Almost blown up a new Victron MPPT 75/15 charge controller!!

Archerite

New Member
Just starting with solar and I got a tiny setup with 2 x 10 watt panels and a single 7.2Ah 12v SLA. Since I did not have any black/red wires that I felt were safe enough with the currents of solar stuff I used a speaker wire that has a single red line on one of it's conductors. The rest is transparent gold like in color and aside from the thin red line both wires look very similar. I know this was dumb to begin with.....

While connecting the battery to the Victron MPPT I connected the positive and negative the same as the PV input....and that turned out to be wrong! I was expecting a spark since that is what I learned from my research but touching the contact of the battery connecting sparked twice so hard it actually vaporized a piece of it!!! Scared to heck out of me and I was shaking offcourse! Looked at the wires to the battery...(don't ask about the connection there)...and then the markings on the MPPT! They were in reverse!!!!

Needless to say there was no sign of life after this incident but nothing burned down either. Then I looked at the fuse in the MPPT and with some effort took it out...and it had blown! I replaced it with a same value from my also new fuse box and....it still worked! I was sooo scared I had just blown away a 130 euro charge controller!! But the fuse blew and saved the day! :cool:

A big applause to Victron for making their controller idiot proof and protect it against stupid! I still think I got lucky with the fuse blowing and the piece of the terminal that is missing did not end up in my eye or something! Remember to Tripple check EVERY connection and use the correct wire colors...even if I still need to do it myself. 😊
 

NOLA_Castle

Learning Everyday....
Just starting with solar and I got a tiny setup with 2 x 10 watt panels and a single 7.2Ah 12v SLA. Since I did not have any black/red wires that I felt were safe enough with the currents of solar stuff I used a speaker wire that has a single red line on one of it's conductors. The rest is transparent gold like in color and aside from the thin red line both wires look very similar. I know this was dumb to begin with.....

While connecting the battery to the Victron MPPT I connected the positive and negative the same as the PV input....and that turned out to be wrong! I was expecting a spark since that is what I learned from my research but touching the contact of the battery connecting sparked twice so hard it actually vaporized a piece of it!!! Scared to heck out of me and I was shaking offcourse! Looked at the wires to the battery...(don't ask about the connection there)...and then the markings on the MPPT! They were in reverse!!!!

Needless to say there was no sign of life after this incident but nothing burned down either. Then I looked at the fuse in the MPPT and with some effort took it out...and it had blown! I replaced it with a same value from my also new fuse box and....it still worked! I was sooo scared I had just blown away a 130 euro charge controller!! But the fuse blew and saved the day! :cool:

A big applause to Victron for making their controller idiot proof and protect it against stupid! I still think I got lucky with the fuse blowing and the piece of the terminal that is missing did not end up in my eye or something! Remember to Tripple check EVERY connection and use the correct wire colors...even if I still need to do it myself. 😊
For your safety, please do NOT start if you don't have proper tools or material to begin with. This event could cost you dearly. You are lucky this time.
 

Archerite

New Member
For your safety, please do NOT start if you don't have proper tools or material to begin with. This event could cost you dearly. You are lucky this time.
You are totally right. 😊

I know I was lucky nothing worse happened than a blown fuse! Even in an experimental non-permanent setup like I have you should still be really careful! A bigger battery with more amps might have caused a lot more damage. I did enough research and reading to know the risks...this was just a stupid mistake. The reason for sharing it was to prevent others from doing the same.

This dumb action was two days ago and after finding a better spot for my panels I was able to get the battery charged. I have only been testing it with a small QC3.0 board to charge my phone and tablets as the load. I did get a 300W inverter but before I dare using it I want to get proper wires and crimps. Also extra fuses and circuit breakers rated for 12v systems.

I learned my lesson from that big spark....it's not a toy!
 

Archerite

New Member
Here is a nice document every noob, like myself, should read before starting with a solar panel electrical installation! ;)


Especially the warning about how 42 volts and very low current could already be deadly makes me even more careful with panels in series! They easily reach that or a higher voltage in the full sun! Lot's of saftey tips and advice on what not to do and how to do it right. It's meant for installers and professionals but I found it usefull to fill in the gaps in what I learned so far. :)
 

curiouscarbon

Science Penguin
Thank you for allowing us to learn from this oops.

This is the second instance of reviving a victron MPPT by way of fuse replacement that I've seen. Good job on the repair. Resisting the urge to build can be difficult. Using the right components the first time can save a headache 😁

(oh! they responded already. doh.)

Good luck on future work and wear those goggles, use insulated stuff, triple check what the red wire is... and keep extra pants nearby! xD

glad the spooky spark came without an ouch.
 

Archerite

New Member
Thank you for allowing us to learn from this oops.

This is the second instance of reviving a victron MPPT by way of fuse replacement that I've seen. Good job on the repair. Resisting the urge to build can be difficult. Using the right components the first time can save a headache 😁

(oh! they responded already. doh.)

Good luck on future work and wear those goggles, use insulated stuff, triple check what the red wire is... and keep extra pants nearby! xD

glad the spooky spark came without an ouch.
Thanks, lucky for me the fuse on the 75/15 is right next to the terminals and is just an automotive blade fuse. :cool:

It's sure is hard (impossible) to resist starting to build, and all I wanted to do is just test if the stuff worked really. I now have a bigger 60Ah AGM battery and a 300 Watt inverter from Victron.....and I REALLY want to test them and see how long my network stuff/ PC can run from it. My calculations say with about 100-150 watts at 220 that should be 15A at 12v and should last at least about 2-3 hours before reaching 50% on the battery. Right? ;)

For safety I got a big fuse block, battery disconnect and ready made cables of 16mm2 and 25mm2 cables with M6 and M8 lugs. But I ordered to small size lugs on some of the cables so they won't fit the M10 bolts on the battery disconnect and even the smart shunt! So tempting to just twist some wires....but waiting for the delivery guy to deliver the lugs and hydrolic-crimper (not a stupid expensive one though)! I thought let's give it a try as I want shorter wires anyway ;)

Ofcourse all connections are going to be insulated, fused and wired to the correct size for the expected Amps I put through them. That victron document I linked to really helps understanding how things work and should be wired.

Thank you :)
 

pda1

New Member
Here is a nice document every noob, like myself, should read before starting with a solar panel electrical installation! ;)


Especially the warning about how 42 volts and very low current could already be deadly makes me even more careful with panels in series! They easily reach that or a higher voltage in the full sun! Lot's of saftey tips and advice on what not to do and how to do it right. It's meant for installers and professionals but I found it usefull to fill in the gaps in what I learned so far. :)
The Victron document is excellent. Thanks for listing it.
 
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