Default charge algorithm for BlueSolar MPPT 75/10

Just upgraded from a cheap PWM controller to a Victron BlueSolar MPPT 75/10 and trying to get my head around the default charge profile it ships with.

From what I can gather, it comes pre-configured for a sealed/AGM lead-acid battery — absorption at around 14.4V and float at 13.8V — but I've not been able to confirm this definitively from the documentation. Has anyone else gone through this when first setting one up?

My situation is that I'm running a 100Ah AGM on a small shed setup, so the defaults might be close enough, but I'd rather not assume. A few questions:

• Without a VE.Direct USB cable or the Connect app, is there any way to verify what profile it's currently running?
• If you're using a Fogstar or similar lithium drop-in, did you have to reconfigure it immediately out of the box, or does it do enough to get by temporarily?
• Is the default bulk/absorption/float sequence actually a proper three-stage cycle, or does it cut corners compared to a programmed profile?

I know Victron's documentation is generally solid but I found the quick-start guide a bit vague on this specific point. Would be good to hear from people who've actually benchmarked their battery state before and after switching from PWM to this unit — curious whether the default settings alone made a noticeable difference to charge quality.

Anyone else gone through this process recently? Worth picking up the VE.Direct cable straight away or is the default profile genuinely usable for a standard AGM setup?

@AlanPalmer57 worth noting the default profile is essentially a generic sealed/AGM curve — 14.4V absorption, 13.8V float if I remember rightly. Fine as a starting point but definitely not optimised for lithium.

When I set mine up on the static caravan I connected it via the VE.Direct to USB cable and used VictronConnect to tweak everything properly. If you're running AGM it's probably close enough out of the box, but if you've got lithium (Fogstar Drift cells are popular on here) you'll want to disable the float stage entirely and set a proper absorption cutoff.

What battery chemistry are you working with? That'll determine how much adjustment you actually need.

@AlanPalman57 one thing worth flagging — if you're running LiFePO4 (hence my username lol) the default profile is completely wrong and potentially damaging. No BMS will save you from chronic overcharge stress over time.

You'll want to connect via the VictronConnect app over Bluetooth and set a proper lithium profile:

• Absorption: ~14.2V
• Float: ~13.5V (or disable float entirely, some prefer this)
• No equalisation

If you're on AGM/sealed then @CharlieStevens85 has it covered and you're probably fine out of the box, just worth double-checking your battery's actual spec sheet rather than assuming the defaults match.

The 75/10 is a solid little unit — been running one on my tiny house setup for two years alongside a Fogstar battery. Never had issues once I got the profile sorted properly.

@AlanPalmer57 the real magic happens once you plug in a VE.Direct USB cable and fire up VictronConnect — suddenly your MPPT goes from "mystery box doing its best" to fully configurable in about three minutes flat.

The default profile won't damage a decent AGM, but it's leaving performance on the table — especially worth sorting before winter when every amp counts. I've got mine dialled in for a Fogstar Drift LiFePO4 (14.2V absorption, 13.5V float, absorption time wound right down) and the difference was noticeable immediately.

One thing nobody's mentioned yet — set a low temperature cut-off if you're in a cold area; the BlueSolar won't do this automatically but VictronConnect lets you configure it properly.

@AlanPalmer57 one thing nobody's mentioned yet — the 75/10 also ships with streetlighting and load output algorithms pre-configured that can interfere if you're using the load terminals. Caught me out on my motorhome build when I couldn't work out why my 12V output was cutting at odd times.

Also worth knowing: even without VE.Direct, you can cycle through the battery presets using the MODE button on the unit itself — hold it for a few seconds. Limited options but useful if you can't get a cable immediately.

@ValleyWanderer is right that VictronConnect transforms the thing though. Once I got proper visibility on my absorption time and tail current, I realised the defaults were keeping my AGMs in absorption far longer than necessary on cloudy days — wasteful and not ideal for battery longevity.