Best Charger for Lead Acid AGM 12v 100ah battery

[poloman]

I've had poor experience with reliability on that particular NOCO model, although the other Genius chargers have been excellent. Other brands/models that I know to be good are:
Xantrex Truecharge2 24V - These have an available temperature sensor for temperature compensated charging
Samlex SEC-series 24V - Good reliability, but no temperature compensation

Is it fine that Samplex is 3 Bank Charger? Will all the AMP still be available when used to charge 1 battery (2 connected in series)?
For example this model -> http://www.samlexamerica.com/products/ProductDetail.aspx?pid=174
Will it have 15A or 5A when used as 1 bank?

 

[mellowhead]

To get the most life, those cheap AGMs need as much care in charging as any other AGM. It's the construction that dictates the requirement.

East Pen /Deja has some quality to it but its cycle life is rather middling compared to better deep cycle AGMs.

Indeed, getting the right AGM is important. In the same way a person can buy a starting battery for their car vs a deep cycle battery for their boat or RV, there are AGM batteries intended for different purposes as well:
standby use; UPS's, power conditioners, building alarm systems, fire panels, emergency exit signs, etc...
and cyclic use; traction equipment, materials handling equipment, floor cleaning, mountaintop radio repeaters... the list goes on.

Even within a given brand, there are often multiple "series" of batteries to meet different industry needs. For example, under the Enersys brand, there are probably (without counting) close to a dozen different AGMs available.

 

[mellowhead]

Is it fine that Samplex is 3 Bank Charger? Will all the AMP still be available when used to charge 1 battery (2 connected in series)?

Yes, you can use only one output of the three and still get the full rated current output.

 

[poloman]

Guys, just want to thank you for your posts. They've been very useful and taught me a lot.

Bought 3 of these chargers -> http://www.samlexamerica.com/products/ProductDetail.aspx?pid=174
They have 3 stages:
Stage 1 - Constant Current or Bulk Charge Stage
Stage 2 - Constant Voltage or Absorption Stage
Stage 3 - Constant Voltage or Maintenance Charging Stage

There is the caution:

3 stage charging is recommended for charging stand-alone unloaded batteries (there is no load connected to the battery when it is being charged).

If a load is also connected simultaneously, a part of the charger's output current will be diverted to this load. Thus, the charger may remain locked in Stage 2 if the current drawn by the load is more than the preset value of threshold current determining transition from Stage 2 to Stage 3 .This will lead to overcharging and loss of electrolyte

For charging a battery when a load is also connected simultaneously, Stage 2 is required to be disabled. (Select 'Battery with load' using DIP switch)

When batteries are connected to controller/throttle and motor. But motor is off. Does it count as 'load'? Can we still use 3 stage charging, or must we choose 2 stage(disable stage #2)

 

[mellowhead]

By that, they mean a continuous load. For you, 3 stage is the way to go. Unless you hook up and find that there is a considerable quiescent draw, but that shouldn't be the case.