Batteries: 1 or 2 vs 1+2 ?

[SkiTundra]

Can someone give me a quick synopsis of how the battery switching/running/charging works in an '08 211. Searched and can't find anything.

If I will be gone for a week and want to make sure that the bilge pumps run and don't run out of battery (I'd rather have dead batteries than a sunk boat) I assume 1+2 is the ticket?

When running, how does charging work? EG if switched to just Batt 2 will it still charge both or just Batt 2? Same for 1+2?

If in 1+2 with Batt 1 @ 40% charge and Batt 2 @ 90% charge, do you effectively have 65% of total capacity (90%+40%=130% of 200% = 65% of 100%)?

Thanks,

[DavidF]

It is fairly simple. You can select either battery 1 or 2 or both batteries together 1+2. Obviously, if you select battery 1 then you are only using and charging battery one. Same goes with selecting battery 2. If you select battery 1+2 then you use and charge both batteries simultaneously. Most battery selector switches are of the make-before-break design which means you can safely switch between battery 1, 2, or 1+2 while the engine is running. However, you can never select "off" while the engine is running or your risk damaging the alternator.

[SkiTundra]

Thanks David. So my assumption that for maximum bilge pump running I want 1+2, regardless of charge level of the 2 batteries, is correct?

Am I correct that in 1+2 the batteries are simply in parallel? The manual implies that when both are selected that one is used for start/run and the other for accessories. ??

Thanks,

[teamenzo]

Yes, my understanding is 1+2 is in paralle.

[intrlaz]

Yes the batteries are in parallel in the ALL position, but you would not want to select ALL if one battery is nearly drained. The battery will rob charge from the other. I would go find a charger, charge each one separately with the switch in the OFF position, and select ALL for before you leave. then go on your trip without any worries

[ffmedic74]

You might want to think about adding a Automatic Charging Relay (ACR) from Blue Sea Systems.

http://bluesea.com/viewresource/526

[SkiTundra]

Thanks everyone. Great info! Like the ACR.

[Flipside]

Before I upgraded two 2 batteries due to stereo upgrades, I accidentally had the toggle switch under cockpit set to "Bilge" instead of "Off" for 2 weeks with no issue. The boat started with no problem. You should have more than enough insurance with 2 batteries.

But if you don't care if both batteries die (which they shouldn't unless your bilge pumps opeate continuously for the 2 weeks), then operate your batteries in parallel i.e. the "1+2" mode. In this mode however, the risk is that both batteries will die and you won't be able to start your engine to get the alternator charging them. I agree that a battery is cheaper than lifting a boat out of the water!

[etang789]

So does this mean I should run my boat with 1+2 at all times?

right now Im running 1 or 2 only they take turns...lol

[Flipside]

Yes, always run batteries at 1+2 setting so the alternator charges both batteries at same time. Then, for example, if you are parked in a cove with engine off listening to tunes, switch to one of the batteries so that the other one is preserved to start the engine should the other battery die. (This assumes you are running a big stereo system with subs and amps. If you have a stock system, then it is unlikely that you'd drain your batteries. If you do, you should be boarding more!)

If you have a stock stereo, or if you are only going to take a short break from boarding e.g. 30 mins, leaving the switch in the "1+2" setting is fine.