EasySolar 24/1600 is not charging batteries properly

DIY
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1

Hello,

I’m new here and a beginner in this area, and I have a problem with my EasySolar 24/1600.

This system is operated as an off-grid installation in a garden shed. The batteries consist of two sets, each containing two lorry batteries. The whole system was installed around 5–6 years ago by an electrician who, unfortunately, can no longer be contacted because he went bankrupt.

I noticed 1–2 weeks ago that the alarm LED kept flashing from time to time. Since the system would then return to normal operation again and again, I didn’t think much of it. A few weeks earlier, I had already noticed that the batteries were not fully charged. Normally, they are fully charged every day, and all three stages (Bulk, Absorption and Float) are shown in the app.

However, when I arrived at the shed on Friday, the fridge was already relatively warm. The alarm light was flashing, so I restarted the EasySolar. After that, the inverter would no longer start and the power was completely off. As I didn’t have time, I left everything as it was. When I came to the shed yesterday, the power was available again. The batteries were just over 22V (when everything was working, the voltage rose to just over 28V) and, as on the previous days, the alarm LED flashed from time to time.

In general, it isn’t any warmer in the shed than it was in previous years, when everything was still working correctly.

Do you have any idea what could be causing this? Could it be the built-in MPPT 100/50, or the unit responsible for charging? Can anyone make sense of the log that can be created with the app?

I don’t want to buy the MPPT on suspicion, even though that would be the cheaper option, nor do I want to replace the entire device if there is a simple, less expensive solution.

I’d be very grateful for any help or advice!

Best regards,

Raimund

2

Hello @MiniR

Please read the voltages from the installed SmartSolar 100/50 50A using the VictronConnect mobile app. The voltage of the solar array in particular is of interest.
Alternatively, measure it at the input with a multimeter.

Please write again, in more detail, what type of batteries have been installed.

3

Hello Dirk,

Thanks for the quick reply. Unfortunately, my responses may be delayed, as I’m not always at the installation and can’t retrieve anything remotely.

Basically, I hadn’t noticed anything unusual about the voltages, but I’ll take screenshots. Can I measure these at the PV terminals on the MPPT with the meter? Do you mean this voltage?

4

From a distance, and with the limited clarity of my crystal ball, I’d suspect insufficient PV input power or faulty batteries… but those are just guesses… we’ll start right at the beginning… the PV section…

In VictronConnect, also have a look under the gear icon and Battery to see what voltages are set there.

What skills and measuring equipment do you have available? Could someone perhaps assist you with troubleshooting?

5

My wife is currently on site and testing it for me. She measured 26–28 V at the PV input when the alarm LED wasn’t flashing, and up to around 30 V when it was flashing.

We’re now also trying to get her to install the app and retrieve the required data. I hope it works!

6

Hello Raimund, that’s not enough voltage…what type of PV panels do you have connected, and how many?

7

It’s currently cloudy here. In sunny weather, I can see in the app that it charges at around 500–650 W. I don’t think it takes in any more than that.

There are three panels. Exactly which ones, I really couldn’t say. I commissioned the installation back then, and I’ve been happy with it so far. They certainly weren’t the latest generation at the time!

I believe I was told that they were designed for 48 V, and that the system was therefore set up as a 24 V installation to provide some reserve.

Should I clean the panels, or could it not be caused by that? Could one of the modules possibly be faulty?

8

Please get someone with electrical and solar expertise to help if you don’t feel confident handling this yourself!

For the solar charge controller to start, you need the battery voltage plus 5 V; once it has started, +1 V is sufficient.

Assuming your batteries are at 28.8 V, you therefore need at least 33.8 V for a reliable start—which you don’t have.

Do you have any documentation for the system?

I would suggest disconnecting the solar panels and measuring the open-circuit voltage.

I would also suggest switching off the EasySolar until the fault has been found, so that you don’t ruin the batteries through deep discharge.

See the first sentence:
Please get someone with electrical and solar expertise to help if you don’t feel confident handling this yourself!

9

I have now also received the battery types.

2x Varta N5 ProMotive Heavy Duty 12V 220Ah (720 018 115 A74 2)

and

2x Varta N9 ProMotive Super Heavy Duty 12V 225 Ah (725 103 115 A72 2)

My wife noticed that the first two mentioned are warm, while the other two are cold!?

