AGM Battery Charging

[pjlhat]

Having just installed 2 X 100amp hour AGM batteries into my Trayon Camper at considerable cost I was advised that I should now install a costly metering device to protect the batteries from the charge of the
alternator:o.
Prior to this I had two 6v lead acid batteries in the land rover and one AGM in the Trayon all being charged via the alternator through a 30amp circuit breaker and all seemed to work OK.

If I install a smaller circuit breaker, say a 10 amp will this give some protection to the batteries.:cool:
Peter

[two up]

Contact drivesafe, sounds like bs to me.

[87County]

I don't have an idea of the system you've got on board and whether it includes a dual battery isolater.

As advised above , contact Tim (drivesafe) Home Page | TRAXIDE - RV | Traxide - RV (http://www.traxide.com.au/) 07 5569 2557 - he's very helpful over the phone.

A lot of members here (incl me) have his dual battery system and even if you aren't using one of his I think he would be the one to give you the right info.

[drivesafe]

Thanks two Up.

Hi Peter and as two up posted, it is BS.

It also sound like your whole set up might not be up to the job.

First off, you can safely charge AGMs mounted in a camper trailer or caravan, by your alternator.

Most new AGMs will tolerate 14.7v but even the older type AGMs, with maximum voltage tolerances of 14.4v will not be harmed if your alternator goes to 15+v during the start-up boost cycle that newer Land Rovers now do.

The reason for this is that the LONG cable run between the alternator, via your cranking battery, and then all the way to your house batteries, will act as a quasi voltage/current regulator.

Next, you should have at least 6B&S ( 13.5mm2 ) cable running between the cranking battery and the house batteries and this can be protected by a 60 amp fuse or circuit breaker, at both ends of the cable.

If your setup has a 30 Circuit Breaker, it sounds like the cabling might be too thin to allow proper charging of your batteries.

This diagram might be of some help.

https://www.aulro.com/afvb/images/imported/2015/06/308.jpg

[pjlhat]

Hi Peter and as two up posted, it is BS.
It also sound like your whole set up might not be up to the job.
First off, you can safely charge AGMs mounted in a camper trailer or caravan, by your alternator.
Thanks Tim, The guys selling the batteries warned me that AGMs do not handle the AMPs of modern day alternators, said it would go egg shaped!!!

My set up has a relay activated by the alternator light connecting a large cable from the alternator to the battery via a 30 amp circute breaker (all that is in the battery bay under the L/F seat) then on to an anderson plug at the back of the cab (as in a 130 dual cab one meter) and then to the back of the Slide On Trayon battery bay adistance of two meters.
What do you think should I up grade the circute breaker and put another one in?
Appreciate your help Peter

[drivesafe]

Hi again Peter and if your two batteries are in a low state when you start your drive, they could easily draw 60+ amps.

So first off, make sure all the cabling from your cranking battery to your house batteries is 6B&S or thicker.

Then I would recommend you fit 50 automatic resetting circuit breakers at each end of the positive cable.

[steveG]

Hi again Peter and if your two batteries are in a low state when you start your drive, they could easily draw 60+ amps.

So first off, make sure all the cabling from your cranking battery to your house batteries is 6B&S or thicker.

Then I would recommend you fit 50 automatic resetting circuit breakers at each end of the positive cable.

I'm thinking that would be 50A breakers - not 50 of them :D

Just FWIW - I've had a 130Ah AGM aux battery in my county for a couple of years now, just charging from the alternator via a SC80 controller. Works perfectly, and no sign of the battery dying.

Steve

[dullbird]

Moved to communications, Audio and electrics as its not really defender specific

[Franz]

Having just installed 2 X 100amp hour AGM batteries into my Trayon Camper at considerable cost I was advised that I should now install a costly metering device to protect the batteries from the charge of the
alternator:o.
Prior to this I had two 6v lead acid batteries in the land rover and one AGM in the Trayon all being charged via the alternator through a 30amp circuit breaker and all seemed to work OK.

If I install a smaller circuit breaker, say a 10 amp will this give some protection to the batteries.:cool:
Peter
I must say that I have my doubts about charging differing battery types from the alternator.


