Will you be using any of your battery powered devices when this battery charger is running, or will this battery charger be put on a battery that has NO major loads on it, Like not even a fully charged cell phone?
These garage chargers are not made to power dc loads and charge the battery at the same time. They might get confused at sudden increases or decreases in amperage required to maintain a voltage, When they get confused, they shut off, but there might also be wild voltage swings when loads are removed.
I have a similar Schumacher to the one you linked, but it is dangerous, in that it will take battery voltage way too high at too high an amperage rate.
I am not familiar with the one Bob linked but Some others have reported voltage over 16 with similar shaped models.
How much charger you require is based on how much battery you have, and I assume you will Start with a wally world group 27/29/31 marine battery.
i would get at least a 12 amp charger for such a battery if one has many hours to plug in, or minimum of 20 amps if time is limited.
If you do not want to have to upgrade later and thus spend even more money, the Iota DLS-30 is a 30 amp charger which is fully automatic, no buttons to press. But one does have to Hook up cables from it to the battery.
http://www.bestconverter.com/Iota-DLS-30-With-IQ4_p_335.html#.WKZ-KdIrKQM
The IQ4 in the model name is required for it to be a 3 stage charger
A group 29/31 battery can easily accept 30 amps no problem, and can also later properly charge a pair of golf cart batteries. Which should get a minimum of 25 amps from a plug in charging source.
Now If one is not using a single of the cheapest of group 27 or group 31 AGM batteries, then one can spend a little bit more and get a 45 amp Converter.
If 45 amps is an option, on this initial or future batteries, then i would recommend the progressive dynamics PD9245, either the standard model or the 14.8v model available here:
http://www.bestconverter.com/9200-148-Volt-Deck-Mount_c_227.html
With the 'remote charge wizard pendant, one can press a button and choose 3 different voltages, but it does ntoe require this input, it is fully automatic.
45 amps is a bit high of amperage for a single100AH marine battery to see every single recharge, but it can handle it. The alternator would feed it that much and perhaps much more, if a jumpstart were ever required.
There is lots of fear of fast recharging batteries and lots of misinformation about 'trickle' charging always being best.
If one has all the time in the world to recharge, and the trickle charger(~ 2 amps) will seek 14.4v or more, then it is better for the battery to be slow charged.
But when the battery needs to be fully charged within 8 to 12 hours, well it is less abusive to battery to recharge at a high rate, than to slow charge it and then have to deplete it much further that night.
Also A high amp recharge is kind of like a slap across the face and a strong coffee administered to a battery which is punch drunk from many partial recharges and many deep discharges.
Do not Fear the high amp recharge, except in very hot ambient temperatures with a very depleted battery.
And the cheaper AGM batteries say to imit amps to 30 per 100AH of capacity. Exceed this rate only if one is able to monitor battery temperature when charging from a low depletion level.
120F is too hot.
Converters do Not care if there are DC loads on teh system while charging the battery. this can be a big plus if one is running a refrigerator while charging the batteries and one is using a 'garage charger'
So This could be one of those things where you can buy the better product now and use it later when you get more batteries, rather than spending less for something inadequate for later.
If you go for the converter over a garage charger, one will need to provide the DC cables to battery. once one knows the length of these DC cables, and can order custom cables from here with top quality tinned copper and ring terminals.
A 4 foot 4 AWG cable with a 1/4 inch ring terminal on Only one end is 11.02$
http://www.genuinedealz.com/4-awg-custom-battery-cables
This is a great price for top quality cable professionally crimped with adhesive lined thick wall heat shrink tubing, with free shipping. Many miles better than a 4 gauge SAE cable sold in auto parts stores, for a similar price.
The end which goes into teh IOTA, one simply removes about 1/2 inch of wire insulation inserts it into the receptacle, and Tightens a Hex or slotted screw down on the stranding. There should be an inline fuse rated to protect the wire Gauge chosen. One choses gauge based on length needed, and for minimal voltage drop at the converter maximum amperage output, but I would not go thinner than 8 awg for 45 amps, and 4AWG would be much better, but kind of overkill
If you later get a pair of golf cart batteries, getting the Iota DLS-30 or PD9245 now will be less expensive than having to buy something lesser now and then getting the 30 or 45 amp converter later.
