12 ft tinnie
12 ft tinnie Lithium Battery Installation Costs
Indicative installed budget for the 100 Ah bank this boat’s 14 Ah a day actually calls for. Every hardware line is priced from the catalogue on this site; the last two are estimates, and they are labelled.
Itemised
Itemised battery installation cost estimate
23%
Is the battery
77%
Is the system around it
| Line | Why | Cost | Source |
|---|---|---|---|
| 1 × iTechworld 12 V 100 Ah | 100 Ah of lithium, the bank this boat's loads actually call for | $450–$650 | priced |
| Victron 18 A DC-DC charger | Sized to the 40 A alternator, not to the bank | $230–$340 | priced |
| Renogy shunt 500 A shunt monitor | Because lithium's flat voltage curve makes guessing state of charge useless | $110–$180 | priced |
| Blue Sea Systems Class-T 200 A fuse | The cheapest line here, and the first thing an insurer asks about | $90–$150 | priced |
| Cable, terminations and fusing | New runs where the old ones were sized for a lead-acid bank | $180–$420 | estimate |
| Installation, assessment and documentation | Suitably qualified labour, plus any licensing or certification the vessel and jurisdiction require | $600–$1,400 | estimate |
| Total, installed | Assessment and documentation required for the vessel | $1,660–$3,140 |
Lines marked priced come from the product and gear catalogues on this site and change when those prices are re-checked. Lines marked estimate are cable and labour, which no catalogue prices — they scale with the size of the bank and with how much the compartment fights you. Hardware pricing is indicative and not yet independently verified.
The same job, cheaper and dearer
Battery refit savings and scope exclusions
The battery brand is the honest place to economise. A budget cell in a dry, ventilated locker, charged through a correctly sized DC-DC charger and fused with a Class-T, is a better boat than a premium cell wired straight onto an alternator. The chemistry is the same; the support and the documentation are what the premium buys.
The charging system is where saving costs you money later. Every failure we hear about traces back to the same shortcut: reusing the existing alternator regulation and hoping the BMS will be polite about it. It will not be.
What we would fit on this boat
| Bank | 1 × 100 Ah = 100 Ah |
| DC-DC | 18 A, for a 40 A alternator |
| Monitor | 500 A shunt |
| Protection | 200 A Class-T at the bank |
Asked most
How much does lithium cost on a 12 ft tinnie?
$1,660–$3,140 as an indicative installed budget, for the 100 Ah bank this boat's load profile of 14 Ah a day actually calls for. The batteries are 23% of that.
What is the single biggest line?
On this boat it is installation, assessment and documentation. Which line dominates changes with the size of the boat: on small hulls it is the labour, on large ones the cells.
Could I spend less?
Yes, and the honest place to save is the battery brand, not the charging system. A budget cell in a dry locker with a properly sized DC-DC charger and a Class-T fuse is a better boat than a premium cell wired straight to an alternator.