10

Mixing different batteries in a set isn’t a great idea.
Balancers are also beneficial, but 5 or 6 years on a set of pb batteries is a good run, longer than many get - depending on how they are treated, of course.

11

I’m reasonably comfortable with electrical work. And when I reach my limits, I have a friend who can help me who is a trained electrician, although he isn’t specifically experienced with PV systems.

I’ll manage to measure the open-circuit voltage. I’ll climb onto the roof once and measure it from each module individually. I assume that’s what you meant by individually. I could measure all three together by disconnecting the plugs at the EasySolar.

I can also take a look at the cables while I’m up there to see whether I notice anything unusual, such as animal bites or anything similar.

And don’t worry! I’m not the kind of person who just starts working if I’m not sure I’m doing it correctly! I value my life too much for that! Especially when it comes to electricity. And DC shouldn’t be underestimated, despite what many laypeople think.

12

Hello Raimund,

Those are lorry starter batteries and are not suitable for solar applications.
Solar batteries are designed for deeper discharge, whereas starter batteries are designed to provide high starting power without being deeply discharged. But lead-acid batteries are actually completely outdated now that affordable lithium batteries are available.

I can’t tell from a distance whether this is problem A or problem B.

The batteries would also need to be checked individually… do you have mains power available anywhere?

Victron has plenty of documentation for each device (which usually isn’t read).

13

Please find out whether the PV panels are connected in series or in parallel.

The technical specifications are usually on the back of the panels :wink:

In addition to measuring the open-circuit voltage, you can also measure the short-circuit current (it’s listed on the nameplate).

14

I had questioned that as well because of the lorry batteries. These were recommended to me when the system was installed. He said that they would be sufficient for my application. I then did some research on forums, and there were quite a few positive experiences with lorry or car batteries. In fact, there was not really much negative feedback. Of course, there was a huge difference in price.

In any case, I’ll measure the open-circuit voltage of the individual panels and observe what it looks like when the sun is shining.

I’ll also disconnect the batteries, charge them and measure the SoH value. It’s possible that one of the batteries is faulty and causing the problem.

And as @Nick writes, I’ll test the whole thing using only two batteries and without mixing the types.

15

If I remember correctly, he said that they are connected in series. I’ll only be able to say for certain once I’ve been up on the roof.

I can measure the short-circuit current while I’m there, of course. I’ll also take a photo of the nameplate while I’m up on the roof.

Thanks for your help for now! I’ll get back to you once I have the measurement data or have found out more about the batteries.

16

For more background, just Google

“checking solar panels”

17

I should be able to check the solar panels. First the voltage, and then the current during a short circuit.

My wife has managed to sort out the app in the meantime. Under the gear icon – Battery, it is set to 24 V. The expert mode, which allows you to set the voltages for Bulk, Absorption and Float, is probably disabled, as it is greyed out and cannot be changed.

According to the app, it is currently charging at around 33 V and 240 W in cloudy conditions.

Are there any recommendations for batteries I could buy as replacements? Initially, I had the 225 Ah ones. I got the other two cheaply and connected them as additional batteries. They weren’t strictly necessary. I thought it couldn’t hurt to have a bit more storage capacity.

18

If you want to switch to lithium, then the only 24 V Pylontech batteries I know of are those, or the ones made by Victron themselves. But I’m sure other people here on the forum can suggest further manufacturers.
This would require some additional planning and hardware as well (a Cerbo for CAN bus communication).
Another issue is that it gets cold in the garden shed in winter, and the batteries may no longer be able to charge at temperatures around 0°C and below.

19

Quick update: I did go up to the roof and inspected the panels themselves and the cables. As I didn’t have a meter with me, I couldn’t take any measurements. They are connected in parallel. So the voltage, at up to 35V, should be OK too. I measured the batteries. I’m now fairly certain that the batteries are the problem! They’re no longer well balanced with each other :frowning:!

Can’t I switch to lithium that easily? Is a Cerbo absolutely necessary then? You’re of course right about the 0°C! That wasn’t a problem with the lorry batteries, though. Does it no longer work below 0°C with lithium? Sorry for all the questions, but I haven’t given any thought to things like this until now!