Community Forums

iluvuk · 03-25-2019, 11:06 PM

Ok, so new problem cropped up this weekend. On shore power magnum inverter/charger charges batteries just fine up to 13.5 v or more. Does the bulk charge, then float etc.
However, new problem has arisen when boondocking. I got low battery voltage after a day and a half so I started my generator like I have done many times before. Passthrough AC works fine from Genset to all outlets; it says passthrough on display so it is not inverting. However, the batteries get minimal charge. Charge display says "Bulk" charging but voltage is only about 12.2v....and erratic. Doesn't charge batteries even to 12.3v after 2 hours. thought I had a bad battery draining current but hooked up to shore power and boom, bulk charge worked fine and up to 13.4v so far. Also, note that driving allows full charge of the batteries up to 13.4v.

So, in short, charger from Magnum inverter/charger works on shore power but is erratic and much lower voltage when on Gen set. Yet, Gen set seems to provide plenty of AC to all outlets. Why am I not charging batteries more than just a minimal low voltage (12.2 v or so) on gen set??? Do you think I have a loose connection from the Gen set to the magnum or??? Any ideas?

twinboat · 03-26-2019, 06:03 AM

First test is the voltage output of the generator. Check at the main 50 amp breaker in the panel, while generator is running under load.

Also check that the inverter/charger isn't set to a very low load sharing setting. If set to 5 amps or something like that, it could cut back the charging when other things are drawing current.

iluvuk · 03-26-2019, 10:26 AM

Quote:

Originally Posted by twinboat

First test is the voltage output of the generator. Check at the main 50 amp breaker in the panel, while generator is running under load.

Also check that the inverter/charger isn't set to a very low load sharing setting. If set to 5 amps or something like that, it could cut back the charging when other things are drawing current.

I will try to find time to go out and check it more closely. In thinking about this, the load sharing setting is the same whether on genset or on shore power and it works fine on shore power. Would the load sharing be a potential issue if the batteries charge just fine on shore power?

I have RV connected to a 15amp outlet via adapter at home just for charging and it works great. So I know 15amp current is sufficient to run that charger in all modes (it has gone through cycles and I have seen Bulk and absorption, etc.).

The other big mystery is why I got so little voltage when gen set was running (12.2v) on the charger DC volts yet all AC outlets were working fine? Plus it seemed like DC voltage was erratic on genset...not steady.