Looking at this on board mountable Battery Tender charger here.
Waterproof Power Tender Plus 12V @ 5A - Automotive - Batterytender.com
I have 2 new AGM Optima Red tops. Is 5 amp charge too much as I see most others doing 1.5amp. If so, the next step is the Battery Minder which also does AGM batteries but has a little more on it than I'm looking for:
BatteryMINDer® 12-Volt 2, 4, or 8 Amp Charger-Maintainer-Desulfator-Conditioner w/ABS-248 | All | Battery Chargers by BatteryMINDers.com

Planning on doing the Marinco plug in the bumper for the block heater & the charger. Not sure yet if I should go with separate Marinco plugs or one for heater & charger. Any thoughts?

 

http://batterytender.com/includes/la...e001e495eac704

 

I have this same one and am very happy with it. That's the one the folks at Battery Tender recommened since you are maintaining two batteries. I bought mine through Amazon for much less.

 

I don't think 5 amps is too much, since the Battery Tender is a controlled charger, it will determine the voltage based on whether the batteries need charged or maintained. Given that, I prefer the battery minder. Theoretically, at least, it will help your batteries last longer. The one I'm using on a deep cycle has been sitting for 5 years now and the battery still works as good as new.

I would do separate plugs. If you need to let the truck sit, you want to be able to maintain the battery without running the block heater. The block heater doesn't need to run all the time and draws a lot of electricity.

 

Thank u David & rsmarcil. Perfect point David, definitely going with 2 Marinco plugs.The Battery Minder does look superior. My concern is the AGM batteries. The Battery Minder does have a switch to choose what battery type you are charging. The Battery Tender does not so my question would be how does it know? Here is the Battery Minder up close........
http://www.batteryminders.com/batter...ages/12248.jpg

 

I have been using the battery tender charger for 4 years to keep my jet ski batteries charged. One of the skis has an AGM battery, one is a traditional battery. The battery tender has worked well for both types.

I also have a sears/craftsman mounted in the truck that I plug in occasionaly when i use the block heater.

 

Thanks Craig. Still researching here & hope to pull the trigger soon.

 

Im getting down to the wire here guys. Gotta order something tonight. I really would like to do the Battery Minder but it not being meant for mounting in the truck is really not leaving me with much of a choice. The manufacture states it will be allright buy I don't know with all the heat, vibration, humidity, etc & it not being sealed like the Battery Tender. I'd hate for it to malfunction due to the enviroment & I end up with a big .

 

Read the "features" tab on the battery minder.

And it has mounting tabs. It looks like it was designed to mount.

 

This is the one I'm looking at David & all I see is water resistant. Website also states for "benchtop use". I do see the tabs for mounting. I was told by Battery Minder it would be better mounted in the cab. I don't know if I wanna do that.
http://www.batteryminders.com/batter...M-p-16179.html

 

That one says it is for AGM batteries. How about this one. It is designed to be mounted and is water tight with the same protected circuits as the other one.

BatteryMINDer® 12 Volt 1.5A OnBoard Battery Charger/Maintainer/Desulfator/Conditioner Model 12151 | Automotive Battery Chargers | Battery Chargers by BatteryMINDers.com

 

When I talked to the rep I did inquire on that particular model at first because looks like that is their only robust "onboard" charger they offer. They told me because I have AGM batteries (Optimas) that it would not charge my batteries to their full potential nor float them at the higher voltage that is required. Looks like this one may be my best bet for whats out there.

 

Maybe a silly question but do you need 2 of these since we have 2 batteries? Thank you.

 

I missed that you had AGM batteries. So you need the AGM one, or the first one you linked. This one.

BatteryMINDer® 12-Volt 2, 4, or 8 Amp Charger-Maintainer-Desulfator-Conditioner w/ABS-248 | All | Battery Chargers by BatteryMINDers.com

It's quite a bit more expensive, though.

As long as both batteries are the same (which they should be) one will do.

 

The only difference is in the software. Reg one floating at 13.2 or the AGM float 13.7 I don't see it to be that important when we are talking half a volt do you?