Hi everyone, new on the scene here and setting up to travel with my camper trailer, I recently returned from a trip up to northern NSW, leaving where it had been perfect weather for a week I stopped at Swans crossing where the weather turned wet and sunshine was limited, then heading south to Narooma it was overcast most days for the next week, at this spot was a grey nomad (although he didn't like me using that term) who was really struggling to keep his batteries charged and every second day was starting his vehicle to put charge into his batteries, I don't remember his input or outgoing specs but it did make me wonder about my planned setup.
my setup to date will consist of 570w solar and 240ah AGM batteries, my usage is a 75lt brass monkey fridge/freezer rated 5ah max and 0.87/24 other than this it's lights and charging phone, kayak battery 17.5ah once a week, and some other usb charging most of these I usually just charge from my car when camping, I guess my other big power user would be my laptop however this was only used when power permitted in the past.
I have installed a dual battery system in my car however I only want to use this as it's intended, while driving from A - B.
Up till now I have been using a 120w panel 80ah old car battery for my laptop and a 35lt gas fridge while camped during my trips away and this seemed to almost cope power wise.
once im on the road if I need more panels then no issues I will buy them but it would be nice to get close to whats needed before I leave.
Mike Harding said
07:35 AM Aug 5, 2021
I've owned a 60L fridge/freezer for some years and have done extensive power consumption testing on it; set at -12C/+2C it uses between 25Ah and 60Ah per day depending upon ambient temperature. My modern laptop consumes about 1A so say 4Ah per day. Sundry other stuff, lighting, water pump, charging etc say 10Ah per day. So worst case is:
60 + 4 + 10 = 74Ah x 13V = 962Wh
Therefore your 120W panel will need 8 hours of perfect sunshine per day - not going to happen.
In reality (say) 300W of panel will put out about 250W in good sunshine so you would need 4 hours of sun to meet your worst case needs - and that's 4 hours of good sun with no shade and the panels being regularly rotated.
I am in the process of upgrading my solar and have come to the conclusion I am always going to need a generator for top-ups here in Victoria where I spend most of my time.
Note: run the freezer at -12C not -18C this is good enough to keep food safe for three months or more and uses a lot less energy.
Peter_n_Margaret said
08:59 AM Aug 5, 2021
You can not have too much solar. Fit all you can.
If you get good charge even on the bad days, the batteries only have to supply over night.
Solar lasts decades. Batteries wear out. More solar is cheaper to maintain.
Cheers,
Peter
Whenarewethere said
09:19 AM Aug 5, 2021
As said above, you can't have too much solar & batteries for inclement weather.
The limiting factor is payload & or room. We are in a car only. So our opinion was to make our fridge as efficient as possible, with additional insulation & increasing wire thickness within the fridge to reduce resistance. Up to 15AH per 24 hours.
If needed we can run the car engine to charge up the batteries, but as we tend to move after 4 days maximum, charging happens by default.
Our 12O watt setup typically puts out 9amps into the batteries via Victron MPPT & up to 11.3amps under perfect conditions. We built quality instead of the cheap Chinese rubbish. Who wants to be remote with third rate rubbish.
We have also built in redundancy, multiple everything & 6awg & 4awg wiring. It's overkill, but it is the easiest way to squeeze blood out of a stone.
Jaahn said
01:27 PM Aug 5, 2021
Hi
My only addition to the statement 'You cannot have too much solar" is to say combined with a quality regulator that has three stages and will drop back to float when the batteries are full early in good sun.
Jaahn
Dick0 said
02:13 PM Aug 5, 2021
Welcome mate,
The more the better combined with a quality solar charger as amplified here so far.
There is lots of info on this topic here.
Good luck!
peatop said
07:14 PM Aug 5, 2021
Thanks everyone, great comments and yes miles of information I have been sifting through also on other sites, the controller is an issue for a few reasons
1. I don't really like single units doing multiple jobs: dc - dc charger/mppt reg so this means I need buy them separately.
