I have been using a old 12vDC 24w Auto trouble light that has a couple of alligator clips to do my pre-charges (image below). It works but is not elegant. So what I am thinking of is a hard wired around the battery disconnect breaker lamp/socket with On/Off button to handle the task. If someone could point me to an item I would appreciate it. I like using a light versus a resistor since it gives me a indication with light coming on and going off as charge happens.
Looking for a simple resistive lamp and socket to work as pre-charge circuit.
- Thread starter Mattb4
- Start date
Just trying to short circuit all the effort by having someone give me their solution. Besides I am old fashioned and use the DR. Frankenstein methods.Lol...
you just want something with an on/off switch? You can just put an on/off switch onto your light bulb there.
You can use an actual light switch, which are like $1 at home depot
Any soft starting circuit should work. There are thousands of devices on aliexpress etc
Doing some research I find that control panel indicators are almost all LED these days. Incandescent mini bulbs are no longer common it seems. However I did find a 120vAC mini (37mm) 25w G8 Halogen bulb and also ceramic sockets that might do the trick. Would liked to have found some sockets designed for a junction box mount with cap. I also would need a double pole momentary toggle and found a 250v 30a unit. All of these are over at Amazon. The reason you need a double pole is the resistor or light goes inline on one leg of the battery and you need to also have the other leg connect/disconnect outside the Breaker.
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Yea everything is LED, you can probably put resistor in series with an LED to get pretty similar result with the power up.
This is like the only incandescent I see for this https://www.amazon.com/Forklift-Bulb-Volt-Watt-BA15d/dp/B0046IJTFE
I don't get your double pole reason, me too dumb, I need a drawing. Is it not all in series?
This is like the only incandescent I see for this https://www.amazon.com/Forklift-Bulb-Volt-Watt-BA15d/dp/B0046IJTFE
I don't get your double pole reason, me too dumb, I need a drawing. Is it not all in series?
Yeah the forklift bulb would likely work if a base/socket was also available.
One pole feeds through the pos and the other the neg. The bulb is inline on only one side. My DC battery breakers have 2 poles. Thus both sides are either open/closed and require a feed through in order to power the inverter when Breaker in open position. Once the circuit is charged having double pole at the toggle ensures it gets removed entirely.
One pole feeds through the pos and the other the neg. The bulb is inline on only one side. My DC battery breakers have 2 poles. Thus both sides are either open/closed and require a feed through in order to power the inverter when Breaker in open position. Once the circuit is charged having double pole at the toggle ensures it gets removed entirely.
many of those bases around
seems they are all metal <__<
seems they are all metal <__<
oh ok, I'd just combine them ?
actually this bulb is pretty nice looking internals https://www.amazon.com/FPE-Forklift-Toyota-69931-14680-71-Aftermarket/dp/B08KWJFQ9M/
same base I think? doesn't say, looks the same though
looks more "robust" internally
same base I think? doesn't say, looks the same though
looks more "robust" internally
Thanks for looking it up. The different base mounting types for that does give me an idea about how I could mount that in a junction box with a hole in the cover above the bulb for indication.
Better idea than my first go round.
When pops would connect his Jupiter 3000w inverter to the battery bank, the inrush would immediately pop the 175amp mrbf battery fuse. Built him a remote on/off switch using this (the thing is a big as your hand spread open) which worked out great to hide a couple sand cast 20watt resistors in parallel connected to a small red diode mounted in a drilled hole so that the diode sticks out the side. Used a tad of hot glue to hold the diode in place.
Turn the knob to 1 and the diode lights for several seconds, precharge accomplished, then turn the knob to 2.
Turn the knob to 1 and the diode lights for several seconds, precharge accomplished, then turn the knob to 2.
Sounds like a good idea. I have already ordered some components to try the 48vDC Forklift bulb idea. When I get them in and assembled I will post some images.
I got in the last of the pieces parts today in the mail. I have most of the 2 new boxes laid out and ready for the bulbs. Some images below of progress.
ETA: Tested the bulbs and switch with a 12 volt battery to check operation. All that is left is to install beside the MCCB breakers. That will not be done until I rewire my battery banks sometime in a few weeks from now.
ETA: Tested the bulbs and switch with a 12 volt battery to check operation. All that is left is to install beside the MCCB breakers. That will not be done until I rewire my battery banks sometime in a few weeks from now.
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Old Timber guy
New Member
Sweet! Just what I' looking for, thanks!
Got the pre-charge boxes in place and used them today after redoing my battery bank. Worked fine. the light came on for a few moments as it charged up and than I threw the main breaker shut. Now all I have to do is be paranoid that I wired everything correct for a day or so.
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LakeHouse
Solar Enthusiast
This is probably too late to be helpful…. But I would recommend a switch that has to be held to close the pre-charge circuit rather than toggled. You don’t want to have any way to accidentally leave that small circuit bypassing your MCCB.
wheisenburg
Independent Solar Consultant
I use a 120 volt lamp socket and an incandescent appliance bulb. I have not tested to know that a 12 volt bulb won't work. I was concerned that at least at the beginning the voltage across the gap would be 50 volts and it might burn out a 12 volt automotive bulb. I don't have it wired up permanently. I just use it as needed. I also found out that my batteries should do a pre-charge if I turn the batteries off, close all the breakers (in the PDP panel and the batteries), and then turn the batteries back on. I agree that if I were going to wire this up, I would use a push button. Part of the reason I didn't wire this up, it that there are 2 separate 250 amp DC breakers. One for each inverter. So I would need two separate light bulbs so I didn't bridge across the breaker outputs. Otherwise if one breaker tripped the wire could carry current from the engaged breaker to the tripped one. That would be bad.
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Understood, that was why I specified a momentary toggle switch.
LakeHouse
Solar Enthusiast
Ah, I missed that detail.
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