OPTIMA Batteries High Performance 34M Sealed AGM Boat and RV Starting Battery, 800 CCA, Dual Terminal, Maintenance Free, Versitile Mounting

Absolutely phenomenal product strong for practically any car and boat OEM compatible perfect. Highly recommended.

I used this battery on my boat as a start battery and running the bilge pumps. Was working even when I replaced it because it was 10 yrs old !!! Unbelievable quality and lifespan. Replaced it with the same battery, just because of age, not failure.

I used them in a 580 Case backhoe and they held up to the off road use and vibration.

I did a load test on this battery right out of the shipping box when it arrived. Rated at 800 CCA (Cold Cranking Amps), my load tester ran the analysis and showed a paltry 98 CCA available. Just for the sake of troubleshooting, we hooked up the battery to our Optima smart battery charger and gave it a few hours to recharge. Once it showed a full recharge, we ran the load test again...with the same exact result...98 CCA. Definitely a "REPLACE BATTERY" situation. But WHY would a brand new battery fail a load test like this? This NEW battery was replacing an older version of the same exact Optima Blue Top battery that I'd purchased in July 2017 (which had worked fine until just two weeks ago when it unexpectedly died and no longer held a charge). AMAZON customer service was GREAT as usual in shipping me a one for one replacement since the older battery was still within the 24 month warranty and I can't say enough good stuff about AMZN customer service. But the fact that the new battery was dead on arrival really had me stumped...Until I examined the bar code numbering on the old battery and the new one that just arrived... Turns out they have the EXACT same bar code numbers. Why is this noteworthy? Because the bar code numbers show you that battery's year of manufacture. In this case, both were manufactured in 2017. So that makes 100% sense for the OLD battery since I purchased it in 2017. But if I buy a new replacement battery in 2019, I would fully expect to receive a battery with a manufacturing date as recent as possible...NOT one that's already TWO years old. No wonder it was dead on arrival. It's been sitting in a warehouse on a shelf for at least two years. 12 Volt batteries have a set shelf life and shipping old ones out to customers is bad business. Optima batteries are usually good, so perhaps this is just a glitch in their system. Either way, be sure to learn how to determine the manufacturing date on ANY expensive 12 volt battery like this when you buy it so that you don't end up with a lemon.

Works great to start a boat. As long as you disconnect the battery during extended periods of non-use, it can sit there and hold a charge for many months. Completely draining a battery is a good way to ruin it. Some things like stereos or the diodes in your alternator will slowly drain your battery when it's not being used regularly. So I disconnect the + terminal every time I park the boat. Then I use a "BatteryMinder" at 2 amps to trickle it back up to full charge with the BatteryMinder set to "AGM" before I tow the boat somewhere to use it. This is an AGM battery. AGM stands for Absorbent Glass Matt. This kind of battery seems to hold a charge a lot longer than a typical battery. And it cranks over the engine with a lot of power. I've always had pretty good luck with Optmas with the red top in cars, but decided to go with this blue top one for my boat. AGM batteries are tougher against being banged around like in a boat, a race car, a dune buggy, etc., compared to regular car batteries. And they're sealed, so you don't get a big mess of corrosion on the terminals. Happy with my purchase.

Great battery and not terribly fussy about installation angle.

I purchased this battery and the deep cycle Optima. The deep cycle battery arrived perfectly and properly packaged. The starting battery (this one) arrived in poor packaging and had obviously been returned to Amazon once before being sent to me. The terminal covers were missing and the box it was in was obviously not the original packing. In addition to the packaging being defective, upon removal from the box, I also noticed that the battery case was damaged (it had been dropped) and was broken. A small amount of acid was leaking out of it. This is where it gets tricky as there have been some here suggesting that you should not purchase a battery from Amazon because they cannot service the product. When I noticed the case was broken, I logged in to get a product return authorization. Not possible from the web site with batteries because they are considered Hazardous Materials. So I called Amazon and explained the problem. The service guy on the phone told me I had two choices: 1: keep the broken battery (find out how to dispose of it) and get a full refund. Or 2: Keep the broken battery (find out how to dispose of it) and get another battery. I could not imagine a better set of options from an on-line retailer. I took the replacement. It arrived properly packaged and obviously never opened before. I am still a very satisfied Amazon customer. For those of you that are concerned about what some others have reviewed as bad service (Amazon not being an authorized service center and not being able to take bad batteries back), all I can say is that my experience was as good as I could expect. I wish the first one had arrived properly packaged and undamaged, but within a couple weeks I was made whole again. So only 4 stars.

I have used Optima batteries for nearly 20 years now. I have never had an issue with them as long as you keep a battery tender on them. I’ve had some over 8 years with absolutely on problems in both of my RV’s. Now I just replaced the original on my 3 year old boat. Don’t need a bad battery in the middle of the ocean.

Have relied on these batteries on my boat for years. I did experience one of my 4 same battery I bought in 2023 failing totally 2 months past the 24 month warranty - not sure why - have normally experienced twice the life in the past - this one that I bought now was identical to the 2023 year version I bought and so far looks good

Marine Batteries for my boat