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RogerDat

LED security, and night light with battery back up completed

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RogerDat

I do not yet have a hydrometer, so cannot check SG yet.

At 545 pm yesterday with charger off, reading was 13.20 VDC, at 530 this morning it was at 13.24 VDC, lights went off at 515 am, I got to it 15 minuets late, looks like it is not pulling many volts.

 

I agree, the CB is a bad idea, but it worked for him more than 5 years I think. I just pull the plug on the charger.

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Oz Jon

I agree, the CB is a bad idea, but it worked for him more than 5 years I think. I just pull the plug on the charger.

 

It's more than a "bad idea" Roger - it's potentially dangerous!

 

Under some circumstances (breaking high load current, maybe from a load short, etc) it could trip, but fail to extinguish the arc between the switch contacts.

 

That can fail to break the current, get things very hot, quite quickly, possibly destroying the breaker and causing a fire. #

 

Best to use devices designed for the job in hand.

 

 

# As thebob said, having a lower, properly rated battery fuse can remove/reduce that risk. It should blow after a short period of CB arcing.

Also, in your application, only pulling about 7 Amps through a 50 Amp CB is pretty safe with a fuse back-up.

Edited by Oz Jon
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Mikala

Most of the circuit breakers I specify in power plants are dual rated for AC/DC applications. Albeit the DC rating is always lower.

 

Sent from my V2s+ using Tapatalk

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RogerDat

My main has CB's, my charger has fuses. I cut power to the charger by pulling the plug.

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Mikala

My main has CB's, my charger has fuses. I cut power to the charger by pulling the plug.

 

Hopefully not under load? :)

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Oz Jon

My main has CB's, my charger has fuses. I cut power to the charger by pulling the plug.

 

The sector you need to protect with a fuse is between the battery and the load.

 

Your battery is capable of delivering at least 100Amps ( probably 200Amps or more) into a short circuit on the load side. - that's a lot of power - can generate a lot of heat.

Edited by Oz Jon
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RogerDat

I think 200 amps would take you out if fully involved!

Charger has 2 internal 20 amp car type fuses between charger and battery, 1, 4amp glass fuse on main power input.

There are 2 12 amp glass fuses between the load and battery, one in each branch (auto, and manual branches.)

The cooling fan also has a 12 amp fuse.

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RogerDat

Micala, The charger has no off switch, so how else to cut power to charger, and no disconnect between battery and load, just like a car or boat circuit.

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Oz Jon
There are 2 12 amp glass fuses between the load and battery, one in each branch (auto, and manual branches.) The cooling fan also has a 12 amp fuse.

 

OK - Good choice - Those are the important fuse locations from a safety viewpoint

 

That 200AH battery you have is a potent current source - it's a serious battery and could deliver a very high current into a short circuit.

Edited by Oz Jon

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Mikala

Micala, The charger has no off switch, so how else to cut power to charger, and no disconnect between battery and load, just like a car or boat circuit.

Just hoping the load is minimized to prevent arcing. I guess load would be minimal after charging batteries.

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RogerDat

I see your point after sleeping on it, you mean in case explosive gas is present right? I have forced air vent t outside installed on sealed box.

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Mikala

I already figured you took care of the hydrogen off gassing Roger. You ain't no dummy!

 

Just always a safety factor to dislodge plugs under load. Arcing will damage the plug / wall socket. If battery charge is complete though, then there should be very little load.

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Woolf

The charger is 12 v 30 amp  about 360 watt

 

on the 220 volt side that should be about 1.6 amps

lets say 2 amp max with losses

 

as the charger is not a inductive load

I cant see that there would be at lot of arcing when disconnecting

 

connecting the charger, there may be some arcing,

charging the capacitor, could draw some high current

 

ok I think that the charger has an invertor type power supply

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Paul

My view is this. Could something happen? As sure as Murphy (Murphy's Law) is alive and well - forever, it could. Is there much of a chance, under the circumstances that it WOULD actually happen? I doubt it. But, that isn't the issue, in my mind at least.

 

The issue to me is, safety, pure and simple. 

 

Last year, while I was away, I had a battery to explode. Til this day, we do not know what caused it. I suspect it shorted inside. My girlfriend was cleaning nearby when it happened. Fortunately, and Thank God, nothing happened to her - aside from her filling her britches. From that point forward, I have exercised even more safety precautions concerning batteries, than I have ever before. 

 

In this case, it is an AC breaker that is between a battery bank and an inverter. Simply put, I would not install ANY breaker there, aside from one rated for DC. These breakers are like $9.00 USD or $10.00 USD each. What is worth your safety, or the safety of your family? For just a few bucks, you can protect them. 

 

As a side note, I have experienced fuse failures. So, double protection isn't such a bad idea either. 

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Oz Jon

.......The issue to me is, safety, pure and simple. Last year, while I was away, I had a battery to explode. Til this day, we do not know what caused it.........

 

Exactly the point I have been trying to make Paul.

 

Batteries (particularly big ones like the 200AH one here) store a lot of energy and can deliver it very fast.

 

If there is an accidental short-circuit somewhere on the load side it can pull a huge current from the battery, cause a lot of heating, fire  and even explode the battery.

 

That's the part of the circuit which most needs to be protected.

 

Easily fixed at low cost with appropriate sized fuses (about 10A - 20A in this case) close to the battery, between the battery and the load.

Edited by Oz Jon
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