Shaving Ice in the Desert
Mobile Hawaiian Ice Vendors Keep Customers Cool in Colorado
This story was originally published on Victron Energy.com
“One of the best things about running a mobile Hawaiian ice business is that your customers – aged from 2 to 92 – are always excited to see you!”
Sisters Tamie and Linda have been operating The Polar Express from a retrofitted school bus for 23 years. It seems their bus doesn’t even have to be open for business to attract customers: “I remember one day our bus broke down when we were driving through a residential area; while we waited for help, kids started lining up on the sidewalk, waiting for us to start serving!”
With growing competition, regulation, and operating costs, the success or failure of their business depends on a good deal of planning, paperwork, and reliable electricity. Their equipment has to work faultlessly all day.
“Imagine you’ve paid to bring the bus to a music festival, and now there’s a line of 50 customers when all of a sudden everything shuts down and you have to leave the counter to see why your battery isn’t working.”
Over the last twenty years Tamie and Linda have tried dozens of inverter, battery, shore power, and backup generator combinations, resulting in all kinds of failure: overheating batteries, machinery shutting down at random, blowing the breakers at the event venue.
“Our ice cream needs to be stored overnight in the vehicle, and every season something would go wrong. More than once we’ve left the truck plugged in overnight only to return in the morning and find the freezer had lost power, and all the ice cream melted. That’s several thousand dollars of product literally down the drain,” says Tamie.
Hawaiian Ice draws more power
Linda and Tamie began selling Hawaiian Ices in response to a shortage of pre-packaged ice cream during the COVID pandemic. Shaved ice was a hit with customers, but it complicated their power needs – requiring more freezers, a bigger refrigeration system for liquid ingredients, and an instant hot water heater to meet health code requirements.
With all these power-hungry appliances, Tamie and Linda didn’t dare to use an Air Conditioner for their own comfort. “Hot weather is good for business, but for us working a hot tin box all day, usually without shade, it makes you sweat just thinking about work.”
Needing a better solution, Tamie reached out to Jason Sloan, owner of Slung-Lo Solar, in Montrose, Colorado. Slung-Lo specialises in the custom design and installation of Victron Energy solar power systems for recreational vehicles and off-grid applications.
After years’ of disappointment, Tamie was reluctant to spend more money on a new power solution. “We grilled – and I mean grilled – Jason over two or three meetings, asking him every question in the book. He was so patient with us, asked a lot of questions back, and showed us several systems they were installing in his workshop to explain how they worked, and how simple they were to manage.”
Free From Worry…
“Tamie and Linda are not technical,” says Jason, “they want to show up, flip on the lights, and start selling shaved ice – and we wanted to make sure they could do that.”
Jason works with Victron Energy devices because of their advanced custom programming capabilities, and the possibility of split-phase and three-phase configurations: “Many of our customers want programming flexibility. RV owners travelling across the country want to maximize their solar usage and minimize costs when connected to shore power at campgrounds. We customize how their systems manage shore power—turning it on and off based on battery charge levels and solar system performance. We design battery capacity to match their desired days– or hours of autonomy, then balance the loads accordingly.”
Building a business with Victron Energy
With a background in building data centers, Jason loves the remote monitoring capabilities he builds into his installations.
“Linda and Tamie haven’t been able to depend on their power system in the past. With the Polar Express installation it was important to me in the early days to see how it would cope with a long weekend. I wanted to monitor it to see that the temperatures were where they should be, and that there was no overload. We’re looking for consistency and reliability during operation – and with Victron Remote Management (VRM), we can confirm that without needing to be on site.”
“We’ve worked with other manufacturers, and we replace a lot of them for our customers. When I started researching who we wanted to partner with from a business perspective, we were looking for quality; a good reputation on warranty; and continually improving equipment, systems, and services. With Victron being a global company with equipment used in a variety of different applications, it helped us make that choice.” In 2022, Jason partnered with Victron Energy distributor Intelligent Controls to access the vendor pricing, system design, and troubleshooting support he would need to grow his business.
“We also do a lot of three-phase and split-phase systems”; he says, “the ability to size them based on customer’s need makes it nice to install inverters in parallel to increase the capacity. We do a lot of large RVs which are full-time homes and have 3,600 watts of solar on the roof, and two 5,000VA MultiPlus II‘s in split-phase – running dryers and three air conditioners. It’s a 140-amp service to the environment!
“Victron gives us the ability to blend solar and shore power. On our really large systems, when we hit a certain wattage draw, we’ll activate shore power to offset the draw on the battery. And then when loads are reduced, we turn it back off. It saves them several hundred dollars a month.”
