Battery voltage with Inverter on.

[john61ct]

Ah, the "nearly" Full got me.

For longevity you would want to finish the several more hours required

using solar or shore power if not motoring all day

to get to 100% Full

14.7-8V until trailing amps tapers to .005C (5A for 1000AH, 6.5A for 1300AH), or no further tapering for a full hour

at least a few times per week.

[wayne.b]

Originally Posted by coopec43

According to my research each T-145 weighs 28kg so you have app 250kg of batteries?

WOW!

Clive

===


Yes, a bit more than that actually. The Trojan web site show them at 33 kg (72 pounds). But we ask a lot of them since we mostly anchor out and try to minimize generator run time. We have three fridges and a household type freezer, in addition to the usual electronic toys. The T-145s have the same form factor as the more common T-105 except for being slightly taller. In our experience they last more than twice as long however so I'm happy with the cost and size trade off.


https://www.trojanbattery.com/product/t-145_plus/

[tanglewood]

The only comment I would have is that from your charging description, it sounds like you are not fully recharging your batteries. Perhaps significantly so.

[wayne.b]

Originally Posted by tanglewood

The only comment I would have is that from your charging description, it sounds like you are not fully recharging your batteries. Perhaps significantly so.

===


Understood. At least once a day we run the generator long enough that the charger goes into float mode. That's about as good as it gets unless we are tied to a dock or running the engines all day.

[tanglewood]

Originally Posted by wayne.b

===


Understood. At least once a day we run the generator long enough that the charger goes into float mode. That's about as good as it gets unless we are tied to a dock or running the engines all day.

OK, good. If your charger setting are correct and you are getting to float, then you should be good. To really know you need to do a load test and see how much you can pull out of the batteries. That will tell you if you have accumulated sulfation and lost capacity. You could have a bunch and not know it because recharging will seem fine.


Have you equalized at all? And those are wet cells, right? A good SG reading will quickly tell all.

[spudsdailey]

The batteries are Trojan, L16-AC. 435 Ah each @ 6volts. There are 6 of them, hence, 1305 Ah bank.
The charger is a Magnum Energy inverter/charger. The charger puts out 130 amps max.
The boat is a 48 foot Offshore. The 40 amps are due to 3 refers, and the Nav equipment, stereo, etc.
Voltage has gone down under this load close to 12 volts. Back on shore power, it re-charges quickly to 100% SOC within an hour or so.
My concern is only when day cruising, is 12 volts or so an issue under load?

[john61ct]

Actually SG only shows SoC, no indication of SoH, residual capacity, only a load test will show that.

But as stated, seems a pretty moot point anyway.

[tanglewood]

Originally Posted by spudsdailey

Voltage has gone down under this load close to 12 volts. Back on shore power, it re-charges quickly to 100% SOC within an hour or so.

This is the red flag, if I'm understanding you correctly. 12.0V is 50% SOC, or down 650Ah.



At 140A charge rate, it should take 5-6 hrs to recharge, not 1 hr. If your charger thinks the battery is full after only 1hr, then I would suspect sulfation. If SG is low, yet the charger thinks it's work is done, then you have sulfation and it's time to start equalizing to recombine as much of it as possible. Measuring SG is easy, so I would recommend as next step. I think it will tell you quite a bit.

[svlamorocha]

Originally Posted by wayne.b

At least once a day we run the generator long enough that the charger goes into float mode. That's about as good as it gets unless we are tied to a dock or running the engines all day.

I bet that "the charger goes into float mode" before the batteries are fully charged. Read Mainesail's site for gory detail. Only safe way to know that batteries are fully charged is to wait til tail current in amps drips below manufacturer's quoted % of Ah capacity, then use the time it took to get there as basis to increase the setting of the charger's absorption phase

[tanglewood]

Originally Posted by svlamorocha

I bet that "the charger goes into float mode" before the batteries are fully charged. Read Mainesail's site for gory detail. Only safe way to know that batteries are fully charged is to wait til tail current in amps drips below manufacturer's quoted % of Ah capacity, then use the time it took to get there as basis to increase the setting of the charger's absorption phase

True. But with a sulfated battery acceptance amps will tail off just like with a full battery, except it's not really full because of the un-reacted sulfur dioxide. Low SG will show that the chemical reaction isn't complete. He's lucky to have flooded batteries so he can diagnose what's going on.

[StuM]

Originally Posted by spudsdailey

The batteries are Trojan, L16-AC. 435 Ah each @ 6volts. There are 6 of them, hence, 1305 Ah bank.
The charger is a Magnum Energy inverter/charger. The charger puts out 130 amps max.
The boat is a 48 foot Offshore. The 40 amps are due to 3 refers, and the Nav equipment, stereo, etc.
Voltage has gone down under this load close to 12 volts. Back on shore power, it re-charges quickly to 100% SOC within an hour or so.
My concern is only when day cruising, is 12 volts or so an issue under load?

Don't believe that! You cannot get FL batteries up to 100%SOC in an hour or so from that low a start point If your monitoring system is showing 100%SOC that quickly there is a problem with your charger settings. It is dropping to float much too quickly and you are operating constantly at a partial state of charge. You are steadily killing your batteries.

[a64pilot]

It’s a Magnum inverter / Charger.
He should be able to add the remote and the BMK battery monitor, that enables him to set the trailing amps current to terminate absorption and the drop to float, this should guarantee that the bank is fully charged.

Just me, but I’d bet that the bank has been chronically undercharged, taking specific gravity readings of the batteries should confirm or deny this. However I’d think an honest, full charge on shorepower and then an equalization should be done, and see if the batteries voltage drop doesn’t take much longer.

However step one is I believe specific gravity readings to determine actual SOC at the end of a charge cycle

[john61ct]

Trailing amps is the best gauge of SoC.

A worn batt will stop tapering at a higher current, so use "under .1A change over an hour" as 100%. SG will show Full as well.

But actually draw current, even at the .05C rate and you'll see voltage drop much faster that it should.

If it hits 10.5V in less than 14 hours, it's scrap.

[tanglewood]

Originally Posted by a64pilot

However step one is I believe specific gravity readings to determine actual SOC at the end of a charge cycle

Exactly. And the specific gravity readings will also tell you when you are done equalizing.


When I first installed my giant Surrette battery bank, I was unknowingly under charging it. It was returning to full voltage and low acceptance amps, but SG was slowly creeping down. It turns out you need to charge them at a much higher charge voltage to really get them full, but that's not the point....


I had to do a lot of equalizing to get the SG back up where it belonged, and by a lot I means DAYS of equalizing, not a few hours. It was broken up into sessions of a few hours at a time while monitoring SG and temp, but it took a very long time.

[john61ct]

Yes even for Trojan, going to 15V is within spec for longevity.

US Battery started it, MS points us to a study from Sandia.

FLA is OK if you go over on AHT a bit, just keep the water topped up.