thinking about buying a battery charger. what should I be looking for in volt and amp.
It all depends on what you want it to do.
Jump start right now Because the vehicle you want to drive has a dead battery ?
Charge up the boat battery for this weekend ?
Go to a parts store in person and see all the many kinds. Read the control panels and the instructions .
The large rolling ones we have in the shop will do it all including load testing . We just get those from Car Quest or Auto zone.
I have a little 12/6v , 6amp in my garage. It will not jump start but it will charge up my parked 79 for tomorrow and is a good power supply for the bicycle pump and stereo test bench .
Definitely get an automatic charger that is switchable to provide amperage for trickle charge to jump starting. They aren’t’t that expensive and well worth it if you have lots of toys…
If you are looking for a charger to maintain a battery for long periods of nonuse or on a vehicle with a large parasitic drain, be sure to get a float charger and not a trickle charger. These are often called battery maintainers instead of battery chargers.
A float charger turns off completely when the battery is fully charged and then monitors the battery and turns on when necessary. This will prevent overcharging and damaging the battery in storage.
If you need a shop charger for charging dead batteries and jump starting vehicles with dead batteries, bigger is better.
A trickle charger is at least what you need. I keep one hady for topping up the battery and helping neghbours who run their old batteries down.
We also have a battery pack that we travel with; it’s neat for jump starts.
A charger with a 6 to 10 amp capacity will charge a dead battery in a reasonable amount of time and can be had for a modest price…The more bells and whistles, the more they cost…You can make a 1 or 2 amp trickle charger out of a discarded wall transformer made for a printer, cordless drill, stuff like that…You want the output to be 12-14 VDC…
This is the jump starter I own. It works, and it only $35 on amazon.
I just have the 10 amp charger and has worked fine for years. I guess I’m on my second one in 50 years. A jump starter though is for jumping batteries, not for charging them up.
Mine is an inexpensive Sears model that seems to do the job for what I need. It has a 12 v/6 v switch, which is something I don’t need b/c I always am charging only12 volt batteries, never 6 v. But it has that switch anyway. And it has another switch, 6 amp/2 amp. That’s useful. I use the 6 amp if I am in a hurry, and the 2 amp if have plenty of time and I want to minimize damage by slowly charging the battery. It has one or two meters on it two which are useful to determine how much more charging is left to do.
It won’t jump start a car, and it isn’t designed to be a trickle charger. For those functions you need specialty models. The usual way I charge batteries is on the 2 amp setting, and let the battery charge slowly for 8-12 hours. Sometimes it takes 24 hours if it is really dead. I’m a diy’er and don’t use it very often, but when I do I’m glad I have it.
At my age I have owned and used every type charger mentioned so far and agree with everyone regarding their use. But as @ken green mentioned you should decide what suits your needs. Large, high amp (100+) chargers have timers. Mid range chargers(10+ amps) don’t and can overcharge a battery to the point that it explodes if left unattended for hours. Trickle chargers will eventually overcharge a battery unless they have a limiter that shuts them off when the voltage reaches about 13.8v and many do and are labeled ‘float’ chargers or some such term.
Consider your needs, @dripper.
I think a jump box is better then a charger that can jump a battery because of the size of the unit. at work I have a shop unit on wheels and that does the job very nicely and at home I have a 2/10 amp unit that does the job. it does sit around a lot between uses, anything more is over kill for my needs