Sentry Battery Chargers

S.A.M. · Post by **S.A.M.** » Mon Jun 07, 2010 5:22 pm

My 2 starting / house and 1 genset batteries are attached to my Sentry 3 bank charger. When the genset is running, at anchor, the main batteries are not charging.

Are there jumper wires I need to add or remove to fix this? The manual is not very clear, but does mention jumpers.

The Sentry charge is older, not electronic and does not have DIP switches.

When I bought the boat the gen battery charger wire was not connected. I guess to solve the problem someone removed the wire.

Thanks for any input.

ready123 · Post by **ready123** » Mon Jun 07, 2010 7:22 pm

Many generators charge their own battery... so if that is the case for yours I would disconnect the genny battery from the Sentry charger.
Silly question but you do have the charger switched on to 120V source like when at the dock when the genny is running?

Big D · Post by **Big D** » Mon Jun 07, 2010 8:00 pm

Jumpers are supplied with some multi-bank chargers to link an unused bank terminal to a bank terminal that is being used. Such as a 3 bank charger in a vessel that only has 2 banks.

In may case, bank one is port engine battery, bank 2 is strb engine battery, bank 3 is the house batteries. The genny battery is charged only by the genny when it is running.

bobg · Post by **bobg** » Mon Jun 07, 2010 9:35 pm

Agreed. All of the setups I have seen do not have the charger connected to the generator battery.

Something else to consider is that some (most?) battery chargers have a protection mechanism that shuts itself down when it detects something else charging the battery - i.e. the engine alternator. This is so the charger and alternator don't overdrive each other and cause damage. The one I had previously did this on a per output basis but I don't know if they are all like that. I haven't checked my current charger. It is possible that your charger detects the genset charging the battery and shuts off.

Big D · Post by **Big D** » Mon Jun 07, 2010 9:53 pm

Typically smart chargers see a conflict and will not charge if another charging source is detected. It's stated that the current charger is older although I suspect it also sees a conflict hense the disconnected charging circuit by a previous owner.

S.A.M. · Post by **S.A.M.** » Tue Jun 08, 2010 9:02 am

I hear what everybody's saying.

But, wouldn't it make sense that you would want to keep your genset battery on the charger while sitting in the slip, to keep it at full charge?

ready123 · Post by **ready123** » Tue Jun 08, 2010 9:07 am

S.A.M. wrote:I hear what everybody's saying.

But, wouldn't it make sense that you would want to keep your genset battery on the charger while sitting in the slip, to keep it at full charge?

Why would it loose charge while doing nothing?

S.A.M. · Post by **S.A.M.** » Tue Jun 08, 2010 10:02 am

I concede to the masses. The wire comes off.

Big D · Post by **Big D** » Tue Jun 08, 2010 11:15 pm

Agreed

Big D · Post by **Big D** » Tue Jun 08, 2010 11:17 pm

As Ready said, there should be no reason to keep the battery on charge, providing you have nothing but the genny hooked up to it. It should keep it's charge unless it's a bad battery or you have a wiring issue.

If you have an "AUTO" start feature, my understanding is power from the battery is used to detect a load, and as such you need to be aware of consumption when this feature is turned on for extended periods without the genny running.