House Battery Maintenance

Moved from Dinghy Towing to Tech Issues

The BatteryMinder float charger is meant to be left on the battery ALL THE TIME! That's what it's designed for! It constantly pulses the battery to ensure sulfation doesn't occur. Read up on them, you'll be surprised! I get 5 years or more out of my riding lawnmower 1 year batteries with no problems using one that's left connected to the battery any time the mower isn't in use - summer and winter.

They never boil any of the water out of the batteries. It sounds like Rupert isn't knowledgeable about "Float" chargers. They don't taper down when the battery's full, they stop charging and monitor the battery till it needs another boost.

rrupert wrote:

You don't have to keep the charger going continuously, just plugin for a day or two every month.

That is assuming that you don't have any significant parasitic loads....AND that they aren't old enough to have a significant self-discharge rate.

If you have a good, well designed maintenance charger, there is no reason to NOT leave it connected 24/7......if you have access to shore power.

Thanks everyone...good advice for sure.....

Water: Water level s/b 1/4" to 1/8" below the split ring that extends down into the cell. Just touching is absolute max and even then may cause some electrolyte to be pushed out of the cell causing corrosion. Check levels every 4 months. More in high use or high temperature conditions.

Charging: Getting the battery to 100% tip top charged before storage is very important. Voltage needs to be 14.4 to 14.8 volts on the battery terminals 2 to 4+ hours to get a full charge. What are your charging voltages?

Float charge in the 13.2 to 13.4 range. Temperature compensated is best in climate extremes. If you cannot float charge... give them a good charging 24 hrs and then disconnect a cable. Clean the battery tops as dirt/crud will conduct and discharge the battery.

Careful how you handle the terminals during installation. Too much twisting or banging can cause the seal around the terminal to break and contribute to corrosion of the terminals.

Don't overly discharge the battery. Down to 12.2 volts or about 50% is time for a heavy recharge with 14.4 volts for at least 3 to 4 hours. OK to charge more often when in use.

DFord wrote:
I second the advice to buy true deep cycle golf cart batteries. There are no 12 volt batteries that will perform nearly as well in this application.

Other than that, keeping the batteries connected to a BatteryMinder whenever possible will help prolong their life. These chargers pulse the battery after their fully charged to prevent the sulfation that kills batteries. The cheapest place to buy them I've found is Northern Tools - https://www.northerntool.com/shop/tools/product_200332201_200332201

You don't have to keep the charger going continuously, just plugin for a day or two every month.

I second the advice to buy true deep cycle golf cart batteries. There are no 12 volt batteries that will perform nearly as well in this application.

Other than that, keeping the batteries connected to a BatteryMinder whenever possible will help prolong their life. These chargers pulse the battery after their fully charged to prevent the sulfation that kills batteries. The cheapest place to buy them I've found is Northern Tools - https://www.northerntool.com/shop/tools/product_200332201_200332201

Hi,

Add a modest solar system with a good temperature compensated charge controller. My marine batteries from Walmart lasted over nine years.

My current telecom AGM jars are 5 years old and still just fine.

My advice is next time get AGMs. They have very little self-discharge and don't need watering. When sitting, just disconnect them.

And why is this in Dinghy Towing?

Next time, get 2 6 volt golf cart batteries from Costco or Sam's Club and wire them in series. Same price as 12 volts, but, with maintanence, will last much longer. You can get the battery watering kits that will let you keep them full with a couple pumps on a squeeze bulb so you never have to open the caps. The golf cart batteries are the most bang for the buck and are true deep cycle, unlike a lot of the RV/boat batteries out there. If they will be "unattended" for 3 months, just fully charge and do not put a trickle charger on them. Last thing you want to happen is for them to boil dry over 3 months. Sitting unused for that length of time is tough on any battery but that will make the best of it.