EHU and low battery reading

[lunno]

Hi all,

Please could I get some advice on the battery volt reading and EHU.

We are away in Switzerland at the minute and we are on EHU and the smart charger is on but the voltage reading on the dashboard keeps getting low down to 11.2, even on hook up. This is especially the case when the fridge and sockets are being used. It is as though the EHU isnt getting used for the fridge, sockets etc and its just using the battery charge.

Voltage seems fine when driving even when the fridge is being used.

We have a Maypole smart charger. A couple of images are attached this is when the fridge isnt being powered as its already at temperature. Thanks in advance

David

 

[kipperman]

EHU seems to be fine on the basis that 1) the sockets are working and 2) the charger is working. Assuming no inverter, the (three pin) sockets are quite independent of the 12V system. Smart charger seems to be indicating a satisfactory voltage ( connected to your leisure battery)

So a couple of questions

1) despite the voltage reading, are you actually having problems ( fridge cutting out etc)?
2) have you found and checked any fuses ( these will be the car type fuses)?

Definitely odd that the charger is indicating 14.2V whilst your voltmeter on the panel is indicating something different. Not beyond impossible that one of them is an inaccurate reading. If there is a heavy load on the 12V system, a 4A charger is not man enough to not only power any 12V equipment (lights and fridge) but also to charge the battery.

Is this a new van to you?

 

[64 SPLIT]

I suspect the reason your meter is showing 11.2V etc is because your pulling power from the battery at the same time - probably more than the smart charger is putting in. I notice it's only a 4A charger which is quite small so will take a looong time (24hrs +) to recharge a reasonable size leisure battery.
To get a true SOC reading from the leisure battery you'd need a shunt fitting to the battery. If you switch everything off, your voltmeter should jump back up.
Do you have the option to switch your fridge across to 240V so it's using the EHU rather than pulling from the leisure battery 12V? This would allow your leisure battery chance to recharge.

 

[lunno]

I suspect the reason your meter is showing 11.2V etc is because your pulling power from the battery at the same time - probably more than the smart charger is putting in. I notice it's only a 4A charger which is quite small so will take a looong time (24hrs +) to recharge a reasonable size leisure battery.
To get a true SOC reading from the leisure battery you'd need a shunt fitting to the battery. If you switch everything off, your voltmeter should jump back up.
Do you have the option to switch your fridge across to 240V so it's using the EHU rather than pulling from the leisure battery 12V? This would allow your leisure battery chance to recharge.

Thanks for the quick reply. In the long term, to allow me to charge everything and not run the battery down would you suggest a better charger?


Thats correct when everything is off it jumps to around 12.4/5


Would this setting be on the fridge or would it be located where it is wired in and something I would need to re wire? I think it all runs through the battery. I could probably do this when we return to the UK.


Whilst we are away, do you think it is just a case lf managing our power usage. Charge when driving and fridge is off?


Thanks for your help!!

 

[lunno]

I suspect the reason your meter is showing 11.2V etc is because your pulling power from the battery at the same time - probably more than the smart charger is putting in. I notice it's only a 4A charger which is quite small so will take a looong time (24hrs +) to recharge a reasonable size leisure battery.
To get a true SOC reading from the leisure battery you'd need a shunt fitting to the battery. If you switch everything off, your voltmeter should jump back up.
Do you have the option to switch your fridge across to 240V so it's using the EHU rather than pulling from the leisure battery 12V? This would allow your leisure battery chance to recharge.

Thanks for getting back to me.


No issues with anything cutting out, just concerened if the battery gets too low we will lose all power. We are away fo 2 weeks.


I will have a check of the fuses, but I though kf everything is working it should be ok? Thanks for the suggestion I will check them.


After 15-30 mins the voltages read very similar. Seems like the smart charger settles down and turns green after been plugged in for 15.


I have had the van 18months. Voltage read a lot higher previously, 13.1+ and still does when driving. Noticed after 24 hours of charge at home it got stuck at 12.9. That was just before we came


Thanks again.

 

[kipperman]

I think you are probably OK - but just be cautious with 12V loading - so be a bit anal about only opening the fridge for as brief a moment as possible. When you get back home, I would be swapping that charger out for something more powerful. Victron are generally the go to brand IMO, but perhaps ask for further advice when you are in that position.

Other thing to consider is how good your leisure battery is - they do age with time and a poor LB will drop its voltage pretty quickly under load.

 

[DXX]

You haven’t mentioned which model of fridge is installed but a fairly common installation CRX50 draws 40W.
Your EHU charger is barely supplying this so with all the wiring / device DC resistance losses and 33 deg C (Zurich temp’ now) I’d say that your charger installation is not up to the job.
Unless you are planning on replacing your leisure battery I’d be very careful not to run it down below 50% SOC or it will de damaged beyond repair.
Ideally you should have solar to back up and assist the EHU.

 

[lunno]

I think you are probably OK - but just be cautious with 12V loading - so be a bit anal about only opening the fridge for as brief a moment as possible. When you get back home, I would be swapping that charger out for something more powerful. Victron are generally the go to brand IMO, but perhaps ask for further advice when you are in that position.

Other thing to consider is how good your leisure battery is - they do age with time and a poor LB will drop its voltage pretty quickly under load.

Great thanks will do. I will change the charger when we get back. And do a battery health check to see how its looking.

Thanks again, always impressed with the help and speed people offer it on this forum.

 

[lunno]

I think you are probably OK - but just be cautious with 12V loading - so be a bit anal about only opening the fridge for as brief a moment as possible. When you get back home, I would be swapping that charger out for something more powerful. Victron are generally the go to brand IMO, but perhaps ask for further advice when you are in that position.

Other thing to consider is how good your leisure battery is - they do age with time and a poor LB will drop its voltage pretty quickly under load.

Great thanks will do. I will change the charger when we get back. And do a battery health check to see how its looking.

Thanks again, always impressed with the help and speed people offer it

You haven’t mentioned which model of fridge is installed but a fairly common installation CRX50 draws 40W.
Your EHU charger is barely supplying this so with all the wiring / device DC resistance losses and 33 deg C (Zurich temp’ now) I’d say that your charger installation is not up to the job.
Unless you are planning on replacing your leisure battery I’d be very careful not to run it down below 50% SOC or it will de damaged beyond repair.
Ideally you should have solar to back up and assist the EHU.

Thanks yes that the model we have. We considered solar panels but managed fine for 10 days in france last year so assumed it was all ok with the appliance we use.