Absorption setting

[donkey]

Hi Guys

Any of you electrical guys any advice please.

I have a Swift PVC fitted with Sargent EC400 series.

I have a pair of AGM (sorry Lenny) batteries in parallel for leisure and a wet lead acid for vehicle battery.

I have 180w of solar and a Victron 100/15 controller

The EC400 gives me the choice of solar to Smart, Leisure or Vehicle battery

In Smart mode it monitors both batteries and delivers the solar according to SOC of batteries.

Now my query is about the best setting for the absorption phase, I am happy with having the float at 13.6v, as that is ok for both types of battery.

Should I keep absorption down to 14.4v, which will somewhat undercharge the AGM or whack it up to 14.7v which the lead acid may not like too much. Or somewhere in the middle?

Geoff

 

[berni109]

I would not be over charging the vehicle battery but if u do and bu99er it it's the cheapest to replace.
https://batteryuniversity.com/
This site is a mine of info for anything battery related hth.

 

[donkey]

Hi Berni

I have already waded through their pages plus various others. I was after a gut feeling from 'OUR' experts.

Looking at data, it appears as though a little higher on the lead acid is not a bad thing as long as it does not go high enough for gasing. But too low on the AGMs over a period apparently gives them a low capacity memory, not unlike Ni-cad cells.

At the moment I have it set at 14.55v and from time to time I will take the AGMs to 14.7 for a while.

Geoff

 

[Insider]

I have a Forte and EC400 with the same function and a Victron 75/15 and I've disabled the Smart charging and use a battery master to keep the vehicle battery topped up. I actually turn off the Sargent system(which causes it to only charge the leisure batteries) as the current draw from it on is quite high. Long term I want to take it out of the equation as it lengthens the cable run from the solar to the batteries therefore dropping the voltage and from memory I think the sargent is limited to max 150W not that I am near that but I do plan on adding more solar. If you take a similar approach then you get to choose the exact setting on your Victron

 

[Lenny HB]

I have a pair of AGM (sorry Lenny) batteries in parallel for leisure and a wet lead acid for vehicle battery.

We you know my answer, dump the AGM's.

The feed to the starter battery is a low current trickle charge and the absorption phase will only be an hour or two (I don't know much about Sargent units) so probably best to set the charger for the crap AGM batteries.

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[donkey]

Hi Lenny
The Sargent unit actually monitors both batteries and totally switches all charge to the one in most need. it checks back every four hours and then decides to switch back over or leave it as-is.
By the way the reason I have a pair of AGMs is because a couple of months ago I obtained a couple of mobility scooters and with some swapping around ended up with two new 95ah AGMs. They actually replaced the original (11 year old) AGM.
I do think that to slightly overcharge the lead acid will be better than undercharging the AGM.
None of this will be an issue when we re-start to use the vehicle, as I will be there to monitor and change the charging regimes as needed.

Geoff

PS. The first trip out is to Patcham as we have a family commitment to attend to.

 

[Lenny HB]

The Sargent unit actually monitors both batteries and totally switches all charge to the one in most need. it checks back every four hours and then decides to switch back over or leave it as-is.

Doesn't sound very good for either battery if the charge cycle starts each time.
Max charge voltage on battery's can vary a bit between manufacturers the normal recommended max it 14.4v.
On a normal system system where the starter battery is only fed a trickle charge constantly, the starter battery will only see the 14.7v for a few hours and then it will drop to the float voltage.
I think I would go for the correct AGM setting as undercharging them does appear to shorten their life. You could connect the van via a timer so the just gets power 12 hours or so once a week that would reduce the 4 hour swap problem.

Which Patcham north Brighton or the village near Worthing?

 

[donkey]

I was a little surprised to find the Victron did not change out of float when the Sargent changed battery priority. I was expecting it to revert to Bulk each time.

The Patcham North of Brighton, I forgot about the other one.