"Doug Kanter" wrote in message
...
Curiosity: Why would I consider buying a gel cell battery? My current
battery is used for running lights, fish finder, and occasional shock
"therapy" when my son is making too much noise and scaring the fish away.
A
trolling motor will arrive soon. I don't use the battery for starting the
motor.


Gel battery advantages:
1) Can't spill. Can even be mounted on its side.
2) Never needs to have water added, allowing you to put it in hard to get
to spots.
3) Is more efficient during the charge cycle.
4) overall life expectancy is usually longer

Gel Battery Disadvantages:
a) costs more
b) for a given size, has a lower amp-hour rating/.
c) has a different "full charge" voltage, making them incompatible with
regular lead acid.


For your application, advantages 1 and 2 are probably signficant, and
disadvantages a and c.

The spill factor is obvious, and can be really important if the battery is
exposed or moved around a lot. Being able to tuck it up in some "it takes
all day to get to" spot is reasonable if you never have to get at it again
for the next 5 years. The cost factor is another obvious one. The final
charge voltage is something that you should consider. Gel cells want to be
topped off with a final charge voltage that is a little lower than a regular
lead acid. If you wanted to hook this up to your boat's alternator and
charge while the engine was running you could end up overcharging the gel
battery and damaging it. You certainly wouldn't want to have a gel and a
regular lead acid connected via the battery switch.


The efficiency during the charge cycle is really only important to those
people who live day after day on a limited amount of charging time. Ocean
going sailors are one example, where they need to recharge their batteries
via the solar cells each day. A small improvement in charging efficiency
can make the difference between getting enough out of the solar cells and
having to run the engine. For a weekend user, you just put the battery on
the charger and let it charge all night, who cares if it took 10 hours
instead of 9?

The amp-hour capacity of the battery could be an issue if are already deep
cycling your battery. The large "marine" style battery (size 27) is
typically around 100 amp-hours in lead acid and only ~80 in gel. If you
need more than 80 amp-hours you will find your gel battery going dead while
the lead acid would have still been okay.

Rod McInnis