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iTECHBCDC25 DC-DC charger problem resolved

May 01, 2020 — BarryK

In the last post in the lithium powerbox project, I reported a couple of issues with the DC-DC charger:

I sent an email to iTECHWORLD Service department, reporting two problems:

  1. The battery-type selector button did not work, it was stuck on "calcium"
  2. The MPPT regulator was not tracking at the peak power point of the panel

I received a reply from Jason, that has resolved the first issue, number-2 is looked at a bit more today.

Before receiving the reply from Jason, early this morning I thought it necessary to perform a more thorough test of the DC-DC charger, solar charging...

Nice sunny day today, last chance as rain forecast over the next several days. In fact, almost exactly one year ago, on an almost identical day, mid-winter, sunny, hardly any breeze, ambient 16 degC, I tested three solar panels, including the Atem Power "250W" panel:

...and recorded a peak power output for the Atem Power panel of 157.2W.

MPPT charging

Early this morning, Friday 1st May, 2020, 9.10am - 9.30am, have tested charging the iTECHBCDC25 with this same panel. Ambient is 17 degC, irradiance is 820W/m2 -- a year ago it was almost the same, 800W/m2.

As the DC-DC charger is stuck on "calcium" battery type, I used my Waeco Coolpower 44 battery box, which has a deep cycle 44AH AGM battery, a closer choice to the calcium charging profile than the lithium battery. Here is a photo:


As the battery is fully charged, I loaded it down by a 40W globe running via an inverter. The panel was outputting 20.3V at 4.99A (101W), and the battery voltage was 14.7V.

I needed to load the battery down a bit more, bring down the battery voltage, so that the DC-DC charger will think the battery state-of-charge is low, and will then pull everything it can from the panel. So I attached my air compressor. Now getting 15.4V at 9.6A (148W) from the panel, battery voltage 12.1V.

Good, but a year ago, I determined the peak power point of the panel to be 16.21V, power output of 157W. So that issue is still there, the iTECHBCDC25 is pulling at a bit off the peak power point.

But, to be 100% certain about this, I really should test for the peak power point at the same time as testing with iTECHBCDC25.


Moving on, the issue of the battery-type button being stuck on "calcium". Here is a photo:


Fast forward to this evening, I read my emails, and here is the reply from Jason:

In regards to the DCDC charger being stuck on calcium, to set it to the correct profile, you will need to disconnect the solar input and auxiliary battery connections, and only have the main(starting battery) connected, in order to change the settings.

...riiiight. Tonight, I used the Waeco Coolpower as the "car battery", connected to the red and black cable of the iTECHBCDC25, and hey, was able to change to "Lithium" type. Good, but the User Manual does not state that the "car battery" only has to be connected. Quoting from the User Manual:

Once correctly installed, the iTECHBCDC25 has MPPT solar
charging for increased solar efficiency.
Once your solar panel has been connected to the solar
input section of the iTECHBCDC25 the charger will
transfer to solar mode when the vehicle is not running.
The initial default setting is for AGM/GEL batteries.
If you are charging a battery of a different chemistry
simply change the battery type by pressing the battery
type selector button on the front panel of the
Once you have selected the new battery type the
iTECHBCDC25 will remain on this battery type until it is
Solar charging requires a solar input of 16 to 25v.
Your solar panel will need to be unregulated when
connecting to the iTECHBCDC25.

Well, that is a relief, the charger is not broken.

My Hyundai Getz has a radio/CD-player that, if the car battery is disconnected, after reconnection, the security-code has to be be re-entered for the radio/CD-player to work again. Of course, that is for security, but it is to be hoped that the DC-DC charger will remember the battery-type setting if the "car battery" is removed! ...yay, it does! 

Tags: nomad