diy solar

diy solar

Help!!! Smoke during top balancing

I cross wired as you recommended and It turns out the one from yesterday works too. I have both set to 3.65 volts and crosswired both sides

So one charger is crosswired and the other charger is crosswired , is that ok?
You need to put the Red wires of both chargers together, same for the Black wires of both chargers, and then put them cross wired as suggest.
If you did set bothe charger to 3.65VDC BEFORE conneting to batteries but in the picutres it shows 3.75V, is that meter error?
 
You need to put the Red wires of both chargers together, same for the Black wires of both chargers, and then put them cross wired as suggest.
If you did set bothe charger to 3.65VDC BEFORE conneting to batteries but in the picutres it shows 3.75V, is that meter error?


Thanks a lot. How’s this looking ?
 

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Couple of optimizations.
1 make a decent set of charge leads and you will get more current flow.
2 swap that improvised busbar on the right side of the picture for the busbar just beside it.
then clamp your leads to the outer edges of the bubars on the positive side and negative side.
the terminal set screws are likely stainless steel and therefore very poor conductors.
 
Thanks a lot. How’s this looking ?

Nothing was wrong with driving both ends of positive bus, both ends of negative bus. It is somewhat better.

If you didn't have two insulated busbars, I would have connected halfway between cell 1 & cell 2, also halfway between cell 3 & cell 4. That would have been perfect balance. Moving the insulated busbars between cell 2 & cell 3 would allow that.
 
Ok thanks, question is it normal that the two cells on the edges are already up to 3.44 but the ones in the middle are still 3.29-3.30

Measuring the same electrical "node" but at a different physical location produces a different voltage reading? Even though busbars are so heavy?
That indicates poor contact. Oxide on aluminum maybe, or not tight enough.

If you measure between two points along the multiple shorted busbars, or between terminals of two cells, do you see 0.07V?
 
Couple of optimizations.
1 make a decent set of charge leads and you will get more current flow.
2 swap that improvised busbar on the right side of the picture for the busbar just beside it.
then clamp your leads to the outer edges of the bubars on the positive side and negative side.
the terminal set screws are likely stainless steel and therefore very poor conductors.


Check this out , the amps went up after changing it
 

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Measuring the same electrical "node" but at a different physical location produces a different voltage reading? Even though busbars are so heavy?
That indicates poor contact. Oxide on aluminum maybe, or not tight enough.

If you measure between two points along the multiple shorted busbars, or between terminals of two cells, do you see 0.07V?

Ok I tightened them and now they’re all at 3.31 up from 3.29
 
Couple of optimizations.
1 make a decent set of charge leads and you will get more current flow.
2 swap that improvised busbar on the right side of the picture for the busbar just beside it.
then clamp your leads to the outer edges of the bubars on the positive side and negative side.
the terminal set screws are likely stainless steel and therefore very poor conductors.


Speaking of the screws. I picked those up to have additional thread room to attach the thick wiring when I assemble this battery. I plan to use this in a solar system in my truck camper. If stainless steel is a very poor conductor, won’t that have a negative effect on the final assembly of the battery and the way the battery charges in the real life application from the solar panels?
 
Speaking of the screws. I picked those up to have additional thread room to attach the thick wiring when I assemble this battery. I plan to use this in a solar system in my truck camper. If stainless steel is a very poor conductor, won’t that have a negative effect on the final assembly of the battery and the way the battery charges in the real life application from the solar panels?
All the current is carried by the busbar to battery terminal junction, the screws and bolts are just there to make sure it's a tight connection.
 
Speaking of the screws. I picked those up to have additional thread room to attach the thick wiring when I assemble this battery. I plan to use this in a solar system in my truck camper. If stainless steel is a very poor conductor, won’t that have a negative effect on the final assembly of the battery and the way the battery charges in the real life application from the solar panels?
Its fine.
The set screw is not intended to be the primary conductor.
Its the surface are of the aluminum terminal and the busbar/lug that carries the vast majority of the current.
 
Guys the bottom of these chargers is getting really hot , can barely keep my hand on it so I sat them up
 

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That is why I suggest to run it at 80% of rating on these cheaply made power supply, you do not want the power supply regulator circuit to short out and dump high Voltage into the cells, you better keep close eyes on them all the time.
 
That is why I suggest to run it at 80% of rating on these cheaply made power supply, you do not want the power supply regulator circuit to short out and dump high Voltage into the cells, you better keep close eyes on them all the time.

Yes I remembered you, I turned them down to 4.5amp
 
That is why I suggest to run it at 80% of rating on these cheaply made power supply, you do not want the power supply regulator circuit to short out and dump high Voltage into the cells, you better keep close eyes on them all the time.
I could be wrong, but at 3.65 volts out of 30, they are likely below 80%.
 
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