Battery Charger Question

[poboy]

I have a Charles Charger 15 amp, 3 bank charger that replaced an identical unit after a lightning strike two years ago. The boat was completely rewired on the 12 volt side after the strike.

Prior to this, with the original charger and in a different marina, I only needed to change the saildrive zincs every two years or so. After rewiring and installing the new charger, I started having to change them every 3 months! About six months ago, I started leaving the charger off when I am away from the boat ( about to weeks at a time) on the advice of a friend. .

The guy who dives my hull reported this week that the zincs still look new. He was worried that they weren't making good contact with the drive unit. Then he asked if I changed anything, like leaving the charger turned off. When I said yes, he said " Oh, well that's why then. Battery chargers eat zincs"

Now I'm really confused. 1 - I thought these chargers were designed as maintainers and therefore could be left on. 2 - I didn't have this problem in a different marina before being struck by lightning. 3) Battery charger wiring is the same as before.

Any clarification or thoughts would be most welcome!

Paul

[CharlieJ]

If they are installed properly, they perform according to specs and will not cause accelerated sacrificial anode wastage.

[poboy]

Thanks. I've checked the install 50 times trying to figure this out. It is installed per manufacturers instructions. Could there be something up or downstream of the charger in the wiring that would cause it function improperly?

[twistedtree]

I'd guess something was done differently when the boat was rewired that is now causing the zinc erosion.

[smac999]

you when you say you left the charger off. is that the only thing off, all other ac breakers on, or did you disconnect shore power during that time?

[djmarchand]

A common cause of this is an internal fault to the bilge water in the DC system. Most common is the bilge pumps, particularly if they are wired backwards.

So check all wire that is down in the bilge and bring it up above bilge water and make sure that your bilge pumps are wired properly and all connections above water.

David

[poboy]

Smac999 - I do not disconnect from shore power, but every thing is off except the breaker for the 120 outlets. I leave a little 120v fridge plugged in to keep the beer cold.

David - now that is very interesting. On the DC side I have three banks - 2 GC2s for the house bank and a group 27 for each engine. The house bank has its own Blue Seas on/off/parallel switch, as does the start bank. I monitor the house bank with a Victron monitor. I have been trying to track down a mystery .8 amp draw on the house bank for a year now. The draw is present even with all switches off. DC leakage in to the bilge could solve both problems! I'll check and report back.

[smac999]

some of those .8a will be the victron monitor

[poboy]

Yeah, I know. The manual says it should draw about .4 amps, if I remember right.