Can you recommend a good battery tester for my 12v boat battery?

[haring]

I have a 115HP Yamaha 4 stroke. I didn't know that you can start it manually..... How? Thanks so much!

 

[mmmbelows]

Check page 83 and 83 of your manual, it shows the procedure, if you don't have a manual it's probably here : http://www.yamaha-motor.com/assets/service/manuals/1/lit-18626-07-13_1370.pdf (Google is your friend)

I'd heavily recommend learning how to manually start your engine before you are on the water again. Remove all the question marks about how to do it now on dry land and with no pressure, as it will be way harder, maybe even impossible, trying to do it for the first time under an emergency situation.

 

[mrfixitchapman]

I have one of these -

Amazon.com: SOLAR BA9 40-1200 CCA Digital Battery and System Tester: Automotive

and a toolbox drawer full of other electrical test gear. The results that I get from this tester match up closely with some of my other test gear. I now use this one first. As a side benefit this one is calibrated to test AGM, absorbed glass mat, batteries as well as gel cell batteries and ordinary flooded cell batteries.

DC

 

[sealark]

If the battery is a couple years old just replace it.

 

[BRT]

Thanks so much for the answers! I would like to test my 12volt boat battery. I have been charging it with my pro charger and it is telling me that there is a problem with my battery. It does crank my 115hp yamaha but I usually have two kids on boards so I don't want to stuck outside on the water.

I have used volt meters and hydrometers before but they are not totally giving the correct result. In the past they told me that my battery was ok but the battery didn't give its full cranking power.

What do you think about the "Solar" battery testers? They test cranking power....

We have had one of the Solar battery testers for several years at our shop and I trust it more and more. You get the voltage reading which tells a lot about the state of charge and then you get a CCA reading that tells a lot about the life left in the battery. When the CCA gets much below what the battery says it is you have limited life left.

A fully charged 12v battery should read 12.7 volts or so after stabilizing. If it reads 12.2 it is really nearly dead. If you don't have enough CCA there isn't much cranking time between 12.7 and 12.2. Yes, yes I realize that CCA is the cranking amps but CCA on the Solar also says a lot about how long the battery will support the load.

 

[ncitro]

I always used something similar to this as it tests it under load. Even when I take them into Napa or Autozone after they use the big computerized tester they use one of these to double check it:

Amazon.com: Schumacher BT-100 100 amp Battery Load Tester: Automotive

It has an element in it that loads down the battery before it reads the voltage to see what the battery does with a load on it (similar to the starter).