Elite Marine

I have several (5) batteries that I would like to connect to a trickle charge for the winter. Do the auto sensor type trickle chargers work for this application? I assume the batteries to be wired series creating one large cell.

88 MACH 1

I would buy 5 trickle chargers and charge them individually. Un less the batteries are the smae sixe and age, you may do more damage than good. Later, 88

mcollinstn

series with 5 12 v batteries will require a charge voltage of 60 volts. Anyhow, there is no way to make the batteries look like one big cell. Each cell is supposed to have 2 volts. Any shorted cell in the link will require the other cells to be charged heavily in to an overcharged condition.

Charge each battery individually, making sure to keep the electrolyte levels up to par.

Connecting the batteries in parallel will cause the batteries with good cells to try to bring up the batteries with weak cells.

One good $30 float charger. Leave it on each battery a week, then rotate it to the next battery...

Elite Marine

Thats what I thought. I just was just hoping for a simpler method.

Thanks

Wally

Ive charged 3 batteries in parallel without any problems.....i first charge them all on a big charger till full then hookup the trickle charger for maint...worked that way for 3yrs

stevel

I've charged 4 identical batteries in parallel before. Make sure they are all fully charged individually before you tie them all together. I have done if for years.

Test the batteries to make sure all of the cells are good. They should be pretty close in voltage.

Steve

SLP

mcollinstn, I have had several chargers over years but have never heard the term "Floater" charger. Can you explain ?

Sam

mcollinstn

A float charger is designed to MAINTAIN batteries, not necessarily to CHARGE them.

A lead-acid cell battery like we all use is designed to stay "healthy and fully charged" at 13.3 volts.

To properly charge a lead-acid battery, you gotta charge it to 14.2 volts and hold it there until it absorbs the charge (this affects the chemical balance of the anode/electrolyte combo).

For this reason, most chargers will throw 13.8 to 14 volts into a battery regardless of what's going on. Granted, they ramp down to a low amperage or "trickle", but the voltage is not optimized for MAINTAINING a battery.

Newer 3-stage ELECTRONIC chargers (Newmar Phase3, ProMariner Flyback to name a couple of good ones) will throw big amps into a battery until it reaches a charge level of 14.2 volts (bulk phase). Then the amps start tapering down until the charger reaches a low level of charge while maintaining 14.2 volts (absorption phase). At that point, the charger drops into Maintenance mode or "FLOAT" mode where the battery is allowed to relax to 13.4 volts but is kept there.

A battery left connected to a "regular" ferroresonant charger (big heavy iron core transformer) will boil electrolyte out and overheat.

That is why it is best to first CHARGE your batteries (and verify the state of charge with a little checker from the auto parts store with the floating balls). Then rotate a FLOAT charger on them to maintain them.

I've got 3-phase electronic chargers in my big boats and I just leave the suckers plugged in year round. No electrolyte loss, no battery problems...

NOTE: Statpower chargers are fine chargers, but if you boat with a genset, be aware that they do not "help" the charging system and will cycle on and off based on timer functions as opposed to full function charger/power supply operation...

mcollinstn

Oh yeah, the optimal charge and float voltages for a battery will vary with the temperature of the battery (lower voltages for hotter batteries). That is why some premium bilge-mounted chargers will offer an accessory temp probe that you stick on the batteries...