#165984  by maccasparks
 Tue Sep 29, 2020 8:16 pm
Looking at getting a 30amp DC-DC charger to help out the ever increasing loads put on my 200AH AGMs with 300w of solar and a 30amp PWM controller with a Juntek monitor. Do I connect the solar and DC charger outputs to the same battery terminals or do I need some sort of changeover device? Also any recommendations on a DC-DC charger ? Keen on this one
https://www.actionoutdoors.kiwi/epages/ ... z7EALw_wcB

cheers
 #165989  by Nut17
 Wed Sep 30, 2020 1:51 am
I have fitted a couple of those units - Supplied by Super Cheap Autos and in both cases they failed within a few months. Even from new, they got very hot within about 30 minutes and the charge current dropped from the rated 30 Amps to around 7 amps. I have just sourced one of these https://au.renogy.com/12v-60a-dc-to-dc-battery-charger/ to fit into our new motorhome. Delivery X Aussie was really prompt and it cost NZ$475 including GST The 40 Amp model https://au.renogy.com/12v-40a-dc-to-dc- ... lar-input/ would work out at about NZ$350 landed including GST. I have yet to install mine but research has shown that these units appear reliable and perform very well. https://www.youtube.com/watch?v=EcVjPap9dkY
 #165994  by Paul
 Wed Sep 30, 2020 7:08 am
Hi AAsolar have a range of DC to DC chargers.Paul
 #165995  by Naki585
 Wed Sep 30, 2020 7:53 am
Redarc do a range of DC to DC chargers. All come with a MPPT controller builtin. We have a 25amp unit and we are very pleased with it. Great products and excellent support

Cheers
 #166010  by David Wallace
 Thu Oct 01, 2020 5:52 am
It will be ok to connected the dc to dc charger and solar to the same battery terminals. I have used a similar dc charger I got from supercheap in our old caravan. I found the 13.2v turn on voltage too high. When it started to charge the current draw caused the voltage to drop and the dc charger would turn off. It would continuously cycle like this making it difficult to put any charge in the caravan battery. In our new caravan I have purchased a Manson SBC-5925 25amp dc to dc charger off Trademe which has a voltage range of 9 to 16volts, works with smart alternators, and has a vibration mode which starts charging when there is vechicle movement.
Cheers David
 #166011  by Derb
 Thu Oct 01, 2020 7:53 am
Hi. In our 1st van I ran a simple Voltage Sensitive Relay via an overload to the back of 2 different tow vehicles and utilised 2 of the heavier 5 pins of a 12 pin trailer plug to Feed the van battery. It worked better than no charging at all but I suspect of fairly ordinary performance.
In the latest van (2014 build) the charging system is a Setec D250S which is both a solar charger plus a DC-DC charger of 20 amp capacity. I have had it tested (Bill’s Bus Stop - Tauranga) on a fine day and it was poking out the full rated 20 amps from solar panels and the same with blankets over the panels and the motor running on the Cruiser. It is performing similarly on the Colorado. Both vehicles have had VSR plus Overloads fitted adjacent to the tug batteries and 12 pin trailer plugs. I am quite satisfied with the performance of this regulator but fully aware that it is limited to wet-cell or AGM batteries and max charging rate of 20 amps. With my 200 a/h of AGM and 450 watt of solar this is fine for me. We do not suffer from power anxiety even though we very rarely run on mains power. Cheers.
 #166094  by maccasparks
 Mon Oct 05, 2020 4:23 pm
Thanks for the info. I have decided to squeeze an extra 2 x 100w modules on the roof for now then probably go with the charger later. Managed to find 2 panel the same with very close voltage 18 v / 17.2 v to my existing 2x 150w for $205 from Burnsco including freight . Happy as.
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