Charging to 100%

[chris_gee]

There are experts in this area. I am not one. There is a view that AGM batteries should be brought up to 100%. Maybe so but how often? Ok if you are on a marina connected to power much of the time.
I bought a boat with 2 lifeline AGMs. At a guess they were 5 years old. I doubt that they were ever on marina and there was no additional power source other than the alternator. Since fuel was limited to 10-12 gallons and there were no LEDS. I doubt that any charging to beyond 80% went on.
Lifeline to actually recommend equalisation if there is charge loss.
I tried this but possibly did not give it enough time.
I had the batteries professionally equalised which I suspect was holding at a fixed current rather than a fixed voltage.
Initially they showed a higher than usual voltage which has since declined. I bought a small solar panel whic I have not yet fitted. While the voltage declined with limited use I found that the acceptance rate was less than maximum ie an hour or so of motoring didn't result in say more than an 80% charge. However a decent say 8 hours of motoring pushed in the rest at say 1-2 aph.
Yes I must fit the solar panel.
Hmm. It seems to me maybe the final charge rate from 80-100% is the area of interest. Likely that can come from solar panels or other ancillary sources. But it will be at a low amps per hour.
I don't claim to know much and there are experts around. It just seems to me if you are mostly on a marina what is the problem? Overnight charging will do it. If not 1. Do you really need to get to 100% most of the time? 2. How many amps do you really need to use? Really really? 3. How much money have you got?
Seems to me that if you cut down on your usage you may be able to work on 50 or 60 - 80% battery capacity range most of the time and periodically take it up to 100%
on solar or by using a generator quite inefficiently beyond the 80% range.
I mean at anchor are you using nav lights apart from an led or solar powered anchor light, radios, lights, stereo? Sure there is refrigeration but maybe less capacity and more efficient or capable of taking a higher rate from the alternator excess?
Dunno mate. Just wonder about esoteric systems.

[nodee]

Livia,
I would like to ad a couple of comments, if I may. First, I am neither a battery expert nor an electrical expert. And, the batteries have only been in place for 1 year and we won't actually move on the boat and start cruising until later this year, so no full time cruising yet. We charge off of standard engine alternators, an 80a Dolphin charger and a solar array of three 135w Kyoceras. The array easily takes the house bank up to 100% and I haven't spent any time catalogging the charge performance because, hey, I see 100% on the monitor regularly so not into the exercise, but that may change as we move onboard and increase the daily draw.

I installed a house bank of 5 Odyssey 2250s and 2 of the Sears Platinums for engine starts. I wanted the larger Odysseys for the house bank and the Sears Platinums didn't come that large. I went with the Platinums for start batteries as I understood they were "Odyssey's in disguise", less $$$ and wanted to maintain the same chemistry and battery age in the charging system.

Anyway, I thought your initial question on this thread was that you were looking for comparable information on non-Odyssey AGM batteries in order to see if there really was an improved charging rates for the Odysseys. While I can't help you find the information you seek, I may be able to add a clue that I haven't seen in this thread so far (or maybe I missed it; my eyes glaze over when I read long technical posts).

My rudimentary understanding of the charge rate process is essentially the charging source is trying to force electrons into a lead plate. The thicker the plate, the more difficult time the electrons have getting to the center of the plate. So apparently, the outer surface of the plate charges first and the inner core of the plate charges last and the electrons have to work harder to get there, hence the slowdown of the charge rate as the charging process approaches 100%.

The main feature of the Odyssey (and maybe other AGM's, haven't researched them) is the TPPL or thin plate, pure lead construction. Ribbon lead instead of plate lead is used in the Odysseys that results in a shallower thickness for the electrons to penetrate per ostensibly the same amount of lead as a lead plate battery. This supposedly allows for the faster charge rate in the Odysseys over thicker plate batteries. So I would think that the answer to your original question about other AGMs might possibly lie in whether or not the TPPL construction is used.

Hope this is helpful. Like I said, I can't really converse in electricalese, so this is just my plain George attempt.
OTOH, maybe I fell victim to the marketting...... at the very least, I am willing to just admit that Nigel is smarter than I am and, since I can't be an expert on everything on the boat, I am willing to outsource to him as much as anyone.

Good luck with your research and I look forward to reading your results and experiences. Kirk

[goboatingnow]

1) Concentrate on alternative / renewalable energy (solar, wind, water, etc.) and not on how many hours you'd need to run a genset to recharge your batteries

Why, I am currently pricing up a solar system, but for the money I can buy a shed load of diesel for my generator, which is very quiet and has a water /gas seperator in the exhaust, no ploosh plossh for me. The numbers dont add up for solar though.

dave

[s/v Jedi]

Nodee: you are right. TPPL reduces internal resistance and higher acceptance rates. It is like a starter battery but the plates are held in place so that they can't short out. But I still consider TPPL better for starting than for deep cycle applications.

Goboatingnow: how did you run those numbers? A 110W panel delivers 650Wh daily in the tropics. That is 3,560 kWh over it's 25 year life span. When it cost you $400, the cost is $0.11/kWh and that seems pretty good to me! I am very sure you are not going to beat that by burning diesel.

cheers,
Nick.

