New battery charger, 18 volts?

[Airspeed]

I bought a new battery charger the other day, put it on my deep cycle battery and let go. It's a fully automatic charger I bought off Ebay, similar to this one,


I let it charge and disconnected it, the next day I checked the battery with my volt meter and it was charged to 18.2 volts. Is that to high a charge?
By the way, I paid $15 for it from that seller, it was advertised as "NEW" and when it arrived it was obvious that it had been used, the ground prong was torn off the cord and it had some wear on the feet.
They gave me a $5 refund and a story in broken english that their "new employee" must have sent me the wrong one by mistake. sure.
http://tinyurl.com/5uyu3b

[madjack]

...I'd send it back...QUICK...before you slag your battery...or worse.....................................

[Alphacarina]

If his battery still reads over 18 volts the day after he removed the charger, I'd say it's probably already too late . . . . .

Don

[BrwBier]

I would think a battery that over charged could turn into a battery not all in one piece. Know what I mean.

[Dale M.]

A typical 12 volt battery will really read about 13.5 volts ... Generally accepted charge "float level" (full charge) is 14 to 15 volts with charger "on" once charger is removed it should settle back down to the 13.5 volts with no load on battery (disconnected)....

If battery is still at 18 volts 24 hours after charger is disconnected I think there has been a subtle chemical change in gattery internal chemistry and it may effect its "capacity"....

IF you connect battery to a "load" does voltage come back to "normal" range?

Dale

[Airspeed]

I found the problem, When I tested it I had it in the camper, I had my solar panel hooked up and it runs through a switch. I thought the switch was off but it was on so I was reading the voltage with the solar panel charging. Yesteday I marked the switch so I know for sure which way is "off".
The battery now reads 14 volts. I thought I fried my battery! At least I know the solar panel still works. Thanks! Aaron

[brian_bp]

I found the problem, When I tested it I had it in the camper, I had my solar panel hooked up and it runs through a switch. I thought the switch was off but it was on so I was reading the voltage with the solar panel charging....

Great, but...
if that was the panel output voltage while attached to the battery, 18.2 V is too much even for charging. Maybe a charge controller should be added between the panel and battery, to regulate the charging rate and avoid excessive charge voltage.

[Alphacarina]

A typical 12 volt battery will really read about 13.5 volts ... Generally accepted charge "float level" (full charge) is 14 to 15 volts with charger "on" once charger is removed it should settle back down to the 13.5 volts with no load on battery (disconnected)....

Float voltage for a standard lead acid battery is 13.8 volts and if it reads any more than 12.6 volts after it's been disconnected from the charger for an hour or two, then something is wrong

12 volt lead acid batteries are made up of six 2.1 volt cells

Don

[capt aaron]

I was at the local RV Parts shop and inquired as to what battery chargers they had. I asked for a multistage charger. They told me they did not have any multistage chargers, and said multistage chargers will over charger my battery. They wanted a couple hundred for their cheapest single stage charger. Being a nautical guy, I was shocked. Their statements and prices confirmed what I had already known. RV technology is outdated. Many high end RV manufacturers use Marine parts. Often times Marine parts are overly priced, but in this case Marine technology was cheaper. I went to my local West Marine store and bought a multistage charger for $35.

[Airspeed]

Hey Capn Aaron, thats a cool looking tear you have there! do you have more pictures somewhere?
I would like to see the rest of the trailer. With a name like Aaron it must be nice!
Aaron

[brian_bp]

I was at the local RV Parts shop and inquired as to what battery chargers they had. I asked for a multistage charger. They told me they did not have any multistage chargers, and said multistage chargers will over charger my battery...

Hmmm.... all RV stuff could be garbage, or the guy at this shop doesn't know what he's talking about. Maybe the second one...

Built-in RV chargers are normally part of converters, and are not cheap, partially because they're designed to put out at least 40 amps, continually. That's different from a portable battery charger; in those, good multi-stage chargers are readily available and affordable.