Iota DLS 90amp IQ4 Charger AC connection / 30amp Receptacle



  • BB.BB. Super Moderators, Administrators Posts: 32,006 admin
    Re: Iota DLS 90amp IQ4 Charger AC connection / 30amp Receptacle


    It is the whole idea of interrelated/down stream protection (or cascading requirements).

    If you have a 30 amp breaker/circuit and a 15 rated socket--Even if the blades do not overheat, the device that plugs into the 15 outlet is designed to carry the rated 15 amp current/XX amp surge until the upstream protective device trips...

    With a typical 15 amp device, that usually means a minimum of 16 AWG wiring to ensure it does not overheat at 15 amps, and will trip a 15 amp fuse/breaker if there is a short in the device at the end of the power cord.

    So, in theory, a 30 amp circuit with a 20 amp socket could cause a device rated for 20 amp socket to overheat its power cord and cause a fire.

    And, from the back of the envelope calculations I have done for the Iota--The supply we are talking about is a 20.8 amp continuous draw at ~117 volts and full rated output.

    Given that NEC requires circuits to only be operated at 80% of (1/1.25) rated load, then 20.8 amps * 1.25x NEC derating = 26 amp minimum rated circuit/circuit breaker.

    Running a 20 amp load on a 20 amp circuit breaker will run the chance that the protective device will eventually trip (could be hours before a trip and still be "legal") or become "unreliable" due to long term excessive heating/thermal cycling of the protective device.

    Surge while it can be an issue (sagging an AC inverter or Generator), is not the reason here for (my) recommendation of a 30 amp circuit.

    When I looked into the issue many decades ago, I don't believe there was a definition of "acceptable" surge current for a 15 amp/14 AWG circuit... And, from what I could find at the time, 45 amps for several cycles of surge current was a normal upper limit for many pieces of computer equipment (i.e., 200 lb 500 MByte Fujitsu Eagle disk drives--ah, the "good old days"). I don't think a surge limiter (MOV/NTC resistor) would address this 30 amp/20 amp issue here.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • VicVic Solar Expert Posts: 3,112 ✭✭✭✭
    Re: Iota DLS 90amp IQ4 Charger AC connection / 30amp Receptacle

    Hi BB Bill,

    Thanks for the details of your thinking.

    Had felt that the responsibility of protecting power wiring/cables ended at the receptacle (the end of an AHJ's scope of inspection). And that it would be the responsibility of connected devices to offer some level of protection for the cable connecting the device to the receptacle.

    Realize that some plug-in devices like residential lamps (floor/table) may well have no included protection for its probable 18 GA 60 degree C rated power cable, and could be mated to a 20 A 120 VAC outlet (in the USA).

    Thanks for the wisdom, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • BB.BB. Super Moderators, Administrators Posts: 32,006 admin
    Re: Iota DLS 90amp IQ4 Charger AC connection / 30amp Receptacle

    In Britain, for example, they have "ring" circuits. You have a run of 230 volt 13 amp wiring with a breaker at each end. It is impossible to draw more than 13 amps down either the left or right wiring... However, at the outlet, you can draw 26 amps.

    So--All (?) their plugs have 13 amp fuses in them.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CDN_VTCDN_VT Solar Expert Posts: 492 ✭✭✭
    Re: Iota DLS 90amp IQ4 Charger AC connection / 30amp Receptacle

    I run Iota's 45,75,90 amp units DAILY on the grid / shore power.

    Reading this thread , all the posts sound great,and seem correct to my thinking. But these Iota's are used differently for each use.
    I use the max rated numbers ..

    Now when I pick on a battery maintainer , size matters , I can have a load of 60A dc with spikes of up to 80 amps for a few hours. The fans on the 90 DLS just run till unhooked and let cool. Im using that loaded amps @ 14 volts (13.9-14.3) . This unit is bolted & hard wired for 30A~ then 2 gauge welding cable to quality battery clamps like jumper cables use. On some of the programming , I have had a load on of 35 amps for two days while waiting for parts to load/program in.
    If im just having a look at a system , I use the 75 (on a 20A~ plug)or if im keeping a unit in the shop for further checking , the 45 that is mobile on an extension cord is used.

    The the IQ4 is used for batterys that are removed for checking after a two day charge & then checked with load testing , midtronics electronic checks for warranty claims if required. if the IQ4 gets any power bumps it starts it's process from the start again .

    Now for solar battery charging , your using these Iota's at max power for so little time , amps in the time as the voltage would boil the battery , so the currant is decreased to stop the battery from being damaged,as the battery is being charged. If you had a load on your batterys , the Iota would pick up that then slowly the batterys would be recharged, if a IQ4 was on a battery, as soon as the load was greater than the Iota could supply , the IQ4 starts it cycle again, or at least mine (2 units) do .

    What these Iota's are great for myself,, is CLEAN 12V (14v is where I have set/trimmed mine) .
    I have used a oscilloscope to check, on programming these new computers we drive , letting the smoke out gets very expensive quickly !!!

    The early 45A Iota's till 1995-1997 uints had huge caps , just plugging in a 15A~ plug without any dc load , you could hear and see the zap/spark .As these driving DVD's became fancier, I needed larger amp units so the new 45a ones and the latest since 2005 don't do that. My early ones all did that.
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