Inverter question

[Traveling_Teach]

Hi just got a new inverter and I like it but I was charging and my inverters display shows almost 14 volts I was at 13.9 when last checked then after few minutes went to flip on inverter to read what batteries were at and it had dropped to 13.3 is this because the trickle charger as my batteries became full or why has this drop in voltage occurred? Also when. Comparing the display to my multimeter it is usually off on the inverter by .15 or so. For example inverter reads 12.5 mm reads 12.72...thanks for any info.

[Traveling_Teach]

Gee goly there are so many scientist here I don't know who to answer first I'll stick with Chad's answer and call it good guys was a general question lol thanks tho

[time2roll]

Sounds normal and operating to specifications. What did you expect to be different?

[DiskDoctr]

What method/wiring are you using to ensure the inverter isn't running when you are connected to shore power?

How are you switching to inverter power when disconnected from shore power?

Do you use a generator? If so, same question applies to shore power/generator.

It is quite important to ensure you do not get a LOOP. For example: Shore power charges batteries, which power inverter, which makes 120V (which should never feed at the same time as shore or generator power), etc.

Since it is a new inverter and you've asked some electrical question, let us double check you to avoid any troubles?

[MEXICOWANDERER]

🙂 You might wish to program your brain to forget the words "Trickle Charge" and leave only "Float Charge" behind. The reason is "Trickle Charge" is a villain. It implies an uncontrolled small charge rate which raises hackles on anyone who suffered the consequences of it 🙂

Just an opinion 🙂

[wa8yxm]

It does indeed sound like it switched to float mode. however without additional informaiton it is hard to be sure.

[Traveling_Teach]

Oh yes and also my converter does have 3 stage and I was thinking that it was because it switched to the float trickle charge. Thanks again

[Traveling_Teach]

I have a pure sine wave 3000watt inverter I use a Progressive Dynamics mighty mini converter/ charger. This info sounds perfect and kind of backs up what I was thinking and been researching. I thank you for details and response. I was testing the multimeter on the connection terminals located on the back of the inverter. I agree with your response.

[Chad_Heiser]

Traveling Teachers wrote:
Hi just got a new inverter and I like it but I was charging and my inverters display shows almost 14 volts I was at 13.9 when last checked then after few minutes went to flip on inverter to read what batteries were at and it had dropped to 13.3 is this because the trickle charger as my batteries became full or why has this drop in voltage occurred? Also when. Comparing the display to my multimeter it is usually off on the inverter by .15 or so. For example inverter reads 12.5 mm reads 12.72...thanks for any info.

We need some more information to properly answer this question. Is your inverter also acting as your battery charger (inverter/charger), or do you have a separate converter that handles battery charging? In either case, knowing the make and model number of the equipment will help to answer your questions more precisely.

From the information you provided, it sounds as though your charger (whether it is the inverter or a converter) has a multistage charge algorithm built into it (which is good). This means it will have Bulk, Absorb and Float (and probably Equalize) settings for charging. That is most likely why you saw the difference in voltage over time, it switched from one charge setting to the next.

As for why your multimeter gives a different reading than your inverter display, this could be a few things. It could be as simple as one is calibrated more accurately than the other. It could be because one is more sensitive than the other. It could be because you are connecting your multimeter at a different location than where the inverter is taking the readings from. (There will be different voltages at different locations in your system due to line loss/overhead in your wiring.)

The most accurate way to take a voltage reading of a battery is when it is at rest and has been so for some time. In other words all loads need to be disconnected (in other words disconnect the battery cables) and let the battery sit for a while so the surface charge dissipates and you get a true resting voltage reading. Then connect your meter directly at the battery terminals, not somewhere down the line in the wiring.