Looking for 12v AC-DC battery charger recommendation.

terracore

I'm looking for an AC-powered DC battery charger for supplementing my battery array on cloudy days.  I am not looking for an inverter charger, or anything that starts a generator.  I have smart and dumb chargers but all the smart chargers I can find are tailored for maintenance free automotive batteries, not an array of golf cart batteries under load. 

Basically what I'm looking for is a charger with thresholds I can set.  Like it doesn't do anything unless the battery voltage drops to 11 volts and then it kicks on and begins charging until it reaches 13v and then goes back to sleep until/if it's services are required again.  Or whatever voltages I set.  Because the solar chargers are doing the heavy lifting and just need help every now and then when the clouds roll in.

This seems like a no-brainer product that should be easy to find but I haven't been able to find it, just a bunch of DIY "workarounds".   If anybody can make a recommendation I look forward to reading it.  Thanks.

BB.

The Xantrex TC-2 series is pretty nice. They are Power Factor Corrected for their AC input, and are much "friendlier" for gensets-though not cheap (they are "effectively" more efficient on gensets vs non-PFC--Can discuss in detail if you are interested).

https://www.solar-electric.com/residential/batteries-battery-storage/battery-chargers.html?manufacturer=101 (scroll down on page)
http://www.xantrex.com/power-products/battery-chargers/truecharge-2-2.aspx

-Bill

terracore

Thanks for your reply!  Maybe I'm not technically savvy enough to understand these products- I don't see features that allow the user to set the voltages at which the chargers turn on or off. Please school me if I'm mistaken!

BB.

Terracore,

You are correct, the TC-2 has fixed charging voltages--Depending on battery type and 2 or 3 step charging cycle chosen.

Here is another thread with a charger from Full River that appears to have a wireless charging interface and potentially high programmability:

https://forum.solar-electric.com/discussion/352285/ac-battery-charger/p1

http://www.fullriverbattery.com/series/chargers/fullriver-fr1-chargers

In the same thread, there is a Concorde programmable (to what degree?) charger too (designed for aircraft charging, probably not cheap):

https://www.aviationpros.com/engines-components/aircraft-airframe-accessories/product/10771553/concorde-battery-corporation-battery-accessories
http://concordebattery.com/otherpdf/BC_8000.pdf

Some of the most configurable chargers I have read about seem to be the Inverter-Chargers--I know you don't need the inverter, but it may be cost competitive compared to the few other programmable chargers out there.

What is it you are looking for? Cycling golf cart batteries are not unusual and even the "simple" Iota chargers with the IQ-4 charge control module seem to keep most people happy...

https://www.solar-electric.com/search/?q=iota

Many (most/all?) have an internal 10 turn pot that can be adjusted to change base charging voltage (you have to remove an external cover to access the pot).

-Bill

bill von novak

terracore said:

I'm looking for an AC-powered DC battery charger for supplementing my battery array on cloudy days.  I am not looking for an inverter charger, or anything that starts a generator.

Because I am cheap I'd use a Meanwell 12V power supply with a voltage controlled timer.  Below 11.5 volts it turns on and supplies 13.8 volts, and then shuts off after four hours.

terracore

Thank you again everybody for your comments.

"What is it you are looking for?"   Example:   Solar panels produce 1000 watts.  Electricity needs are 500 watts.  80% of the time, everything is peas and carrots.  20% of the time, dark clouds roll in and solar panels produce 250 watts.  Since I have access to the grid, it makes more sen$e to occasionally replace 250 watts with grid power for a short period of time than buying a huge battery bank. Sometimes, it might be longer.  But whatever the case, simply looking for a plug-and-play gizmo that will sense a programmable battery level and begin charging, and then shut off at whatever programmable level I choose.  It doesn't seem like rocket surgery, and it also seems like nobody makes such a gizmo.

BB.

There are "hybrid" inverters (inverter-chargers) that can do this (I think) from Schneider, probably Outback, and others. No standalone charger that I can think of (I am not in the solar biz--So that opinion does not mean much).

In general, cycling batteries runs your cost upwards of $0.45 to >$1.00 per kWH (battery replacement costs, inverter/charger/etc. hardware costs, lower system efficiency, etc.)...

So, for most people with utility power, the cost of utility power is cheaper than the added wear and tear on your battery bank. (in California, my summer afternoon peak power costs can exceed $0.46 per kWH--So close to breaking even).

https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHEDS_E-6.pdf

If you wanted to estimate state of charge with a simple voltmeter (i.e., when battery falls below ~12.3 volts or so--ref 12 volt bank), and turn on the charger until the battery is >14.4 volt volts or so-->~80% SoC from utility charging)--Not the most difficult thing to do with a modern Raspberry Pi or Arduino or other single board computer connected to a 120/240 VAC power contractor for the external power supply AC input.

You can also go with a shunt based battery monitor and set the "alarm contact" to 50% on and 80% off (suggested values)...

https://www.solar-electric.com/search/?q=battery+monitor

Some of the Victron and Xantrex Battery monitors have the programmable "alarm contacts".

I am sure that there are other good ideas out there too...

-Bill

Estragon

It seems to me a simple float charger set to just under solar charge controller float voltage might do what you want.  It would hold battery voltage at 13.x if need be, but otherwise do nothing. To the extent possible, the solar controller would hold battery voltage higher and supply loads.  If a cloud rolls by, battery voltage would drop and the AC charger would kick in to hold float voltage.  The battery would only cycle if grid power was lost - essentially a UPS?

terracore

Maybe I'm overthinking this?  I'm currently using one of these units that detects low voltage and switches to grid until the batteries recover.  I was thinking it might be easier on the batteries (extend their life) if I didn't let them drop so far in voltage to begin with.  I think he unit can be reconfigured to turn a dumb charger on/off as well but I didn't want to lose the primary function of the unit or buy a second one if there was a charger on the market that was configurable.

https://www.amazon.com/gp/product/B07D41S7CK/ref=as_li_ss_tl?ie=UTF8&psc=1&linkCode=ll1&tag=cd023-20&linkId=9b3de391da07d45f13cc81c676e13918&language=en_US

Estragon

At 11v, you'll be taking the battery down to near dead, which will reduce expected cycle life considerably.  If it's likely this only happens a handful of time over the chronological life of the battery (eg. 5-10yrs), that's not a big deal (as the battery will likely die of old age before it dies from cycling).  If more frequent cycling is likely, shallower cycling should give you more cycles.

With true deep cycle batteries, we use 50% as a rule of thumb balance between long life and system size / cost.  This would be about 12.1v.  

Fully charged is generally ~12.7 (may vary some depending on the battery).  

terracore

I have my system to switch to grid when batteries are about 50%.  The primary reason for installing the switch was to make the batteries last as long as possible, and also I didn't want to be stuck with nearly dead batteries if the grid power goes out.  I have another transfer switch set on a timer so the system will never try to use DC power when the sun isn't out unless the AC power fails.

I've looked for a programmable float charger... no dice.  Anybody have a recommendation?

tabbycat

The Sterling Procharge series of chargers seem to have everything you need. They are marine rated so should be reliable.

mcgivor

tabbycat said:

The Sterling Procharge series of chargers seem to have everything you need. They are marine rated so should be reliable.

Translation, Marine = Expensive 

Estragon

Agree that "Marine = Expensive".  Sometimes the extra cost does have some utility (eg. better circuit board coating, water-tightness, vibration resistance, etc), but that utility may be of limited value in a non-marine application.