Battery Charger

[HarrisonP]

I can't find a 12 volt battery charger with user set voltage such as 14.82 for bulk and 16.25 for equalize. That may be because I'm only looking at nonexpensive portable chargers. Does anybody here know of such an animal?

I mean this as a backup charger for use with my generator not a solar controller. I have that covered.

[Mike90250]

Backup charger only needs to be able to accomplish BULK stage , after that you are wasting fuel.

[HarrisonP]

Thank you. My current equipment bulks at 14.4 volts and my new battery wants 14.82 volts.

[Mike90250]

Thank you. My current equipment bulks at 14.4 volts and my new battery wants 14.82 volts.

Well, it's better than nothing, and if you run the genset in the AM, and bulk the batteries up, the solar can often get them started in Absorb

[Sunking]

You do not require anything fancy on a generator. It would be a waste of money. All you need is a charger that has EQ voltage only of the appropriate current capacity. Run the generator early in the morning until you see the charge current start to taper off. Turn it off and you are good to go.

You want a charger that can supply at least a C/8 charge current, and no greater than C/6. So if you have a 200 AH battery would be 25 to 35 amps that outputs 15 to 17 volts. For those times you need to EQ the batteries, run until your hydrometer quits rising for a period of 1 hour. One voltage does it all, the battery regulates the voltage, not the charger. If you use 14.82 volts just means you run the generator a lot longer and burn more fuel than necessary.

Give you another tip. You set your voltage on your charge controller to low. If you use the battery manufacture setting, I guarantee you it is too low. To find the proper voltage, you use your temperature corrected hydrometer to tell you what to set the voltage too. When you see your controller switch to Float Mode, wait an hour and take specific gravity measurements. If it is less than 100%, turn the voltage up. Repeat each day until you see your batteries reaching 100% SOC. Chances are you wil never see that happen which means you are chronically undercharging your batteries and destroying them.

What solar users do not understand those battery manufacture recommendations are based on using commercial AC power that is unlimited and availble 24 hours a day. With solar power is not predictable and you only have a few precious hours and do not have the luxury of time. Solar is not capable of fully recharging your batteries in most systems because you do not have enough panel wattage to begin with. That leaves you to having to use a generator more frequently than necessary.