Renogy DC to DC Charger 12V 20A - Multi-Stage Charger for LiFePO4, AGM, Gel, Flooded Batteries | Car, RV, Marine & Boat Battery Charger with Bluetooth Compatibility

Updated review - I made a mistake. I have a parasitic load on my system but it's not this DC DC charger. I pulled the charger out of the system and still had the same discharging of my batteries I was attributing to this charger. Adding the charger back into the system and no detectable difference to this discharge rate. This charger works great and it's easy to set up and modify the charging parameters through the app; which I really appreciate. Easy to set it up so it keeps my LiFePO4 house batteries at ~80% while my boat sits during the week. ---- old review ---- Charger works as advertised but there is a much larger than anticipated parasitic load when not charging. I estimate it to be about 1 amp. Drained a 100Ah AGM dual purpose battery from 12.7 to 12.0V in ~48 hours. Anyone else experiencing this? Is there a fix (softwear or otherwise)? This charger isn't useful for marine applications where there are often days to weeks between motor use with this magnitude parasitic load.

Excellent product. Installed it in my boat to keep my electronics battery charged while on the water

Works as advertised. According to the bluetooth, that you have to purchase separately, the charger is putting out 20amps. Installation is easy.

I purchased this Renogy REGO 12V 20A DC-DC charger (RBC20D1U) in May 2025, and it has been a nightmare. This is actually my SECOND unit, as the first one failed completely and Renogy made me jump through endless troubleshooting hoops to get a replacement. Now, the replacement has failed in a way that is incredibly dangerous. The internal isolation components inside this charger completely failed and allowed massive BACK-FEEDING from my house battery bank straight back into my vehicle's starter battery and alternator system. It began severely overcharging my vehicle's electrical system while the engine was running, spiking the voltage and nearly causing catastrophic damage to my vehicle's computers and wiring harness. This is a severe fire and safety hazard. When you try to get a warranty resolution, customer service forces you right back into a script of repetitive tech-support loops instead of honoring their warranty. If you value your vehicle's electronics and safety, avoid this charger. I am demanding a full refund.

Works good, also got the BL2 bluetooth interface (cool that they give you a lower price option in case you don't need BT). The instructions are good (Made in USA), app works good, the until has lots of charge profiles and even current limiting. My only disappointment was that you can only choose from 10A increments for the current limiter. We get 10, 20, 30 and 40 and well I need 25... ohh well