Charging the house batteries

[DiploStrat]

Pugslyyy knows is way around the Fuso.

Generators are good for heavy, immediate loads, like a microwave or an air conditioner. (I run these off of batteries, but that is another story.) A genset is less effective for the long hours of acceptance charge required by lead acid batteries. If you are not going with Lithium batteries, then shore power or a solar kit is almost essential to fully charge a large battery bank. Unlike a cruising yacht (or narrow boat), motor vehicles rarely run their engines long enough to achieve a full charge.

 

[Alastair D(Aus)]

AGM charge rate

Two points of caution when using AGM batteries. They are great when used away from the engine but hate getting hot and it will shorten their life dramatically. The least appreciated fact is that AGM batteries do not like to be charged fast since they need time to allow the gas that is always produced to be absorbed into the mat. Look at the manufacturers specs for your AGMs and you will find that most will recommend something like 20A as a max for a ~100AH battery. It does vary with brand. This is the main cause of the swelling often seen with AGMs.

So I can make use of all my solar, shore or alternator charge I have switched to LIFePO4 (LFP) batteries. They will accept huge charge rates without problem and the discharge capability is frightening, literally if shorted. You do need to be more careful re max & min voltages but they can be discharged to 20% SOC and still give good life. Their weight is ~1/2 that of lead acid for the same capacity. Since say 200AH of AGM will only give 100AH of usable capacity taken to the recommended 50% to give good life, you can use 120AH to get the same output with LFP.

The downside to LFP is price but the difference is dropping. When you do the sums for higher performance and expected life of ~10+y for the LFP if treated right, then it is a serious consideration.

 

[pugslyyy]

Two points of caution when using AGM batteries. They are great when used away from the engine but hate getting hot and it will shorten their life dramatically. The least appreciated fact is that AGM batteries do not like to be charged fast since they need time to allow the gas that is always produced to be absorbed into the mat. Look at the manufacturers specs for your AGMs and you will find that most will recommend something like 20A as a max for a ~100AH battery. It does vary with brand. This is the main cause of the swelling often seen with AGMs.

So I can make use of all my solar, shore or alternator charge I have switched to LIFePO4 (LFP) batteries. They will accept huge charge rates without problem and the discharge capability is frightening, literally if shorted. You do need to be more careful re max & min voltages but they can be discharged to 20% SOC and still give good life. Their weight is ~1/2 that of lead acid for the same capacity. Since say 200AH of AGM will only give 100AH of usable capacity taken to the recommended 50% to give good life, you can use 120AH to get the same output with LFP.

The downside to LFP is price but the difference is dropping. When you do the sums for higher performance and expected life of ~10+y for the LFP if treated right, then it is a serious consideration.

I'm sorry but I have to flat out disagree with your assessment of AGM batteries.

One of the great benefits of AGM batteries is that you can charge them at much higher rates than a flooded battery.

For example, I could theoretically charge my 4 GPL-4DL batteries with up to 2500 Amps.

http://www.lifelinebatteries.com/rvflyer.php?id=8

 

[IGBT]

Yes, Lifeline specifically says you want to really dump the amps into their AGMs during bulk phase. 100 amps into a 200AH bank is not too much according to their engineers.

 

[DiploStrat]

An interesting, anecdotal comment on Lithium batteries:

-- They may not like heat, and,

-- They may need lower charging voltages.

The latter would would ironic after the whole world has finally gotten to higher charging voltages for lead acid batteries. Watch this space.

http://www.technomadia.com/2015/02/living-the-lithium-lifestyle-3-5-year-lithium-rv-battery-update/

 

[steve4wdaus]

In our Amesz we have 350 watt solar panels, camper batteries of 3 x 120 amp AGM. We found the standard alternator charges at 70 amps. Once our solar panels fully charge the camper batteries, they then charge the truck batteries. Also the camper batteries can be switched to start the truck if the truck batteries fail, gives you piece of mind when in the middle of the outback.
http://www.4wdaus.com/index.php/amesz-4x4-mods/57-amesz-solar-power

 

[Alastair D(Aus)]

I'm sorry but I have to flat out disagree with your assessment of AGM batteries.

One of the great benefits of AGM batteries is that you can charge them at much higher rates than a flooded battery.

For example, I could theoretically charge my 4 GPL-4DL batteries with up to 2500 Amps.

http://www.lifelinebatteries.com/rvflyer.php?id=8

I hesitated before posting because I did not want to start an argument that always seems to surrounded batteries & charging.

Pugslyyy is quite correct for his batteries as his specs show but note that battery cited is:
The Lifeline GPL-8DL is a high performance, Mil-Spec, AGM battery, produced in the United States.

I too planned to use Lifeline for this reason before I changed to LFP.

If you look at many of the specs for more run of the mill AGMs you will find much lower figures and sometimes warnings.
eg for a Fullriver 105AH
http://www.batteriesdirect.com.au/files/products/DC105-121332110312_1.pdf

I apologise if I overstated my warning. I was really trying to point out that all AGMs are not the wonderful batteries they are portrayed and looking at the specs before buying is worthwhile. Lifeline are a premium product and work well, mainstream brands often do not.

There are days when I wish I never touched the keyboard!

 

[SkiFreak]

I There are days when I wish I never touched the keyboard!

There are days when I wish I did not get out of bed.

 

[Alastair D(Aus)]

An interesting, anecdotal comment on Lithium batteries:

-- They may not like heat, and,

-- They may need lower charging voltages.