Different battery types require differing charging voltages as can be seen from this Projecta 15A charger manual.


https://www.aulro.com/afvb/images/imported/2014/04/215.jpg (http://s1122.photobucket.com/user/desertman6/media/Disco/BatteryCharge.jpg.html)


The AGM battery is charged at 14.4V during the bulk cycle and the Wet/Calcium gets 14.7V. This would lead me to believe that if the alternator puts out more than 14.4V you are overcharging (and thereby reducing the life of the AGM battery).


I'm no expert on the matter but have had an AGM fail on me and I believe overcharging was a part of the problem. I also have 2 x GEL's (which require a lower charging voltage than AGM's) in the van which charge off the alternator but these have a DC/DC charger in front of them that regulates the charging voltage.


On the other end of the scale, I believe that undercharging an AGM will also shorten its life.

[rover-56]

It is my understanding that an AGM can take any amps that the alternator can provide, as long as the battery is not fully charged. Then it is important to control the voltage to 14.4 max. Pretty much the same as a conventional wet cell battery.
Really annoys me that people who we should be able to rely on give BS advice in the hope of selling something.:censored:

Terry

(PS Not you Tim)

[drivesafe]

Hi Franz and the I personally would not use Gel batteries in any RV situation. They are just not suited to RV applications.

But even where Gels have been used, I have never heard of anybody having any sort of problem with overcharging them when they are fitted in a camper trailer.

As far as AGMs go, older AGMs had a maximum tolerance of 14.4v but most AGMs today have a tolerance of 14.7v.

[steveG]

I'm certainly no expert either, but my view is that batteries in 4wd's are always a compromise, and never going to last as long as what you could achieve in a non-mobile installation.

Heat, deep discharge, vibration and not keeping them topped up when sitting for long periods I'm convinced do more damage to a battery than a couple of tenths of a volt off a perfect charge voltage will.

Steve

[inside]

Different battery types require differing charging voltages as can be seen from this Projecta 15A charger manual.
I have Optimas and it says 13.65 to 15.0 volts, no amperage limit. I trust the battery manufacturer more than the charger manufacturers.

[Franz]

Hi Frans and the I personally would not use Gel batteries in any RV situation. They are just not suited to RV applications.

But even where Gels have been used, I have never heard of anybody having any sort of problem with overcharging them when they are fitted in a camper trailer.

As far as AGMs go, older AGMs had a maximum tolerance of 14.4v but most AGMs today have a tolerance of 14.7v.


Hi Tim,


Why do you think the GEL's are unsuitable for RV applications?

[Homestar]

I only use my good old fashioned alternator to charge my 100Ah AGM battery. After 3 days of use I can tell you the poor old alternator gets a good workout for the first half hour back on the road...:D

It takes a bit to bring it right back up to full charge, but I've found 2 to 3 hours does it fully from a low charge. If its not 100% when I get home, I stick the solar panel back out for a day to top it off.

Just got back from a few days up the bush. It was at 11.85 volts (around 35% SOC) after 3 days in the one spot - running a 38 litre fridge and some LED lighting) - with pretty crappy weather, so the solar panel wasn't doing much. 1 and a quarter hour trip home and it is at 12.45 volts (around 85% SOC).

That's from an old fashioned Bosch 55 amp alternator that maxes out at 13.8 volts.

[Homestar]

Hi Tim,


Why do you think the GEL's are unsuitable for RV applications?

My only guess would be that they won't accept a large charging current like an AGM battery will. I would think without driving a loong way each day you wouldn't get enough charge into them? Only guessing here mind you.:)

[drivesafe]

Why do you think the GEL's are unsuitable for RV applications?

Hi again Franz and for the very reason you pointed out, they have too low a maximum voltage level.

[DiscoMick]

I have heard people who should know their stuff argue that for vehicle use the old wet cells are the best choice because the GELs and AGMs are overpriced for what they do. They argued it was better to pay less for wet cells and accept they might not last quite as long, but you could afford two of them for the price of one AGM.
Last time I had to replace the wet cell in the camper I looked at AGMs, but I could get a wet cell for $160 whereas the AGMs were around $300 and I just couldn't justify the extra cost. Plus the camper battery is charged through DC-DC and 240 volt multi-stage chargers so that's some protection against overcharging.
What do you think?

