More power for your money

 
RCB+ & Fogstar

Many customers are considering upgrading their onboard power to lithium-based systems, looking for the longer time between charges and higher consumption that lithium provides. They are taken by the higher useable capacity, smaller footprints, lighter weight, improved battery management and the faster charging that LiFePO4 batteries offer them.

But is installing lithium expensive?

It needn't be. Fogstar is a multi-award-winning British lithium battery brand, designed and supported in the UK. Pair one of its Drift batteries with an alternator-protection solution designed for the job, and you get the best of both worlds: a lower price and a more effective system.

We priced the same 12V lithium upgrade two ways. One using Victron's popular SuperPack batteries and twin DC-DC chargers, the other using Fogstar's Drift range of batteries and Cristec's RCB+ battery relay.

On a £2,000 system build, the Fogstar Drift and Cristec RCB+ build came in around £400 cheaper than the Victron specification — nearly 20% — with 30Ah more battery and, where the alternator can supply it, a faster charge time through its higher alternator charge ceiling.

What both quotes share

The core of each build is identical:

  • Victron EasyPlus Compact 12/1600/70-16 inverter/charger: enough to boil a travel kettle or run a microwave

  • BMV-712 Smart battery monitor with temperature sensor

The BMV-712 battery monitor counts exactly what goes in and out, so you read true remaining capacity and time-to-go rather than guessing from voltage — which matters most on lithium, where voltage barely moves until the bank is nearly empty.

It can sound an audible overvoltage alarm as standard, and with the temperature sensor fitted a temperature alarm too — so a developing fault gets your attention rather than going unnoticed.

Same hardware, same price, in both quotes. The difference comes from just two lines: the battery, and the alternator-charging path.

The battery

Victron quote Fogstar quote
Battery SuperPack 12.8V/200Ah Drift 12V 230Ah
Capacity 200Ah 230Ah
Price £620.83 £416.66

The Drift gives 30Ah more capacity for £204 less. It also sits on roughly half the footprint of the SuperPack, though it stands around 40 mm taller.

It comes well equipped:

  • Grade A EVE cells

  • Built-in heating for cold-weather charging

  • Bluetooth monitoring via the Fogstar app

  • IP67 protection and a 10-year warranty

The alternator path

Victron quote Cristec quote
Charging 2× Orion XS 50A DC-DC 1× RCB+ Adjustable
Charge current 100A 30–120A adjustable
Price £375.00 £178.38

Conventional engine alternators need to have a limit placed on the current delivered to a lithium battery, to protect them from overheating.

The RCB+ is a smart battery coupler that shares alternator output between the starter and lithium banks — limiting service current and preserving engine-start capacity.

One unit instead of two. One set of cabling, one mounting position, and a charge ceiling 20A above the twin-charger build. Fanless, ignition-protected to ISO 8846 / SAE J1171, 3-year warranty.

The totals

  • Victron build: £2,045.92

  • Fogstar + Cristec build: £1,645.13

  • Saving: £400.79 — 19.6%, with the larger bank and the higher charge ceiling on the lower-priced quote

The takeaway

The lower-cost lithium build is also the one with more battery and more alternator headroom. A single RCB+ replaces a pair of DC-DC chargers, a 230Ah Drift replaces a 200Ah SuperPack, and the same Victron inverter/charger sits at the centre of both.

Or put the saving toward capacity. Step up to a 460Ah Drift and the build comes to around £1,870 — still under the £2,046 Victron price, with more than double the battery: 460Ah against 200Ah.

 
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