Specific Gravity Meter/Battery Hydrometer

[geekygrilli]

Hello people

Does anyone know where I can get a decent (yet cheap!) Specific Gravity Meter from? Can you get digital ones?

I don't really want to replace all my batteries if i don't have to, so thought I would set about testing the cells to see why my range has dropped...

I want to buy the meter so I will always have it to hand for future use - seems like a useful tool.

Any help appreciated

Christopher

[GregsGarage]

Have you tried Halfords?

Greg

[geekygrilli]

Yeah, I got a floating type one, but I thought it was possible to get digital ones?

Either way its gonna take ages to measure each cell of each battery

[ChrisB]

You should be able to tell the duff cells with a voltage load test, watch for batteries that sag below the others and these will almost certainly be the suspect ones.

Specific Gravity Meters are OK but will only give one side of the story and are really only useful for determining a fully charged cell.

I've had batteries before that give an excellent SG reading yet you load them and they fall right over due plate corrosion etc

Dont think theres a digital one out there, but if there was I doubt it would be cheap

I'd load test them and watch the voltages on each battery, if the battery is particularly bad you might even find it will gass under load another sign things are wrong.

Dont be too quick to hook out what you may think is a duff battery, it could be depending on the charge/discharge routine, its maybe just that its become exceedingly un-balanced from the pack and just needs some gentle extra charging to bring it back up, all depends on how hard you use them and type of charger.

Hope that helps

ChrisB

[GregsGarage]

Your float type hydrometer is all you need. It will tell you if any batteries need charging and can indicate a problem, but as Chris has said, a good hydrometer reading doesn't mean a good battery. Digital hydrometers do exist but won't leave much change from £2k! Probably the best, reasonably priced hydrometers are the refractometers. One example is found here, http://www.tpishop.co.uk/product.php?id=40. It's still 10x the price of a Halfords one though.