The latter would would ironic after the whole world has finally gotten to higher charging voltages for lead acid batteries. Watch this space.

http://www.technomadia.com/2015/02/living-the-lithium-lifestyle-3-5-year-lithium-rv-battery-update/

Diplostrat,
As I said in my response to Pugslyyy I regret posting and overstating re AGMs as I can see I was too generalised in my comments, it was intended as a warning and I was tired when I did it.

Your link re the LFP experience is a good one based on first hand experience which is rare. I am aware of the things they mention. I think experience and technology have moved forward in recent years. I did not advocate LFP as a drop in replacement for lead acid, but with a little care and the right setup they are worth considering.

My 320AH @12v LFP setup weighs in at 47Kg/103lb
The Lifeline AGMs I was going to use were 2 x GPL-8DA=510AH @12v weighing 142kg/312lb
Both combinations give approx 250AH usable (80% LFP vs 50% AGM)

Lifeline are a premium AGM and the cost for the LFP was only slightly more when I bought them last year. Included in MY perceived advantages was a weight saving of 95kg/209lb.

I have used several AGMs as a second battery in my 4wds over past years and ruined several before learning why. The first cause was heat even at the front of the engine bay of a Landcruiser. The second was overcharging, resulting in case bulging and one split using the standard alternator. These were not Lifeline, but other well known brands - Fullriver and Remco. I did not do my homework when I switched from wet cell deep cycle to AGMs and suffered the consequences. When I saw the new LFP technology advancing I eventually decided that I wanted to move in that direction and did a lot of reading first. I am not saying they are for everyone but I think that in a few years they will be the house battery of choice. The pricing will be a major factor.

In my Landcruiser I now use a well cell deep cycle in the engine bay. In my Isuzu NPS300 expedition truck I have the above LFP setup in a 'cool' location and conventional wet cells as the starters.

LieshaShannon on this site has an all electric expedition vehicle using LFP batteries and his experience will be good to follow. He is well ahead of me in development.

 

[pugslyyy]

I'm not against LFP batteries - they definitely are the future. For me it's not clear that we've reached the inflection point, but we are getting close.

The current benefits of LFP
- smaller size
- lower weight
- greater discharge (80% v. 50%)
- higher number of cycles (2000+ v. 1000)

The current negatives
- higher cost
- adapting the electrical system (charge profiles, etc) for the new battery technology.


I'm pretty certain that the next time I spend $2000 on batteries I won't be buying AGMs. But hopefully I won't be spending $2000 on new batteries any time soon.

 

[IGBT]

The major negative for me on LFP is lack of warranty or local dealer. There are only a few distributors in the USA and questionable warranty.

Who wants to pay $500 to ship $400 of batteries back to China?

Lifeline comes with a good warranty and tons of local distributors.

 

[DiploStrat]

Diplostrat,
As I said in my response to Pugslyyy I regret posting and overstating re AGMs as I can see I was too generalised in my comments, it was intended as a warning and I was tired when I did it.

Your link re the LFP experience is a good one based on first hand experience which is rare. I am aware of the things they mention. I think experience and technology have moved forward in recent years. I did not advocate LFP as a drop in replacement for lead acid, but with a little care and the right setup they are worth considering.

No worries, Mate! The choice of Lifeline batteries was made for me, so I can claim no particular skill in this area. I did look at lithium, but I could not find an off-the-shelf battery that I would trust. AM Solar have just started discussing lithium batteries, but it is still bleeding edge stuff. http://www.amsolar.com/home/amr/page_331_131/400_amp-hour_lithium_battery.html And $3200 for 400Ah.

Hopefully, if I take care of my AGM's, I will get five years or more out of them.

Part of the challenge will be, as Pugslyyy noted, getting the right charging profiles. Of late, everyone has been pushing the voltages way up. (I note that your link calls for up to 14.9v @ 25C; that's a lot.) If Lithium cells really want a 13.5v charge, then we are going to be going back to dual regulation or looking for lithium starter batteries AND reprogramming the vehicle charge profile. All of this is a bit too pricy for me at the moment.

Safe travels!

 

[IGBT]

I have a coworker who has 11 years on his Lifeline AGM which is what sold me on them (I had been considering being a test subject for LiFePO4 before talking with him).

 

[charlieaarons]

FWIW (and it worth something because Unicat designed the system), my camper uses two Sterling BB1250 battery-battery chargers in parallel of course. They automatically turn on/off at 13.2V and bump the voltage up a bit for faster charging and have some other intelligent characteristics such as temperature sensing.
My Lifeline house batteries are 8.5 yrs old and still alive. Solar panels keep them charged when sitting.
Sterling's alternator to battery charger AB12210 accomodates LiFePO4 batteries.

Charlie

 

[DiploStrat]

FWIW

Charlie,

A friend of my uses a pair of Sterling B2B's on his Unimog as well. The BIG problem that he had was that the Unimog's charging voltage never got high enough for the AGM's. He has had good results (once he got past one unit that was DOA) for a couple of years; greatly reducing his generator use.

I initially installed a Sterling A2B (the 210A model) and was very happy until we hit cold weather. When the temperature drops, my Chevrolet's charging voltage ramps up to 15.5v and the Sterling shut down with a non-adjustable high voltage cut out. It is possible that their newer 400A unit has a higher cut out voltage. Of course, if you are already running at those voltages, then an A2B or a B2B is a bit moot.

The key point is that you need to know the voltage/temperature range of your charge source and confirm that it matches the voltage/temperature range demanded by your battery.