Is this maintainer safe for my AGM Sprial cells?

[Johnny248]

As I posted before, I found out my HF Float chargers are not safe for AGM batteries. In fact, last winter, one ruined my Optima Red Top while floating side for the winter.

Anway, I have:

Optima Yellow
Optima Red
Exide Orbital Blue
Exide Orbital Red

This Shumacher maintainer is is $21 at Wal-Mart, it says "multi-stage" on the box which I think is what is required for AGM Batteries. I am thinking that I can buy four of these for the price of two "Battery Tenders". Do you guys think this is safe to maintain my batteries?

http://www.batterychargers.com/ProductDetail.aspx?ProductName=94026970

Also, what are your thoughts of wiring the four batteries in parallel with this one maintainer on it after they have all been up to full charge?

 

[wrcsixeight]

What voltage does your HF maintainer bring the batteries to?


Multistage usually refers to bulk/absorption/float stages of charging. I have never before seen a maintenance charger call itself multistage.

My Schumacher charger 2/12/25 amp charger will take the battery voltage much too high.

AGM batteries self discharge so little, I'd consider just getting a timer and run the HF maintainer for an hour a day or less to keep them at full charge. I would not keep 4 batteries paralleled when on a timer.

I think the HF maintainer would be incapable of bringing 4 paralleled batteries to too high of a float voltage. You need to make sure they do not stay over 13.6 volts at 75 degrees f

 

[Warstud]

I picked up the SC-1200a at WM for $35....it's a 2v-8v-12v that goes into float mode after it's charged.

http://www.batterychargers.com/ProductDetail.aspx?ProductName=94026806ACP

 

[Johnny248]

According the the HF Manual, it says not for use on AGM batteries, and the specs show as:

Output 12v
Capaticity 5-125 Ah Batteries
Maximum Output 13.2v

Here is a link to the product.
http://www.harborfreight.com/automatic-battery-float-charger-42292.html

The Schumacher manual shows specs as:

Output Current Rating 1.5a
Max Charge voltage 14.8v
Maintain Voltage 13.3v

and the box says:

- 1.5 Amp / 18w 6v/12v Automatic Maintainer

- Microprocessor Controlled Multi-Stage charging for added precision, safety & battery life

- Float Mode Monitoring automatically maintains optimum battery charge

- Auto voltage detection automatically detects 6 or 12 volt batteries.

and back to the manual:

The unit has Four LEDs on it.

A/C Power
Connected
Charging (lit is charging, flashing indicates battery problem)
Charged (indicates fully charged and in maintain mode

It also shows different battery types and estimated charging time, and as far as maintain it states

"when lit, the charger has started maintain mode. In this mode, the charger keeps the battery fully charged by delivering a small current when necessary. If the battery voltage drops below a preset level, the charger will go back into charge mode until the battery voltage returns to the full charge level, at which point the charger will return to maintain.

NOTE The maintain mode technology utilized in Schumachers maintainers allows you to safely charge and maintain a healthy battery for extended periods of time.

 

[Johnny248]

Originally Posted By: Warstud
I picked up the SC-1200a at WM for $35....it's a 2v-8v-12v that goes into float mode after it's charged.

http://www.batterychargers.com/ProductDetail.aspx?ProductName=94026806ACP


I have this Napa by Midtronics charger also, 85-437

http://www.napaonline.com/Search/Detail.aspx?R=NBC85437_0006389653

and it has a switch for AGM or flooded, but I'm not sure if it has an actual float mode or not. It does 2amp, 10amp, and 60amp.

 

[dwendt44]

Don't they usually have a unit on display that's out of the box?
they do at the local Wally Worlds. The box and the owners manual should be around somewhere. Ask and read the book.
It should say something about the AGM batteries.

My 2¢

 

[wrcsixeight]

My main complaint with my 2/12/25 amp sc2500a Schumacher is that it doesn't always go into float when it should, but keeps raising the voltage into the high 16's, well after my amp hour counter says the batteries are full.

Sometimes it will shoot so high it turns itself off.

I have to monitor it, until it goes into float mode.

Float mode on flooded or deep cycle is 13.2, on AGM/Gel setting it is 13.6.

 

[Warstud]

I called Shumacher on that same issue because my charger said 100% charged and voltage was 16.8v ...which seemed high. They said it can get as high as 17v. I'm guessing it's the surface charge.

 

[Johnny248]

Originally Posted By: dwendt44
Don't they usually have a unit on display that's out of the box?
they do at the local Wally Worlds. The box and the owners manual should be around somewhere. Ask and read the book.
It should say something about the AGM batteries.

My 2¢


It does not say anything specific one way or another.

 

[Corvette Owner]

I have a small switchable 1 amp / 2 amp battery tender. They say the 1 amp is for AGM batteries. Have been using it on my Corvette for several years with no problem.

 

[Mr_Accord]

Do yourself a favor and get a CTEK charger

...Amazing little charger that supports a wide variety of different batteries including AGM its a great plug it and forget type of auto charger for storage batteries.

http://smartercharger.com/ctek-multi-us-3300/

 

[unDummy]

Pick any charge that offers AGM. The simpler it is, the better. I'd recommend that Napa one mentioned over the Schumaker.

Battery tenders that are plug-in and forget are useless. Pick any simple charger you want. Use a outlet timer and set it to work an hour every day. There is no need for a tender to be connected and powered 24/7 for the entire winter.

Most newer chargers, that are overly electronic, will fail you if you have a power surge, storm/lightning, or power outage... Then, your battery will either be cooked overcharged or drained dead.

For anyone with a Schumaker voltage issue, what DMM are you measuring the battery with?

 

[Errtt]

That CTEK is a slick looking unit.

I have had good luck using the BatteryMinder 12248 for AGM