Recommendations for Hydrometer & Amp-hour meter

G'day Wok,
The most accurate type of hydrometer is the buld and pipette type, where you suck the electrolyte into the hydrometer and read the float. They should be stored in a shock proof storage, something like a roll of foam is fine and stored on their side after they have been flussed out with fresh water and dried. Of coarse these are only good for liquid batteries and not gel type. You can get digital ones but they do take up a lot of room and I have found that they lose calabration quite easily and quickly. As for the amp-hour meter I haven't really heard of such a thing. The amp hour rating of a battery is the amount of amps that a battery can put out for one hour. So if a battery has a twenty amp-hour rating you can put a load of twenty amps on it and it will last for one hour. However you can also put a 5 amp load on it and it will last 4 hours, one amp- it will last 20 hours ect. This is assuming that the battery is in good condition and fully charged of course. So all you really need is a amp meter to measure this. But I recommend that you compare the amp meter to a multimeter at least every twelve months as they can go out of cal.
As for data logging I can't really help there as I haven't done it before but would be interested to find out how you do it.

Hope this helps.

Wok.
If your prepared to go to the trouble of setting up a data logger you can do it the way its done in proffesional battery systems. What you use is an A/D converter conected to the negative terminal of your battery measuring the voltage across the earth lead of the battery. then write a program to sample the voltage about every minute, store the data in two files one for negative numbers and one for positive.At the end of the day total the files and record your gain or loss. Eric.

Dear Wok
The Plasmatronic regulators (PL20,PL40 & PL60) have an amp hour display. They can also be hooked up to a PC, but the stand alone display will give you AHrs in, AHrs out, SOC, bat V, SolarV, A in, and A out. Much better than Hydrometer. There may be cheaper ways if you dont need a good regulator (about $400 for the PL20 from memory).
Cheers John

lots of info on "digital hydrometers" on net ...but expensive approx US$2000

Thank you David C & Nudenut,

The Manson product is interesting........even found they make Dc-dc converters!...bonus.

Nudenut.....I never even thought of putting 'digital' in front of hydometers!!........duh..duh...........

Have a great Christmas & safe 2005 guys...........

Thks

Wok.
If you use the voltage on the negative terminal to input your data logger you dont require a shunt as the battery earth strap is the shunt, as far as calibrating it goes you just turn on your lights and note the voltage and calculate the amps from the lights power. If you have this system you dont have to use a hydrometer because you know the state of charge. Eric.