Lifeline Batteries Charge Rate

[Ip485]

Given around a 650AH Lifeline house bank and assuming discharged to 50% of capacity, what would be the maximium rate of absorption during the intial charge phase - in other words what would be the ideal amps for a charger to put back into the batteries? I appreciate the rate of absorption will tail off.

Also I have these;

https://www.mg-solar-shop.de/media/p...M096B00_EN.pdf

what would you expect the real life experience in the tropical zone would be for these panels in terms of amps returned to the bank, given they are flat mounted and not shaded?

I think for a 12V system each panel should produce between 100A and 150A per day, so two panels will produce around 150 - 300A in a day or equivalent to running a charger for 2 to 3 hours, but with the advantage that as the absorption tails off the efficiency increases.

In theory therefore three of these panels might replace somewhere over 300A in a day?

I am interested to see how close panels will get to supporting a 600AH house bank, given a typical draw for fridge, freezer, chart plotters and general lighting etc.

[john61ct]

.2C is the minimum for longevity.

.4C would be sensible

up to .85C is safe but that gets expensive, since acceptance will hold for a short time only

For a 600AH bank that's 120, 240 and 510A rates respectively.

[john61ct]

The ratio between panels and bank is not as relevant as

1 insolation conditions, and

2 simply replacing more than what loads have consumed each day.

Put an AH counter in place to see the actual consumption average per 24 hours.

[Ip485]

For a 600AH bank that's 120, 240 and 510A rates respectively.

Thank you John.

So I am taking that to mean charging with a 240A charger would not be a bad arrangement - but 240A chargers seem very difficult to come by?

People like Victron seem to go to 100AH chargers, so at that sort of level at least 2 100AH chargers would need to be run together?

[rom]

So Ip485 what is the conclusion of your investigation (per you other thread) ? Are the batteries dead ?

I have the same panels, branded benQ, but actually the same, rated 330W. Flat mounted as well.

I have four of them. Last year, same period I was in sub tropcial region, 14°N. At 1pm the panels would output 375W each. Yes, that is more than rating.

I have 1000Ah battery, deep cycle, allegedly Gel, but not AGM. I usually cycle them from 10% down to 30% DoD. On very rare occasion do I go below 60% SOC.

I do not have a generator and my alternators are disconnected from the house battery 330 days a year. I do not go often to marinas and even when I go I usually don't plug in. I live on the boat 365 days a year. Yet my batteries are usually full long before lunch, at least per victron's point of view, which suits me well.

If I were to listen to forum experts I would have to buy a generator and a second charger. The installation would be heavy, complicated, noisy, smelly and twice as expensive. I would rather change the batteries before their potential life expectancy (say 10/12 years). But once again per Victron recommendations I believe I am taking pretty good care of them. Time will tell.

[Paul L]

Originally Posted by Ip485

Thank you John.

So I am taking that to mean charging with a 240A charger would not be a bad arrangement - but 240A chargers seem very difficult to come by?

People like Victron seem to go to 100AH chargers, so at that sort of level at least 2 100AH chargers would need to be run together?

As your batts charge the amount of charge acceptance decreases. If you start with 240 amps it will quickly start accepting less. So a very large initial charge shortens the charge time only a small bit. Check this article for an example How Fast Can an AGM Battery Be Charged..? Photo Gallery by Compass Marine How To at pbase.com
A 125 - 150 amp charge would be a good trade off for your setup.

[Captain Bill]

You can find that information in the lifeline technical manual available here:
Knowledge Center - Lifeline Batteries

Note that lifeline AGMs can be charged at a rate up to 5C in the bulk phase, or 3100 amps for your 620ah bank according to this manual.

[Ip485]

Rom - no final conclusion yet as they are still on test, the suppliers wanted to do several cycles, but the outcome is not looking good. I should know the final result in the next few days as the actual suppliers are coming to do a complete audit of the whole system and fit brand new Lifeline AGMS.

I have two panels, and will install one more. My combined chargers are 110AH, one 50AH and one 60AH, yet to be established if they can be run together, but I gather the answer is probably yes. I do have an 8KW genset, but like you, prefer to minimise its use - noisey smelly thing - actually it is pretty good and discharges beneath the boat. I also have a Balmer.

I have learnt so much thanks to you and others, and will not be in the same situation again (I hope), albeit I am still puzzled, so that part is still work in progress.

My first job is then to do my own audit, a complete review of consumptions rates, amps input form the various sources etc.

I also wish to be satisfied if there are any other improvements I can make, or anything else I can do to improve the system.

Thank you for your interest.

[rom]

If you haven't purchased the new AGMs yet you may as well buy GEL or standard deep cycle batteries. There seem to be a consensus that they are more forgiving than AGM.

[john61ct]

Originally Posted by Ip485

so at that sort of level at least 2 100AH chargers would need to be run together?

If you mean mains power, yes.

Alternators go that and higher.

Or you compromise and accept a bit lower longevity at say .2C, won't affect overall charging time much when getting to 100% Full, that takes 4-6 hours regardless.

[john61ct]

GEL has very specific requirements, and only last long if you really care for them properly, same as AGM but more so.

FLA won't accept much higher than .2C, and even .1C is OK. They will usually last longer than AGM too, much less fussy and more robust.

And cheaper

[john61ct]

Originally Posted by rom

Yet my batteries are usually full long before lunch, at least per victron's point of view, which suits me well.

What is Victron's trailing current specification for defining true 100% Full for their batteries?

Or if yours aren't made by Victron, what make/model are they, and do you know the spec?

Are you verifying your solar gear is actually getting you to that mfg spec using an independent ammeter?

[hellosailor]

"My combined chargers...yet to be established if they can be run together, "
Depends on how clever they are. If the two chargers happened to have identical charge profiles, set to identical voltages, they might co-operate. But let's say both chargers are putting out 14.4 in the initial bulk phase. Charger #1 sees the battery has come up to 13.8 volts and it cuts over to float charge. Charger #2, which wanted to see 13.85 volts because it simply was built with different components, may be perplexed at why the apparent battery voltage dropped. Will it stay in bulk? Or go to float?\
As a practical matter you may need to put meters on both chargers, run a couple of complete cycles, and see what they are up to, both in amps and volts. The only silicon kids that REALLY play nicely with strangers, are the old ones. The dumb loyal faithful servants, usually with a big transformer and no concept except "fixed output voltage". (Hey, at least they're loyal and predictable.)

[john61ct]

As a practical matter multiple charge sources with wildly different setpoints are just fine running concurrently.

As long as each of them won't actually cause harm on their own they can all be thrown into the mix NP.

Easier with FLA of course, wider ranges do less harm.

[hellosailor]

You must trust the silicon critters more than I do.

I remember the first time we found out a "new" battery charger was designed not to charge a battery that had gone below 10.5 volts, as a safety feature. After forty five minutes of checking power cords, breakers, wires, scratching heads...

Heck, when you think they are both working, one might actually just be loafing around and silently laughing its wee silicon head off behind your back.

Sometimes it is nice to know for sure, and not guess.