Schumacher Electric
This is a chinese made unit is all you'll find in local stores. IT'S A BITCH. which says Schumacher inside but isn't affiliated with any american whatsoever (it's a lie, and it's been designed by chinese to fail).
your alternative is a hugely over-price chinese unit "advanced model" which not only has the problems below probably, due to complexity of them, have far worse un-repairable problems
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* there are many too costly asian components - including 3 processors - all seemingly un-necessary to "do the job" it does. analysis: you have to pay for it and it's all the store has in stock
but we'll see this is A DESIGNED TO FAIL chinese unit. you have to pay for the gear, but the gear is DESIGNED TO FAIL
* fire hazard - the charger section is "normally charging" ... there's a coil which must be energized so that it is NOT charging. any failure of components leads to ALWAYS charging where when pick up the box it's so hot inside that the outside plastic box is warm enough to warn you something is wrong with it - even though it's not been charging anything. it has to detect a need not to charge then energize a coil to STOP charging. this also is abusive to the coil and uses power - when NOT charging energy is required in both circuit sections.
* fire hazard - not failsafe design. any failure leads to "always charging" whether connected to NO BATTERY, a charged battery, or bad battery (which is very unsafe)
* fire hazard - runs hot enough to brown-bake board it's on yet maybe not to desolder itself
* despite all the components, it always powers two circuits whether or not connected to a battery
* the 12V switch falls to 6V about 1x a month. it damages the battery un-attended by forcing it down to 6V and keeping it there until you walk by and notice your "tended" needs tending itself.
* the wires ends are unsafe. they aren't far enough apart to connect to a car battery. when you pull apart (in the winter) even using a too for insuring that "goes right", the plastic splits in the cold weather.
* if unplugged the battery backfeeds into the unit, causing a drain on the battery if your home's power is out
* when a 470uF 25V capacitor bulges on the charging circuit, the unit runs unusually hot whether not charging or connected to already charged battery. the cap failure cause an "always on" situation. as i said before - any component failure MUST lead to 0 charge 0 heat. why is because we all know charging a car batter is A DANGEROUS JOB (education on why that is, is omitted)
* (still testing, apparently true) when that CAP is replaced - the unit appears to work but no longer "monitors" the battery ... indicating one of the 3 chinese chips (which are NOT replaceable, education omitted on why) are blown out due to the failure, and the "tender" has become a rudimentary small cheap charger, not a tender. it no longer blinks to orange to check for trickle charging
it's supposed to TEND the battery un-attended safely: not destroy your battery and possibly burn your house down.
destroy one battery you've killed off more than you paid for the charger, now need both a battery, charger, and perhaps a cab ride