Eliminate onboard chargers?

Wait just a minute - I own a good portable battery charger w/ 12/24 and maintenance setting so why do I need an onboard charger? Couldn't I run leads from the batteries to a remote yet accessible spot to connect the charger cables to? That would save me the effort of opening the battery boxes. That wouldn't be any more trouble than plugging in a dedicated charger and I'd save $2-$300. Can anyone tell me why this wouldn't work? My starting battery only needs a top off every now and then so it's really only the TM batteries I'm concerned about.

Thanks in advance to all who reply.

[TerryMac]

See post on boat board.....you'll be fine and cheap fix is available

Steve,
This is exactly what I do. I have a good portable battery charger that is fully automatic with many features. When I need to charge my trolling motor batts I unplug my trolling motor from the trolling panel on my boat. I have another plug rigged up to go from the panel to my charger. When the batts are charged I plug the bow mount back in and I'm done. I could not see the value in buying an on board charger for $150. I know guys that carry an extra charger anyway just in case there on board quits for some reason.
Just my 2 cents
IGuy

[KM]

Unless you connect directly to the batteries, which can be difficult in some rigs, you will not get as efficient of a charge when going through the plug due to the ressistance caused by the many different crimps and connections and length of wire going to the batteries from the plug. It is just better to charge directly to the batts. That is one reason to have an onboard charger over a portable.

Unless of course you have 3 seperate, good quality chargers which I would need to charge my 36 volt system in a reasonable amount of time. Just some food for thought.

KM

I use a portable charger to charge my two trolling batteries. I plug in the trolling panel up front and my batteries are in the back. No problem. Some days I'll drain them. Next morning, full charge. No hassle Good luck,
Bucko

Similar to IGuy, I had the Lund dealer set mine up for backcharging. Bought a pretty good charger (no float position, though), Lund dealer cut the leads off and put a plug on that plugs into where I plug the troller in, and wired the boat to backcharge. It's worked fine, however, if I had to do it over again I'd spend a couple hundred more and go ahead with a three bank pro 10/10/3 for the convenience. In fact, had I done so, I probably would have saved myself a battery. I inadvertently left the key in the on position sometime late last fall (powering gauges up), discovered it several weeks later after battery was flat and had been for several weeks. Battery was shelled. I assume the Pro would have kept it up. Also, the Pro would likely be installed in a more out of the way place, saving space. I keep the other charger under the console (for road trips). Good luck on the water. John.

[John H]

This will work fine for one battery- but if you have 2 batteries then you will have problems. If the 2 are in paralell (12v motor) your automatic will not know when both batteries are fully charged. If one batt is weaker than the other it would never get fully charged because the better battery would get full, and then charger would cut off. I think a series set up would cause even more problems. You can get a good on-board to charge 2 batts for about $100 which is not bad since the cost of one fully automatice portable is 50-60 bucks. And no more pulling charger in and out of boat, just run extension cord out and plug it in.