.

The alternator field disconnect is completely independent of the main switch. Leaving them unhooked will cause no harm.

 

[Sanwizard]

That is an excellent point.

Use a momentary switch in line to charge the caps, then turn on the main switch.

 

[rmaddy]

Use a momentary switch in line to charge the caps, then turn on the main switch.

This suffers from the same issue that you are replying to. Using the right kind of multi-position switch with the pre-charge resistor built in helps ensure things work correctly. Using a momentary switch works just fine as long as you actually remember to use it first. It's not foolproof. I say this from experience. I have a simple on-off main switch with a separate momentary pre-charge button wired to it. It works great. But one time I forgot to press the button and luckily the massive spark that took a chunk out of the battery terminal didn't damage things too badly.

 

[WYtreasure]

Use a momentary switch in line to charge the caps, then turn on the main switch.

Would you link an example please? I know nothing about the product but a momentary switch seems like a great way to minimize arcing. Am I correct or not?

 

[WYtreasure]

This suffers from the same issue that you are replying to. Using the right kind of multi-position switch with the pre-charge resistor built in helps ensure things work correctly. Using a momentary switch works just fine as long as you actually remember to use it first. It's not foolproof. I say this from experience. I have a simple on-off main switch with a separate momentary pre-charge button wired to it. It works great. But one time I forgot to press the button and luckily the massive spark that took a chunk out of the battery terminal didn't damage things too badly.

Yikes, if it's not idiot-proof, it's not for me.

 

[Sanwizard]

Would you link an example please? I know nothing about the product but a momentary switch seems like a great way to minimize arcing. Am I correct or not?

Sure. The momentary switch is RED, so it stands out, and its only used after maintenance, so rarely. The switch and resistor are in parallel with the main switch. I turn on the BMS, then hit the red button for 5 seconds, which charges the caps in the inverter, then I flip on the main. Works perfect as long as you dont have dementia, or tend to work on electrical stuff after a couple six packs. ?

 

[Sanwizard]

Sure. The momentary switch is RED, so it stands out, and its only used after maintenance, so rarely. The switch and resistor are in parallel with the main switch. I turn on the BMS, then hit the red button for 5 seconds, which charges the caps in the inverter, then I flip on the main. Works perfect as long as you dont have dementia, or tend to work on electrical stuff after a couple six packs. ?

Dont mind the dust. Thats from Rocksil insulation I use in the winter. Its around -7 degrees C today.

 

[FilterGuy]

 

[FilterGuy]

BTW: The above is part of this resource:

Inverter Disconnect Switch with Precharge

To get the paper, click on the orange button at the top of this page. This circuit is designed as a disconnect switch that allows the user to pre-charge the inverter capacitors before turning the switch completely on. 26 June 2020 update: At...

diysolarforum.com

 

[chrisski]

BTW: The above is part of this resource:

Inverter Disconnect Switch with Precharge

To get the paper, click on the orange button at the top of this page. This circuit is designed as a disconnect switch that allows the user to pre-charge the inverter capacitors before turning the switch completely on. 26 June 2020 update: At...

diysolarforum.com

I have the components to install something like it. For mine, I got a this blue sea switch.

The switch I bought is not foolproof since :

1) It can allow it to be rotated in both directions 360 degrees
2) Physical layout had me wire it so the resistor is in the 2 position.

Unfortunately the foolproof switches in the resource above would not work physically with my busbar and battery placement.

 

[FilterGuy]

Unfortunately the foolproof switches in the resource above would not work physically with my busbar and battery placement.

System design is all about tradeoffs around cost, functionality, usability, safety, reliability, aesthetics, and so on. We all have to look at the goals and constraints of a particular situation and then make the tradeoffs necessary to meet those goals as best as possible....and that means we often have to give up on some things that we feel are less important than others. As an example, some folks may think the extra cost to go with a Class T is an obvious no-brainer..... Others may not have the budget and are willing to go with something less expensive but perhaps a little less safe.

The great news is that this forum gives you many perspectives and [usually] discusses the pros and cons in a civil and logical manner. This allows the reader to understand and make informed decisions for themselves.

 

[FilterGuy]

Unfortunately the foolproof switches in the resource above would not work physically with my busbar and battery placement.

Could you fashion a dog-leg shaped bracket that would keep the knob from turning from Off to 2?



It might not be pretty.... but it might work.

This kind of thing is when I wish I had a good 3D printer!!!

 

[chrisski]

Could you fashion a dog-leg shaped bracket that would keep the knob from turning from Off to 2?

View attachment 87225

It might not be pretty.... but it might work.

This kind of thing is when I wish I had a good 3D printer!!!

That would actually work really well.. I’d probably need to grind part of the handle off to allow it to rotate through 270 degrees. I’ll definetly think about doing this. Thanks.

 

[FilterGuy]

BTW: The perko switch is only about 1" larger than the blue Sea switch and the Marinco is only about .85" larger .... but if it does not fit it does not fit.

 

[chrisski]

BTW: The perko switch is only about 1" larger than the blue Sea switch and the Marinco is only about .85" larger .... but if it does not fit it does not fit.

No room to fit without redoing the whole powerboats. If a perko switch was made with the patterns reversed it would have fit.

 

[rmaddy]

That would actually work really well.. I’d probably need to grind part of the handle off to allow it to rotate through 270 degrees.

You'd have to remove the whole lower half of the handle just to rotate the switch 180º.

 

[FilterGuy]

You'd have to remove the whole lower half of the handle just to rotate the switch 180º.

Yup.... my first thought on how to do it may not be the best, but the concept still has merit. Perhaps a screw sticking out of the bottom of the handle and another screw out of the face at about the 6:30 position that blocks it from turning clockwise.



Note: The knob never has to get all the way to the '2' setting. Full-on is achieved at the 1+2 setting. Consequently, you could put a second screw at about the 11 o'clock position as well. That way it is clear it must be turned all the way back to get to the off position.

 

[Checkthisout]

An interlock would be easy. Just make the push button momentary switch block the battery switch lever from turning until you push the momentary switch.

Lots of ways to do this with different kinds of switches.

You could even use a solenoid with a timed delay to block the main switch from being turned until the momentary was held down for X seconds or whatever, giving the caps time to charge up.

 

[Checkthisout]

Use this to keep it from turning until your momentary button is pressed but then allow it to be turned off quickly without having to do any extra steps.

https://www.amazon.com/Atoplee-Electric-Assembly-Solenoid-27X29X18mm/dp/B0125VGLT0/ref=sr_1_7_sspa?crid=1K73VYUHKUUB8&keywords=12v%2Bsolenoid&qid=1647236297&sprefix=12v%2Bsolenoid%2Caps%2C162&sr=8-7-spons&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFMMFpLM05PTlNXSVMmZW5jcnlwdGVkSWQ9QTA5ODMyMjgzSTNVOFVCR0VFSUozJmVuY3J5cHRlZEFkSWQ9QTA1MjI5NjBYWFc1UEUwMVhYS0Umd2lkZ2V0TmFtZT1zcF9tdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl&th=1