Two years in - EG4 LifePower4 Lithium Battery | 48V 100AH | Server Rack Battery

Been running a similar rack setup on the narrowboat for about 18 months now, though I went with Fogstar Drift cells rather than EG4 — mostly because getting anything shipped from the States to a marina address is its own adventure.

Curious how yours has held up through a British winter specifically. My bank took a proper beating last January when we had that sustained cold snap. Lithium and cold don't always play nicely, and I found my BMS cutting out at lower states of charge than I'd expect when ambient temps in the engine bay dropped below 5°C.

A few things I'd love to know from your two years:

• Capacity retention — are you still seeing close to rated capacity, or has there been measurable drift?
• BMS behaviour — any nuisance trips, particularly under high inverter loads?
• Communication — are you pulling data via CAN bus into a Cerbo GX or similar, and how reliable has that been?

The server rack form factor made a lot of sense for me on the boat because space is genuinely at a premium. Stacking vertically in the engine room versus trying to wedge prismatic cells into awkward bilge spaces was a no-brainer.

What's your charging setup look like? I'm running a Victron Multiplus-II and a couple of Renogy panels on the roof, which works well enough but I'm always tinkering.

Two years is a meaningful milestone with lithium — long enough to see past the honeymoon period. Would be good to hear whether EG4's quality control lives up to the marketing, especially for anyone in the UK considering grey-importing them.

Great thread @PeteJames! I'm also on a narrowboat and went the Fogstar route about eight months ago — four 100Ah Drift cells in a 48V configuration. The marine environment does throw up some interesting challenges that land-based setups don't face, doesn't it?

One thing I'd flag for anyone considering rack batteries on a boat is condensation management. I've got a small desiccant pack near the battery compartment and it's made a noticeable difference. Also worth checking your bus bar connections more frequently than you might on a static installation — the constant vibration from the engine and movement through locks can work things loose over time.

How are you finding temperature management through winter? Mine sat in the engine 'ole which kept things reasonably warm, but I know some folk struggle with charging cut-off on colder mornings.

@PeteJames @NorfolkBoater — worth flagging something neither of you mentioned: rack-mount batteries on a narrowboat need to account for hull flex and vibration in a way static installations don't. The bus bar connections on compressed-cell formats can work loose over time if the rack isn't properly braced against the steel hull. I've got mine mounted on 20mm rubber anti-vibration mounts between the rack feet and the sole boards, and I torque-check every terminal connection quarterly with a calibrated torque wrench — not just a "feels tight" check.

Also, Victron's DVCC implementation matters enormously here. If you're not running a Cerbo GX to coordinate charge sources properly across the BMS, alternator, and any shore power, you're potentially letting the BMS do all the heavy lifting on charge cutoff, which isn't what it's designed for long-term.

@DefenderAdventure raises a fair point about the rack-mount angle — I learned this the hard way on my own boat before I moved the batteries off it entirely into the garden office setup I run now.

The thing that caught me out wasn't movement per se, but condensation cycling in a poorly ventilated locker. Even with Victron's monitoring flagging nothing alarming, I was getting micro-corrosion on the busbars that I only spotted during a routine inspection. Swapped to a proper vented enclosure with a small desiccant pack and haven't had a repeat in 14 months.

If you're using any rack battery in a marine environment — EG4, Fogstar, whatever — treat the housing as seriously as the cells themselves. The battery is often fine; it's everything around it that fails first.

@DefenderAdventure and @CallumHobbs have got the vibration angle covered well, so I'll add something slightly different — EV charging from a narrowboat setup is a genuine game-changer if you get the battery bank sized right.

I'm running my car off the boat when moored at home rather than paying for a driveway charger install. The rack batteries handle the overnight draw surprisingly well, but you absolutely need to be honest with yourself about your solar or alternator replenishment the following day.

Caught out badly last February — short days, overcast, barely moving the boat — and pulled the bank too low trying to top up the car. Victron Cerbo logs told the whole sorry story afterwards.

Size your bank for two days of EV charging without any input before you commit to this lifestyle. Learned that one the expensive way.