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

[Photographer]

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

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

[a64pilot]

Just one cranking battery? I'd replace it if its over two years old with a Walmart battery, and depending on age, your engine may have a starting rope as a back up, the older ones did.
Do you have two batteries or just one, if only one consider adding another as a back up with an isolator switch if your concerned.

Most auto parts stores will load test a battery

[Geek_Guy]

I use a Harbor Freight tester. It does more than just measure the voltage. It also simulates a load. I have had batteries that had voltage but couldn't provide amperage. WIth those the tester starts reading good, but when you apply the simulated load it will quickly drop to the red unacceptable range.

Here is the link to the tester that I have.

100 Amp 6/12V Battery Load Tester

I run through my batts a couple times a year. Eliminated lots of issues.

[skipmac]

Originally Posted by a64pilot

Just one cranking battery? I'd replace it if its over two years old with a Walmart battery, and depending on age, your engine may have a starting rope as a back up, the older ones did.
Do you have two batteries or just one, if only one consider adding another as a back up with an isolator switch if your concerned.

Most auto parts stores will load test a battery

I'll add a vote for a second battery, especially if you are taking kids out and possibly a ways from home or the dock.

To do it right you would need to add a switch and/or isolator of some variety. If you decide to do this there are diagrams on the internet or ask here and someone will point you to a link.

[tfrank]

I bought 2 Sears DieHard batteries and they have a 3 year full replacement warranty. After 2 years and 4 months, one wouldn't hold a charge long and Sears gave me a new one at no charge.

[Photographer]

Originally Posted by skipmac

I'll add a vote for a second battery, especially if you are taking kids out and possibly a ways from home or the dock.

To do it right you would need to add a switch and/or isolator of some variety. If you decide to do this there are diagrams on the internet or ask here and someone will point you to a link.

Thanks so much! This is what I am going to do!
Anybody has a link which isolator switch to get and how to set it up?

[boatbod]

A good battery tester is something made by Midtronics. That said, it'll cost you more than a battery so I suspect you'll have better mileage by taking the battery to a shop that has one and is prepared to test your battery for you.

Sent from my SM-N920V using Cruisers Sailing Forum mobile app

[HankOnthewater]

Pull-start a 115 HP outboard? Doubt it that can be done.

The old fashioned way and likely still the best, is testing the voltage of that battery with a large load applied. Prices for testers $60-$300. Although there are also more digital ways of testing like here: Electronic Testers | Matson

The idea to have 2 batteries is a good one.

A recent thread on this forum discusses ways of connecting/combining batteries is: http://www.cruisersforum.com/forums/...ll-168915.html

Particularly post #12 in that thread shows many links; of those links the last two might be valuable for you.

[Cheechako]

Originally Posted by Photographer

Thanks so much! This is what I am going to do!
Anybody has a link which isolator switch to get and how to set it up?

Just google Battery switch. They are common. Perko is one name. The hot + leads from both batteries go to the switch. One hot lead comes off the switch. You can select 1, 2 , ALL or OFF with the switch. A simpler option would be those switches that go on the battery post. You could then switch one ON and leave the other OFF for reserve, or vice versa.

[skipmac]

Originally Posted by Cheechako

Just google Battery switch. They are common. Perko is one name. The hot + leads from both batteries go to the switch. One hot lead comes off the switch. You can select 1, 2 , ALL or OFF with the switch. A simpler option would be those switches that go on the battery post. You could then switch one ON and leave the other OFF for reserve, or vice versa.

This is the easiest, cheapest way to add a second battery and also add the ability to keep one isolated for backup starting. You just have to remember if you want to charge both batteries from the engine keep the switch to BOTH but the you have to remember to turn the switch to 1 or 2 when the engine is off so one battery is isolated and will not accidentally be discharged.

[svJasmine]

I second the Harbor Freight (or other) load tester. Its the only way to REALLY know.

Rich

[a64pilot]

Originally Posted by HankOnthewater

Pull-start a 115 HP outboard? Doubt it that can be done.

When I was about 12 yrs old I pull started our then new Mercury "tower of Power" In line 6 cylinder 100 Hp outboard, at that time the most powerful outboard made.
Now close to being 60 yrs old and I can still hand prop a 600 HP, 1,340 cu in aircraft engine, it's not so hard as you may think if you don't start out on the compression stroke of a cylinder, have to get a running start.
I had to unfortunately pull start Envinrude 70 HP outboards once, we had dual everything on that boat, except one fuel tank, water in the fuel and quickly dead batteries soon after, empty the strainer, pump the bulb, run engine maybe 5 min until water again filled the strainer, repeat.

Modern four stroke, maybe you couldn't pull start one of those, I think my Mercury Verado didn't even have the option.

[basssears]

Originally Posted by Photographer

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

I have one... very convenient because you don't have to have fully charged the battery - then let it rest - before charging.

That being said, it's new to me and I'm not quite 100% sold on its accuracy yet... my two house batteries in my van RV are draining faster than I think they should with the draw that's on them yet the Solar tester says the batteries are all fine. So maybe the tester isn't that accurate, but I haven't had time to investigate further, maybe something's drawing more than it should and the tester is fine.

One thing to keep in mind at least with the "Solar" testers (dumb name, BTW, nothing solar about them) is for them to test a battery accurately they need to know the battery's rating in cold cranking amps... it is my understanding some of the more truly "deep cycle" house batteries don't even have CCA ratings.

[Dave22q]

Plug a voltmeter into your 12 v system and be aware of the readings. Amazon has very inexpensive ones designed for use in cars.

[robgrant1]

Sounds like you've got a solution, but for the files, I've been happy with my Xtreme Charge. It tests, de-sulfates and charges 12v, lead-acid batteries. Here's a link to it: https://www.amazon.com/Xtreme-Charge.../dp/B001JSTM8I