Hydrometer

[LONG_KEELER]

I used to keep a hydrometer on board which was very handy for checking the battery, but sealed batteries have made the device redundant.

I'm looking for a cheapo gizmo alternative but are they just voltmeters ? I only use leisure batteries for house needs rather than starting . Are volts still an accurate guide ?

TIA

 

[thinwater]

Voltmeters and hydrometers (or better, a refractometer) do not measure the same property. Thus, they are not interchangeable.

(The first measures the chemical state of charge, the latter measures the voltage of a stack of plates, which you can relate to chemical state of charge, but is not the same thing and can give a different result due to shorting, draw, or surface charge).

And cheap gizmos are often just wrong.

 

[VicS]

I used to keep a hydrometer on board which was very handy for checking the battery, but sealed batteries have made the device redundant.

I'm looking for a cheapo gizmo alternative but are they just voltmeters ? I only use leisure batteries for house needs rather than starting . Are volts still an accurate guide ?

TIA

I have a couple, similar to these two:-

Led Battery And Electric Circuit Tester | MicksGarage
https://www.amazon.co.uk/Amtech-L4300-Battery-Alternator-Tester/dp/B00BTF6T6Y/ref=asc_df_B00BTF6T6Y/?tag=googshopuk-

21&linkCode=df0&hvadid=310668964056&hvpos=&hvnetw=g&hvrand=16201340245903676990&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=1007057&hvtargid=pla-562722380761&psc=1

Both pretty useless.

 

[Refueler]

Halfords years ago sold a Tester .... has LED's that show state of battery .. and if engine running - state of alternator .....

Its not as good as the Hydrometer for battery - but it does work. I still have mine ....

The problem is that battery by that tester and also by Hydrometer can show good state - but once you apply serious power demand - battery just does not deliver.

The best tester - the large H frame jobs auto service and car breakers have ... it puts a very high load across the battery and shows voltage drop.