2. I don't know what size to buy as yet.
I like the idea of the Victron for the BT app and once I change to LFP batteries this will prove to be very helpful for keeping an eye on everything.
My 12v wiring from the car boot to the control board bus bar and battery is 6 awg and on the control board its 8 awg as connections become an issue with bigger gauges.
from my panels im just using what came with them but definitely looking at upgrading them to 8 awg or higher for main cable again this will depend on total solar output spec's.
the 12/24v fridge cable looks to be to light and will be replaced, I have builtin redundancies for backup but hope to never use them (we live in hope)
Aus-Kiwi said
07:42 PM Aug 5, 2021
Solar is great for thermal insulation . The hot part is where theres no solar !! In summer !
Craig1 said
08:03 PM Aug 5, 2021
Peter, some enlightened members will comment/correct me here, but there is a table that says use as much heavier cable as possible, but if a short bit needs to be smaller, ie connect to a small terminal, so be it, but you will still gain an advantage. Hope that is not for 240/415 only.
-- Edited by Craig1 on Friday 6th of August 2021 09:34:33 AM
Whenarewethere said
08:14 PM Aug 5, 2021
Use a short section of lighter cable that will fit into the terminal blocks. It will have more resistance but it's not an issue being a short length. Better to have the bulk of the run heavy enough.
iana said
09:39 AM Aug 6, 2021
Just remember any weight added to the roof of a van particularly full height vans will have the effect of raising the center of gravity, and hence will effect stability.
peatop said
03:01 PM Aug 7, 2021
iana wrote:
Just remember any weight added to the roof of a van particularly full height vans will have the effect of raising the center of gravity, and hence will effect stability.
I don't think that will be an issue with my camper trailer and free standing panels, but good point,
Bicyclecamper said
04:10 PM Aug 7, 2021
I am limited to how much I can carry, that is lift by my person, so the weight of my portable 80 watt Jaycar panels is right at my limit. I was given a 120 watt portable, from a family member who gave up c.vaning, but have since sold it as it was too heavy for me. My 80 watt panels currently service my single agm battery adequately, as we only use 8amps per night.
valiant81 said
11:38 PM Aug 7, 2021
Hi all; After camping for a week in south Tasmania over the queens birthday weekend and with 240 watts of solar, 440 Ah of agm batteries i found that i was running out of power. The weather was rain, drizzle and fog that did not lift for several days and bloody cold as well. I also have a 20 Amp DC to DC charger, but you need that connected to the car to be able to charge. Ended up borrowing one of the other campers gen set and 15Ah smart charger. This helped a lot.
On returning home i ended up purchasing a smart 30 Amp charger and wiring that into the house batteries. This put in just over 300 Amps over around 10 ~12 Hours, so the house batteries were probably down in charge because of insufficient charge for the week away. The batteries are just on 2 years old at the moment. My van is now connected to mains power while at home and so the smart charger is on but with full batteries the charger now is in sleep mode with the batteries at 100% fully charged. I also purchased a smart bridge that monitors the charge/ discharge of the batteries and also gives a readout like a fuel gauge as to the capacity of the batteries.
So charging the house batteries at home is not a problem , but free camping, that is were i now also have a 2Kw generator that plugs into the mains input of the caravan. That will only be used if and when the house batteries get down a bit to far and require charging during the day. I just plug the generator into the mains input on the caravan and the battery charger takes over and starts charging if needed.
I have the usual things in my caravan, led lighting, tv and sat receiver, diesel heater and more led lighting outside, and finally a 40 ltr Engel fridge. A small inverter ( 300 Watts ) for recharging the computer or my for my electric shaver. Gas for the fridge when camping and hot water/cooking.
The smart charger and smart current bridge are also able to be bluetoothed to my phone and i can check on the state of the batteries and the action that i may need to take. So looking forward to our next trip away and free camping and further testing on my set up.
