Volvo D1-20 battery alarm

[Adam Turner]

Boat is 2010 Bavaria 32 Cruiser, engine has 460 hr.

Had some battery alarms and battery indicator said replace so I bought a new starter battery.

Went out once and had a few battery alarms. Voltage on instrument pane was lowish, so I put that down to battery having been mouldering in a warehouse. Went out a second time, no battery alarms, so content with that theory.

Today, a few days later, went out and battery alarms were continuous.

No alarm idling in neutral.

Alarms start after a few mins under load at 1500 rpm

Starter battery voltage on instrument panel 14.3V, gradually declining with each new alarm to 13.1V. Although did pop up again to 13.4V. Revs and engine load from headwind pretty constant.

All readings are within normal range so alarm “shouldn’t” sound. But maybe decline indicates there is a charging problem.

Back at marina, level went to 14.1V once back in neutral and was 14.7V just a minute or so thereafter, BEFORE reconnecting shore power.

Thoughts, advice, guidance?

Thanks!

Adam

[symphony2]

The alarm is indicating a problem with charging - that is the alternator, not of battery "health" which the voltmeter is measuring. You have a split charging system which first charges the start and then the house banks, although once the new start battery is up to charge requires minimal charging from the engine. You need to measure the volts and amps coming from the alternator to the house bank and the resting voltage of the house bank to see if this is fully charged.

My guess is there is a problem with the alternator, either as simple as a loose drive belt or with the alternator itself.

[Yngmar]

Yup, sounds like a slipping alternator belt. Inspect for belt dust, check tension, and adjust. Might as well order a new belt, it's probably ground down by now and you should always carry a spare aboard anyways.

[Adam Turner]

Hi,

Thanks. Yes, I'd had battery alarms last season, which were due to a loose nut on the alternator. Accordingly, I'd given the alternator a good look over and was pretty sure it was OK. For example, the mark I'd set on the adjuster hadn't moved, so I didn't think the problem was there. I do carry a spare belt tho, thx

This time round it looks like the problem is different. When the alarm sounded, I disconnected the (recently installed) solar panel. The alarm stopped pretty much immediately.

So looks like battery is charging fine from engine, but solar was pushing it into the high zone (currently 36C here). We're going to see how to limit the output of the solar panel to stop this.

I'll check back in if anything new shows up.

[SYJetzt]

Which kind of charger do you have for your house bank? Diode splitter, VSR or B2B charger? Which kind of house bank? Lead or lithium?

[Adam Turner]

Thanks all. As mentioned above the cause was the solar pushing voltage high while the engine was running. I have a Victron controller so can disable charging from the app while under engine.