PDQ OWNERS FORUM

"Lady of the Lake" is currently set up with wet cells and I would like to go to gels (I have brand new ones that came off of "Stories She Could Tell" after the hurricane took her from me). Since gels require a different charging voltage, is there an adjustment I need to make to allow the starting battery to be charged from the 9.9s? If so, where is this done? I can handle the change in my house charger and the solar panels but was not sure what to do with the engine charging source.

There is no voltage adjustment or regulation on the Y9.9. It is a permanent magnet alternator with diode bridge rectifier and will boil the electrolyte in a charged wet cell or ruin a charged gel cell unless the output is diverted to a load (about 70Watts per engine). I use a 150watt bulb in a lamp thru my inverter to provide a load when running both engines with charged batteries.

Is this standard? Does everyone run a load to protect the batteries? Is there a way to limit the charge? Have I already done damage at this point if I have not run such a load? Any help would be appreciated, I want to do this right.

Sam

Hi Sam,
As long as the batteries are NOT fully charged there is no problem. If they are fully charged, (like after being plugged in at a dock) you will see the voltage go to 15, 16, 17 .... unless you add load. Gels should never be charged over 14.2V. A wet cell battery will begin to gas when overcharged but a gel cannot which eventually destroys it. Check your DC voltmeter often!!
Chet

I always keep her plugged in at the dock and charging. So what is recommended is to run a load while underway? What is the output of each engine's charger? Is there no regulator that can do this automatically? Sounds like a disaster waiting to happen.

If my math is correct, I need nearly a 12 amp draw on the system while underway with both engines running?

70W per engine * 2 engines = 140W

140W / 12V = 11.67 amps

Is this correct?

What about a switch in the charging circuit to open the circuit to the battery bank when it is fully charged and not allow any further charging of the battries? Will this damage the charger?

Sam,
You are exactly correct in your calculations.
It is very difficult to find a 140W 12DC load which is why I use an AC desklamp with a 150W bulb plugged into the AC outlet powered thru the inverter. It works great.
Chet

I believe if you switch off the engine output when it is running that some very high voltages would be induced in the stator coils resulting in arcing and damage to the stator.
Chet