Help with interpreting Victron Connect data

[Ingwe]

Our van is stored inside a hangar so the solitary 120w solar panel is of no help in topping up the two 110Ah lithium batteries. There is a Battery Master fitted and I have connected a timer so that the electric hook-up, which charges only the leisure batteries, comes on once a week, for an hour. My concern is that the voltage of the cab battery is showing today at 12.54v. The leisure batteries are13.27v which I understand remains pretty constant until they eventually drop right down.

I’ve read that it’s preferable not to store lithiums fully charged. They were fully charged when we returned from our last trip a couple of months ago but have now dropped to 89%. I’m sure that when we were travelling the reading from the cab battery was 12.7 i.e. full but now, it’s reading 12.54. This is enough to start the engine I hope, but I was wondering whether it is pointless having the lithium charged for one hour a week, when that doesn’t have the effect of fully charging the cab battery.

Would I be better off buying a smart charger like the C-tek and connecting that directly to the cab battery, with or without the timer i.e. if it’s a smart charger, can leave it on the whole time. I’m not fussing about the leisure batteries at all. i just want to ensure that, if we don’t go out in the van for a month or six weeks say, the lithiums and the Battery Master will keep the cab battery sufficiently charged.

I’ve also put screen shots of the ‘History’ function of Victron Connect and wonder if it’s possible to tell, from the data, when and how much current is added to the leisure batteries during the one hour per week hook up.

Thanks.

 

[ChrisL]

The shunt says you've consumed 31ah if this number is decreasing then all should be good, if not and its increasing then your charging regime is not sufficient to keep both batteries topped up. Can you increase the duration and or the frequency of the active charger period?

 

[Ingwe]

The shunt says you've consumed 31ah if this number is decreasing then all should be good, if not and its increasing then your charging regime is not sufficient to keep both batteries topped up. Can you increase the duration and or the frequency of the active charger period?

Thank you very much for the reply ChrisL

It is easy to change the timer to increase the length of each charging period or have several charging periods for any duration I choose.
So should I check next week and see if the last discharge is less than 31ah (should this not be 32ah from the data?). If it is more than 32ah I should increase the charging regime either or both of duration and frequency?
Just trying to get my head round it all.

 

[AdrianChen]

Your start battery is still pretty full I think, not far off 90%, so the regime you have seems to be working - From memory LA batteries start to get more sulphation when stored under 12.4v, so it's nice to keep them above that if possible.

Given you are using a battery master, that "charges" when the two are 0.8v different, the Lithiums at 13.27 will still be connected to/charging the start battery and keeping it well charged so I doubt it will fail to start the engine for a while yet.

From what you've said in a couple of months you seem to have lost about 10% SOC from your cab and hab batteries so you could perhaps go to 1.5hrs on the timer and see what happens.

I personally don't think I would worry if the Hab batts charge back into the 90's since there is a constant draw on them, and even if there is some degredation, they will probably outlast your ownership of the van!

The only thing that may happen is if the weather gets cold enough for the leisure batteries to turn off charging, usually around 5°c, then you might miss a recharge or two - in which case they will drop down a bit more - but will still be keeping the cab battery in a good enough state to start the van. But I would be inclined to check more frequently if we get a real cold spell

 

[ChrisL]

Thank you very much for the reply ChrisL

It is easy to change the timer to increase the length of each charging period or have several charging periods for any duration I choose.
So should I check next week and see if the last discharge is less than 31ah (should this not be 32ah from the data?). If it is more than 32ah I should increase the charging regime either or both of duration and frequency?
Just trying to get my head round it all.

I would definitely check next week after a charging session and then again just before the next charging session that would show if you're running at a deficit or not and how many ahs you are consuming then it would be a case of increasing duration or frequency until you're putting in as much as your using.

^{_{Subscribers  do not see these advertisements}}