Sent from my GT-P5210 using AULRO mobile app

[drivesafe]

Hi DiscoMick and you are far more likely to get overcharged house batteries when you use a DC/DC device and/or battery charger.

With tens of thousands of my customers using nothing but the alternators to charge the house batteries, when towing a camper trailer or caravan, I have never heard of one of them over charging house batteries.

But there are plenty of cases of runaway battery charges cooking house batteries and the is a known problem that can occur when running a fridge off a battery that is being charged by a DC/DC device.

The problem occurs when the fridge cycles on, causing a small voltage drop, which then cause the DC/DC device to carryout a boost cycle.

These boost cycles are time oriented and have nothing to do with the SoC of the battery. So they just keep repeatedly over charging a fully charged battery.

This situation can repeat itself all day long and when you get to your destination you find you have cooked batteries.

This problem is so commonplace that a number of the installation manuals for different brands of DC/DC devices actually info the installer/operator not to power a fridge from a battery being charged by that DC/DC device.

Again, never heard of an alternator cooking house batteries.

[DiscoMick]

Thats very interesting information, thanks for that.

Sent from my GT-P5210 using AULRO mobile app

[pjlhat]

Again, never heard of an alternator cooking house batteries.
Hi Tim
Revisiting my origial post about charging AGM Batteries. I do not wish to use my cranking battery at all for the compressor fidge I have installed in my slide on Trayon camper so no need for the SC80 12v controler.
What I have is the alternator charging two 100amph AGM house batteries through a 30 amp circuit breaker. I also have a stand alone 120 watt folding solar panel with what appears to be a built in regulator, plus two 80watt panels mounted on the the roof of the Landrover un regulated that I manually control with an isolating switch depending on the battery voltage that I have metered. Un able to test the batteries for specific gravity, my battery supplier tested the batteries with some fancy gear and said they were about 50% and that the above set up was not charging the house batteries?? that panels and alternator would be working against each other!! The batteries are new but I am unable to get 3 days of fridge power even with the solar units helping out as sun permits.

Any advise would be greatly appreciated, thanks for your time.
Peter

[DiscoMick]

I looked into that a bit, not being any kind of expert I should add, and concluded the best way was to separate two batteries with a battery controller (a Traxide in my case), so one is being charged by the alternator to run the vehicle and, when its charged, the controller links the two together. The Traxide allows some of the charge in the starting battery to be drawn on to run the fridge, so I effectively have about `1.4 batteries.
I can use the solar panels to directly charge the second battery, without affecting the charging of the first battery by the alternator.
Charging the house battery by both the alternator and the solar at the same time sounds a bit likely to cause problems.
Incidentally, don't your solar panels have a regulator to prevent overcharging?
Be interested to know what others think.

[DiscoMick]

Hi Tim
Revisiting my origial post about charging AGM Batteries. I do not wish to use my cranking battery at all for the compressor fidge I have installed in my slide on Trayon camper so no need for the SC80 12v controler.
What I have is the alternator charging two 100amph AGM house batteries through a 30 amp circuit breaker. I also have a stand alone 120 watt folding solar panel with what appears to be a built in regulator, plus two 80watt panels mounted on the the roof of the Landrover un regulated that I manually control with an isolating switch depending on the battery voltage that I have metered. Un able to test the batteries for specific gravity, my battery supplier tested the batteries with some fancy gear and said they were about 50% and that the above set up was not charging the house batteries?? that panels and alternator would be working against each other!! The batteries are new but I am unable to get 3 days of fridge power even with the solar units helping out as sun permits.

Any advise would be greatly appreciated, thanks for your time.
Peter


Before I installed the Matson DC-DC charger I found the charge from the vehicle was not charging the battery in the camper enough while I was driving with it plugged into the trailer plug and the Engel fridge was running off the AGM battery, maybe because of voltage drop down the wiring to the trailer battery. The Matson bumps the charge up to 20 amps while the engine is running. The Engel fridge is running off the battery in the camper, but cycles on and off. Now it seems to work fine.

[DeanoH]

Hi Peter, We have a similar setup to you on our OKA. ie. two roof mounted solar panels and a separate vehicle battery(s) and two house batterys. I had a portable fold up panel of 140 watts but no longer use it was unnecessary.


