Atem Power 12V 20A DC to DC Battery Charger with MPPT Solar
2 reviews
Looks good but has a serious design flaw – This unit looks well made and comes complete with quality pre-terminated cable stubs, making installation easy. As a DCDC charger running from a vehicle, it does what it says on the box. I am charging a Lithium battery so required a suitable charge profile. The voltage and current profile and end of cycle charge cut-off seem to work fine. So far so good. But it is the MPPT solar input that is the disappointment. This unit does not commence charging a battery until the solar panel is producing in excess of about 35W of power. Then the MPPT charger seems to work fine. Below this, the unit refuses to charge a battery and just constantly restarts and fails to charge. So a normal vehicle roof mounted solar panel of 110 to 160W in overcast weather has insufficient output to get this unit to start charging, even though 3+ amps of charge (enough to run a fridge) is available from the panel. My Renogy and CTek MPPT solar controllers do not behave in this way. I was forced to buy an additional, better designed, solar charger to charge my batteries rather than rely on the Atem MPPT solar input. Unless this shortcoming can be overcome, I can not recommend this unit which is unfortunate as in other respects, it should be a winner.
Good Product When it Works – I bought this charger from an eBay seller last April and the charger has worked well for 9 months. However, it has now developed a fault where I can no longer select the battery type. The seller won't respond and there are no company details to be able to contact them. This item is cheaper than normal but, I would advise against buying this to save money, spend a bit more and buy from a reputable seller and manufacturer. Note that companies such as Jaycar are rebranding this exact device but you should have some comeback from them. I'm stuck with a useless box and a loss of $170 so, be warned.
I want to update you on this review, the seller has now contacted me and is offering a replacement, however, the problem still stands because if the seller hadn't responded, eBay won't help so you are stuck.
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Poor DC DC charger design as well. It does not produce the rated 20A output reliably. Update on the above review after longer term use. The ATEM DC DC charger is also poorly designed in my view. Turns out that the ATEM 20A DC DC charger function doesn't work well if your vehicle has a Smart alternator. The ATEM 20A DC DC charger reduces the charge current output when the alternator voltage starts to fall below 13.8 volts. At 13.2 volts, which is a common trickle charge voltage from a Smart alternator when the headlights are on, charge current is down to 15A. At 12.8 V output from the Smart Alternator which is a MAINTENANCE voltage, charge current from the ATEM DCDC charger falls to about 10A. All charging ceases from the ATEM charger if the alternator voltage falls below 12.5V which is common when the SMART alternator turns off during a long drive. Therefore, I do not believe that this ATEM 20A DC DC charger is suited to modern vehicles with SMART alternators - which is almost all newer vehicles. Compare this with Redarc, Renogy or CTEK DC DC (and many others) chargers that can operate at full current even when the input voltage falls below 12 Volts. The ATEM unit will probably work as advertised if the SMART alternator function is disabled, or an old fashioned fixed voltage alternator set to 13.8 to 14.6V is used. Unfortunately, I wasted my money on this unit.