View Full Version : Battery charging

01-11-2012, 03:32 PM
I have four battery's and I'm buying a four bank charger question is can I leave the battery's all hooked up while I charge all four or do I need to disconnect them?

01-11-2012, 04:59 PM
I definitely recommend disconnecting the batteries from the boat (or whatever they are in).

01-11-2012, 05:13 PM
How are the batteries wired? Single bank of 4, 2 banks of 2, single and a bank of 3?

01-11-2012, 06:03 PM

01-12-2012, 08:40 AM
I am not a fan of battery tenders. I am a fan of disconnects and trickle charging for short periods before use. I always trickle charge anything I haven't used in awhile 24 hours before expected use if I can. I get long life out of my batteries on all my boats, motorcycles, and vehicles at home. Even those that are used every few weeks instead of daily. We have tried all kinds of trickle chargers on our equipment at work. I see shortened battery life on expensive batteries at work but other factors could be in play.

01-12-2012, 09:00 AM
I have 3 batteries all hooked up.

I leave them all on one 'trickle charger'. Sends a small amount of juice to the batteries to keep them charged. Once they are charged, it turns itself off. Works great. Been using it for years!


Battery Tender is the correct term, I believe.

01-12-2012, 09:13 AM
Battery tender or trickle charger for battery maintenace. I leave my 2 batteries hooked up together. Connect charger on one and, switch set to "all" and both will charge. Thats how both charge while engine is running.......

01-12-2012, 09:17 AM
Battery tender or trickle charger for battery maintenace. I leave my 2 batteries hooked up together. Connect charger on one and, switch set to "all" and both will charge. Thats how both charge while engine is running.......

That is exactly what I do............family's been doing it for years and have had zero battery problems.

01-12-2012, 09:19 AM
Battery Tender, all my toys have em and they are used while they sleep so when its time to get up I just turn the key. In spring if the jetski is slow to get things moving that is what the portable jump box is for. When in the garage I just set it and forget it, spark proof, water proof can beat it really and the quick connectors are great for tight battery locations so you arent fumbling around for little blocks and screws in the dark.

I love em!


01-12-2012, 12:43 PM
I picked up the NOCO GEN2 NOCO Genius Black 12-24V 2-Bank 20A On-Board Battery Charger from Amazon for $113 Free Ship. Connected both batteries. Used it since August, no problems. It's plugged in full time this winter. There's a 4 bank version for about $175. Once connected to the batteries, leave it in the boat and plug into 110v in garage or at dock.

01-12-2012, 08:52 PM
I'm not sure if I remember what my Battery switch says on it I thought it just says on/off I haven't noticed it say "all" maybe I haven't been paying attention

01-12-2012, 09:31 PM
Okay to clarify I just went and took a peek at it and theres off/on/combine battery's so I have a single charger so to charge all at once the switch should b in the combine battery's position yes?

Now when I'm out and pounding the stereo should it be in that position aswell? I'm assuming yes or the addition of two more battery's is kinda pointless right?

Now if it's only in the on position using a single battery do all the other battery's charge off the alt while running or no?

01-12-2012, 10:41 PM
You may very well also have a Voltage Sensitive Relay. In my boat is on the other side of the panel where the battery switch is mounted. See attached for a description of a VSR. If you have a VSR (and wired correctly), you leave the switch in the ON position. The VSR will then join the batteries when the alternator is charging them. When you stop the engine and just playing the radio (house battery), the voltage will drop and the batteries will split. This way you will only drain the house side leaving the starting battery with a charge. With a VSR, you would only use the combine in case of failure of the VSR and a dead start battery.

If you donít have a VSR, combine when running the engine. That way you are charging both batteries off the alternator while running. When not running and playing the radio for a period of time, switch to on. That way you will only drain the house battery.

I'm guessing at how your boat is wired. So the above may or may not be true. I suggest you closely examine your setup so that you understand it. You have not replied as to if your batteries are wired in parallel and if so how.

There is a good battery thread at http://mastercraft.com/teamtalk/showthread.php?t=3557&highlight=battery+relay+charging

Hope this helps.

01-12-2012, 10:53 PM
One battery is wired directly to one side of the switch.

One other battery is wired directly to the other side of the switch and also has the other two added battery's wired to it in parallel pos to pos neg to neg

My switch is a blue sea Switch with the above switching positions

01-12-2012, 11:24 PM
After looking on blue seas website I have answered my own questions and seeing how my stereo is wired.

In the on position you are using the main battery in normal use and the alt is charging both the main battery and house battery. My pos lead for my amp is off the house battery which is the battery that has the additional two battery's hooked up in parallel.

So having the leads from my onboard charger hooked up to one battery to charge all the battery's at once it should be in the combine battery's position to make sure every battery is being charged.

I understand the way the system is wired and the positions of the switch

01-13-2012, 12:55 AM
This may be of interest to you as well.