I assume you have a compressor type fridge (eg. Engel/Waeco) and not one of the power hungry 3 way type fridges ? Whilst these can be quite good on gas they are murder on batterys and not suitable for prolonged use on batterys.


I would suggest you have another look at Tims circuit in post 4 with particular regard to the cable size and the 50 amp breakers.


I am assuming you have relay switched the power from the alternator to the house battery so as to isolate it from the vehicle battery which is good but when you say the relay is powered from the alternator light I guess you mean it's activated from either the ignition or the alternator pulse output to the tacho ?? ie. engine running = relay operated, engine off = relay off ?


Assuming the above I'd suggest you diode the 80 watt panels (if they're not already) for their protection and connect them to a suitable solar controller. I'd replace your relay with at least a 50 amp rated change over relay using Tim's circuit with the relay replacing the SC80 which as you say you don't need. I'd connect the output of the solar controller to the normally closed side of the relays change over contacts and the alternator output/vehicle battery to the normally open side of the change over contacts. The centre contact goes to the house battery.


This configuration allows the vehicles alternator to charge the house batterys when the engine is running with automatic change over to the vehicle mounted panels when the engine is off. :)


This is the configuration I have and it works very effectively for us. A variation we have is a simple switch in the operate path of the relay so that the solar panels can be connected to the house battery only and it's not switched to the alternator when the engine starts. I built this in as an option but haven't used it as the system worked fine as it was from day 1.:) Another variation I built in was a second relay to isolate the solar panel output from the solar reg when the house battery charging source was the alternator, but I don't know if this is really necessary.


You mention that your portable panels "appear to have a built in regulator", which is a bit of a worry. From my experience the stuck on the back regulators are usually of very low quality, indeed if you have one.
Whilst I'm merrily spending your money :D:angel:, why not buy two regulators the same ? one for the roof mounted 160 watt and one for the 120 watt portable panels. This way you would be able to fault find/swap if need be as long as both regs were both rated at a min of 160 watts.


The portable panels reg could be left mounted in/on the camper with a suitable plug to connect the panel directly to it. For good results it is best to have the portable panels solar reg as close to the house battery as possible.


Check that the chassis earths of the batterys and appliances are all good. Is there a separate earth connecting the trayon to the Landy chassis ?


As I said at the start we have this setup (with a few extras) on the OKA and it works fine for us. :)




Deano :)

[drivesafe]

that panels and alternator would be working against each other!!

Hi Peter and I don't know why an EXPERT would tell you that having power from an alternator and a solar regulator feeding into the same battery would work against each other.

Mate, that is pure fiction and the 'EXPERT' that told you that might be an expert at paining fences but they sure as hell know nothing about auto electrical charging systems or how to charge batteries.

From what you have posted, and as I have already pointed out, your charging problems sound like they are being caused by grossly undersized, and any EXPERT should have picked this up in the first place.

You need to sort that out before you do anything else.

Next, it is actually an industry standard to have power from an alternator and a solar regulator feeding into the same battery, and it does not cause any form of problems.

Last but not least, you need a solar regulator on that 80w solar panel on the roof of your land rover because if you forget just once, you will cook your batteries.

An 80w solar panel can force the terminal voltage of any form of lead acid battery to over 17v and if this is left unchecked for a while, just a few hours, you will permanently damage the battery.

[DeanoH]

..................................An 80w solar panel can force the terminal voltage of any form of lead acid battery to over 17v and if this is left unchecked for a while, just a few hours, you will permanently damage the battery.




Even worse when there's two of them




"...................................... plus two 80watt panels mounted on the the roof of the Landrover un regulated ............................"




Deano :)

[pjlhat]

[QUOTE=DeanoH;2324316]Hi Peter, We have a similar setup to you on our OKA. ie. two roof mounted solar panels and a separate vehicle battery(s) and two house batterys. I had a portable fold up panel of 140 watts but no longer use it was unnecessary.


I assume you have a compressor type fridge (eg. Engel/Waeco) and not one of the power hungry 3 way type fridges ? Whilst these can be quite good on gas they are murder on batterys and not suitable for prolonged use on batterys.


I would suggest you have another look at Tims circuit in post 4 with particular regard to the cable size and the 50 amp breakers.


