Iota battery charger wiring questions

Re: Iota battery charger wiring questions

wolamin wrote: »

I am unfamiliar with wiring battery chargers... I know that one should normally place a fuse within 18" of a battery, but is it necessary/advisable to also put a fuse 18" from the charger (Iota DLS-30) as well?

Fuses (and breakers) are installed closest to the source of "high current". The Iota (and solar charge controllers) are designed to limit their output current to their rated values (a 30 amp Iota can only output ~30 amps maximum).

The battery bank, in almost all applications, is the source of high current. A single battery can output 100's of amps into a dead short, and larger battery banks can output 1,000s to 10,000s of Amperes into a dead short.

So over current devices should be near the battery bank, the source of the "unlimited" current.

Each wire/cable leaving that point should have its fuse/breaker that is no larger than the rating of the wire/cable to the "remote" devices/branch circuits. For example, a 14 AWG wire should have no more than a 15 amp fuse/breaker (per NEC). And your maximum current should only be 80% of fuse/rated wiring (15 amps * 0.80 = 12 amps max continuous load/charging current).

I've currently got a 60A fuse by my deep cycle 12V battery before an anderson connector. Do I also need to put a 60A fuse between the battery charger and the anderson connector that will mate?

No, the Iota can only output a maximum of 30 amps. The fuse/breaker/wiring should be rated for 30 amps * 1/0.80 = 37.5a or ~40 amps minimum (or next higher available fuse/breaker).

So, if you use NEC, the minimum rated wire AWG for 40 amp branch circuit would be 10 to 8 AWG (depending on insulation, conduit fill, etc.).

If you use Marine Specifications, then a 40 amp branch circuit would use a minimum of 12 to 10 AWG wire.

Also, with DC power, you have to worry about voltage drop too... For 12 volt systems, you should design for a maximum of 0.5 volt drop (11.5 volt minimum battery voltage and 10.5 inverter cutoff voltage, surge current is ~2x maximum continuous current flow).

I also wonder just what the wire capacity is on the DLS-30... I can't tell from looking at it whether it will take 4 gauge or just 8 gauge wire.

Finally, I'd like to mount the iq4 onto the iota charger. It looks like I should just open up the charger and put a bolt through the hole next to the fan to hold the iq4 in place, but I was wondering if there is a more secure way to mount.

I don't have an off grid power system--So I cannot tell you. Others have called/email Iota customer support and found them to be very easy to deal with.

-Bill