Weird voltage spikes with Solar and CTEK D250se

[Indigrey]

Hi all,

I have installed a leisure battery with CTEK D250se and have added a 120w folding solar panel input into the CTEK. I am running a Dometic CFX3-45 compressor fridge. All appears to be working great but when the solar is connected, the monitoring log shows some weird voltage spikes every now and then which are always 36.96v. Obviously this shouldn't really be possible with the ctek controlling the charging.

I don't get the spikes when just running without solar.

The panel is wired into the CTEK with the positive to the solar input and negative to the common ground on the CTEK.

Any ideas what's causing the spikes? Should I be concerned?

I've included some logs to show it. Where the spikes go off the chart, they are 36.96v

 

[Pauly]

That sounds a bit weird, if you are monitoring the leisure battery voltage (ie the ctek output) then its possible you have a faulty unit ?
My 250 had a faulty solar side and i ended up having to return it and got it replaced, might be worth shooting ctek an email and pointing out your issue and see what they say ?

Dont think i would want to run with the solar connected too much as your battery is not going to like that voltage very much, i would imagine its only momentary but best to be safe than sorry

 

[Pauly]

Looking at the middle log it also shows quite a high charging voltage mid to late afternoon, seems a bit too close to 15V ?

Can you clarify what battery you are running, i assume its AGM and you have the black flylead shorted to negative to increase the voltage but even so that s seems a bit higher than it should be ?

 

[Indigrey]

My battery is a Yuasa Active Leisure Battery L36-AGM, 95Ah, and the AGM wire is grounded for the CTEK.

The rise in the middle log was when the solar panel was in full sun and it reached its peak at 14.59v

It's continued to behave again OK today without the solar connected so I'd agree there's probably something going on with the solar control side on the CTEK, as the monitor seems to work OK and it's fine when charging off the alternator too.

I'll send them an email and see what they say, will report back when I get a response!

Thanks

 

[Salty Spuds]

What’s the maximum VOC of your solar? Iirc the Ctek can only take upto about 23v max.

 

[Indigrey]

Rated power: 120W
Open circuit voltage: 21.6V
Maximum voltage: 18V
Maximum current: 6.67A

 

[Indigrey]

Just measured it at 22.5v though and it's slightly cloudy so it may have gone over 23?

 

[Salty Spuds]

Rated power: 120W
Open circuit voltage: 21.6V
Maximum voltage: 18V
Maximum current: 6.67A

That shouldn’t be the problem then

 

[Salty Spuds]

Just measured it at 22.5v though and it's slightly cloudy so it may have gone over 23?

It’s deffo 23V max for the Ctek, it’s a bit worrying that the panel is already over it’s max stated voltage even on a cloudy day.

 

[Pauly]

Double check all the specs of your panel output vs ctek input

Not sure how the ctek would behave receiving over voltage ?

 

[mmi]

Where the spikes go off the chart, they are 36.96v

If all the spikes have exactly the same value - I'd say it's the monitor (it is BM2?) creating ghosts. Have you tried to reboot the monitor - disconnect it for a minute? You don't have another - to connect in parallel?

Just searched through my BM2 logs and indeed the value "36.96" can be found every now and then. I don't have any charger - just plain van - the sample below is from starter battery.

 

[Indigrey]

It is bm2, that's interesting that you're getting the same random spikes, I do think my panel is capable of over 23v though so I might get a different controller or reduce the voc of the panel. I haven't tried resetting, but as it only does it when solar is connected, I'm convinced that's where the problem lies in my setup

 

[Pauly]

If all the spikes have exactly the same value - I'd say it's the monitor (it is BM2?) creating ghosts. Have you tried to reboot the monitor - disconnect it for a minute? You don't have another - to connect in parallel?

Just searched through my BM2 logs and indeed the value "36.96" can be found every now and then. I don't have any charger - just plain van - the sample below is from starter battery.
View attachment 128515

That’s interesting

Anyone else ?

 

[Indigrey]

Just ordered a couple more battery monitors and noticed the spec says this...

Compatible with all 12-volt vehicle batteries;
Voltage: 9-16V

So in theory it shouldn't even be able to read 36.96v as that's way above its working limit

 

[Dellmassive]

I've noticed this over the last week.

i think its a glitch in the new APP version.

my blips seem to coincide with me checking the BM2 APP and getting a sync and updated.

I've has the same blips with my battery pack all week.

they have added the 1/7/15day view modes in the APP now.

here is my plot from this week.

 

[mmi]

Perhaps also an £30 "investment" in a multimeter having peak min/max function. Extremely useful as the solar panel gets older

 

[Dellmassive]

it looks like to me that every time i manually open the BM2 APP to check the status it loggs a BLIP.>>?

 

[Dellmassive]

its defo not the battery or setup.

its the APP . . . as the BM2 FW has not been updated.

but the APP version has.

im showing

APP Version 3.4.1 - Android Phone OS


++++

I've submitted a "data Abnormal" Feedback request visa the APP Help menu.


.

 

[Indigrey]

Mines the same version, but strange how mine hasn't done it at all today, its only done it with the solar panel connected. Is yours doing it without a solar input?

 

[Dellmassive]

umm . . . yes , well I've had solar connect all week.

via a Victron 75/15 mppt controller.

its on a Lithium battery.