I am assuming you have relay switched the power from the alternator to the house battery so as to isolate it from the vehicle battery which is good but when you say the relay is powered from the alternator light I guess you mean it's activated from either the ignition or the alternator pulse output to the tacho ?? ie. engine running = relay operated, engine off = relay off ?


Assuming the above I'd suggest you diode the 80 watt panels (if they're not already) for their protection and connect them to a suitable solar controller. I'd replace your relay with at least a 50 amp rated change over relay using Tim's circuit with the relay replacing the SC80 which as you say you don't need. I'd connect the output of the solar controller to the normally closed side of the relays change over contacts and the alternator output/vehicle battery to the normally open side of the change over contacts. The centre contact goes to the house battery.


This configuration allows the vehicles alternator to charge the house batterys when the engine is running with automatic change over to the vehicle mounted panels when the engine is off. :)


This is the configuration I have and it works very effectively for us. A variation we have is a simple switch in the operate path of the relay so that the solar panels can be connected to the house battery only and it's not switched to the alternator when the engine starts. I built this in as an option but haven't used it as the system worked fine as it was from day 1.:) Another variation I built in was a second relay to isolate the solar panel output from the solar reg when the house battery charging source was the alternator, but I don't know if this is really necessary.


You mention that your portable panels "appear to have a built in regulator", which is a bit of a worry. From my experience the stuck on the back regulators are usually of very low quality, indeed if you have one.
Whilst I'm merrily spending your money :D:angel:, why not buy two regulators the same ? one for the roof mounted 160 watt and one for the 120 watt portable panels. This way you would be able to fault find/swap if need be as long as both regs were both rated at a min of 160 wa

Thanks Deano, Yes I use the ignition light to activate the relay to charge the house batteries and yes we replaced th

[DiscoMick]

Hi Peter and I don't know why an EXPERT would tell you that having power from an alternator and a solar regulator feeding into the same battery would work against each other.

Mate, that is pure fiction and the 'EXPERT' that told you that might be an expert at paining fences but they sure as hell know nothing about auto electrical charging systems or how to charge batteries.

From what you have posted, and as I have already pointed out, your charging problems sound like they are being caused by grossly undersized, and any EXPERT should have picked this up in the first place.

You need to sort that out before you do anything else.

Next, it is actually an industry standard to have power from an alternator and a solar regulator feeding into the same battery, and it does not cause any form of problems.

Last but not least, you need a solar regulator on that 80w solar panel on the roof of your land rover because if you forget just once, you will cook your batteries.

An 80w solar panel can force the terminal voltage of any form of lead acid battery to over 17v and if this is left unchecked for a while, just a few hours, you will permanently damage the battery.


Is that also true for AGM batteries?

[pjlhat]

[QUOTE=DeanoH;2324316]I assume you have a compressor type fridge (eg. Engel/Waeco) and not one of the power hungry 3 way type fridges ? Whilst these can be quite good on gas they are murder on batterys and not suitable for prolonged use on batterys.


Thanks Deano,
I will take a while to digest all the info and may come back for some clarification latter.
Yes I do use the ignition light to activate the relay and yes we have replaced the Gas fridge with a wako 90 litre compressor fridge.
Thanks again.

[drivesafe]

Is that also true for AGM batteries?

Hi Mick and Yes.

Agms are lead acid batteries, as are Gel batteries.

BTW you can mix any type of lead acid battery ( Wet, AGM or Gel ) with any other type and solar regulators and alternators, charging the same battery or batteries, will have no problems fully charging them.

[pjlhat]

Hi Tim thanks for the details between you and Deano I have a lot of info to digest. I want to get this right as future camping will be long periods and off the beaten track with a compressor fridge.
Is there any way that a laymen can test the amount of charge in an AGM battery, I currently use the voltage as my indicator when the fridge is drawing power.:confused:
Peter.

PS Thanks to Dave and all who are responsible for this forum enabling us Landy owners who like to do their own work and modifications an avenue of expert help. Many thanks:)

[steveG]

My understanding is that you need to disconnect any load or charging and let the battery sit for a bit then check the voltage.
If its under load you're not going to get a valid reading. As an extreme example - your battery might be full charged but if you crank the engine the voltage could come down to 10v or so (which is lower than a completely discharged battery if you look at the SOC charts).

