Sterling BB122470-12 Volts in, 24 Volts Out, 70 Amps - Pro Batt Ultra Battery to Battery Charger

UPDATED REVIEW:In retrospect, this thing is a poorly conceived hunk of dangerous plastic. I will be posting pictures later. Extremely poor heat management which the unit simply could not handle. Also inexcusable configuration for the screw terminals, making it impossible to properly torque the terminals. What could they have been thinking? I’ve now installed two Victron Orion converters (non smart) that are operating perfectly and safely — metallic units with large heat sinks that can actually handle the current. Stick to Victron, folks!Previous review:Had a bit of a hiccup when I first installed it because I needed a custom charge profile for my lifepo4 house battery -- unit seemed to want to stay in standby. For some reason, after sitting a day or two with the custom settings, it started to work again and has been working ever since. As other reviewers have mentioned, it's a very smooth install - I was very surprised that it functions so well and so safely without the need for ignition relay (although I was prepared to install one, after I observed how well it functioned without one, I decided it would be a wasted effort to install the relay). I love that the recommended diagram advised connecting the negative of my house battery to the negative/chassis ground of the vehicle starting battery -- feels like a better set up than what I had before. My only concern will be heat on hot days in the summer since the unit seems to warm up pretty quickly and is installed in a fairly confined space within my vehicle, but will need to wait to see what happens when we get to that. I will probably end up purchasing the remote display unit (not available on amazon) for around $100 -- allows shut off and reduced power control without having to dig into my electrical setup and fool around with the awkward buttons -- which brings me the biggest downside of the unit and the reason for 4 stars -- I wish it allowed for digital configuration. Configuration is definitely challenging using the combination of the two buttons and needing to hold them down for specified periods of time (found myself having to use my smartphone timer to accurately time). This would be a significant advantage of the Victron buck boost which was the alternative i considered, but about 30% more expensive and slightly less powerful but more configurable.

This unit is a total piece of crap. As an electrical design engineer with 30+ years of military, telecom and consumer product experience, it's hard to conceive how this product got past CE, the approval agency, let alone get out onto the market.Bad design decisions are numerous;1) the input screws with the highest current that need the most torque to tighten down are obstructed by a name plate,2) the programming interface and multiple function indicator lights are so poorly designed, it won't unambiguously tell you what you need to know and what state it is in, and it doesn't do what it is supposed to do much of the time. These will create incorrect settings leading to dangerous battery conditions, especially with Li Ion chemistry.3) The manual is poorly written with improper or omitted specifications (no maximum output current is specd at all, and input currents are given as a range -- from 70 to 90 Amps -- with no explanation for this variance, when in reality the minimum input current must go close to zero when a battery is fully charged), and what are the allowable mounting positions and clearances?4) There is so much non-standard English usage and incomplete sentences, along with random afterthoughts that don't follow any sort of organized paragraph structure, that I question the organization and design process of the converter itself.5) They even have the wrong URL (usa.com) for their own website printed in the instructions.6!!!) The worst offense is THEY FUSED THE COMMON NEGATIVE TERMINAL, so if the unit shorts out and blows that fuse, you still have a shorted out power converter connected between both batteries!These design defects are both dangerous and inexcusable. It is not a product I can trust. I want a complete refund.

I have purchased 2 now, and both times upon receiving the B2B charger case has been majorly broken, and clearly isn't from a shipping mishap. Terrible ethics to be sending out many clearly broken items.