Public Event Power Grid
Tamie and Linda almost always have a grid connection, but when they don’t they need to be able to power all their loads. By adding even a small amount of solar on top of the bus they can maintain all their refrigerated equipment and run their shaved-ice machine and other appliances without being plugged in.
Just last weekend, they attended an event at which vendors paid for a power supply using a generator mini-grid. Unfortunately, the site generator broke down and it took almost two hours to get it back up and running. Tamie and Linda’s solar system provided uninterrupted power – resulting in their best weekend on record for sales! "If we were wondering about our investment before ….we’re not wondering now!” they say.
They also enjoy the benefits of an air conditioner on hot days; they have fewer hours of autonomy when it’s in use — resulting in the battery State of Charge (SoC) dropping to 20% after six or seven hours of operation. But they can go all day without plugging in and still drive home with some battery power remaining.
Jason’s System design considerations
The vehicle spends considerable time parked between events. To maintain optimal SoC levels, Jason incorporated a second 230Ah smart battery that integrates directly with the Cerbo GX, which manages battery charging across all devices through direct connection and the inverter via the VE.Bus.
“We installed a 30-amp shore-power inlet RV connection—similar to what they’d encounter at shows. We then used a dogbone adapter to step down to 15 amps and configured their system with a 13.5A current limit to prevent blown breakers. Nobody wants to be that person at an event!”
“Based on their consumption patterns and system requirements, we installed a Quattro 24/5000/120 inverter/charger. Given their high amperage draw we opted for a 24-volt system with a 230Ah battery.”
“Sizing the battery bank largely revolved around being able to travel between shows in Utah and Colorado. In desert areas where it’s warm, they needed to run the air conditioner for at least four hours or use the generator.”
“When planning the installation, we needed to decide where the equipment would go and how to keep it cool – and dry. The freezers generate significant heat, and onboard the bus the atmosphere can be humid, necessitating a watertight electrical system. We also needed easily accessible emergency shut-offs. Our solution was a waterproof alluminium enclosure for the Victron equipment. The box features a floor-level vent for cool air and a top exhaust vent allows airflow across the equipment. A Ruuvi temperature sensor connected to one of the Cerbo GX relays automatically controls internal fans based on the box temperature, ensuring the Victron equipment and battery stay cool and dry.”
“Their generator sits on a custom rack at the back of the vehicle with a cable running to a port on the van’s side, allowing them to plug it in. When the generator starts, there’s a delay on the AC switch to allow for proper warm-up—particularly important at altitudes of 6,000 feet and above, where they often attend events.”
An automatic start/stop generator function is triggered by battery state of charge. “We allow the batteries to run fairly low before the inverters automatically shut off. On the DC side a BatteryProtect device is configured to shut off their LED lighting at 30% state of charge acts as a friendly reminder to those working inside that it’s time to start the generator!"
The power system in The Polar Express includes:
- Quattro 24/5000 inverter charger
- Orion Tr-Smart 12/24-15 DC-DC charger
- SmartSolar MPPT 100/20
- Cerbo GX
- 230 Ah LiFePO4 Epoch Battery
- BatteryProtect
- 400 watts of Rich Solar Mega 100 Flex solar on the roof
A Cerbo GX MK2 helps ensure remote support capabilities. “When they need assistance, they can connect it to their phone, give me a call, and I can log into their system and either verify that it’s working as designed or provide support if needed.”
Jason installed a custom switch panel in the rear of the bus and added adjustable LED lighting systems on the side, integrated into wall-mounted switch panels. The bright and colourful lights attract attention to the van when parked, and the interior LED lights serve as an indicator signal; when they go off, Tamie and Linda know it’s time to start the generator. The BatteryProtect automatically shuts off the LED lighting when battery SoC drops to 30%.
After a few months living with the new system, Tamie and Linda’s anxiety over how it’s all going to work out is starting to thaw. “The first three weekends we ran it hard, and the weather was hot. Every time we got in the bus, we’d hold our breath and think, ‘Okay, what’s going to go wrong next?’ But already I’m starting to not even think about the power system…and I never thought that would happen!”
“You know it’s an intelligent solution when it feels easy and makes life simpler for your customer,” says Aaron Hanson, owner of Intelligent Controls. “Nobody wants technology for technology’s sake. At the same time, it’s hard to get a high level of performance from highly advanced, customized products and solutions. So to have a customer that’s not technical but loves the outcome is a testament to how Victron ‘just works.’ Jason’s success in the marketplace drives future business and shows new customers that they can achieve a level of reliability and performance using Victron equipment that would have been impossible in the past.”