I am trying to get a handle on various expenses that one might encounter as part of a solar install and future replacement of items. To that end, what has been your experience with AGM batteries WRT to the number of years before replacement. I know Lithium batteries are relatively new in the RV application but with claims of 2000 recharge cycles, it sounds like they should last many years before replacement. Calculating a budget for such replacement is necessary to avoid a sudden cash crunch down the road, seeing as these batteries are not inexpensive (today prices) and they should all be replaced at the same time from what I am reading.
All insight welcome.
Bill and Linda said
07:45 AM Aug 14, 2014
Brian:
Howard is probably the best reference I know of as a user as to battery life.His AGM’s (Lifeline – the same company that makes aircraft batteries) lasted about 5-6 years as I recall.Like all batteries their capacity just started going downhill.You will have to search his Blog to find it.
For most users I would not recommend the Lithium Batteries.AGM Batteries, properly cared for, don’t just quit.They just star running down and get to a point where you have less and less useable amps.And yes, never replace one battery.Doing so will almost guarantee the other batteries will go bad much sooner.
Remember, AGM batteries, like lead acid, should not be discharged more than 50% of their ratings as a normal event.That means if you have 300AH worth of batteries you should use only 150AH.This means having a good battery monitor that will give a good “gas gauge” reading of how much you have used and what the charge percentage is.Voltage is not a good indication of charge for this purpose.
The TriMetric battery monitor is a very good choice IMO.It’s simple to use and very easy to install.This link is for two of the models.They make a TM2025-RV as well.They all work the same, just different form factors.
Although expensive, if the budget will allow, Lifeline AGM’s are well worth the money because they are truly maintenance free.If you should forget to properly service lead-acid (wet cell) batteries they can be damaged.So, IMO for the long term you will more likely get better life out of the AGMs just do to the practical nature of servicing the batteries.Others may have different opinions as they never forget to service their batteries. But most forget and I know I did in earlier days.
As you may know, AGM’s can be placed anywhere in the rig, without ventilation, and in any direction.I.e. there is no “up” side other than access to the terminal.This can be a huge advantage if you need to place them in the basement due to space limitations.They do not vent any gases.I do recommend 6 volt batteries wired for 12 volts. Lifeline makes all different sizes and voltage configurations.
Finally, you need a good charger.A three stage “smart” charger for the AGM’s.While very rugged, for long life they require a charger that will charge them properly and moreover not over charge them.
Trust this was helpful as a first overview.
Here is the link to Jack’s Battery and Solar page.Get a cup of coffee, there is a lot of info here including about battery chargers.
I have read Howard's thorough journal entries on his solar set-up and Jack's also. Great references, as you say. I also agree, that top of the line batteries such as the Life Line's are the way to go. My preliminary plan is about 660-880 Ah of capacity (330-440 usable) so either 6 or 8 batteries. If 5-6 years is average life expectancy then I should be able to calculate a budget for their replacement.
I plan on having all those other goodies you mentioned as part of a complete package. Do it right the first time, as they say.
-- Edited by biggaRView on Thursday 14th of August 2014 08:08:14 AM
Technomadia said
09:45 AM Aug 14, 2014
We've been running LFP for 3 years now.. here's our page on them with costs and such:
We did a 2.5 year update earlier this year in a video that is also on the page (excuse the poor quality.. bad internet day).
We've not used them long enough to give a long term projection, and still consider them a bit in the non-mainstream play land. Unless you're looking to be on the cutting edge and take the risks that go along with that - we don't recommend them for most folks. But happy to share our journey with them.
By the math, the LFP *should* be cheaper in the long run than AGM. But that math is all theory right now. But, we are incredibly happy with their performance and all the other benefits they give us.
- Cherie
BiggarView said
10:01 AM Aug 14, 2014
Cherie, I have been following your experience also. Excellent background info for those of us still in research mode and even those ready to take the plunge. Since we are still more than 4 years away from starting (hopefully less) good intel and bright prospects for future technological advances in batteries bode well for us. As we get closer, we look forward to more updates from you which will aid in our final decisions in this area.