-- Edited by valiant81 on Saturday 7th of August 2021 11:40:33 PM
peatop said
04:08 PM Aug 8, 2021
valiant81 wrote:
Hi all; After camping for a week in south Tasmania over the queens birthday weekend and with 240 watts of solar, 440 Ah of agm batteries i found that i was running out of power. The weather was rain, drizzle and fog that did not lift for several days and bloody cold as well. I also have a 20 Amp DC to DC charger, but you need that connected to the car to be able to charge. Ended up borrowing one of the other campers gen set and 15Ah smart charger. This helped a lot.
On returning home i ended up purchasing a smart 30 Amp charger and wiring that into the house batteries. This put in just over 300 Amps over around 10 ~12 Hours, so the house batteries were probably down in charge because of insufficient charge for the week away. The batteries are just on 2 years old at the moment. My van is now connected to mains power while at home and so the smart charger is on but with full batteries the charger now is in sleep mode with the batteries at 100% fully charged. I also purchased a smart bridge that monitors the charge/ discharge of the batteries and also gives a readout like a fuel gauge as to the capacity of the batteries.
So charging the house batteries at home is not a problem , but free camping, that is were i now also have a 2Kw generator that plugs into the mains input of the caravan. That will only be used if and when the house batteries get down a bit to far and require charging during the day. I just plug the generator into the mains input on the caravan and the battery charger takes over and starts charging if needed.
I have the usual things in my caravan, led lighting, tv and sat receiver, diesel heater and more led lighting outside, and finally a 40 ltr Engel fridge. A small inverter ( 300 Watts ) for recharging the computer or my for my electric shaver. Gas for the fridge when camping and hot water/cooking.
The smart charger and smart current bridge are also able to be bluetoothed to my phone and i can check on the state of the batteries and the action that i may need to take. So looking forward to our next trip away and free camping and further testing on my set up.
-- Edited by valiant81 on Saturday 7th of August 2021 11:40:33 PM
This is exactly what's been bothering me, although I have been planning to follow the warmth, head north in the colder months and south when hot, but this does not make up for those extended cloudy periods and shady conditions, but I think I have sorted most of it out now with my planning for upgrades of panels and batteries, I think the sooner I change to lithium the better the system will cope with the problematic discharge amounts created by extended low input of cloudy or shaded days. and also the use of a solar blanket and or one of those flexible panels as your backup.
Thanks for everyone's input so far it's certainly been very helpful along with other posts I've read on here I'm almost a solar techi lol far from it but getting quite capable at sorting out most of my problems.
Mike Harding said
05:32 PM Aug 8, 2021
peatop wrote:
I think the sooner I change to lithium the better the system will cope with the problematic discharge amounts created by extended low input of cloudy or shaded days. and also the use of a solar blanket and or one of those flexible panels as your backup.
Lithium batteries will not provide better support than lead acid; unless energy in equals or exceeds energy out you are going to run out of power.
I looked at solar blankets long and hard and decided not to buy one; they appear to be always significantly over-speced and, it seems, most (all?) are not waterproof!
Whenarewethere said
06:07 PM Aug 8, 2021
Lithium will make no difference. You simply replace one set of issues for another set of issues.
I also looked at solar blankets. By the time you calculate the actual area of the solar cells not one blanket I looked added up.
For that matter most glass solar panels do not add up either.
Peter_n_Margaret said
06:22 PM Aug 8, 2021
Lithium are not magic. You can still only get out what you put in. They are just batteries.
Being able to put more in is the answer. Get more solar.
Cheers,
Peter
Jaahn said
08:10 PM Aug 8, 2021
Bicyclecamper wrote:
I am limited to how much I can carry, that is lift by my person, so the weight of my portable 80 watt Jaycar panels is right at my limit. I was given a 120 watt portable, from a family member who gave up c.vaning, but have since sold it as it was too heavy for me. My 80 watt panels currently service my single agm battery adequately, as we only use 8amps per night.
Hi
I have used 80W panels as portables in the past, 4 of them for 320W and wired in pairs with plugs and sockets. Easy to handle and in good sun 2 might be enough. I have in past times seperated a pair of folding panels to make then easy to handle.
Using good quality rigid panels seems to be much cheaper than blankets and the specs of expensive blankets seems to greatly exceed their performance !
