artfulltune
Senior Member
Hello James, the Balmar regulator displayed immediate charge rate with the batts at 40-50% are @14.4 bulk, about equal to lower helm console mounted Xantrex & Renogy remote displays when I am on shore power AC.
I understand 50% discharge is FLA. If it is also the same for AGM, as far as Odyssey goes, why spend the extra money if you don't need to store them on their side?
Also. what is used to measure SOC as far as capacity left or used?
I understand 50% discharge is FLA. If it is also the same for AGM, as far as Odyssey goes, why spend the extra money if you don't need to store them on their side?
The positioning is one advantage, not one we've needed.
Two other AGM advantages are reduced off-gassing (more important if batteries are in living spaces), and the whole maintenance-free thing (especially if access is difficult). These two are part of the reason we usually gravitate toward AGMs, but I don't mean these as valid reasons for everyone.
Yes, AGMs have a higher charge acceptance rate but the amount of time they are accepting a higher rate of charge does not lead to anything but a marginal decrease in charging time. Furthermore, you need an alternator(s) that put out enough juice to take advantage of that acceptance rate.If it matters, there's another advantage, for some, that I forgot to include. That's the one about a higher charge acceptance rate, which in turn can (might) mean faster charging.
Isn't perfect for everyone. For instance, if you have a couple large banks on a small multi-bank charger... then charger limitations probably negate the AGM fast charging advantage.
OTOH, if you have bank with it's own dedicated, relatively high-amp charger, then AGMs can accept a more significant bulk charge and a higher absorption voltage even as amperage begins it's decline. (Compared to FLAs/SLAs.)
In our case now, we would generally run the generator at anchor twice/day, to coincide with (electric) cooking times. That means heating water and charging batteries at the same time. A relatively short 2-hour genset session can cram a decent recharge into our AGMs... so our AC-only freezer and fridges (powered by an inverter/charger bank) can stay happy...
On the last boat, we eventually had a 60A charger on one main bank, a 50A inverter/charger on the other main bank, and an older 40A multi-bank charger that I could select for either or both of those banks too. A couple hour-long genset sessions per day at anchor kept our AGM banks relatively highly charged.
BTW, I'm not really trying to sell AGMs. They work for us, but they're not the right solution for everyone in every situation. I think FLAs still have a solid place in the line-up, as do gels probably (no experience with those), and of course the newer LFP solutions so far seem nifty for house loads. In our case, I just juggle ease of use versus effectiveness versus cost... to arrive at what works for us so far.
-Chris
Yes, AGMs have a higher charge acceptance rate but the amount of time they are accepting a higher rate of charge does not lead to anything but a marginal decrease in charging time. Furthermore, you need an alternator(s) that put out enough juice to take advantage of that acceptance rate.
Chris, I have timed how long it takes to charge my flooded batteries on alternators and on shore power with a 125-amp charger. From a 50% depth of discharge, it takes about 5.5 hours by either method (920-amphour bank). Regardless of the charging method, AGMs simply do not charge appreciably faster than flooded batteries. There are other good reasons for AGMs to be a better choice in some use cases, but speed of recharging is not one.I've not timed it... nor done the math to compare times... just accept that "faster" is a good idea for our situation.
And I'm not at all considering alternator charging; instead I'm using the generator and a high-amp battery charger.
-Chris
Chris, I have timed how long it takes to charge my flooded batteries on alternators and on shore power with a 125-amp charger. From a 50% depth of discharge, it takes about 5.5 hours by either method (920-amphour bank). Regardless of the charging method, AGMs simply do not charge appreciably faster than flooded batteries. There are other good reasons for AGMs to be a better choice in some use cases, but speed of recharging is not one.
I agree on the charging.
I know I am a pain on this, but. Kilovault just had another price drop! https://www.altestore.com/store/dee...-lithium-solar-battery-p41627/#KLV2400HLXPLUL
Panbo did two write ups on them. Built in auto heater, Bluetooth, 7.5 year warranty.
$880/200ah sale price with a $1995 list price. Seems insulting doesn't it?
Guess all the inexpensive drop-ins are starting to drive the overpriced guys down. There are lots of choices in 200ah LFP right off Amazon for $600-650
I believe Panbo generally liked Kilovault. Will Prowse hasn't done a tear-down on Kilovault, but has on other batteries such as Ampere Time, one of the low cost Amazon batteries.
Folks, regardless of where these LFP are assembled, they are built from Chinese components with minerals (Lithhium, cobalt, etc) mined in SE Asia and Australia. Build quality is improving rapidly. There is absolutely junk in the marketplace, but the gap between known hi-quality such as Battle Born and their low cost competitors is shrinking.
Peter
If I did the math right and assuming nominal temps, that would mean your set-up would take approx 3.84 hours to replenish 50% of 920 flooded.
Or it would take 2.5 hours to replenish 50% of 920 of their AGMs. (Maybe would need a 185A charger to do that?)
Is my math wrong?
Yep, initial math incomplete, sorry. I suspect I should have added another 3-4 hours to each for absorption time.
Using Lifeline's formula:
[(DoD / 100) x Rated Capacity] / Charger Output + Absorption Time = Charge Time
920 Rated Capacity
120A charger output
3 hours = Absorb time (from table)
Their table suggests 3 hours of absorption time for DoD between 30-50%, and then 4 hours for above 50%. I've used 3 hours.
