UHG

[mira1]

I have 2019 zion had it out for a drive to charge up my batteries drove for
about 3/4 hour and batteries didn't come up very far from 13.1v to 13.2v
is this normal or should it been higher. Thought I read some where that you should idle around 2500 rpm for a couple of mins before UHG starts charging
is this correct? ( I did not do this) or do I have a problem.
Thanks Joe

[rowiebowie]

You might actually be fine and just need a bit longer charging time.

I'm assuming you have the lithium package, in which case 13.1 volts may only be 40-50% charged. Depending on the size of you battery pack and the ouput of your UHG, you may need a bit more time to get 90-100% charged, which should be somewhere between 13.3-13.4 volts.

[mira1]

Thanks for reply I have two banks of 200ah lithium batteries

[Davydd]

2500 rpms are highway speeds. High idle boost the rpms in the range of about 1200 on my Sprinter. It is not needed to charge my batteries. If I turn on the engine at normal idle I get charge input to my house batteries. It is just a good practice to according to MB to do so to burn off DEF particles. That’s why they supply a high idle option. Still the practice is to drive at highway speeds for a time after 2 hours of idling.

[Belzar]

How cold was it? Your batteries may not have actually started charging until heaters brought batteries up; to temp. Also, lithium draw and voltage readings are not linear: 13.2 is pretty close to "full".

[markopolo]

From halfway down the page here: Marine lithium batteries in operation | Nordkyn Design

Voltage reading Assessment Capacity

13.3V or more Near full Over 80%

Above 13.2V Plenty of reserve At least 70%

Below 13.15V Getting on the low side Less than 40%

Below 13.0V Definitely getting low Less than 25%