mpt-7210a solar boost charger (is mine broken)

[jimmyhackers]

hello all..... recently got myself an mpt-7210a solar boost charge controller. but i think its not playing ball.

its linked upto 40w of solar panel and charging a pair of 12v 20ah SLA batteries in series to make 24v.

the batteries are balanced by a lead acid battery balancer, which appears to be working/balancing them fine.
https://www.ebay.co.uk/itm/Solar-System-Battery-Balancer-Equalizer-For-Lead-acid-Batteris-HA01-HA02-Charger/123235021743?hash=item1cb16133af:m:mJJJN8srJeP-rb_mFVq7d_w

they are also linked upto a 1000w UPS (uninteruptable power supply)

essentially the problem is the charge controller doesn't appear to be sensing the battery voltage correctly.
setting the battery voltage to 26v and the charger says they are full and stops charging.... changing it up or down seems to make no difference. even when its set to 30v it says the battery is full and doesn't charge.

im not sure whats up with it..... either its broken of the battery balancer or the UPS is messing with it some how.

any help would be appreciated.

 

[jimmyhackers]

ignore me and everything above.......i connected the battery terminals up wrong

im a dingle, the problem is solved now.......sorry.

funny thing is there's a video on youtube and they guy did exactly the same as me......

 

[jimmyhackers]

turns out something is wrong with my unit......but its not the problem described above. but may of been caused by the problem above.

in the morning when it turns on automatically. it senses my 24v battery as 40v and refuses to charge it...... : s

disconnecting the battery for a few minutes fixes it. or shorting out the leads (capacitor discharge sparks happen) fixes it instantly. and the unit begins normal operation.

i can only presume that on its downtime.....it randomly charges up a capacitor to 40ish volts, then on its "on time" this overvoltage remains tricking the unit into thinking the battery is full and never connects itself upto the battery to start charging.

all in all very annoying.

if anyone can shed some light on this id be very greatful

 

[jimmyhackers]

third post lucky i hope.

i have removed the pair of large 100v capacitors on the battery terminal side of the board and seemingly its fixed. knowing my luck it'll probably blow up on me

no overvolting reading (40-42v) and not charging when the panel gets light in the morning.

seems to work fine....ill report back if anything goes bad.

 

[jimmyhackers]

argh......

this thing is so annoying......ive watched as many youtube vids as i can about other peoples experiences......and i think i get whats going on.

removing the capacitors actually didn't fix anything.....after being off for the night it turned on at 42v and didnt start charging.....its annoying as i can only get it to replicate this fault after it being off for the whole night.... making testing a 24hour per change test thing.....

anyways...i turned the fan speed setting from the lowest to the middle.....its noisey now but actually turned on and sensed 24v which is correct battery sensing...

all i can figure is the fans extra load is knocking down the voltage enough for it to start thinking it should be producing.

ive seen a lot of failed fan videos about this unit online.....it wouldnt be to far of a reach to deduce that this extra initial voltage(nearly 4x recommended) on startup is whats killing the fans.

all in all it seems like poor design. or my unit is defective.....the ebay people are sending a new unit apparently so ill be able to see in 3-5weeks :S

 

[jimmyhackers]

once again.....randomly the panel will be fine one day and not fine the next.....

for a test ive removed/unplugged the cooling fan......as the levels of power i was putting through this thing didnt even make the internal heat sink warm.

the power that was used for the fan is now going into my batteries instead.....meaning the unit turns on at a lower power and gives more charge to my batteries....

for the past two days its started charging and working without a hitch...... no incorrect battery voltage sensing etc.

so far so good but i dont hold up much hope for it not spazzing out again.

id suggest complete removal of the fan with anyone using around 100watts of panels or less with this unit.....just test the internal heatsink with your finger while its at your max output. if its cold/warm....your probably fine to do so.

 

[chamiscastillo]

Hey man, nice story lol
Idk if mine is Broken, until know i was using It to charge a 13s pack with a 12v solar panel, Been working okay, but i tried to charge a battery with another battery, was not succesful.

Now i plug the battery to either side and it shows same voltage for both ways, in and out, It stops sending voltage when turn off with okay key,

Advice?

 

[jimmyhackers]

i bought a different controller
https://www.ebay.co.uk/itm/Universal-MPPT-Boost-Solar-Panel-Battery-Regulator-Charge-Controller-24V-72V/322747476483?hash=item4b253faa03:g:Ch8AAOSwEVtcAW2z:rk:2f:0

this works fine for me