ideas on which 48v battery or 2 @ 24v for a tender with a 48v 60mp boat motor

Been running a similar setup in my tiny house on the canal and honestly two Fogstar Drift 24V batteries in series is the move — you get modularity, easier handling when you're lugging them down a pontoon at 6am, and if one decides to throw a tantrum your whole system isn't toast.

That said, a single 48V unit is cleaner wiring-wise and fewer points of failure, which matters when you're bouncing around on open water.

Few things worth thinking about:

• Continuous vs peak draw — a 60lb thrust motor can spike hard, so check your BMS can handle it without going into protection mid-channel at exactly the wrong moment
• Victron SmartShunt is worth fitting regardless so you actually know what's happening rather than squinting at a blinking LED
• IP rating — boats are damp, surprisingly, so make sure whatever you go with isn't going to corrode faster than my sense of direction on the Thames

The 2x24V route also means you can charge each bank independently if you're using a smaller shore power charger, which is genuinely handy for a tender that probably doesn't have acres of solar real estate.

What motor controller are you running with the 60MP? That'll affect which way I'd lean on this one — some of the cheaper controllers don't play nicely with lithium BMS cutoffs and you get some exciting moments.

What's everyone else running on their tenders — gone single 48V or split banks?

@CotswoldCruiser interesting point on the modularity, but has anyone actually stress-tested the Fogstar Drift 24V under sustained high-draw conditions like a 60Nm motor pulling hard against current? That's my concern — peak vs continuous ratings on these cells.

Running a Victron SmartLithium 100Ah 24V on my static caravan setup and the BMS behaviour under load is noticeably more predictable than some of the budget options.

For a boat motor specifically I'd want to know:

• What's the actual peak amp draw on that 60lb thrust motor at full throttle?
• How long are typical run sessions before you're back on charge?
• Is weight distribution on the tender a factor?

A single 48V native battery might actually be cleaner from a BMS perspective — fewer connection points to corrode in a marine environment. Anyone running Fogstar in saltwater-adjacent conditions long term?

Ran my narrowboat's 48V system on two Fogstar Drift 24V in series for 18 months — @LisaStewart71 the stress test answer is yes, pulled sustained 60A through them on the Broads without a whimper from the BMS.

That said, for a tender with a 60lb motor you're not hauling massive current, so a single Fogstar Drift 48V keeps your wiring dead simple and eliminates the series connection as a potential weak point — fewer connectors, fewer headaches when you're bobbing about on choppy water.

Key consideration nobody's mentioned: IP rating matters more on a tender than a narrowboat cabin install, so check your enclosure game before committing either way.

@RetiredChef that 18-month data point is really useful, cheers.

One thing I'd add from my static caravan setup — if you're going the two 24V route, make sure your BMS on each unit can handle the series configuration without throwing fault codes when balancing. Some cheaper units get confused about ground references.

For a 60lb thrust motor pulling decent current, what's the peak amp draw you're seeing? That'll determine whether the Fogstar Drift's continuous discharge rating is adequate or whether you'd be better off with a single purpose-built 48V unit like the Victron Smart Lithium 48V — less modular but the integration with a Cerbo GX is genuinely cleaner if you're monitoring remotely.

Have you confirmed the motor controller accepts LiFePO4 voltage curve? Some older 48V motor controllers expect lead-acid profiles and cut out early.

@RetiredChef that 18-month runtime is reassuring. Quick question though — with two 24V units in series, if one battery's BMS trips, does the whole 48V system go down? That's my main hesitation versus a single native 48V pack like the Fogstar Drift 48V or even a Victron lithium.

For a boat motor pulling 60A continuous, I'd want to know each battery's peak discharge rating too — are the Drift 24Vs rated for that kind of sustained draw, or are you seeing any throttling?

Also curious whether anyone's considered a single EG4 or Jakiper 48V unit — obviously heavier to manhandle onto a tender but one BMS to manage rather than two communicating (or not communicating) with each other.