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  Topic Review (Newest First)
07-01-2008 04:55 AM
Rockter Stsrt the motor and put a wee multimeter over the battery terminals to see if it's charging. It should read about 14V if it is charging.
06-30-2008 10:46 PM
SEMIJim Both our boat batteries, one new last season and one at least a season old, I imagine, sat in the garage all winter. Hooked them up to the plain old Sears automotive charger prior to putting 'em back in the boat this spring. The older battery was a bit reluctant to take a full change, but, ultimately, it did. I start on "both" and the ammeter usually settles back down to "0" pretty quickly, despite the fact we've been experiencing hard starting, the 1st start of the day, so far this season. (The boat has a TrueCharge 10A [per battery] charger running off of shore power.)

We've got a commercial lawn mower. 16HP Kohler engine. It's got a fairly large (for a mower) battery in it. It sits out in the micro-barn from the last cutting in the fall to the first cutting in the spring. The original battery, after about 3 seasons of that, needed the charger for the first start in the spring. It wasn't until season 5, I think, that it finally gave up the ghost and wouldn't hold a charge anymore.

I find it hard to believe storing a new battery for several months off a charger did any serious harm to it, but I'm willing to be proven wrong.

06-30-2008 08:57 PM
Originally Posted by hellosailor View Post
Which magic elixir was that? I've yet to find someone who used one, and still had good batteries six months later. But I'm willing to look & learn!
I used "Battery Equaliser", but in all honesty I think reviving the batteries had a lot more to do with modern microprocessor controlled charger than with that stuff (hard to tell now, I did both things at about the same time).

I am yet to try using equalization mode of the charger - may be my battries will be even more lively then (but in any case even 70% of the full charge is plenty in my case).

Those automotive chargers are definitely not very good, and my past experience with them was pretty marginal - they certainly don't charge a battery to a full capacity and won't bring back it's useful life.
06-30-2008 07:52 PM
Battery on concrete

helosailor-----------Was returning faulty in warranty battery at the time.
06-30-2008 05:35 PM
Trekka I have taken batteries that appeared to be lost, such as described in this thread, and by charging using a modern charger brought them back to usuable life. Modern chargers, especially if using their restorative modes, can often revive batteries. Anyone not using a micrprocessor controlled 3 or 4 stage charger is abusing their batteries. Those basic automotive battery chargers are crude and hopelessly obsolete.
06-30-2008 05:29 PM
hellosailor Brak-
Which magic elixir was that? I've yet to find someone who used one, and still had good batteries six months later. But I'm willing to look & learn!

The concrete story has been repeatedly debunked for modern batteries, I find it hard to believe Interstate themselves would tell you that in the last 40 years. Concrete as a problem with old porous battery cases, but for modern plastic cases? Absolute nonsense. The only problem with concrete is that it usually means a slab floor, which is cold, and cold hastens self-discharge and damage. The concrete itself matters about as much as the color of the paint on the car/boat that the battery is located in.

From Interstate's own web FAQ pages:
Interstate Batteries FAQ :: Does it hurt my car battery if I set it on concrete?

A: No, the type of plastic (polypropylene) used in battery cases today is a great electrical insulator, therefore cement causes no electrical discharge effect to the battery. "

Once upon a time, battery cases were wood covered in asphalt, I believe, and that was replaced by "hard" rubber, but plastic has been the rule for a very long time now.
06-30-2008 04:35 PM
brak I had my deep cycle batteries sit all winter prior to buying the boat (and who knows how long before). I had them charged with a less than satisfactory charger last season (before switching to smart charge) and this winter they were on a single small solar battery (which probably did not make enough difference).

In may I charged them one more time with old charger, and it appeared that they are nearly dead - low voltage, not enough power. Then I did two things:
1) added sulphur removing liquid
2) used smart charger to charge them properly (it took a day from where the old charger thought it was done).

The result - batteries are holding 70-80% charge (relative to what they should) and work great.

The lesson here is - sometimes "dead" battery isn't.
06-30-2008 04:21 PM
Never ever

I have been told by Interstate Batteries to never leave a battery sitting on concrete for any length of time because this will hasten discharge. Set it on a piece of wood or a couple of wooden slats so it's not sitting directly on concrete.
06-30-2008 01:59 PM
sailingdog I hope, by trickle charger, you mean an intelligent three-stage charger. A 2/10 amp car battery charger will do a pretty good job of frying a deep cycle battery if you're not careful.

The alternator may read as high as 15 volts... depending on the RPM of the engine, the charge level on the battery and whether it is internally or externally regulated. Anything above 14.7 or so is going to boil off electrolyte in the battery if used for an extended period of time. As HS has said, it should read about 14.4-14.6 Volts at cruising speeds.

Originally Posted by northstarjim View Post
Thanks guys - I figured as much. Next winter -what should I do? I have both a trickle charger and a regular battery charger - should I just use the regular 10A charger every couple of weeks or so? or keep the trickle charger attached for longer periods?
Also - how exactly do I check the alternator output? Attach the positive lead at the positive terminal of the alternator and the negative to the other/ground terminal? I assume it should read aroung 13 volts?
06-30-2008 01:47 PM
hellosailor Either one would do, I'd suggest the trickle charger since it is "enough". How long a period will depend on the amperage it supplies versus what the batteries need. But also, since AGM batteries can't leak acid, you don't need to hide them, you can put them wherever it is convenient.

To check the alternator output, put the plus and minus probes from the meter on the matching battery terminals (an easy and safe place to access) while the engine is running. At "cruising" rpms, you should see 14.4 volts, sometimes as low as 13.8 volts depending on the system and the battery condition. Off by a point or two doesn't matter, there's some float in the meters and tolerance in the systems.
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