Is this normal - Battery charging.

[Tim Sparkes]

Yesterday I noticed something that I hadn't seen before. Probably because I have the drivers seat out for another job and noticed it but thought I'd check.

I had EHU connected which was powering a Victron Energy IP22 12\15. This was charging the leisure battery.

I also had a Victron Energy IP65 12/4 charging the starter battery.

Every once in a while I noticed that the IP22 stopped charging the leisure battery and at the same time the CTEK250SA DC-DC powered up indicating that the vehicle alternator was charging the leisure battery. This lasted 3 seconds max and then reverted to the IP22 charging. This cycling happens on average every minute.

My question as above. Is this normal?

 

[Nigel W]

interestingly I noticed that when I have a charger on the vehicle battery then the Sterling BtoB kickers in and it starts to charge the leisure battery. So one charger is charging two batteries.
just wonder if you disconnected the EHU If yours would do the same? If so then you have a conflict perhaps?

 

[Tim Sparkes]

interestingly I noticed that when I have a charger on the vehicle battery then the Sterling BtoB kickers in and it starts to charge the leisure battery. So one charger is charging two batteries.
just wonder if you disconnected the EHU If yours would do the same? If so then you have a conflict perhaps?

I disconnected the EHU and the CTEK doesn't seem to react. It only seems to do it when both are connected and the IP22 pauses charging to (I think) sense the state of charge.

 

[Dellmassive]

have you both got an IGN or BCM Run feed connected to the DC-DC?

Ie - DC-DC should only run when ignition etc on?


I've seen some people say that the D250SA will start DC-DC charging when the starter battery is high enough voltage (from solar) even when the IGN feed is off.

I've not had one to test myself.


Most smart chargers will stop charging and sample the battery voltage every min or so as part of the "Smart Charge" profile as well as monitor the current being drawn.


im wondering if the CTEk is reacting to a volt spike and kicking in briefly?

 

[Nigel W]

My Sterling does not have a ‘run’ signal connected so is triggered by voltage which is probably why mine works in this fashion ( handy tho).

 

[Tim Sparkes]

have you both got an IGN or BCM Run feed connected to the DC-DC?

Ie - DC-DC should only run when ignition etc on?


I've seen some people say that the D250SA will start DC-DC charging when the starter battery is high enough voltage (from solar) even when the IGN feed is off.

I've not had one to test myself.


Most smart chargers will stop charging and sample the battery voltage every min or so as part of the "Smart Charge" profile as well as monitor the current being drawn.


im wondering if the CTEk is reacting to a volt spike and kicking in briefly?

Yes the ignition feed is connected to the CTEK.

 

[Dellmassive]

just checked on the Renogy DC-DC (has an ignition feed)

same thing is happening here.

The starter is on EHU Victron 12v/15A charger, which is charging the starter battery.

The Renogy DC-DC is seeing the raised starter voltage and indicating the ALTERNATOR is running (even with IGN OFF)

The Renogy has started charging the Leisure battery.


Seems this is a feature of most modern DC-DC chargers . . . that even when they have the IGN/BCM RUN feed connected and switch off. They will startup when the starter battery voltage is high enough.


So with either EHU charger OR a solar charger connected to the tarter battery, both can be charged via the DC-DC


NO EHU, battery Low.



.

And ALT shown as OFF.




Then EHU connected to starter . . .




DC-DC now shows ALT power . . .



..

Victron shows 8A going to starter.




starter shows voltage increase. . . .




BMV shows 3.2A going to AUX battery via DC-DC . . .




and AUX battery shows a voltage increase.





Happy dayz . . . .

 

[Nigel W]

Dellmassive - you truly are a star, always so helpful and it is really appreciated

 

[Tim Sparkes]

Cheers @Dellmassive much appreciated. I have previously spoken to @travelvolts about a similar issue with the vehicle being on EHU and somebody starting the engine and hence the DC-DC and that the two chargers are smart enough to sort themselves out. I'm guessing this is the same with these two chargers?

Just wondering how the IP22 can accurately sample the Leisure battery if the DC-DC is kicking in and charging it?

 

[Tim Sparkes]

Just found this from @travelvolts

 

[Dellmassive]

Cheers @Dellmassive much appreciated. I have previously spoken to @travelvolts about a similar issue with the vehicle being on EHU and somebody starting the engine and hence the DC-DC and that the two chargers are smart enough to sort themselves out. I'm guessing this is the same with these two chargers?

Just wondering how the IP22 can accurately sample the Leisure battery if the DC-DC is kicking in and charging it?

It's the same as using a spare battery to jumpstart the van...

Imagine connecting 3x spare batteries with 3x set of jump leads to the van....

They will all have power and will equally try and charge the van or flat battery simultaneously.

Dc-dc and EHU and solar are effectively the same thing....

Just sources of power from different locations . . .. how the charge or current flows will depend on the Voltage (pressure) of each source and the resistance...... but that's getting a bit geeky.


But its correct that you cant accurately determine the SOC etc when multiple charge sources are connected as they effect each other.


But ultimately wherever the power comes from the net result will be a charged battery.

Assuming you have EHU, solar, dc-dc, etc.