Cable Connections: Battery Bank

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Comments

  • TexasOffGridTexasOffGrid Posts: 20Registered Users ✭✭
    Well, My KID charge controller stopped working after 7 months...just went dead.  I sent it in for warranty.  The Tech said that four (4) capacitors were blown...and the unit saw 250+ volts?  I have a surge protector on the system...and 30A breaker...they were fine.  Is it possible I have a voltage leak in the system?  Yes the system is grounded!  Any ideas?  Thanks.
  • westbranchwestbranch Posts: 5,041Solar Expert ✭✭✭✭
    what brand of surge protection, and diagram of wiring with sizes if possible would be immensely helpful... lightning is a specialized beast as you obviously know
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge, Hughes1100 Sat Modem
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Raj174Raj174 Posts: 605Solar Expert ✭✭✭✭
    edited March 16 #64
    @TexasOffGrid  
    250+ volts PV input. Very likely lightning. Did you have a Midnite SPD installed between PV + and - inputs? 

    Rick
    12 x 300W Renogy PV, MNE175DR-TR epanel modified, MN Classic 150, Outback Radian GS4048A, Mate3, 54.4V 207AH HI Power LiFePO4 no BMS, 4000W gen.
  • TexasOffGridTexasOffGrid Posts: 20Registered Users ✭✭
    Hi, Yes, had a midnight SPD between the PV and Charge Controller.....on the positive line only...
  • Dave AngeliniDave Angelini Posts: 3,761Solar Expert ✭✭✭✭
    Well that is not good!  Do you think lightning and surges only like (+) ?
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • westbranchwestbranch Posts: 5,041Solar Expert ✭✭✭✭
    I have  to assume they were 115 V for DC and not any of the higher rated DC ones or  for AC?



     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge, Hughes1100 Sat Modem
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Raj174Raj174 Posts: 605Solar Expert ✭✭✭✭
    @TexasOffGrid
    I believe it should have been wired between PV + and PV- with a ground connection. Will Midnight replace under warranty?

    12 x 300W Renogy PV, MNE175DR-TR epanel modified, MN Classic 150, Outback Radian GS4048A, Mate3, 54.4V 207AH HI Power LiFePO4 no BMS, 4000W gen.
  • TexasOffGridTexasOffGrid Posts: 20Registered Users ✭✭
    Yes, Midnight repaired under warranty.
  • TexasOffGridTexasOffGrid Posts: 20Registered Users ✭✭
    Help....just burned through my third warranty repair on the MIdnite KID??????  NO load on the system....just charging the battery bank.
  • westbranchwestbranch Posts: 5,041Solar Expert ✭✭✭✭
    This may help...double check the wiring of the neg PV , It can only go to the Kid... no other connections allowed.
    The Kid can have only 1 connection to the battery IIRC...




     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge, Hughes1100 Sat Modem
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • softdownsoftdown Posts: 1,824Solar Expert ✭✭✭✭
    The input and Battery fuses on the Kid Controller are 40AMP....so I switched my 30A fuse between the controller and battery to 40AMPs...same result with overheating and the Kid failed.  To answer Estragon:
    The Rebulk and absorb voltages were set to battery specs.  I have a 3000 Watt GoPower inverter, and run two freezers on it.  The freezers are rated at 5 and 7 amps respectively.   Yes, 3 strings of 24V. 
    Midnight Solar is sending me a new controller...and I am going to buy an automotive quality fuse to the batteries.
    Thank you for the inputs.
    BB has an EE background and is our most prolific poster. OP must have misunderstood when told that automotive type fuses are not designed for long periods of high loads. 

    This may confuse me a bit. Why would they use inferior fusing technology on an automobile that cost well over $100,000? Blowing a fuse is often catastrophic and most people are not equipped to quickly diagnose the problem and replace the blown fuse. On the other hand, a small, simple fuse is often easy to diagnose.

    I also don't really understand what makes a fuse designed for higher loads for longer periods. Though it is clear that construction has very large visible differences. The automotive fuses are pretty compact and one can easily see the size of the copper that determines the max. load size. Other fuses are comparatively huge and all is hidden except for an external tube with copper legs for positive and negative connection.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • EstragonEstragon Posts: 2,433Registered Users ✭✭✭✭
    I don't think it's necessarily a case of "inferior technology", but more a case of using the right tool for the job. Fuses have different time-to-open, max operating current, max fault current, etc ratings depending on the application.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • cow_ranchercow_rancher Posts: 96Solar Expert ✭✭✭
    Automotive fuses are the same as fuses that are "comparatively huge and all is hidden except for an external tube"  a fuse is a fuse, except for slo-blow fuses, they protect the wiring from becoming a fuse.

    Rancher
  • BB.BB. Posts: 27,551Super Moderators admin
    The problem has been seen with automotive type fuses is that the connectors to the blades on the fuse seem to be a weak spot.

    An old time poster here had an automotive fuse (holder) assembly that failed and almost caught fire (as I remember)... Fortunately for him, he had the fuse assembly in a metal (j-box?) of some sort. The fuse+holder were only used for less than rated current--Here is one old post (2012) where he talked about the problem.

    Re: Using 32V car fuses in 24V PV systems

    In my opinion a few volts won't make a lot of difference. I know of one case where they were used on a 1Hp 240 VAC motor that didn't have internal overload protection. Added after having motor re-wound several times. After that, only the fuse blew if the motor got stalled. That said, the current was already limited to what the windings would pass before burning up. On a more serious note, I nearly had a fire with the combination of one of those 30A fuses and it's plug in holder, where there was continuous 20A or so current. Seems a resistance built up between the fuse blade and the holder clip. Melted the holder, blackened the fuse leg, ate part of the blade away with arcing, still the fuse didn't blow! When I found it by accident when checking voltages and discovering a drop where there shouldn't have been any, the whole mess was welded together. Had to cut it open to see what had happened. After that, I soldered the wires directly to the fuse blades and have had no more problem. Used to have similar electrical problems with 12 volt motorbike systems years ago, at points where the wires were crimped into connectors. Just something to consider.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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