Thunder DCDC charger.

Submitted: Monday, Sep 13, 2021 at 09:57
ThreadID: 142557 Views:4377 Replies:3 FollowUps:0
This Thread has been Archived
Stevo_62 wrote "Just installed 20A Thunder dc-dc charger in tub of Dmax to charge 2nd battery which runs fridge. When I start vehicle it flashes 0%, 80%, 88% then 100% for about 3 minutes and display turns off, no lights. Is this normal or do I have a problem? Manual doesn't seem to provide answer"

Thread has been archived, but I think I have a definitive answer.
Your wiring from alternator/crank battery to DCDC is not heavy enough. The manual specifies minimum gauges of wire for distance from DC source to charger.

I got one of these put in my camper trailer by a professional auto-electrician. The trailer's existing wire from Anderson plug to batteries was 8g wire, and old mate just tapped into that. My charger did exactly what Stevo_62 described.

I replaced the 8g with 6g as specified in the manual for distance needed in my instance.

Problem solved.

I believe with lighter gauge wire, the initial voltage is sufficient to wake the charger, but once current starts, the voltage drops below the required threshold.
Back Expand Un-Read 2 Moderator

Reply By: qldcamper - Monday, Sep 13, 2021 at 10:08

Monday, Sep 13, 2021 at 10:08
Heavier cable is always good for better efficiency but voltage drop is exactly what a good quality DCDCcharger is designed to overcome.

Redarc for example will operate as low as 9 volts ish getting to the charger.
AnswerID: 637900

Reply By: Dunworkin - Thursday, Sep 16, 2021 at 06:17

Thursday, Sep 16, 2021 at 06:17
Thank you for that, I will try heavier gauge wire
AnswerID: 637941

Reply By: gerard m2 - Sunday, Sep 26, 2021 at 20:34

Sunday, Sep 26, 2021 at 20:34
I had one of these Thunder DCDCZ chargers that worked ok for about a year, but had similar intermittent issues. Finally gave up on it in Broome last month and installed a Redarc after a local auto sparky reckoned it was useless. No more problems at all after the Redarc was installed.
AnswerID: 638088

Sponsored Links