Questions for all of the battery & solar experts

[Zai]

I have 600 amp hour of batteries (lifeline) and I have 600 watts of solar.
I have a Philppi BM 1 battery monitor. I am using 94 as a PEF and 1.12 Perkut factors on the monitor.

As I understand it we can not trust the battery monitors for the bottom line of soc. The only way to know for sure is to due the 20 hour test, which is very impractical on a live aboard.


Also from reading the Lifeline manual it says that a full charge is when the batteries acceptance rate reaches .5 percent of the banks rated capacity, which in my case would be 3 amps or less. This happens in the absorption phase.

Is the float phase just to maintain the charge? Not really contributing to adding amp hours to the batteries?

Lifeline says in the manual that a battery with 12.8 volts after standing for 4 hours without a charge or load on it is fully charged.

Typically my solar covers all of my day usage with enough left over to charge the batteries in the absorption and float modes.

In the morning I typically have a DOD of 8-12%

If in the morning I start the engine to give the batteries a quick bulk charge, the batteries will accept about 70 amps for a few minute and the taper down to 50 amps, after that it tapers down to about 25 amps after 50 minutes or so.


Does this sound normal? Is it necessary to use the motor every day, or can I use the solar panels for a slower bulk phase, assuming I always get to 3 amps or less in the absorption phase?

[billknny]

You do not need to charge from the motor every day.

You are treating your batteries very gently, with minimum discharge, and that is a good thing. One the other hand, your current charging routine is very hard on your engine. Bring the batteries up to full every 2 or three days, and you will be fine.

Discharging 25 to 30% of the batteries capacity over 2 or three days without using the motor, and then bulk charging them with the engine on the third day will have a negligible impact on your battery's life, but will extend the life of your engine greatly.

[StuM]

Originally Posted by Zai

I have 600 amp hour of batteries (lifeline) and I have 600 watts of solar.
I have a Philppi BM 1 battery monitor. I am using 94 as a PEF and 1.12 Perkut factors on the monitor.

As I understand it we can not trust the battery monitors for the bottom line of soc. The only way to know for sure is to due the 20 hour test, which is very impractical on a live aboard.


Also from reading the Lifeline manual it says that a full charge is when the batteries acceptance rate reaches .5 percent of the banks rated capacity, which in my case would be 3 amps or less. This happens in the absorption phase.

Is the float phase just to maintain the charge? Not really contributing to adding amp hours to the batteries?

Lifeline says in the manual that a battery with 12.8 volts after standing for 4 hours without a charge or load on it is fully charged.

Typically my solar covers all of my day usage with enough left over to charge the batteries in the absorption and float modes.

In the morning I typically have a DOD of 8-12%

If in the morning I start the engine to give the batteries a quick bulk charge, the batteries will accept about 70 amps for a few minute and the taper down to 50 amps, after that it tapers down to about 25 amps after 50 minutes or so.


Does this sound normal? Is it necessary to use the motor every day, or can I use the solar panels for a slower bulk phase, assuming I always get to 3 amps or less in the absorption phase?

If you are still at 88-92% SOC on a 600Ah bank in the morning,I would expect 600W should get you fairly full by late afternoon. Try going without the engine run for a few days and see whether your SOC% in the morning starts to decline. If it starts to decline, then do an engine run first thing in the morning.

[john61ct]

Originally Posted by Zai

Is the float phase just to maintain the charge? Not really contributing to adding amp hours to the batteries?

Exactly, just to counter self-discharge when no loads.

But carrying loads AMAP so as not to initiate another wear cycle is important.


> Typically my solar covers all of my day usage with enough left over to charge the batteries in the absorption and float modes.

Better IMO to say enough to fully charge the bank, primary function, with enough left over for the usual loads. You can reduce loads when needed.

> In the morning I typically have a DOD of 8-12%

Good for longevity.

> If in the morning I start the engine to give the batteries a quick bulk charge, the batteries will accept about 70 amps for a few minute and the taper down to 50 amps, after that it tapers down to about 25 amps after 50 minutes or so.
>Does this sound normal?

Yes depends on amps and bank's CAR

> Is it necessary to use the motor every day, or can I use the solar panels for a slower bulk phase, assuming I always get to 3 amps or less in the absorption phase?

For longevity, 3-4 days a week reaching endAmps before dropping to Float is enough.

On solar-only days, measure trailing amps see how it goes, if good on sunny days - depends on weather of course - then maybe the ICE charging can be scaled further back.

A good logging tool helps, some SCs do that, but a central BM is better.

[Johnniegee]

Save the engine buy a genarator to top off the bank every couple of days

[MJH]

Originally Posted by Zai

I have 600 amp hour of batteries (lifeline) and I have 600 watts of solar.
I have a Philppi BM 1 battery monitor. I am using 94 as a PEF and 1.12 Perkut factors on the monitor.

As I understand it we can not trust the battery monitors for the bottom line of soc. The only way to know for sure is to due the 20 hour test, which is very impractical on a live aboard.

Also from reading the Lifeline manual it says that a full charge is when the batteries acceptance rate reaches .5 percent of the banks rated capacity, which in my case would be 3 amps or less. This happens in the absorption phase.

Is the float phase just to maintain the charge? Not really contributing to adding amp hours to the batteries?

Lifeline says in the manual that a battery with 12.8 volts after standing for 4 hours without a charge or load on it is fully charged.

Typically my solar covers all of my day usage with enough left over to charge the batteries in the absorption and float modes.

In the morning I typically have a DOD of 8-12%

If in the morning I start the engine to give the batteries a quick bulk charge, the batteries will accept about 70 amps for a few minute and the taper down to 50 amps, after that it tapers down to about 25 amps after 50 minutes or so.

Does this sound normal? Is it necessary to use the motor every day, or can I use the solar panels for a slower bulk phase, assuming I always get to 3 amps or less in the absorption phase?

I have a 450Ah house Gel battery bank with 560W of solar panels and let the solar panels do all the charging as I am on a mooring buoy 24/7/365. Only if the batteries get down below 80% do I consider charging via the diesel or dock.

I echo your concern about State of Charge (SOC). I don't like the thought of adding one more gadget to the panel but a Balmar Smartguage Battery Monitor is suppose to provide SOC within +-5% at all times. However, if you read their manual, it is less accurate during any charging which isn't commensurate with solar, of course; to me this sounds like you either have to disconnect the solar or maybe only read it at night.

~ ~ _/) ~ ~ MJH

[StuM]

Originally Posted by john61ct

> Typically my solar covers all of my day usage with enough left over to charge the batteries in the absorption and float modes.

Better IMO to say enough to fully charge the bank, primary function, with enough left over for the usual loads. You can reduce loads when needed.

I think the way the OP put it is more accurate. The primary draw will be the day usage. The batteries can only be charged with what is left after that daily draw.

[john61ct]

Well my nighttime usage is **far** greater than in daytime, so at least a few days per week the charging becomes top priority to get to 100% Full.

It is usually easy to cut back on the loads as needed, the essentials aren't even 10%.

But everyone's situation is different, as usual YMMV

[Zil]

The 20 hour test you reference is not to determine State of Charge. It is to determine the overall condition of the battery and how the AH now compare to AH new.
The amperes accepted at charging voltage is a fair way to determine full SoC.

[john61ct]

Yes, they already stated they are using .005C endAmps for SoC Full.

And wrt the load test, they meant the need to know residual capacity in order for AH counting BMs to be accurate.

Only SmartGauge does not need that parameter to be updated, in fact with a coulomb counter, it should be able to help **you** estimate SoH without doing a load test.