As pointed out when free camping you do need to make enough power every day or at most two, which will match what you use in that time. Lithium is only a battery for short term storage just like lead acid does. You must make the power to use power.
Jaahn
-- Edited by Jaahn on Sunday 8th of August 2021 08:23:04 PM
peatop said
01:56 PM Aug 9, 2021
Isn't the idea behind Lithium about usable power more than the amount you use? meaning that if I have 2 x 100ah batteries my estimated usable amps before recharge is 100 amps before damage occurs to the batteries, where if I have the same in Lithium then I have up to 160 amps usable amps (still not sure on the correct figures), this give you some protection for low solar output during extended periods, ofc you still need the capacity to fully charge them but you have more usable amps therefore longer time to wait for the weather to clear, shade change or you move locations charging your batteries via your dc to dc charger ect.
I guess the heading give the wrong idea my bad, It should perhaps read "solar, building in redundancies" I'm just trying to limit issues with power created buy unseen circumstances (gotta keep that beer cold).
Whenarewethere said
04:06 PM Aug 9, 2021
I have 104AH of batteries so I have 104AH of usable capacity if needed. Actually a bit more as I draw down the batteries at such a low rate over week.
If you drawn down the battery 80% once a month or a bit more once a year. That is only 60 times over 5 years. So what, most of the time you are probably only doing 30%. The battery will not fall off a cliff at 300 80% cycles.
But the fact remains is that you can use the full capacity of the battery when it's needed.
Peter_n_Margaret said
05:08 PM Aug 11, 2021
peatop wrote:
Isn't the idea behind Lithium about usable power more than the amount you use? meaning that if I have 2 x 100ah batteries my estimated usable amps before recharge is 100 amps before damage occurs to the batteries, where if I have the same in Lithium then I have up to 160 amps usable amps (still not sure on the correct figures), this give you some protection for low solar output during extended periods, ofc you still need the capacity to fully charge them but you have more usable amps therefore longer time to wait for the weather to clear, shade change or you move locations charging your batteries via your dc to dc charger ect.
This fallacy of only being able to discharge an AGM (or other lead acid battery) to 50% of its rated capacity is rubbish. You can safely discharge AGM batteries to zero rated capacity (10.5V) without damage.
The life of AGM batteries is best measured in total power in and out, not by depth of discharge or cycles.
The lithium will hold a higher voltage for deep discharges and that may be useful if you are running high power appliances.
Cheers,
Peter
laurieoz said
05:45 PM Aug 11, 2021
Peter_n_Margaret wrote:
peatop wrote:
Isn't the idea behind Lithium about usable power more than the amount you use? meaning that if I have 2 x 100ah batteries my estimated usable amps before recharge is 100 amps before damage occurs to the batteries, where if I have the same in Lithium then I have up to 160 amps usable amps (still not sure on the correct figures), this give you some protection for low solar output during extended periods, ofc you still need the capacity to fully charge them but you have more usable amps therefore longer time to wait for the weather to clear, shade change or you move locations charging your batteries via your dc to dc charger ect.
This fallacy of only being able to discharge an AGM (or other lead acid battery) to 50% of its rated capacity is rubbish. You can safely discharge AGM batteries to zero rated capacity (10.5V) without damage.
The life of AGM batteries is best measured in total power in and out, not by depth of discharge or cycles.
The lithium will hold a higher voltage for deep discharges and that may be useful if you are running high power appliances.
Cheers,
Peter
Hi
Where do you get the technical data from that you can safely discharge AGM batteries to zero without damage?
Why is 50% always (from what i see) quoted
I would like to read technical papers
Laurie
Whenarewethere said
06:11 PM Aug 11, 2021
Look at the battery data sheet for the battery. The total life watt hours of the battery is not a great deal different to whether you discharge 30%, 50%, 80%.
Peter_n_Margaret said
09:36 PM Aug 11, 2021
laurieoz wrote:
Hi
Where do you get the technical data from that you can safely discharge AGM batteries to zero without damage?