[Livia]

Nick - Thank you for your entire post. In particular that was an excellent walk through for me on the Honda 2000. When we have the system set up I will give some real world information on what amps we are able to get out of the Honda before it goes POP.

Thanks Kirk. Your post is spot on to would be a good way to approach what Odyssey claims is the benefit (TPPL). I don't know if any other AGMs are the same kind of "TPPL" as Odyssey. I'll look into it.

[s/v Jedi]

Originally Posted by Livia

Nick - Thank you for your entire post. In particular that was an excellent walk through for me on the Honda 2000. When we have the system set up I will give some real world information on what amps we are able to get out of the Honda before it goes POP.

Hi Livia,

The idea is to prevent it going POP. If you take it to charge the batteries with more than 100A you will overload the genset. It will work but it won't last and hurt the wallet.
When you build a system out of components, it needs engineering to set it up so that everything runs within specs. I'm sure I could make it charge with 150A for a short while but that is just not the right approach.

cheers,
Nick.

[tallyhorob]

Originally Posted by s/v Jedi

Nodee: you are right. TPPL reduces internal resistance and higher acceptance rates. It is like a starter battery but the plates are held in place so that they can't short out. But I still consider TPPL better for starting than for deep cycle applications.

Goboatingnow: how did you run those numbers? A 110W panel delivers 650Wh daily in the tropics. That is 3,560 kWh over it's 25 year life span. When it cost you $400, the cost is $0.11/kWh and that seems pretty good to me! I am very sure you are not going to beat that by burning diesel.

cheers,
Nick.

Have to down grade that a bit, it will never do the same all 25 years there will be a decline in watts. New panels are coming out soon so I don't think anyone would keep one for 25 years with new improvements. But I do like the sun instead of diesel just for the "green effect" if nothing else

[s/v Jedi]

Tallyho! Rob,

I don't know about other brands of panels but my Shell Siemens panels carry a 25 year warranty stating they will stay within specs for that period. The non-maintenance long life span of solar panels is why they beat wind generators easily.

cheers,
Nick.

[feelsgood]

Thats it I have had enough of electrics and all the costs and worry. I am buying a smaller yacht that I can handle easier and get out in more. I am having a small diesel that I can hand start. all oil lights in and nav. I will get more for my boat now than I will pay for the smaller yacht and save a bloody fortune on the electrics I wont buy. I will save a fortune on anchoring as I dont want to go into marinas and pay for electric and will be healthier because instead of stroling up the gangway I will be rowing ashore. Yes NO outboard either so no petrol to pay for. Going from a 65hp motor to a 10hp I am going to save a load of cash in the fuel department.
So all in all a happy Bunny. But I will still watch the forum cause I LOVE IT

[Maine Sail]

Originally Posted by s/v Jedi

Tallyho! Rob,

I don't know about other brands of panels but my Shell Siemens panels carry a 25 year warranty stating they will stay within specs for that period. The non-maintenance long life span of solar panels is why they beat wind generators easily.

cheers,
Nick.

Ditto. My Siemans panel is performing just as it did when new even at 11 years old. It shows no signs of deterioration except for some slight dullness to the anodizing on the aluminum frame..

[chala]

Originally Posted by s/v Jedi

This is a nice refreshing thread! I can add these considerations:

1. It was mentioned (by Barnie I think) that one could use two house banks instead of one. This allows using one bank while charging the other to 100%. However, this system is destined to fail for several reasons:

- If you have solar panels, they would charge the bank you are not using. This means that 100% of solar power is used to charge batteries. This immediately results in the losses of charging and later discharging batteries. If the solar power was used for current power consumption you skip those losses and only the excess solar power is used to charge batteries. Also, as the batteries are nearing 100% charge, only part of the solar power is used and the rest goes down the drain.
ciao!
Nick.

It is all depending on what some one is trying to achieve. If it is to top up a battery to 100% using a solar array (charging voltage above 14.4V for a 12V system) it is far better to do it on a battery that is not in use. So for this reason I prefer two banks, one on duty, the other one disconnected from a load. I also prefer to charge an individual battery instead of a block of batteries in parallel or in series. In this way I can observe the charging behaviour of each battery.
I am not a fan of batteries in parallel. 1: for safety reasons, one faulty battery can bring down the lot. 2: for efficiency reasons. When paralleling batteries one must consider the losses in transferring energy between batteries.
Good management of batteries is no more complicated than sailing a boat.

Originally Posted by s/v Jedi

Also, as the batteries are nearing 100% charge, only part of the solar power is used and the rest goes down the drain.
ciao!
Nick.

Not always, it is all depending on the size of the solar array and how the charge is managed.

[Livia]

Thanks again to everyone who responded. We installed the batteries.

SV Estrellita 5.10b: 500 Amps!

I'll post at some point in the future when I have some real world experience at anchor with them.

[motion30]

The honda 2000 will put out 1.6 kw , when overloaded it will kick out , not sure of the overload amps rating I guess I am missing something When talking battery charger amps why are we using dc amps when the charger need ac amps input ? My two 55amp iotas need 26amps ac total max They will charge my 500amp life lines to 95% fairly quick but that last 5% takes a long time