Battery charging - how full do you charge yours?

[Guy]

Evening all,

As a percentage how full are people charging their leisure batteries? I have installed a Fogstar Drift today and on powering on the built in app showed the battery at 48% so i have been happily charging via the solar most of the day. I assumed batteries get charged to 100% but having read some of the tech spec on the app it suggests on charging to 30-50% of capacity which I was a little surprised to read.

Are people really only charging to 50% capacity?

 

[rod_vw]

We have Roamer 230Ah lithium charged by one (or all) of the following, Victron XS 50A, Victron Solar with 200W on the roof, Victron 15A mains charger all set to charge to 100%. AbleMail ATM 12-2 draws a little every night so when only the solar is available i.e. parked out of use about 1% is drawn off in the dark hours replenished during the day at this time of year.
My Victron units are set-up as per Roamer's website, Set-up Guides

Fogstar no doubt have similar advice on their website to match the characteristics of their batteries. Knowledge Hub

 

[Lebowski]

My self built 184Ah (24V) household battery is charged to 100% by

1: Pekaway s40 solar charger using 4x 200Wp Craig Solar panels

2: 2x Victron XS1400 set to +-40A each

3: maybe shore power based of a Victron 3000/24/50 invertor. Maybe meaning the invertor will be integrated into the system but EHU might not.

Reason: my van is built for off-grid use and the chances are extremely low I'll ever use an EHU.

1 is active, 2 and 3 will be connected later this year and my system is active since approximately May 2026 and is expanded in phases (money and time are constraints). It will also get an Ablemail 12-2 starter battery top-off charger to profit from the massive household battery as opposed to using a small second solar panel as a separate system.

The Pekaway Core Pro (will buy around October) will send the ATC signal to the XS1400, my system relies on solar from March through September, the XS1400 needn't do anything when it's sunny outside. I will also include the 'engine running' signal from the vehicle ECU to not start the XS1400's while the engine is off. The XS1400 puts a load on the vehicle electric system requesting the alternator to stay on.

 

[Raul a/3]

It will also get an Ablemail 12-2 starter battery top-off charger to profit from the massive household battery as opposed to using a small second solar panel as a separate system.

Is there a 24/12 model? I'm using an isolated orion 24/12-9 for that at present.

 

[Lebowski]

I'm using the 12-12 and will probably add a separate stepdown to get to 12,5V IF I decide to keep my secondary 12V circuit at 12,4 or less.
My vehicle has a 24V circuit as primary with most of the power hungry consumers on it, the secondary has only 3 fans and a toilet on it, and the Ablemail after I've included it into the electrical system.

 

[Lebowski]

Source: AMT12-2 Trickle Charger charges Vehicle Battery from Leisure Battery with Solar Charger /Mains Hookup or only a Secondary Battery - Ablemail Electronics

 

[Lebowski]

I just performed a bench test and it works like a charm, if you're in the opportunity to buy an Ablemail 12-12 I'd do it.

Hooked it up to my power supply and played around with 12,40 down to 11,01 Volts on the starter battery voltage and then you see it switches itself on automatically. It can be overridden manually in the App over BlueTooth to set it on/off, this is one cool toy as it's afaik the only trickle charger that can be set for AGM/Lead-acid batteries, as the regular Votronic and Victron LiFePo4 invertors also have a trickle charger function BUT this is suited for LiFePo4 only as the device has only ONE charging profile and as you know, the charging profiles for LiFePo4 and AGM/Lead-acid are not the same.

Note: there was no connector on the household battery terminal and this could be a 'bug' in the Ablemail software as it provides the same voltage in the App as if it were connected to a household battery. Normally, in-vehicle, this situation would never happen as you always have two connectors from two separate batteries connected.

 

[Raul a/3]

I thought you have a 24V habitation battery.
That's the reason I asked about 12/24, I also changed the habitation to 24V. Currently charging the starter via a 24/12 orion.

 

[Lebowski]

You are right. I have a 24V household battery and I've just updated the settings to reflect that.

 

[Lebowski]

Household battery minimum Voltage to start charging the Starter battery is set to 28,39V. Will change down to reflect real world conditions later, first I'll need to put it into the vehicle but want to combine this with putting an Audrio seat swivel under the seat and placing two Victron XS1400 DCDC chargers as the seat needs to come out and it's heavy, I only want to handle it once.

The Ablemail is set to programme 4 (default) and may change that to setting 8 to reflect higher parasitic drain from the starter battery if the starter battery is draining faster than expected.

In February I was in Andorra and after 4 days my starter battery was flat as I did not have a household battery yet and I used the two top lights in the cabin and the four top lights in the rear, that caused the starter battery to go flat so quick.
Now I have a household battery and run the lights off that, and a dashcam will also be connected to the household battery to prevent parasitic drain and to prevent the dealership from cutting the video feed when servicing the vehicle. Will probably buy a cam with locked power connectors for that reason.

The goal is to NEVER have an empty starter battery during the normal conditions of the battery, not counting when the SoH is so bad it needs to be replaced with a new battery.

Note: In previous posts I named the Ablemail 12-12 but the correct name is 12-2

 

[rod_vw]

Hi @Lebowski as you know I've has a Ablemail 12-2 installed for a good while now and it functions perfectly.

Regarding the Lithium battery problem that I had when I saw you earlier in the summer, that is all fixed now. The battery has been back to the manufacturers where they found a fault (not software) in the BMS and have repaired / changed it, that was all done within the day. I dropped it into them at about 9:30am and had a phone call at lunch time to say that it was all repaired and I could collect it. Excellent service from Roamer!
We are back across (under) the English Channel next Wednesday for another wander in Europe.

I guess you will be trying those wiring looms when you fit the seat swivel, please give me some feedback on that.

For those hoping to fit R&J double seat swivels to post 2023 LHD Crafters/TGEs there should be a resolution to the wiring loom problem available soon, watch the R&J website or contact them.