Steve

[DiscoMick]

Hi Tim thanks for the details between you and Deano I have a lot of info to digest. I want to get this right as future camping will be long periods and off the beaten track with a compressor fridge.
Is there any way that a laymen can test the amount of charge in an AGM battery, I currently use the voltage as my indicator when the fridge is drawing power.:confused:
Peter.

PS Thanks to Dave and all who are responsible for this forum enabling us Landy owners who like to do their own work and modifications an avenue of expert help. Many thanks:)


I have two ways to test mine.
1. I bought a plug from Jaycar which plugs into a cigarette lighter and reads the voltage. So it is reading whatever the current is flowing through the electrical system. If the engine is running it will read what the alternator is putting out. If the engine is stopped it is reading the battery. When I start the vehicle I can watch the reading go up as the alternator kicks in, usually to sit around 13 volts.
I can plug it into my camper and read the camper's battery. Only cost about $20. Very useful.
2. If I attach my multi-stage battery charger it first gives a reading of the state of the battery, before beginning to charge it.

[DiscoMick]

Hi Mick and Yes.

Agms are lead acid batteries, as are Gel batteries.

BTW you can mix any type of lead acid battery ( Wet, AGM or Gel ) with any other type and solar regulators and alternators, charging the same battery or batteries, will have no problems fully charging them.


Yes, I've used my 80 watt solar panels with the regulator on both wet cell deep cycle and AGM batteries and it all worked fine. In sunny weather the battery is usually fully recharged by mid-morning after running down a bit during the night. Then it just stays charged while there is sunlight.

[drivesafe]

Hi pjihat and as per our phone conversation, here is the Loaded Voltage Chart.

https://www.aulro.com/afvb/images/imported/2016/06/640.jpg

[drivesafe]

My understanding is that you need to disconnect any load or charging and let the battery sit for a bit then check the voltage.
If its under load you're not going to get a valid reading. As an extreme example - your battery might be full charged but if you crank the engine the voltage could come down to 10v or so (which is lower than a completely discharged battery if you look at the SOC charts).

Steve

Hi steveG, there is a lot to this subject and the link below will give you a bit more insight to SoC and battery capacity.

http://www.aulro.com/afvb/technical-chatter/212373-battery-voltage-state-charge-2.html

[DiscoMick]

Hi pjihat and as per our phone conversation, here is the Loaded Voltage Chart.

https://www.aulro.com/afvb/images/imported/2016/06/640.jpg


Yes, I read somewhere that a cell is typically 2.1 so 6 x 2.1 is 12.6. Probably varies I guess.

[pjlhat]

Hi Deano, Thanks for all the time and details:) I have digested it now plus a few yarns with Tim and now ready to revamp my set up.:)
I have decided to go with Tims Diagrame on post 4 with the SC80 plus built in 50 amp circuit breaker. Have ordered it and just waiting for it to arrive. All other gear I can sorce locally. With regard to the fixed solar panels on the roof are yours fixed or are you able to slope them to suit your camp position. Would be interested in a method of tilting them so one can still get the best of positions view and weather wise.:angel: The other thing is would it be practical to have one large regulator that could handle both the roof mounted panels and the fold up panel. With the regulaor mounted in the Trayon and accessed by two external sockets. If so the question is then what size regulator. Looked at one on ebay 30A solar panel control regulator 12v 24v Auto 360w/720w for LED light. Is that some thing that would suit:confused:
Peter.


[QUOTE=DeanoH;2324316]Hi Peter, We have a similar setup to you on our OKA. ie. two roof mounted solar panels and a separate vehicle battery(s) and two house batterys. I had a portable fold up panel of 140
You mention that your portable panels "appear to have a built in regulator", which is a bit of a worry. From my experience the stuck on the back regulators are usually of very low quality, indeed if you have one.
Whilst I'm merrily spending your money :D:angel:, why not buy two regulators the same ? one for the roof mounted 160 watt and one for the 120 watt portable panels. This way you would be able to fault find/swap if need be as long as both regs were both rated at a min of 160 watts.
The portable panels reg could be left mounted in/on the camper with a suitable plug to connect the panel directly to it. For good results it is best to have the portable panels solar reg as close to the house battery as possible.