Good morning everyone,
I apologize in advance for my lack of experience with electricity.
I live in Italy; finding rest areas with electricity during the summer is quite difficult. Therefore, I’d like to know if purchasing Bluetti products could at least partially solve my two main problems. I would be grateful for any kind advice.
My first (and biggest) problem is this: I’d like to be as independent as possible when it comes to charging my e-bike. It involves being able to charge an 840-watt battery (is it realistic to imagine doing this at least five times before the Bluetti is completely empty?). These are the charger’s technical specifications:
Charging Voltage (DC): 58.8V
Charging Volt (AC): 100-240V
Max charging current: 12 A
Rated output power: 705.6 W
Frequency: 47/63 Hz
The second problem is less important to me, but if I could solve this too, my situation would be perfect. It involves this: I have an additional air conditioner in the camper (I’m not referring to the one in the driver’s area, which works with the engine running); this air conditioner could be useful in summer, at least in certain particularly hot places, for at least three hours a day. The air conditioner’s technical specifications are as follows:
Power supply: 230V 50Hz
Maximum current consumption: 4.9 A
Inrush current: 19 A (0.15 sec.)
Power consumption: 950 W
Required generator: 2200 W
Your e-bike is likely a 840 watt hour battery. Typically only 90% of the power station battery is usable (with the rest being saved for protection). So a Bluetti Elite 100 V2 would have 921.6Wh “usable”. You have to charge the e-bike battery via AC since DC is insufficient. To run the AC inverter you have to convert DC power to AC and there is an efficiency rating each AC appliance can produce. It’s almost never 100% unless its purely resistive. AC chargers generally have some sort of switching mode with capacitors, resistors, etc. to charge the battery then trickle to 100%. Both the charger and the AC inverter aren’t 100% efficient. Say the charger is 90% efficient and the AC inverter is 90% efficient. 0.90X0.90 would be 81%. 840/.81=1037Wh. 840Wh to the battery. An additional 197Wh consumed by Bluetti due to conversion losses. Think of it like you are an Uber driver and are a delivering groceries to a location for $10, but you took a wrong turn and had to burn through an extra $4 worth of gas. Had you been 100% efficient you would have only burned through $2 worth of gas, but you are still getting paid the same amount for the trip. To fully recharge your 840Wh e-bike battery 5 times would require 1037X5 or 5185Wh.
Since you also want to involve the air conditioner, given its specs, you are limited to a capable inverter as the lower budget Bluetti units (like Elite 100 or Elite 300) likely will not run the compressor based AC without killing it.
This is where it gets out of control fast. You are talking $1600 USD for an APEX head unit, followed by $2000 for a 5000Wh B500K expansion battery, or $1200USD for the B300K which has 2764WH. The Apex 300 head unit itself is 2764Wh battery internal. Assume your AC consumes 700 watts for 3 hours at 85% efficiency. That’s 2100/0.85 or about 2500Wh (2.5kWh) a day. For 5 days you’ll consume 12.5Kwh. Pair that with the 5kWh you consumed to recharge the e-bike for 5 days and you require a total of 17.5kWh. That’s 3 B500Ks and the head unit, for a total of $7,600 USD. This is obviously unfeasible not only due to cost, but weight and space in your rig. Something has to give. Now I’m making an assumption here that you don’t have solar, which I assume you do. But how much? If you can produce 1200 watts per hour, then given a sunny 5 hour day you’ll regenerate 5kWh BACK a day, keeping you at a net positive, but if your rig is small and you only have space to recharge at 500 watts per hour, you will need to sacrifice something, likely the AC. There are roof mounted 12V air cons which significantly reduce power, but they are only as effective as the amount of space you are cooling. The more BTUs you require, the less effective the 12V systems are. Realistically, given what I’ve explained above, if you rely on your e-bike 5 times a week and you recharge it once a day, you need MINIMUM 5kWH a week, so depending on how much solar you can regenerate will dictate how many battery banks you need. In other words if your solar potential is great, you need less battery storage, but the more battery storage potential you need the more money it will cost.
Basic math= Every day you consume 2500Wh to run the A/C for 3 hours and 1037Wh to recharge the e-bike battery once for a total of 3500Wh +/-. If you recharge the Bluetti unit at 85% charging efficiency you will require 3500/0.85 or 4117Wh a day. This means you need to average 823 watts per hour from solar for 5 hours to break even each day recharging your e-bike from empty to full once and run the A/C for 3 hours.