Small inverter / UPS backfeed to input?

[Optimistically]

Hello - is it normal for the input power cord (the cable from the 230VAC mains) to a small inverter / UPS to remain live after you unplug it (or after the grid drops)? In other words, for the inverter to backfeed 230VAC to its power supply cord in addition to its output outlet? If so, does it only do so temporarily or whenever the inverter is delivering 230VAC?

 

[soulie]

nope shouldnt do that .,you do get it on some battery appliances but at very low voltages ie if you have say a shaver and you leave it connected to the charger but unplugged from mains it will run the battery flat .

 

[Tomtomtom]

This sounds not just not normal but insanely dangerous.

 

[soulie]

let me guess its made in China by someone .like "fonky dooey" brand and the reason why the tiger on the box is leaping is because he licked the 2 pin plug .

 

[Optimistically]

I agree - I will monitor it and see what’s going on. I think it is a cheap Chinese import…

 

[soulie]

I agree - I will monitor it and see what’s going on. I think it is a cheap Chinese import…

at a minimum unplug the cable from the device when not charging .the current will be very low but it can cause problems

 

[Optimistically]

at a minimum unplug the cable from the device when not charging .the current will be very low but it can cause problems

Related question - I have this small inverter (1,400W) connected to two 12/13V BlueNova Lithium batteries in series to make a 24V unit. Is it necessary to have a battery balancer unit like this between the two batteries? Or is that overkill?

Lithium 24V Battery Balancer / Equaliser (suitable for all battery types) - 24V

Lithium 24V Battery Balancer / Equaliser (suitable for all battery types) - 24V Secure Shopping ✓ . Buy Online Pay with and more.

leroymerlin.co.za

 

[soulie]

Related question - I have this small inverter (1,400W) connected to two 12/13V BlueNova Lithium batteries in series to make a 24V unit. Is it necessary to have a battery balancer unit like this between the two batteries? Or is that overkill?

Lithium 24V Battery Balancer / Equaliser (suitable for all battery types) - 24V

Lithium 24V Battery Balancer / Equaliser (suitable for all battery types) - 24V Secure Shopping ✓ . Buy Online Pay with and more.

leroymerlin.co.za

if you charge the batteries seperately no ,if charged at 24v probably .ask @wingnut771

 

[soulie]

bosch makes a 24 volt charger with a centre tap for balancing if needed

 

[Optimistically]

bosch makes a 24 volt charger with a centre tap for balancing if needed

Thanks - they are charged automatically in series by the inverter.

 

[Optimistically]

at a minimum unplug the cable from the device when not charging .the current will be very low but it can cause problems

What sort of “problems” could it cause? Backfeeding? Draining the battery too quickly? What else?

 

[marbro]

Related question - I have this small inverter (1,400W) connected to two 12/13V BlueNova Lithium batteries in series to make a 24V unit. Is it necessary to have a battery balancer unit like this between the two batteries? Or is that overkill?

Lithium 24V Battery Balancer / Equaliser (suitable for all battery types) - 24V

Lithium 24V Battery Balancer / Equaliser (suitable for all battery types) - 24V Secure Shopping ✓ . Buy Online Pay with and more.

leroymerlin.co.za

R700 bucks to make sure R15k worth of batteries are safe.... id do it

 

[Optimistically]

R700 bucks to make sure R15k worth of batteries are safe.... id do it

Agree - seems a no-brainer. But was wondering if the BMS built into the BlueNova batteries might do it automatically? More than R15k these days to replace two Li batteries…sadly…!

Will try to ask BlueNova for their advice also…

 

[soulie]

What sort of “problems” could it cause? Backfeeding? Draining the battery too quickly? What else?

all of those and maybe a child sticking the plug up its nose .pacemaker etc

 

[Optimistically]

So…I used a multimeter to see what readings I am getting when, in my view, the input power cord should be dead…

Tried both AC300V and DC settings…

Any clues?

 

[Rickster]

Shouldn't this trip a breaker or summon the magic smoke monster?

 

[lightpixel]

RCT Power Trolley models have the same issue. I have two of them. They both do it. I figured it out by unplugging the units while it was inverting. Got a small sting.

 

[Optimistically]

RCT Power Trolley models have the same issue. I have two of them. They both do it. I figured it out by unplugging the units while it was inverting. Got a small sting.

Indeed. I also got an unwelcome shock when touching what I thought was a disconnected power cord. Is this normal / safe?

 

[lightpixel]

It seems normal with these units. Safe no. Well not ideal. I will test the output with a multimeter on both and let you know what readings I get.

 

[Optimistically]

It seems normal with these units. Safe no. Well not ideal. I will test the output with a multimeter on both and let you know what readings I get.

I can’t tell - is it backfeeding DC from the batteries or AC from the inverter output?