What comes first, the charger or the batteries

[Guaranteed]

Hello,

I’m having some confusion on my new to me boat regarding the power system. These are pretty broad questions and I’ve been reading but think I need some more pointed insight or confirmation.

While on shore power I see my batteries discharging sometimes..this happens with very limited draw.. maybe a few lights and the fridge running..
How can this be? Charger should convert to DC and supply what is needed and give the rest to the batteries? I only see maybe 5 amps coming from the charger with amp clamp.. it’s a 30 amp charger.. with batteries at 50% shouldn’t I get a crap load of amps to charge my batteries before I hit float? Which seems I rarely do even on shore power.

Also... while looking into my system I see the alternator is 4amp 12v?? 4 amp alternator?? How can that charge my bank... I’ve seen alternators in the 50-100 amp range

I believe my equipment is suspect

I have a Charles 9000 battery charger year unknown.. that always hums but I see no amps on the built in meter..

My batteries are 2 -cabela group 24 75amp hr.. crap

My alternator is prestolite 4amp 12v.

My theory is my batt charger is crap.. only supplying +/- 5 amps
My batteries are crap.. AGM that never get full charge so killing them.
My alt is very confusing as I can’t find any literature on it.. but by the sticker on it ... it’s crap.. 4 amps will not charge anything.. and I have started the motor and see no amps on the installed amp/volt meter in the nav station

Do I need complete and total system overhaul or can I get something first before the other... charger first.. then batts then alt?

Thanks

[a64pilot]

Is your charger rather large and heavy and has a 60 hz hum when operating?
If so then I’d suspicion it’s an old dinosaur like mine was, a monstrous heavy transformer that had only one voltage output, no three stage charging. It worked sort of, but nowhere near as good as a modern three stage charger.

I’d look into getting a good, modern three stage charger, and be sure to get one that the voltages are individually adjustable, programmable if you will not one that only has two or three battery types to chose from.
Depending on how much money and what your goals are, you may want to check into a combination charger / inverter.

I can’t imagine a 4 amp alternator myself can you post a picture of it?

I would say “fix” your shore charging first if In fact it’s what I suspicion it is, assuming of course your often plugged into shore power or use a generator to charge, if not then forget it until later.

I would go to a big charger, say 60 amps, that will shorten charging time if you ever use a Honda etc. and it’s my belief that chargers etc will last longer if they are not always running near wide open. That generated heat and heat seems to shorten electronics life.

[Guaranteed]

Hi thanks for the reply... the boat is an 86 Catalina.. I believe a refit was done in 2006.. I imagine the charger must be from that era.. yes it looks pretty basic.. didn’t see any dipswitches.. silver stainless case
I’ll work on posting pics of both

[Guaranteed]

[Guaranteed]

[pcmm]

Originally Posted by Guaranteed

Attachment 194320

I had one of those, similar symptoms. Humming right along but not charging batteries. Junk it and get a Promariner Pronautic 40 amp charger. Those old Charles feroresonant chargers will ultimately kill your batteries as they don't have 3 stage charging like a modern charger will.

I suspect your 4amp alt is 4amps of excite current not output. the model number is the model of the regulator not the alternator.

[Guaranteed]

Great! Thanks for the confirmation on the charger. I couldn’t find ANY info on the alt.. I’ll keep looking.

I’m mostly day sailing but plan on some overnights and a week on the hook for July 4th.. do you think a new charger will be able to muscle my batts thru for now?

I have 200 watts of solar and since I have been actively trying to figure this out I went to the boat yesterday afternoon and it was the first time I saw them at 100% 14.7... they soon started to fade to 13.3 that evening... all the while being on shore power

Now I’ll go there.. how about a few recommendations for charger/inverters and batts... I’ve seen a lot of talk about firefly for gel and golf cart 6v Duracell? ... I guess a no on standard AGM... don’t really want to get into a big refit project right now but I also only want to spend the money once. Haven’t done any research on chargers yet.

[a64pilot]

It’s very likely that your shore power charger is outputting 13.3 V or thereabout, over time that will charge a battery, eventually.
Of course it depends on what your battery wants for float voltage, 13.3 is float for mine, not others.

You need to do some kind of capacity check, even a rudimentary one, do you have an amp counting battery monitor?
The perfection one where amps are continuously adjusted over 20 hours is ideal, but most of us can’t do that, we don’t have the equipment.

However just unplugging from shorepower and running off of the bank overnight can give you a decent idea if your bank is shot or not, especially if you know how many AH were used.
It’s not precise by any means, but if you have a 400 AH bank and use 50 AH overnight but wake up with bank voltage of 11.8, they are shot of you started with a full bank

[Guaranteed]

I’ve been unplugged even for a short time and notice my bank going down pretty fast.. with maybe only fridge, fan and accessories going.. maybe 5amps?

I’ll do that again but keep good notes. I think the batts are toast too tho

[a64pilot]

See how long it takes for them to drop to about 12V, and about how many amps on average you are using.
The 12V is going to be close to 50% SOC, close enough anyway, it’s not precise by any means.
Average number of amps times number of hours will give you an approximate number of AH used.

Now this is pure redneck totally non precise way of doing things, but it out to give you a good idea.

They key is to try to ensure your honestly full charged to start with, if your charging source is above 14V and it’s outputting slightly more than the number of amps being used, then again by Redneck system your close to full, but if you outputting 15 amps but only using 5, then your not close to fully charged.

[hellosailor]

"My batteries are crap.. AGM that never get full charge so killing them."
As the Mad Hatter said, "But it was the very best of butter!"
It is easy to kill any batteries, even the best of them. You don't say what your batteries are, or how old they are. Could just be a combination of old age and bad charging (over or under charging or deep cycling) have used them up. There will be a manufacturing date code either on the top label (sometimes punched out) or else dot-matrix printed or embossed into the battery case, usually an inch or so down one of the sides, often hidden under a big paper label. Every battery is date-coded for warranty purposes, sometimes the code is YYWW for year and week of manufacture, or other obscure ways that the battery maker or a dealer can translate for you.
You also should get a decent multimeter that can reliably tell you voltages and amperages, so you can verify that parts of the electrical system are or aren't behaving properly. $25-200, depending on the quality and source. Anything cheaper will not be reliably accurate.

[Guaranteed]

My knowledge base on this is about redneck level so I’m getting your drift.
It’s rainy here so I’ll doubt I’ll be seeing that solar kick to above 14v... highest is usually 13.7... that’s with the nav ammeter and ampclamp .. I’ll run the test tonight and report back.. hope I don’t murder the batts ... but if I’m already worried about that I know my answer on needing new batts and charger.... both

[Guaranteed]

They’re “cabelas” group 24... I’ll check the date. I’ve got a fluke multimeter.. not sure if qualified to read it but seeing usually < 5 amps after the charger but before the batts even when they’re way down.. again the thing that got my antennas up was seeing discharge while on shore power

[AKA-None]

Think of it this way. Assume both your charger and batteries are crap. With a new charger and crap batteries you likely won’t hurt your batteries. But with new batteries and a crap charger then you will likely start trashing your new batteries.
So get the charger first. My opinion ymmv

[Guaranteed]

Makes sense... while I’m killing my bank tonight I’ll research charger/inverter