HF controller question

[Ntrain2k]

How exactly do you wire the HF controller up to just be a PDU setup?

I tried just hooking it up to the battery side only, but don't seem to be getting anything.

Thanks in advance.

[dnix71]

The new one with the digital display? If you hook up a battery there is a push button to the left of the one/off switch in the upper right. If both are on you should see battery volts. If you don't, turn the unit around and replace the 4 amp car spade fuse in the back.

You don't need tools. Just pull the black plastic cover off the fuse in the middle.

[Ntrain2k]

Yep, that was it. I posted before I did some real testing on the unit.

Turned the switch on and got no display, so I thought something was up. Tested the outputs and saw that they were working, then found that the black dot next to the display was a seperate on/off for it.

I already had a controller I was planning on using for it, based mostly on what I have read on here and on the 12VDC yahoo list.

Wired it all up today in the poring rain. Was interesting to find it putting a charge into my battery in the 100% overcast conditions that we had.

One more question, does anyone know the useable reserve time on a group 31 yellowtop optima?

I don't think I saw a real rating for it on the web site.

Thanks again!

[dnix71]

The published reserve is over 10 hours, typically. If you discharge them hard, use 1/2 that value.

Many Optima's are agm's so you need to be careful not to overcharge them (>15 volts will gas). If the vent pops, your warranty is void.

http://www.batteriesareus.com/index.php?main_page=page&id=2&chapter=0

[wooferhound]

W O W

 I had thought my Harbor Freight controller was dead out of the box. Was thinking that Push-button was a power LED indicator. I went and recovered the controller from my Parts Stash and hooked it up and there it is working wonderfully.

Thanks Y'all

[Ntrain2k]

Thanks!

Yes, it is an AGM.

I currently have the cutoff point on the controller set to 14.58 volts.

The specific rating that optima gives on this battery is:

Capacity: 75 Ah (C/20)

Reserve Capacity: BCI: 155 minutes

(25 amp discharge, 80°F (26.7°C), to 10.5 volts cut-off)

So this means I could draw 25 amps for approc 155 min(at 80degreesF) before it drops to 10.5 volts, right?

and 14.5 amps for 310 min until it hits 10.5?

Of course I plan on not dropping that low on the voltage.

[dnix71]

That's the theory. The C/20 for 75 AH means 75 amp-hours / 20 hours = 3.75 amps.

If you pull 25 amps then your get only 25 amps x 155 minutes/60 minutes per hour = 64 amp hours.

14.5 x 310/60 = 75 AH

If you believe Optima, you can pull some pretty decent current without losing capacity.

I wouldn't take a lead acid battery, even an Optima, below 12.3. Below that invites sulfation.

If you only discharge to 12.3 then you will get 45% of the 75 amp hour rating. That's why I say take their number and halve it. 35 amp hours is a safe, realistic discharge value.