Why is 50% always (from what i see) quoted
I would like to read technical papers
Laurie
Multiply cycles x Ahrs per cycle to find total life in Ahrs.
Where do you get the technical data from that you can safely discharge AGM batteries to zero without damage?
Why is 50% always (from what i see) quoted
I would like to read technical papers
Laurie
Multiply cycles x Ahrs per cycle to find total life in Ahrs.
Cheers,
Peter
Thanks
I seem to read all the time you should not take battery below 50%
Jaahn said
10:28 AM Aug 12, 2021
Hi Laurie
It is interesting in the modern world how "facts" can be twisted to sell a product. This certainly applies to lithium batteries and solar. What starts as a practical observation over the years becomes a set in stone rule to be used for frightening a customer into making a choice in a sellers favor. The current sellers often believe what they say is gospel truth and will argue it with no proof except a few advertising quotes.
I would have to say that often forums might not be the best way to find reliable facts either !
Jaahn
Whenarewethere said
11:11 AM Aug 12, 2021
laurieoz wrote:
Peter_n_Margaret wrote:
laurieoz wrote:
Hi
Where do you get the technical data from that you can safely discharge AGM batteries to zero without damage?
Why is 50% always (from what i see) quoted
I would like to read technical papers
Laurie
Multiply cycles x Ahrs per cycle to find total life in Ahrs.
Cheers,
Peter
Thanks
I seem to read all the time you should not take battery below 50%
A bit like the world being flat until someone did their due diligence. Even then you were executed because the facts did not suit the current view.
Hi everyone, new on the scene here and setting up to travel with my camper trailer, I recently returned from a trip up to northern NSW, leaving where it had been perfect weather for a week I stopped at Swans crossing where the weather turned wet and sunshine was limited, then heading south to Narooma it was overcast most days for the next week, at this spot was a grey nomad (although he didn't like me using that term) who was really struggling to keep his batteries charged and every second day was starting his vehicle to put charge into his batteries, I don't remember his input or outgoing specs but it did make me wonder about my planned setup.
my setup to date will consist of 570w solar and 240ah AGM batteries, my usage is a 75lt brass monkey fridge/freezer rated 5ah max and 0.87/24 other than this it's lights and charging phone, kayak battery 17.5ah once a week, and some other usb charging most of these I usually just charge from my car when camping, I guess my other big power user would be my laptop however this was only used when power permitted in the past.
I have installed a dual battery system in my car however I only want to use this as it's intended, while driving from A - B.
Up till now I have been using a 120w panel 80ah old car battery for my laptop and a 35lt gas fridge while camped during my trips away and this seemed to almost cope power wise.
once im on the road if I need more panels then no issues I will buy them but it would be nice to get close to whats needed before I leave.
I've owned a 60L fridge/freezer for some years and have done extensive power consumption testing on it; set at -12C/+2C it uses between 25Ah and 60Ah per day depending upon ambient temperature. My modern laptop consumes about 1A so say 4Ah per day. Sundry other stuff, lighting, water pump, charging etc say 10Ah per day. So worst case is:
60 + 4 + 10 = 74Ah x 13V = 962Wh
Therefore your 120W panel will need 8 hours of perfect sunshine per day - not going to happen.
In reality (say) 300W of panel will put out about 250W in good sunshine so you would need 4 hours of sun to meet your worst case needs - and that's 4 hours of good sun with no shade and the panels being regularly rotated.
I am in the process of upgrading my solar and have come to the conclusion I am always going to need a generator for top-ups here in Victoria where I spend most of my time.
Note: run the freezer at -12C not -18C this is good enough to keep food safe for three months or more and uses a lot less energy.
If you get good charge even on the bad days, the batteries only have to supply over night.
Solar lasts decades. Batteries wear out. More solar is cheaper to maintain.
Cheers,
Peter
As said above, you can't have too much solar & batteries for inclement weather.
The limiting factor is payload & or room. We are in a car only. So our opinion was to make our fridge as efficient as possible, with additional insulation & increasing wire thickness within the fridge to reduce resistance. Up to 15AH per 24 hours.
