What type of shore power chargers do you use?

[John61CT]

Yes, all lead batts need 3 stages, 2 transitions to be precise.

The first transition from CC (Bulk) to CV (Absorb) requires nothing from the charger but a max voltage, it is controlled by the batt chemistry.

The second transition to Float should only take place after endAmps show the bank is 100% Full.

Only few and usually expensive charge sources do that properly.

Just a basic egg-timer for Absorb Hold Time isn't "smart" enough. User-adjustable, a bit better.

Smarter is an algorithm that uses a sliding multiple of the time it took to go from CC to CV, usually not user-adjustable, but if so even better.

Really doing it right requires integration with a shunt-based Battery Monitor.

So if you need proper automation *and* a high amp rate, be prepared to spend at least a few hundred, maybe less if second-hand.

So if you're on a budget, being the regulator yourself, doing it manually,

with a decent current-limited adjustable Power Supply,

no "smart charger" trying to automate things,

is a good solution.

 

[Weight]

The Experts have gone off thread. OP has one small battery he wishes to charge. Not massive truck starting batteries. A charger from NAPA or Sear's or such will recharge the battery. OP will have to disconnect when the battery is charged as the cheap charger doesn't turn off. But under OP's observation there is no reason it will not work. The charge maintainer will probabley recharge the used battery in a couple or three days.

 

[jimindenver]

It is pretty simple math really. How much power will you remove nightly? How many amps is the maintainer rated for? How many watts is the in dash inverter rated for?

A 66 Ah battery is not small. You need to provide it with enough incoming power not only to over come the self discharge but also charge it. A factory installed inverter is rarely big enough to handle much.

It is not easy to provide a answer when you do not have the info needed to say it will or will not work. So either provide the basic info or make a test run and see what happens. Personally I am a big fan of push the button and see what happens. Otherwise the math is pretty simple. Take 10 amps out and try to recharge with something intended to keep the battery from discharging which takes a certain amount of power to begin with is a pretty low possibility of success. I would love to say it will be okay but when it fails I will look like a dumbass.

Again, a set of jumpers between the starting battery and the house battery every night for a short time will provide much more power while running the vehicle than using a maintainer while driving all day. You could reverse it and charge the yellow top and use the starting battery as a house bank if you actually use that little power. Should you use too much you can use the yellow top to jump the starting battery and get going again because the the starting battery is going to recharge much faster than the yellow top ever will on the maintainer.

You do have a set of jumper cables already I assume. Nothing to buy and much more effective although I do suggest that you get something decent to recharge the yellow top in between trips. You need a battery charger, not a trickle charger.

 

[DLTooley]

As 'weight' above noted the Yellow Top is a dual purpose battery. You are right to have caution, but I think you are all good - so long as you maintain that caution as what you are doing is not standard.

If the fan is your only load you might not need any charging at all over four days, but you do want to watch the state of charge on the battery, a good habit to start, and keep.

I think the trickle charger would work. Most are at 3 amps as I recall, so if you discharged the Yellow Top 24 amp hours it would take 8 hours to recharge it. And you pretty much only want to do that when you are driving. Charging directly from the alternator is much quicker, but I think that is something you DON'T want to do through a cigarette receptacle as the load is probably too high.

A direct wire from the starter battery terminals is the best way to do this, distance and wire gauge matters as the precise charging voltage will drop the farther away you are. A manual connect/disconnect or a simple switch would work occasionally. I've used cheap household light switches on 12v, but not for that heavy of a load.

The best solution might well be to swap out your starter battery for the Yellow Top. Do note that according to optima the Yellowtop is only rated for 300 discharge cycles (doesn't say how deep), and that's not a whole lot.

I have a Red Top Starter, as I recall it is 35ah - I'd guess the only difference with the Yellow Top is the added capacity.

This does sound like a good learning setup, if an unusual one. In-line fusing is something you should consider.

One place to search for that is Amazon - I found a cool ciggy receptacle volt meter that also had USB ports and an ammeter for less than the Walmart price. Don't leave it plugged in when you are parked for an extended period!

 

[John61CT]

I think the trickle charger would work.

It won't. They are for maintaining a full battery on float, fighting self-discharge while in storage.

Completely useless for recharging any battery that's depleted more than a few percent.

 

[Scout]

Thanks for all the replies. There's alot of good information here. I'll have to read it a few times to get it all. I didn't know the yellow top was dual purpose ill have to look at that. I used to use it for a winch on my trailer and itd pretty old so I'm not so mych worried about destroying it. More it blowing up or leaking. Sounds like an experiment ill let you know how it goes.

 

[DLTooley]

It won't. They are for maintaining a full battery on float, fighting self-discharge while in storage.

Completely useless for recharging any battery that's depleted more than a few percent.

As I also stated, (most) trickle charges provide 3 amps and that will limit the effectiveness.  At this bank size it isn't completely useless, and for a four day trip it may be all the OP needs.