Your bank size, 50% DoD, at your charge rate of almost exactly .13C:
[(50/100) * 920] / 125A + 3 = 6.68 hours @ charge rate of .13C
If you were capable of charging at .2C (Trojan's recommendation for their AGMs), then it might look like:
[(50/100) * 920] / 184A + 3 = 5.5 hours @ charge rate of .20C
If I were to use your bank size and my theoretically-achievable charge rate (.27C):
[(50/100) * 920] / 248A + 3 = 4.85 hours @ charge rate of .20C
I think.
And I suspect at least one and maybe 2 or more of those theoretical hours in each formula outcome might be about the final .05C tail, but I don't know that for sure.
I've been focused on one of our 3 banks, the one that powers the inverter and therefore keeps the AC-only freezer and fridge powered up... and for now, that's our only bank we can charge at that .27C rate. So that's why we have AGMs on that bank.
I suspect we can all quibble about how much "faster" is really useful. For us, more charge "faster" is good enough.
DC loads on the two main banks are comparatively miniscule, and our charging capacity for those isn't as tall anyway... so AGMs for "faster charging" isn't really necessary. OTOH, I can't easily get there from here to water one of those banks, and AGMs make that whole service thing easier for me.
-Chris
But there is another thing that happens that reduces the effectiveness of higher charge current. The higher the bulk current, the sooner you get to absorb, which would seem like a win. But it's only a partial win because the higher bulk current causes you hit the absorb voltage at a lower SOC. That leaves more of the charge cycle handled by absorb, which is slower. These are made up numbers, but an example would be that at a lower bulk current the transition from bulk to absorb happens at 80% SOC, leaving 20% to be finished in absorb. But with a higher current the transition happens at 75% SOC, leaving 25% to be finished in absorb. So with a higher bulk current, you shorten bulk, but lengthen absorb. The net does get shorter, but not by the amount you shortened bulk, and it's a diminishing return as you add more and more bulk current.
For something like that, I don't think Amazon is the place. Have you ever tried calling them for tech support on a product like that? I would rather deal with a dealer or the manufacture..
Damn, already bought Renogy AGM 12V 100 Ah battery and 100W solar panel kit (which includes 30A PWM Battery Solar Charge Controller). Hope I have better luck with Renogy than mvweebles did!
I Also have the Vevor 2.500 kW pure sinewave inverter (fridge, microwave) , and Jupiter 2kW quasi sinewave inverter (lights, heater).
I was (maybe naively) wondering if anyone had run the two inverters in parallel with success off the common 100Ah battery (low enough battery impedance).
For emergency use only in kitchen of house
Thanks, Terry
Hey all, anyone have experience with Renogy batteries? Thinking of getting these https://www.renogy.com/deep-cycle-agm-battery-12-volt-200ah/ for house bank and bow thruster. Could I also use one for a starting battery for a Lehman 120? They seem to be the most affordable AGMs I’ve found. Want AGMs because batteries are right under salon in engine room.
No experience with their batteries, but had stupendously awful experience with them as a company. Inverter arrived clearly DOA (throwing over-temp error in 50-degree ambient temps). You have no idea the hoops they sent me through to RMA. Ultimately required a BBB complaint and credit card dispute. Still had to dog them for 2 months to actually pay
If you buy, do it via Amazon. But seriously, in a world of poor customer service and tech support, they really stand out in my mind. Waste of time.
Peter
How do you quantify "safe"?
Do you have some kind of monitoring system to test the air you are breathing, or are you saying they are safe just because you are still alive?
Just curious.
Absolute Junk. And Renogy is a despicable company not honoring warranties and the worst customer service I have ever experienced.Hey all, anyone have experience with Renogy batteries? Thinking of getting these https://www.renogy.com/deep-cycle-agm-battery-12-volt-200ah/ for house bank and bow thruster. Could I also use one for a starting battery for a Lehman 120? They seem to be the most affordable AGMs I’ve found. Want AGMs because batteries are right under salon in engine room.
I just started to point out that you missed the absorption cycle, but see you caught the omission. But there is another thing that happens that reduces the effectiveness of higher charge current. The higher the bulk current, the sooner you get to absorb, which would seem like a win. But it's only a partial win because the higher bulk current causes you hit the absorb voltage at a lower SOC. That leaves more of the charge cycle handled by absorb, which is slower. These are made up numbers, but an example would be that at a lower bulk current the transition from bulk to absorb happens at 80% SOC, leaving 20% to be finished in absorb. But with a higher current the transition happens at 75% SOC, leaving 25% to be finished in absorb. So with a higher bulk current, you shorten bulk, but lengthen absorb. The net does get shorter, but not by the amount you shortened bulk, and it's a diminishing return as you add more and more bulk current.
Mirrors my experience with Renogy with a DOA 12v>>2000w inverter. They wanted me to replace a nearly new battery bank that was showing 12.4v at rest saying it was dead. And that was only the beginning.Absolute Junk. And Renogy is a despicable company not honoring warranties and the worst customer service I have ever experienced.
This was a brand spanking new Renogy 100Ah AGM, less than 4 very shallow cycles. It could barely deliver 72Ah. Renogy gave the customer a run around for months and he finally gave up. I got $10.00 for it at the scrap metal yard... Yet another very unhappy Renogy customer..