If needed we can run the car engine to charge up the batteries, but as we tend to move after 4 days maximum, charging happens by default.
Our 12O watt setup typically puts out 9amps into the batteries via Victron MPPT & up to 11.3amps under perfect conditions. We built quality instead of the cheap Chinese rubbish. Who wants to be remote with third rate rubbish.
We have also built in redundancy, multiple everything & 6awg & 4awg wiring. It's overkill, but it is the easiest way to squeeze blood out of a stone.
My only addition to the statement 'You cannot have too much solar" is to say combined with a quality regulator that has three stages and will drop back to float when the batteries are full early in good sun.
Jaahn
Welcome mate,
The more the better combined with a quality solar charger as amplified here so far.
There is lots of info on this topic here.
Good luck!
1. I don't really like single units doing multiple jobs: dc - dc charger/mppt reg so this means I need buy them separately.
2. I don't know what size to buy as yet.
I like the idea of the Victron for the BT app and once I change to LFP batteries this will prove to be very helpful for keeping an eye on everything.
My 12v wiring from the car boot to the control board bus bar and battery is 6 awg and on the control board its 8 awg as connections become an issue with bigger gauges.
from my panels im just using what came with them but definitely looking at upgrading them to 8 awg or higher for main cable again this will depend on total solar output spec's.
the 12/24v fridge cable looks to be to light and will be replaced, I have builtin redundancies for backup but hope to never use them (we live in hope)
Peter,
some enlightened members will comment/correct me here, but there is a table that says use as much heavier cable as possible, but if a short bit needs to be smaller, ie connect to a small terminal, so be it, but you will still gain an advantage. Hope that is not for 240/415 only.
-- Edited by Craig1 on Friday 6th of August 2021 09:34:33 AM
Use a short section of lighter cable that will fit into the terminal blocks. It will have more resistance but it's not an issue being a short length. Better to have the bulk of the run heavy enough.
I don't think that will be an issue with my camper trailer and free standing panels, but good point,
Hi all; After camping for a week in south Tasmania over the queens birthday weekend and with 240 watts of solar, 440 Ah of agm batteries i found that i was running out of power. The weather was rain, drizzle and fog that did not lift for several days and bloody cold as well. I also have a 20 Amp DC to DC charger, but you need that connected to the car to be able to charge. Ended up borrowing one of the other campers gen set and 15Ah smart charger. This helped a lot.
On returning home i ended up purchasing a smart 30 Amp charger and wiring that into the house batteries. This put in just over 300 Amps over around 10 ~12 Hours, so the house batteries were probably down in charge because of insufficient charge for the week away. The batteries are just on 2 years old at the moment. My van is now connected to mains power while at home and so the smart charger is on but with full batteries the charger now is in sleep mode with the batteries at 100% fully charged. I also purchased a smart bridge that monitors the charge/ discharge of the batteries and also gives a readout like a fuel gauge as to the capacity of the batteries.
So charging the house batteries at home is not a problem , but free camping, that is were i now also have a 2Kw generator that plugs into the mains input of the caravan. That will only be used if and when the house batteries get down a bit to far and require charging during the day. I just plug the generator into the mains input on the caravan and the battery charger takes over and starts charging if needed.
I have the usual things in my caravan, led lighting, tv and sat receiver, diesel heater and more led lighting outside, and finally a 40 ltr Engel fridge. A small inverter ( 300 Watts ) for recharging the computer or my for my electric shaver. Gas for the fridge when camping and hot water/cooking.
The smart charger and smart current bridge are also able to be bluetoothed to my phone and i can check on the state of the batteries and the action that i may need to take. So looking forward to our next trip away and free camping and further testing on my set up.
