Trying to choose the right Shore Supply Transformer for your boat can be a bit of a minefield. For most, the choice probably boils down to price and physical size. But is it really this simple or should we be looking more closely when choosing the right shore supply transformer for our boats?
ISO Boost are a well-established company with years of experience dealing with shore supplies. We spoke to their Vice President, Declan Sexton, to find out more.
First, we asked about what to look for first when identifying the right transformer. Declan explained:
“When looking at shore supply transformers we always start with the 3 basics”:
Operating Voltage – generally here in the US we use 240V, in Europe they may use 400V.
Capacity – this is the kVA rating of the transformer. There are a few standard sizes and as a rule of thumb you need 12kVA (50A) for small to medium-size boats and 24kVA (100A) for medium to large boats.
Physical size – remember you want the transformer installed somewhere out of sight but accessible and not so enclosed it might overheat.
So far then it all seems quite straightforward. However, a quick search online shows a huge difference in price between transformers with apparently identical electrical ratings, so we asked Declan why this might be.
“Quite simply there are only 2 reasons why apparently identically rated transformers differ in price; quality and functionality.”
“In terms of quality the old saying of buy cheap, buy twice applies. There are many inferior products out there that aren’t made using the correct processes or high-quality materials. A good transformer should last years — a cheap one will need replacing before you know it. Also look for quality in design as many well-built but poorly designed transformers can only work in an air-conditioned environment. Here at ISO Boost, we favour the Energy Solutions transformers because they are electrical specialists that make their products in the UK to the highest standards and to a robust and reliable design.”
“In terms of functionality modern shore supply transformers come with a vast array of options. Many essential, many desirable and some all but useless to only a tiny percentage of people. The rule here is don’t get sucked into paying extra for a function you will never use.”
After talking to Declan, we have summarised below some of the common options and functions offered by the leading shore supply transformers on the market:
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Power Monitor – common with the high-end manufacturers this is quite desirable as they often monitor voltage, frequency and current and can confirm the state of the shore supply before the output is connected to the boat’s switchboard.
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Event/alarm recording – this is often seen as essential. It allows you to quickly identify any issues and can help to determine if the issue is with the shore supply, the on-board electrics, or the transformer itself.
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Multiple input voltages – as long as the transformer can accept the shore supply voltages you use then that is all you need. Most of us don’t commonly swap between the US and Europe so be careful of paying too much for this option.
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Voltage boosting – many systems onboard cannot cope with the large voltage fluctuations experienced by shore supplies. The best shore supply transformers therefore have a voltage monitoring system that will automatically boost the voltage to ensure the supply to the boat remains unaffected during drops in the supply. Systems range from simple boost transformers to complex constant correction and regulating transformers. Given the sensitivity of many onboard systems to voltage fluctuations we would not recommend buying a transformer without a boost function.
One final note on shore supply transformers is to remember that whilst a good quality transformer should last for years, they don’t last forever — and that means at some point in the future you may have to replace it. At this stage the decisions you have made in purchasing and fitting the original transformer may well come back to haunt you, so choose well.
As if to highlight this point, Declan tells us about the new Energy Solutions Iso-boost range of transformers that ISO Boost have helped develop and are distributing in the US.
“We have developed these for one reason — people need them! If you can’t find a transformer of the same rating that’s the same size (or smaller) than your old one, then replacing it can quickly become complicated and costly. This is exactly the position people with the old and discontinued Charles Industries transformers were in. That’s why we worked with Energy Solutions to make sure their new Iso-boost range are a direct like-for-like replacement of the old Charles Industries products.”
So, there you have it — all the information to make sure you buy the right shore supply transformer that gives you all the functionality you need, whilst not paying for dazzling options you’ll never use.
Our thanks to Declan Sexton and ISO Boost USA
