Testing the two bulbs.... So is this a quarter of an amp?

This is testing a 5 watt bulb. A 7 watt bulb measured 0.42

More importantly, how did you take that picture?

The cat obviously. It's nice having an extra pair of paws around.

Well, your voltage is going to vary depending on load and charge, but

7 watts / 12 volts is not too far from .42 amps.

I'd guess that the 7 watt bulb isn't really pulling quite 7 watts for some reason and the same for the 5 watt.

Wait, how did you take a picture of your camera?

I'm hoping there's a picture showing his camera, phone, and both hands next.

One thing that continues to surprise me is how ... organic all this feels. That's probably the exact wrong word given this is electricity, but the answers don't seem to be precise. Instead, numbers vary on charges and equipment.

Kind of reminds me of baking.

The 7 watt bulb seems almost twice as bright as the 5w.

Gonzo actually did take that one.

Alright, we've finally had some sunny days. I come home and the batteries are all full. Nice ...

But I've been having difficulty figuring out when they are full. Both the small digital readout and the GZ meter say about 80%, for instance. Using a voltmeter, otoh, I get 12.6v almost exactly, if I use the multimeter to test the battery directly.

There is an anderson port on the front of the GZ, however, and when I test the voltage off THAT, I get about 12.3

What gives?

12.6 is full. but batteries after getting any kind of charge will say that 12.6 or so, as its called a surface charge. after they sit for half an hour or hour the correct charge will indicate. so take a reading when they are no longer charging. but it seems you are at full or near it.

I got up around 5 a.m. to restart the fire, and realized the batteries had been sitting idle for the night. I took another reading with the multi-meter and got 12.7.

Right now, with the sun beginning to rise (charger says it is charging) and the computer plugged in, it reads 12.47

ETA: The voltage moves around when the batteries are under any load. Ray, as you said the batteries read 12.6 if they have been getting any kind of charge--seems to work the opposite direction for load.

Alright. More battery system questions. I am considering purchasing a new inverter--I suspect the inverter built into the GZ system may be an issue.

How can I get an accurate read on battery charge? At night, with the batteries not receiving a charge or being used, I get readings around 12.7 or higher, voltage.

When I fire up the system, the GZ readout tells me I'm down around 60% capacity.

The GZ system has a DC anderson port on the front, and if I check the voltage there I get 12.2 v, and if I check one of the other batteries I get 12.7~

My typical battery load doesn't exceed 100 W--it's just computer, lights, phone. So I don't need a particularly large inverter and it's not a huge investment, but just wondering if anyone has thoughts on this, or if it has any actual impact on performance.

Right now I use the GZ for a pair of 30 W panels that use a proprietary connection, and the built-in inverter.

Thanks for everyone's help on all this. I think the size of the system is almost there, I just want to make sure it's operating as it should. The GZ system is a legacy issue I may have held onto too long, but it does serve a purpose right now.

An anderson port is just a connector, right? What does it connect to? Staight to the battery terminals? Are you reading the voltage on your meter in both cases or is there a separate meter built into the GZ?

The sun is coming up and so batteries have begun charging so the voltages/%full have all changed. The anderson port on the front has to be powered on, so I am not sure if it is a direct connection.

Dunno. Some small load inside the GZ maybe. Do you get the same voltage on the batteries if you measure across both of them instead of just one?

If I measure across the two batteries outside the GZ, yes, they show the same voltage individually and together (one probe on each battery). There is one more battery inside the unit.

After testing the two outside, I tested the anderson port again, and again got a lower voltage. As you said, probably some load inside. Just wondering if this is an urgent issue--as in the batteries performance is impacted--or more of a confusing cosmetic issue, which can be dealt with more gradually.

I'm resisting putting the GZ on ebay just because I don't want to ship it, but they go for like $600-700 on there. Still holding out for a local buyer.

okay if you test each battery with nothing hooked to it if it shows less after being charged previously then you have a weak battery.

if you have things hooked to it and its good then that stuff is drawing somehow. you have to figure out where that draw is coming from.

a battery that is still good that reads 90% after sitting for awhile without being under any load still performs. just wont last as long. no worries.

you may have just one battery that has a bad cell and it is affecting all the others. that is another reason to check each one individually after it has sat with no hookups to it.

and systems perform best if all the batteries are exactly the same kind and size and brand when used with a charging system. you can get away with different batteries but the weak ones will eventually kill the good ones.

i have no idea what your inverters or chargers are doing but would look first at your batteries especially if not new.

also measuring the voltage past the batteries is suspect as you get line draw and the readings are always low. like on my boat if i got 12.6 on a battery i will get 12.5 at the helm on the meter up there. but full voltage when it is charging.

i have two batteries on a trolling motor that work fine but after sitting for a few hours they read 85%
and 90%
but then fully charge in just a few minutes on a charger where it should take an hour or more. so who knows with older batteries.

batteries that are older say a year or two need to be equalized on a charger that has the capabilities. and also put on the recondition setting if any issues with them.

generally if the system is working fine you can go crazy trying to get it perfect.

you can try just hooking up to one battery and using it to see how it works and then try the other . but since i see you have two different batteries i suspect the weaker one is messing with your other one.

From my experience with my car - one of those whiz-bang chargers brought a battery back to life, but it took several cycles of charging/discharging. Like six or seven times.

Just remember if you go unhooking batteries to test them that if your solar panels are putting out any electricity and the charge controller isn't hooked to a battery you will fry your charge controller.

It sounds like your system is working fine. There's always going to be voltage variation within the system depending on where you test the voltage. Having your inventor turned on will create a small draw.


That is an accurate read.

yes you should or must disconnect before unhooking. and likely your system is okay if your batteries show 12.6 but if they are weak they decay quickly especially under any load. and your invertor does draw some so when hooked to it you get lower reading of the battery.

if i did anything it would be to have new batteries which can never hurt and you can add a switch to put the old ones online if you run low on juice ever.

Ray,

He just bought new batteries. He also just bought new solar panels and charge controller. That combined w/ the readings he's getting mean his system is almost certainly working fine. He's much more likely to damage something unhooking stuff to test every component than just accepting the fact that different meters read differently, he'll get vastly different readings depending on the current load. The same meter when hooked to different parts of the system also reads differently.


El,

If you truly want to understand your electrical system (loads, volts, charge rate) you need to buy a battery monitor. A handheld meter isn't going to do it.
Most charge controllers come w/ them built in. They're cheap to add, Just type "battery monitor" into Amazon and pick your poison. It'll have a shunt in it and you'll have a permanently connected digital display that will tell you the the voltage, how many amps the solar panels are putting into the system and how many amps of load you have. The better ones also tell you things like percentage of bank left, approx how many hours you have left given average draw, how long it'll take to fully charge the batteries at the current rate, etc., all w/ the push of a couple of buttons.

My current charge controller has an lcd display which I can toggle between reading voltage on the battery side, voltage on the panel side, % charged, amps currently coming in from the panels, net amps, and amps currently going out of the batteries as load.


Batteries are hard/ take a lot of effort to get "100% full". It's less important that your battery regularly gets "100% full" than never getting more than 50% depleted. Think of a battery (or battery bank) as a funnel. It takes very little to fill the bottom of a funnel but to fill the very top of a funnel takes much more. It's easy to get batteries nearly full and that's all that really matters, though you should occasionally get them completely full and equalize them by raising the voltage.

In your system the easiest way to do this would be to get them "nearly full" using your solar panels and then run your generator and hookup your new battery charger to the battery bank for a few hours every other week or once per month.