-- Edited by valiant81 on Saturday 7th of August 2021 11:40:33 PM
This is exactly what's been bothering me, although I have been planning to follow the warmth, head north in the colder months and south when hot, but this does not make up for those extended cloudy periods and shady conditions, but I think I have sorted most of it out now with my planning for upgrades of panels and batteries, I think the sooner I change to lithium the better the system will cope with the problematic discharge amounts created by extended low input of cloudy or shaded days. and also the use of a solar blanket and or one of those flexible panels as your backup.
Thanks for everyone's input so far it's certainly been very helpful along with other posts I've read on here I'm almost a solar techi lol far from it but getting quite capable at sorting out most of my problems.
Lithium batteries will not provide better support than lead acid; unless energy in equals or exceeds energy out you are going to run out of power.
I looked at solar blankets long and hard and decided not to buy one; they appear to be always significantly over-speced and, it seems, most (all?) are not waterproof!
Lithium will make no difference. You simply replace one set of issues for another set of issues.
I also looked at solar blankets. By the time you calculate the actual area of the solar cells not one blanket I looked added up.
For that matter most glass solar panels do not add up either.
Being able to put more in is the answer. Get more solar.
Cheers,
Peter
Hi
I have used 80W panels as portables in the past, 4 of them for 320W and wired in pairs with plugs and sockets. Easy to handle and in good sun 2 might be enough. I have in past times seperated a pair of folding panels to make then easy to handle.
Using good quality rigid panels seems to be much cheaper than blankets and the specs of expensive blankets seems to greatly exceed their performance !
As pointed out when free camping you do need to make enough power every day or at most two, which will match what you use in that time. Lithium is only a battery for short term storage just like lead acid does. You must make the power to use power.
Jaahn
-- Edited by Jaahn on Sunday 8th of August 2021 08:23:04 PM
Isn't the idea behind Lithium about usable power more than the amount you use? meaning that if I have 2 x 100ah batteries my estimated usable amps before recharge is 100 amps before damage occurs to the batteries, where if I have the same in Lithium then I have up to 160 amps usable amps (still not sure on the correct figures), this give you some protection for low solar output during extended periods, ofc you still need the capacity to fully charge them but you have more usable amps therefore longer time to wait for the weather to clear, shade change or you move locations charging your batteries via your dc to dc charger ect.
I guess the heading give the wrong idea
my bad, It should perhaps read "solar, building in redundancies" I'm just trying to limit issues with power created buy unseen circumstances (gotta keep that beer cold).
I have 104AH of batteries so I have 104AH of usable capacity if needed. Actually a bit more as I draw down the batteries at such a low rate over week.
If you drawn down the battery 80% once a month or a bit more once a year. That is only 60 times over 5 years. So what, most of the time you are probably only doing 30%. The battery will not fall off a cliff at 300 80% cycles.
But the fact remains is that you can use the full capacity of the battery when it's needed.
This fallacy of only being able to discharge an AGM (or other lead acid battery) to 50% of its rated capacity is rubbish. You can safely discharge AGM batteries to zero rated capacity (10.5V) without damage.
The life of AGM batteries is best measured in total power in and out, not by depth of discharge or cycles.
The lithium will hold a higher voltage for deep discharges and that may be useful if you are running high power appliances.
Cheers,
Peter
Hi
Where do you get the technical data from that you can safely discharge AGM batteries to zero without damage?
Why is 50% always (from what i see) quoted
I would like to read technical papers
Laurie
Look at the battery data sheet for the battery. The total life watt hours of the battery is not a great deal different to whether you discharge 30%, 50%, 80%.
Multiply cycles x Ahrs per cycle to find total life in Ahrs.
Cheers,
Peter
Thanks
I seem to read all the time you should not take battery below 50%
Hi Laurie
It is interesting in the modern world how "facts" can be twisted to sell a product. This certainly applies to lithium batteries and solar. What starts as a practical observation over the years becomes a set in stone rule to be used for frightening a customer into making a choice in a sellers favor. The current sellers often believe what they say is gospel truth and will argue it with no proof except a few advertising quotes.
I would have to say that often forums might not be the best way to find reliable facts either !
Jaahn
A bit like the world being flat until someone did their due diligence. Even then you were executed because the facts did not suit the current view.