Anyone else using a Victron SmartSolar with a leisure battery bank on a static setup — what's your absorption voltage set to?

I've had my 200Ah AGM bank (two 100Ah batteries in parallel) running off a 400W panel array through a Victron SmartSolar MPPT 100/30 for about eight months now. Set it up following Victron's default profile for AGM, so absorption is sitting at 14.7V and float at 13.8V. Batteries seem healthy enough but I've been reading conflicting things about whether that absorption voltage is on the high side for AGMs in a UK climate where they rarely get fully discharged.

The thing is, I'm not cycling these particularly hard — it's a static shepherd's hut setup, mostly running LED lighting, a 12V compressor fridge, and phone/laptop charging. Most days the bank only drops to maybe 70–80% state of charge overnight. I've seen some people on here and elsewhere dropping absorption down to around 14.4V for lighter-use setups, claiming it extends battery life without really hurting recharge performance.

Has anyone actually experimented with this on similar kit, or spoken to Victron or a battery manufacturer directly? I'd love to know whether sticking with the default is genuinely fine or if I'm quietly cooking my batteries on sunny days.

@PikeRuss what AGM brand are you using? That matters quite a bit actually — manufacturer specs vary more than people realise.

For context, my backup setup (shore-based, not cycling hard) runs absorption at 14.4V on sealed AGMs, which is fairly conservative. My boat bank I push to 14.7V because it gets hammered more regularly and needs a proper top-up.

The Victron defaults are reasonable but they're genuinely just a starting point. Key thing people miss — absorption duration matters as much as the voltage target. If your bank is regularly reaching absorption quickly, that can indicate either the bank is undersized for your loads or it's not actually discharging deeply enough to warrant a long absorb phase.

What does your daily depth of discharge look like typically? That'd help narrow down whether the voltage setting is actually your real variable here.

Curious about this too — I've got a similar setup on my narrowboat (static most of the time, shore power as backup) with a 200Ah Fogstar AGM bank through a SmartSolar 100/20.

@CliffGazer raises a fair point about manufacturer specs. Mine recommend 14.7V absorption but I've seen people running anywhere from 14.4V to 14.8V on similar banks.

One thing I've wondered — does the temperature compensation setting make a noticeable difference in practice? We get some cold nights here and I've never been totally sure whether the automatic compensation is actually doing anything useful or whether I should be manually adjusting seasonal profiles.

Also, are you using the VictronConnect app to monitor cycle data? I've found the battery voltage history useful but I'm not sure I'm interpreting the absorption duration graphs correctly.

Hey @PikeRuss, good question. I'm running a similar static setup — 200Ah AGM bank through a SmartSolar 100/30. I dropped absorption down to 14.4V from Victron's default after noticing my batteries were getting quite warm during long sunny days. Made a noticeable difference.

Worth also looking at your absorption time setting rather than just the voltage — I shortened mine to around 2 hours since the bank rarely gets genuinely depleted being static. Victron's adaptive absorption helps here too if you haven't already enabled it in the app.

@Emma1996 on a narrowboat setup I'd be a bit more conservative with voltages generally given the enclosed battery compartment — heat management matters more in confined spaces.

Have you checked actual battery terminal voltage with a multimeter while charging? Sometimes there's enough voltage drop through cabling that what the controller thinks it's pushing isn't quite what the batteries are seeing.

Great thread, this. @PikeRuss I'd echo what @Russ1960 seems to be getting at — static setups really don't need aggressive absorption voltages. I've got a 240Ah AGM bank (three 80Ah Leoch batteries in parallel) on my SmartSolar 100/50, and after a bit of experimentation I've settled on 14.4V absorption with a fairly short absorption time, around 2 hours max. The key thing people often overlook on static setups is that your batteries rarely get deeply discharged, so there's genuinely no need for lengthy high-voltage absorption cycles. I'd also strongly recommend enabling the adaptive absorption feature in VictronConnect if you haven't already — it adjusts the absorption duration based on actual bulk time, which is brilliant for partially-discharged banks. @CliffGazer makes a fair point about manufacturer specs too; worth cross-referencing whatever Victron defaults to against your specific battery datasheet.

Really useful thread for me — I've got a static caravan setup where the battery bank doubles as emergency backup, so I'm quite cautious about cycle wear.

One thing I haven't seen mentioned: does the absorption time matter as much as the voltage itself? My SmartSolar is on the default adaptive absorption setting, but I've wondered whether capping it manually (say, 2 hours max) would reduce stress on the batteries without leaving them undercharged.

Also, @OwenYoung83 — you mention not needing aggressive charging on static setups, but does that change if the bank sits at a low state of charge for a few days (bad weather, heavy use)? Presumably you'd want a proper full absorption cycle occasionally to avoid sulphation?

Running two 110Ah Fogstar AGMs here if that's relevant to anyone's experience.

Worth mentioning the EV angle here — I use my bank for overnight trickle charging a small EV via a 13A socket, so the batteries are cycling pretty hard daily. Found that with AGMs under that kind of load, absorption voltage actually matters more than people think. Running mine at 14.7V rather than dropping it lower, otherwise the bank never fully recovered after heavy discharge sessions.

If you're just running lights and leisure loads, sure, back it off. But if you're putting any real demand through @PikeRuss, stick closer to the manufacturer spec. Check what your specific battery brand recommends — there's variance even within AGM chemistry. Fogstar's spec sheets are decent for this kind of detail if yours didn't come with clear documentation.

Interesting point from @DodgyDrifter — I'm in a similar situation, using my static caravan bank to trickle charge an EV overnight through a 13A socket. That extra load means I've had to be more deliberate about absorption voltage settings because the batteries rarely get a proper rest. I'm running Fogstar lithium now rather than AGM, so my parameters are quite different, but I'm curious — for those still on AGM with an EV charging load, are you seeing accelerated plate sulphation? I've read conflicting things about whether partial state of charge becomes more problematic under consistent overnight discharge cycles.

Really interesting thread. @PikeRuss, with AGMs I've found staying around 14.4V absorption works well for a static setup — Victron's defaults can sometimes be a touch aggressive for batteries that aren't getting full cycle usage regularly. One thing worth checking in the VictronConnect app is your absorption time as much as the voltage — on a lightly cycled static bank, a fixed shorter absorption period can reduce stress on the plates considerably. Also make sure temperature compensation is enabled if you haven't already, especially heading into winter. AGMs really don't like being overcharged when it's cold.

Good thread this. @PikeRuss I run a similar AGM setup on my static and settled on 14.4V absorption after experimenting a bit — @BevHughes is spot on there. One thing worth adding though: with a static install where the batteries aren't getting regularly discharged deeply, I'd really recommend keeping an eye on your absorption time rather than just the voltage. Victron's adaptive absorption is brilliant for this — it shortens the absorption phase when the battery hasn't been heavily discharged, which reduces the risk of overcharging a bank that's mostly sitting topped up. Makes a noticeable difference to battery longevity in my experience.

Been running 14.4V absorption on my AGM bank too, but the bit nobody's mentioned yet is absorption time — that matters as much as the voltage itself. Victron's adaptive charging algorithm will shorten it automatically on days when the battery was already fairly full, which is exactly what you want for longevity on a static setup that isn't being hammered daily.

@PikeRuss worth checking your VRM dashboard (or the app if you're not on VRM) to see what your actual daily absorption durations are looking like. If it's regularly hitting 2+ hours you might have an underlying issue beyond just the voltage setting.