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Random Quote: Junior, when we get home, I'm gonna punch your mmoma right in the mouth Sheriff Beuford T Justice Smokey and the Bandit
I had both wet cell batteries go bad last weekend and made the mad dash to replace them just before closing ..... They are the Blue Optimas,,, once in, they worked great, however the house battery got so hot that the top to the battery box was wrm to the touch, so my mechanic said it was bad as well.
He also informed me that gell cells are not recommended for the OX 66's.
My question is two fold,,,,
1) Should I take the Optimas back and get three wet cell batteries ?
or
2) Can I keep the Optimas and charge them with a trickle charger in between trips and then mix with a deep cycle wet cell for the house battery,
First of all, AGMs & gel cells are two very different battery types. The only similarity is the price.
Second, provided the voltage regulator on the motor, regardless of type, is set to proper voltage for the gel cell (it is different than AGMs & wet cells) there is no reason for not using gel cells if they are your choice.
I have had the same gel cells in my Cummins powered sig boat for 9 years.
Even though gel cells have served me well for a long time my replacements will be AGMs. For my kind of boating they are better suited. They charge more readily than a gel cell & hold their voltage longer during slow loading (as in overnighting, lights) like a gel cell. They also have a long useful life span like the gel cell. They use the same voltage from the regulator as a wet cell.
If I were a dayboater I'd be more inclined to find a much cheaper but good HD wet cell & replace it every 3 or 4 years.
There is a big difference between a wet cell start battery and a gel battery. A wet cell start batary has 550 to 1000 cold crankikng amps and a Gel has 400 cold cranking amps. A gel is more like of a wet cell deep cycle/house battery, not recomend as a start batter. A gel may work but a wet start battery will work better.
Doug makes excellent points, but unfortunately many outboards do not allow adequate voltage regulation. I have owned 6 large outboards in the last year, and all had voltages in the 14.3 to 14.5 volt range. This is way too high for real gel cells, but are fine for AGM batteries. Gel cells cannot tolerate voltage over 14.1 volts.
Doug makes excellent points, but unfortunately many outboards do not allow adequate voltage regulation. I have owned 6 large outboards in the last year, and all had voltages in the 14.3 to 14.5 volt range. This is way too high for real gel cells, but are fine for AGM batteries. Gel cells cannot tolerate voltage over 14.1 volts.
An OX66 will put out over 14 VDC at idle. Gel killer.
Go with a good lead acid battery.
__________________ Baitkiller= Accredited Marine Surveyor
Bait fear me, fish just laugh.....
The little Dutch boy was just buying time...
The AGMs should be OK with the Yamaha charging voltage. One of the problems I have buying AGMs is that you have to spend big $$$ to get one with enough reserve capasity. Most of the yamaha motors need a minimum reserve capacity of 182 minutes. Yamaha owners take a look at your owners manual.
Can someone explain to me why an motor needs to worry about "reserve cpapacity"? - for any engine?. If a batt has, say 1150 MCA, who cares about reserve? You know it's not weak or abnormally low if it has 1150....How does an engine know if it's 182 or 135?....
Thanks to all,,, I think I get it,,, Optima's are AGM got that from the manufacturer,,so they are not gel cells, sorry for sounding uninformed but that's what I am,,,,, I think I'll go to Sears and get the third one in AGM from them for the house bat. I'll deal with the voltage issues, although I did notice on the volt meter from the gauges that the batteries di get as low as 12.4v while we were out bottom fishing with the electronics running.
you are not reading the batts when the engine is running -the 14.2 just means your engines are emitting a charge...it does not mean there is anything worthwhile on the other end receiving it for storage (batt)
12.4 volts is very acceptable, items running, engines off. Avoid going below 12.2 volts--which is approximately 50% discharged.
Also check the voltage at the batteries with a digital volt meter; the voltage as indicated by the electronics may be decreased by corrosion, poor connections or undersized wiring etc.
Gel Cell Batteries and Yamaha two strokes 
IGFA Certified Observer
