hansvonpensch

I measured the voltage on my Hobbico Torqmaster 12v 4.5 amp batteryat 12.8v and then ran my boat about 5 minutes until I could only get maby 1/4th the speed I started with. Then measured the voltage at 12.2 volts. Is it working ok.

Ghost in the shell

after charging, it should read somewhere around 14v, then tail off to about 13.12v, so if its reading 12.4, chances are its not fully charged, thus unable to give the demands of the motor. pop it on charge over night and see what it reads after.

mfr02

After fully charging, measure the voltage, like Ghost says, should be almost 14v. Then switch it on and re-measure when the battery has a little work to do. Any reduction in voltage should be minimal, a drop of more than a half volt indicates that the battery is unable to deliver, either because it isn't charging in the time allowed or the charger isn't delivering.

hansvonpensch

I was told that a 12 volt lead acid would choke when trying to deliver amps to 2 graupner 12v 700s and it was comparable to getting only about 8 volts and it would kill the battery early.

mfr02

A normal SLA will deliver a fearsome amount of current. You will notice this every time a car starts. Due to its construction, plates in a fluid, the current through the plates causes uneven heating and thus warping in the plates. Taken to its extreme, this will eventually cause the plates to touch. This is a short circuit internal to the cell and causes what we in the trade used to call a "BIG BANG". For very high current look at NiCad, NiMH, Lithium, but if using Lithium make sure that you have the appropriate type of controller that will avoid damaging the battery.

LtDoc

A lead-acid battery, especially if your actually talking about a 'gell-cell' type, just isn't a 'surge' capable thingy. At least not for very long, or for very often. They can deliver some fairly high current flows, but not as much as other type batteries. There are a lot of "if's" in that, but typically true just the same.
I think I'd have to agree with the other posts, the battery probably just isn't getting fully charged, or maybe it's sort of wore out, kind'a? I think I'd take a look at all the rest of the system too. Anything getting unusually warm? Everything that needs it is greased good?
- 'Doc

As a last resort, paint the @#$ thing pink! Pink batteries are always the best, everybody knows that...

hansvonpensch

I switched to a 9 cell nimid home made pack from the 12v lead acid and it went from about 8 or 9 to 12 or 13mph, how long does the lead acid have to sit on the shelf befor it goes bad.

mfr02

For a brand new SLA, reckon on a self discharge rate of about 5% per month. This will take it into the iffy area in a year and a half, but it will require cycling to bring it back to proper life again. They are designed to be used rather than stored. Used, they can last for years and years and.....