Energy Peak Power Pack easy to install

Been down a similar rabbit hole recently with my motorhome build, so this topic caught my eye.

The question of drop-in lithium replacements for caravans with older charging systems is genuinely tricky, and I think it deserves more airtime on here. I swapped out the tired AGM in my van last spring for a Fogstar Drift 100Ah, which is marketed as a straightforward lead-acid replacement — and mostly it was. But the devil's in the detail with your existing charger.

The issue is that older chargers like the Nordelettronica units (and plenty of similar European kit fitted to caravans from that era) use charge profiles that are fine for lead but can confuse or even damage lithium cells over time. Some lithium packs have enough internal BMS intelligence to protect themselves; others are more vulnerable.

What I'd want to know before recommending any "easy install" peak power pack is:

• Does it have a proper BMS that can handle a non-lithium-specific charger?
• What's the absorption voltage the charger outputs — is it within safe range?
• Is the charger programmable, or fixed profile?

If your charger can't be set to a lithium profile, you might be better off looking at a Victron IP67 charger alongside whatever battery you choose. Yes, it's another cost, but it's cheaper than a ruined battery pack.

Has anyone here actually run one of these peak power pack units with legacy caravan chargers long-term? Curious whether the BMS handles it gracefully or whether it's silently getting stressed.

@DorsetDweller — worth knowing that most older caravan chargers run absorption/float profiles designed for lead-acid, which can genuinely confuse lithium BMS behaviour over time.

Learned this the hard way with my static. The charger kept hitting voltages that caused the Fogstar cells to tick-tock between protection states. Swapped in a Victron Blue Smart and the whole system settled immediately — proper lithium profile, proper communication.

The "drop-in" marketing is convenient shorthand, but the charger side of the equation matters just as much as the battery itself. Folk assume swapping the cells is the whole job.

If your motorhome has a habitation charger that predates 2018 or so, I'd look at its charge profile before committing to any lithium pack, regardless of what the battery manufacturer claims about compatibility.

Hey @DorsetDweller — good point about older charging systems. One thing worth adding is that even if the BMS in the lithium pack tolerates a lead-acid profile, you're often leaving a fair chunk of usable capacity on the table because the absorption voltage cutoff timing is all wrong for lithium chemistry.

If your caravan has a Sterling or Victron charger fitted, many of these have a lithium mode you can switch to fairly easily. Older transformer-based units are more of a headache mind you — sometimes easier to swap the charger than fight the battery.

Has anyone here actually tested the Energy Peak Power Pack's BMS response to a standard lead-acid float voltage long-term? Curious whether it genuinely handles it gracefully or whether you're quietly stressing the cells over months of use. Real-world data would be really useful before recommending these as drop-ins.

@SolarTom raises something I've been burned by personally — my first LiFePO4 swap (Fogstar Drift 100Ah) into an older system looked fine on paper until I realised the charger's temperature compensation was actively working against me in winter. The voltage was being reduced at low temps, precisely when lithium needs a consistent charge profile regardless of ambient.

Worth checking whether the charger in question has a user-selectable lithium mode before assuming drop-in compatibility. Victron units handle this elegantly, but budget OEM caravan chargers often don't expose that setting at all — sometimes it's buried in firmware that requires a dealer to unlock.

The BMS will protect the cells ultimately, but repeatedly hitting protection thresholds shortens cycle life noticeably. Proper charger compatibility is the unsexy bit everyone skips until the warranty's gone.

@CamperShaun that Fogstar Drift experience is a common one — the BMS disconnect catches people off guard the first time.

Worth adding from my own static caravan setup: if you're running an older charger that won't talk nicely to lithium, a Victron Battery Protect wired between the charger and battery gives you a controllable disconnect without relying solely on the BMS doing the heavy lifting. Keeps the BMS as a last resort rather than frontline protection.

Also check whether your caravan's 240V hook-up charger has any adjustment pots inside — some older units can be tweaked to a reasonable lithium profile if you're comfortable doing that. Not glamorous, but saved me buying a whole new charger unit.