Brian
-- Edited by biggaRView on Thursday 14th of August 2014 10:01:20 AM
I am trying to get a handle on various expenses that one might encounter as part of a solar install and future replacement of items. To that end, what has been your experience with AGM batteries WRT to the number of years before replacement. I know Lithium batteries are relatively new in the RV application but with claims of 2000 recharge cycles, it sounds like they should last many years before replacement. Calculating a budget for such replacement is necessary to avoid a sudden cash crunch down the road, seeing as these batteries are not inexpensive (today prices) and they should all be replaced at the same time from what I am reading.
All insight welcome.
Brian:
Howard is probably the best reference I know of as a user as to battery life. His AGM’s (Lifeline – the same company that makes aircraft batteries) lasted about 5-6 years as I recall. Like all batteries their capacity just started going downhill. You will have to search his Blog to find it.
For most users I would not recommend the Lithium Batteries. AGM Batteries, properly cared for, don’t just quit. They just star running down and get to a point where you have less and less useable amps. And yes, never replace one battery. Doing so will almost guarantee the other batteries will go bad much sooner.
Remember, AGM batteries, like lead acid, should not be discharged more than 50% of their ratings as a normal event. That means if you have 300AH worth of batteries you should use only 150AH. This means having a good battery monitor that will give a good “gas gauge” reading of how much you have used and what the charge percentage is. Voltage is not a good indication of charge for this purpose.
The TriMetric battery monitor is a very good choice IMO. It’s simple to use and very easy to install. This link is for two of the models. They make a TM2025-RV as well. They all work the same, just different form factors.
http://www.bogartengineering.com/products/trimetric/from_tm2020_to_tm2025
Although expensive, if the budget will allow, Lifeline AGM’s are well worth the money because they are truly maintenance free. If you should forget to properly service lead-acid (wet cell) batteries they can be damaged. So, IMO for the long term you will more likely get better life out of the AGMs just do to the practical nature of servicing the batteries. Others may have different opinions as they never forget to service their batteries. But most forget and I know I did in earlier days.
As you may know, AGM’s can be placed anywhere in the rig, without ventilation, and in any direction. I.e. there is no “up” side other than access to the terminal. This can be a huge advantage if you need to place them in the basement due to space limitations. They do not vent any gases. I do recommend 6 volt batteries wired for 12 volts. Lifeline makes all different sizes and voltage configurations.
http://www.lifelinebatteries.com/rvdeepcyclebatteries.php
Finally, you need a good charger. A three stage “smart” charger for the AGM’s. While very rugged, for long life they require a charger that will charge them properly and moreover not over charge them.
Trust this was helpful as a first overview.
Here is the link to Jack’s Battery and Solar page. Get a cup of coffee, there is a lot of info here including about battery chargers.
http://www.jackdanmayer.com/rv_electrical_and_solar.htm
I have read Howard's thorough journal entries on his solar set-up and Jack's also. Great references, as you say. I also agree, that top of the line batteries such as the Life Line's are the way to go. My preliminary plan is about 660-880 Ah of capacity (330-440 usable) so either 6 or 8 batteries. If 5-6 years is average life expectancy then I should be able to calculate a budget for their replacement.
I plan on having all those other goodies you mentioned as part of a complete package. Do it right the first time, as they say.
-- Edited by biggaRView on Thursday 14th of August 2014 08:08:14 AM
www.technomadia.com/lithium
We did a 2.5 year update earlier this year in a video that is also on the page (excuse the poor quality.. bad internet day).
We've not used them long enough to give a long term projection, and still consider them a bit in the non-mainstream play land. Unless you're looking to be on the cutting edge and take the risks that go along with that - we don't recommend them for most folks. But happy to share our journey with them.
By the math, the LFP *should* be cheaper in the long run than AGM. But that math is all theory right now. But, we are incredibly happy with their performance and all the other benefits they give us.
- Cherie
Cherie, I have been following your experience also. Excellent background info for those of us still in research mode and even those ready to take the plunge. Since we are still more than 4 years away from starting (hopefully less) good intel and bright prospects for future technological advances in batteries bode well for us. As we get closer, we look forward to more updates from you which will aid in our final decisions in this area.
Brian
-- Edited by biggaRView on Thursday 14th of August 2014 10:01:20 AM