Loads of batteries, loads of chargers. How do you choose what you need?
Regular Discharge, or Emergency Backup
The primary factor in choosing a battery charger is, what do you want to use it for. If your batteries are used in an emergency situation only (eg, something that runs only during a blackout), versus regular use (eg, powering your off-grid system at night) then your charging requirements are vastly different. If you're regularly discharging your battery you'll need to make sure the charger has enough power to recharge it in the interval you have not using the battery (ie, if you use it every night, you must be able to recharge it within 8-10 hours for instance). If your battery is used purely in emergency situations (such as for an emergency lighting system), you can often proceed with a trickle charger. It may take a long time to recharge your battery, but you generally only need to use it in uncommon situations, so the recharge time is of little significance.
Most batteries naturally discharge over time. You can't leave them on a shelf for extended periods, and expect them to operate as designed when you decide to finally use them. This natural discharge is overcome by the practice of trickle charging. A trickle charger basically counteracts the natural discharge effects, and ensures your batteries are ready to use all the time. If you don't keep them topped up, they'll slowly become less and less useful, until ultimately they won't work any longer (and often can't be rescued from this state). Trickle chargers aren't usually powerful enough to recharge a drained battery quickly, and may take 24hrs or more to recharge it fully. For an emergency power source, this is fine. You keep it charged, use it in an emergency, and when the power is available again, it can recharge fully, ready for next time.
A standard battery charger takes a moderate approach, balancing charge rate with charge time, and heat. It will usually recharge a battery overnight (or during the course of a day if it's used overnight). They'll provide a solid charge.
Fast charging is actually a relative term, based on the size of the battery (or batteries) you're charging. If a charger has the ability to charge from almost flat within say, a few hours, that would be considered a fast charger. You can usually discharge your batteries at a FAR greater rate than you can recharge them, so being able to recharge as quickly as possible is essential in various situations. There are limits to how fast a battery can be safely recharged, as excessive charging rates will create too much heat, which can destroy the battery.
You don't always have to determine what sort of charging you're doing in advance. A multi-state charger will allow you to set a charging rate suitable for what you're doing at the time. Whether it's fast charging so you can get your car started, trickle charging for your boat battery while it's in the garage for the winter, or somewhere in the middle. Multi-state chargers allow you to select the most appropriate rate for what you're doing at the time.
An intelligent battery charger is a highly clever, adaptive style charger. These chargers can do the thinking for you, allowing a "set and forget" approach to battery charging. They monitor the battery voltage and adjust the charging current accordingly. Some will even have an optional temperature sensor, to keep an eye on battery temperature to make sure the heat generated doesn't become an issue. You can usually override the automatic selection of charge mode if you do want to take control, but you can usually just connect the terminals and let it figure things out for itself. The charger will then charge as fast as practical to do so, then slow things down eventually to a trickle, to maintain the battery's charge for you. Intelligent chargers are definitely the best option if you're unsure what charge condition your battery is in, or you don't really understand electrical principles - they're safe and effective for just about anyone to use.
If you're unsure which battery charger to choose, our friendly team can help you make the right choice. Just consider what sort of batteries you're charging, as that's probably the first question our team will ask.