AGM Battery maintenance/charging for dummies?

[dwh]

Bringing back a dead Optima using their second battery scheme can be done by any battery charger. The reason for the second battery, is that some chargers will give up if the battery is at too low of a voltage.

My antique Shauer charger will do it [EDIT to add: without the second battery]. It's too stupid to know how to give up. It has an internal auto-resetting breaker, so it tries until it gets too hot, then the breaker kicks. Then it cools off and tries again. Over and over. Each time a little juice gets into the dead battery. Eventually, the battery voltage rises enough, that the charger can actually start doing a proper charge.

Now...whether getting a charge into that Optima will actually bring it back from the dead...who knows. It might take a full charge, and then be dead the next day. You'll have to see how it goes.

 

[wrcsixeight]

Lots of guys over on RV.net rave about this charger:

http://www.amazon.com/Black-Decker-VEC1093DBD-Battery-Charger/dp/B000EJQJ1G

 

[dwh]

Lots of guys over on RV.net rave about this charger:

http://www.amazon.com/Black-Decker-VEC1093DBD-Battery-Charger/dp/B000EJQJ1G

Yea. I dunno about that one, but one problem with a lot of the "digital control panel" chargers is they don't hold their settings if you unplug them. So, if you use it in an RV, then every time you plug into shore power, you've got to diddle the buttons on the charger.

I prefer one that is configured with dip switches. Set it and forget it.

 

[dwh]

So would this be suitable? http://www.northerntool.com/shop/tools/product_200483765_200483765

Is there any advantage to going with the Guest Charger? http://www.westmarine.com/webapp/wc...151_10001_29100_-1____ProductDisplayErrorView Is the 10amps of the Guest a significant improvement over the 8amps of the BatteryMINDer?

Will either/both of these bring back a 100% dead optima without the trickery of putting a good battery in parrallel?

The Battery MINDer is a good charger. I would buy one, but not for my use. I regularly recharge the house battery in my camper from a little generator because I like to spend a week or more at place when I find a site I like. So, using an 8a charger is going to require double the generator run time of a 15a charger. I don't want to go larger than 15a though, because I'm only using a 105ah flooded deep cycle battery and don't want to put too much charger on it.

The difference between an 8a charger and a 10a charger? Depends on how you do the math. It's 20% from the top down, or 25% from the bottom up.

 

[dwh]

Hey, wait a minute. I just noticed that the Battery MINDer you linked to at Northern Tool is one of their TWO AMP units. That's NOT the 8a version.

Here's the 8a version:

http://www.amazon.com/BatteryMINDer-Volt-Amp-Battery-Charger/dp/B000X2B0RW

 

[Arya Ebrahimi]

Oops! I knew I didn't want the 2A version but somehow overlooked it. Since the 8A version is basically the same price as the Guest and I can get the Guest locally, I think I know what to get now.

Thanks!

EDIT: On the other hand, that charger you posted has some pretty nifty features. Any idea how weather resistant it is? Mine would be mounted in my trailer which is weather resistant but not water tight. (Build thread is on the first page of the expedition trailers forum titled: Mobile Base Camp Build)

 

[dwh]

EDIT: On the other hand, that charger you posted has some pretty nifty features. Any idea how weather resistant it is?

Oh sure, I know exactly how weather resistant it is. Not weather resistant at all.

No biggie for me, it'll be inside the van.

 

[takesiteasy]

Oh. And I wouldn't have any problem at all with using the Battery MINDer (which is not the same as Battery Tender) charger and letting the IBS tie the batteries during shore power charging.

Thanks for the info- I actually have the Battery Tender Plus. I will look into the Battery MINDer.

So, there's no provision with this system to manually separate the batteries? Probably too late now but I'm talking about something like this with an ON/OFF/AUTO feature where the switch is in the cab.

Yeah, the off feature would be a good addition to the IBS. You can manually link them but not the other way around.

 

[1911]

Oh. And I wouldn't have any problem at all with using the Battery MINDer (which is not the same as Battery Tender) charger ...

But that's the Battery MINDer - I wouldn't do it with any *other* 3-stage charger.

The little 8a charger will get them both fully topped off and then float them. And, who knows...the "de-sulphation" might actually be good for the batteries.

I own enough equipment and vehicles (including at least four or five AGM batteries) to use a fair number of trickle chargers/battery maintainers, and have tried several different brands over the years. In my experience, the BatteryMINDer is superior to all others that I've tried, including the name-brand Deltran Battery Tender. You can buy the BatteryMINDer very reasonably at most chain auto parts stores and at Northern Tool. NT puts them on sale a couple times a year.

 

[FusoFG]

There are of course, a few exceptions to the rule. Interstate as I recall has one flooded battery that they recommend taking up to an unholy 15.8v (as if there is actually a charger on the market that can do that...

I have a Xantrex xc 5012 50 amp charger that will charge up to 3 isolated battery banks that can be any combination of FLA GEL or AGM.

It will operate either as a 2 stage (bulk, absorb, off) or a 3 stage (bulk, absorb, float).


It also has an equalization mode to desulphate FLA batteries. In that mode it charges at 15.8-16.0 volts for one hour then switch back to normal charge mode.

It will charge a dead battery.

My 2 FLA engine starting batteries are 9 years old and after sitting idle over the winter they wouldn't hold a charge and the specific gravity varied from red to green in the 12 cells.

After 4 equalization cycles all the cells are in the green and the batteries are fine again. The charger manual recommends equalization at least every 12 months.


The house batteries are 3 yellow top optimas that are 8 years old. (I have 4 other yellow tops in various vehicles that are still going strong after 11 years.)


I have a Yandina battery combiner with a remote switch that can be set to separate / automatic / combine.

I set it to separate when plugged in and let the charger charge the engine batteries and house batteries with the correct volts for each type. I set it to automatic when unplugged and the house batteries are isolated from the engine battery and when camping and combined when the engine is running. The combine position allows the house batteries to jump start the engine if necessary.

If I ever replace the engine batteries with AGM batteries I will leave the switch in automatic when when plugged in.

 

[taugust]

I have a Battery Minder as well. I recommend it, but it does seem to have one shortcoming. It doesn't want to recharge a dead battery. It will charge for a time, then kick out of its cycle. You could try this several times to get enough charge in the battery for it to do its thing. I have taken to bulk charge on an older 10a charger for a few hours to get the state of charge up to a reasonable level, then switch to the Battery Minder to top it up and desulphate. I rotate 3 batteries on it for a week at a time each to keep them maintained and topped up.

It brought back a FLA that someone had thrown out as dead.

 

[1911]

I have a Battery Minder as well. I recommend it, but it does seem to have one shortcoming. It doesn't want to recharge a dead battery.

Though to be fair, a trickle charger/maintainer is not designed for this purpose - better as you say to use a higher-amperage charger to get them up to some reasonable state of charge first.

 

[cnynrat]

Just another option to consider: When the Deltran charger in my AT Horizon failed I talked with AT about what they recommended replacing it with. At the time (~2 years ago) they were using the NoCo Genius chargers. The chargers in their Marine product line are fully sealed if that makes a difference to you. I've had one in my trailer since then and it seems to take good care of my AGM battery.

 

[timber]

I have had good luck with the NOCO Genius. Here is the one I have been running for a year and a half or so.
http://www.geniuschargers.com/GEN1

 

[slomatt]

+1 for the NOCO Genius. I bought a G1100 for use with a 28ah AGM battery and it is working well.

- Matt