Optimal T@B 400 Battery Charging with Generator

JeffroNC

Hi,
I have been experimenting prior to our upcoming trip which will include several multi-day stays with no electricity. Some will be in shade so I want to be able to get the most bang for the buck on a 3 hour generator run. The on board converter/charger is supposedly 55A.
I ran the battery down to 80% as indicated by my Victron 712 and then plugged it in to 30A shore power to simulate running the generator. The charge rate was only 4A with no other loads and after 3 hours the state of charge was 83%. Not very good return.

Would an external charger plugged in to the generator work faster? If so, any recommendations? There are hundreds of them available.

Cbusguy

My experience has mirrored yours....except with a 320.    I would use an external charger to get a quicker charge.    Many have recommended a norco genius charger,   I purchased it based on those recommendations.   It has some odd behaviors I would never have noticed except I am ocd about my batterys.    The plus is it charges everything....the minus is when it thinks the battery if charged it cuts off and nothing you can do will change that.......

I have an old schumacher battery charger I prefer.   

rfuss928

Generally, safe charging current limits are about 10% of the batteries rated amp-hour capacity.  This rate is applicable to the "bulk" phase of charging that is usual for a battery SOC in the 50-80% range.  The "absorption" phase is usually about 1-2% of amp-hour rating and lasts for hours. 

When charging with a generator, the most efficient use of run time will result by maintaining batteries at 50-80% SOC and not trying to achieve 100%.  Charge early in the morning with the generator for bulk recovery if needed and let the solar "top off" the charge during the day.

Have fun

Bob

DougH

I didn't even know that many chargers out there including the Noco have limits on the Ah they can charge.  Since I have VMAX batteries, I like this model that goes up to 300Ah and only does 15A (though they have higher current models).  Guess I just wanted more clearly defined stages...

  https://www.amazon.com/dp/B00JH76KDI

But even VMAX states each battery in a bank should be charged standalone if you have more than one.

EDIT:  Like the Charge It! chargers too. 

JeffroNC

@rfuss928 That makes a lot of sense. I will test that out tomorrow.
Thanks