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Whiskey Jack
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# Posted: 16 Nov 2025 08:58am
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Been a while since I posted, as not much has changed at the bunkie.
We had sone issues this year with our batteries. We run two 6V Trojan T-105 FLA batteries connected in series. After 5 years, one of them is toast. We got a lot of corrosion on the positive terminal this year.
We have a 330 watt solar panel that we moved a bit further away a couple years ago to get about 3 times the length of sun exposure. It's about 100' away.
We run 4 LED lights and charge Ryobi batteries a couple phones, and the occasional laptop.
We run a SureSine-300 Inverter, and use an Epever Tracer MPPT charge controller.
As of yesterday, with full sun and the lights on, these were the readings.
PV: 43 V
PV: 0.2 A
PV: 170 kWh
Batt: 13.6 V
Batt: 0.4 A
Load: 0.1 A
Load: 34 kWh
I honestly have little to no idea what most of the numbers represent outside of the Battery Voltage.
So, my questions are, what should I do to optimize the system. Are there any tweaks I can make to have it run better?
We're going to need new batteries soon. I managed to find the exact same battery to replace the toasted battery, so we're up and running. Ideally, I would prefer to leave the batteries overwinter, but we do get cold (-40 and lower).
The batteries are in a box outside, but I could build an insulated one to try and keep them a bit warmer.
What type of battery would be recommended? Selection here is very limited (Northwestern Ontario), but we can now get ReLion LiFePO4 batteries. I did notice that the amp hours are quite a bit lower than the Trojans, but I don't really understand what that means in practice.
Any guidance is greatly appreciated, and please explain like I'm 4 and not too smart. 
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FishHog
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# Posted: 16 Nov 2025 10:15am
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your lead acid batteries don't mind being cold as long as they are fully charged. No need to warm them. That is completely different than LifePo4.
You should be able to get any LifePo4 battery in any size you want, not sure why you think you can only get Relion. Even amazon has a wide selection these days, but there are lots of options out there.
The thing with lead is you really shouldn't drain them past 50% capacity, and not even that often, LifePo4 can easily run down to 20% capacity so you get more power out of them, but they come with issues that cold weather causes. Basically if you want to charge them, they need to be above freezing.
You numbers look reasonable, batteries almost charged so amps being put into them is low, just topping them up. But since we don't know your parameters of your charge controller its hard to know. If your using the preset lead acid charge level on Epevers, its only going to charge to 13.8v, so your almost there.
Suggest you do some research before you make a change. I could type novels on the subject, but its already on the internet so do some research. DIY solar forum has very good beginner info.
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Steve_S
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# Posted: 16 Nov 2025 10:19am
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Those 2 batteries in series still only give you 225AH "GROSS" of which you can only use 1/2 that at best.
A single 12V/105AH LFP battery would easily replace those and likely provide more deliverable power than those Trojan's (even if brand new & fresh).
LFP can sagfely discharge in those Cold Temps but you cannot charge them below 0C Temp. There are a number of batteries that have internal warmers which will keep them at +5C so they'll take a charge. These of course cost a bit more but it's not crazy. You can also put the LFP in the house/cabin without major concern... FLA is a NoNo because they offgas Hydrogen and you sure as heck do not want that in any living space.
I'm surprised your old batteries lasted given that what you have for solar likely never managed to do an Equalizing Charge as it is grossly under capacity to do so... It's unlikely they ever really hit a full charge & got equalized, which likely killed 1/2 their lifecycle right off the bat.
In order to make suggestions/recomendations, would need more details on the gear you have in place, what you are using now and plan on over the next few years. I'm up near Algonquin Park so I know what your dealing with pretty much with regards to our weather & sunhours.
We have some advantanges here... We don't have Crazy Assed Tariffs nor the hassles imposed on our southern neighbours which means we can still get great deals and do things far more cost effectively. Unfortunately, you picked a terrible time in the year to start furtling around with your solar system.
TBH, a good rethink on how your setup may be in order... Panels are quite cheap now compared to even a couple of years ago and LFP battery prices have really fallen a lot.
Appreciate that a 350W Split Cell Panel costs us $232 while a 410W Split Cell panel costs $257 and 600W Bi-Facial Split Cell is $305 (In CAD local warehouse price)
Have a look here. This is a quality Canadian Vendor who's put togethert these kits. Quality Goods from Victron & Others (1st Tier quality) at very respectable pricing for retail.
https://www.solacity.com/product-category/kits/kits-cottage/
FYI - Important: Many people lean towards AIO's (All in Ones) which have the Solar Controller (s), Inverter & Charger all in one unit. These are NOT optimal for Part-Time or Low Usage scenario's. Modular Builds with separate Solar Controller(s) & Inverter/Charger are best as the SCC's can stay online all the time to keep batteries up while the Inverter/Charger can be shutoff to prevent parasitic waste. AIO's also use more power when operating and are a bit less efficient overall.
Hope it helps, Good Luck.
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travellerw
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# Posted: 16 Nov 2025 12:10pm
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As Fishhog says, there are novels about this stuff. However, I will give some key points as my system is in a cold location (Northern Alberta), so shares that with yours.
First, have you done an ampacity calculation on your wires. You say the panel is 100' away. I'm guessing that means 100' away from the solar controller? So you are pushing 47V with a max amps of about 8 over 100'. A quick calculation says you would need 8AWG with a 3% loss. 10AWG would have a 5% loss!
For my system, I chose FLA over LiFePO4 due to the cold weather issue. I didn't want the hassle of building an insulated box and then giving up the energy to heat the batteries. I built my system 4 years ago, but if I had to do it again I would consider LiFePO4 and the hassle.
For FLA, the secret is having enough capacity. More=better for longevity. As others have said, not pulling below 50% is crucial. However the higher you can keep the state of charge (SOC), the longer FLA will live. If you are going to keep FLA, then I suggest you double the batts (4 6 volt).
As to corrosion. Ensure you are using some sort of anti corrosion paste (some people just use vaseline). Second, you have to ensure things are super clean before you make the connections. Finally, ensure your connections are tight. You need to check them about once a month and re-tighten as necessary.
WATER WATER WATER.. Super important to monitor the water levels in FLA. You need to make sure they never run low. If the plates ever get exposed to air, it will do damage to them and massively shorten the life of the batteries. You need to top them up with distilled water regularly!
Another suggestion would be to ditch the Epever controller. While they work, they are not the best, especially in shady or cloudy environments. Victron are cheap enough now. With that being said, I would prioritize the batteries before replacing the controller.
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paulz
Member
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# Posted: 16 Nov 2025 02:10pm - Edited by: paulz
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Great advice from the pros here. I’m in your 4 year old mentality, except my area doesn’t freeze so my cabin runs on Lfp, have some experience there. But I have lots of Flas in vehicles, generators.. The corrosion mentioned is non stop, water top ups and battery brushing..
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MtnDon
Member
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# Posted: 16 Nov 2025 02:26pm - Edited by: MtnDon
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Regarding the batteries with heaters. The ones I am familiar with use power from the solar panels, or whatever other charger one may have. The battery BMS will direct solar power to the heater if the temperature of the battery is below the safe level. Once the battery has warmed, the BMS will direct power to charge the battery as normal. The battery does not use battery power to heat the battery.
I just thought I'd mention that as some people have wondered about that.
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travellerw
Member
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# Posted: 16 Nov 2025 02:47pm
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Quoting: MtnDon The battery does not use battery power to heat the battery.
That is my understanding as well. I worried that be a problem in really cold temps. Depending on how cold the battery got in the night, it could take a really long time to warm it back up. Its possible that it may never get warm enough.
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Whiskey Jack
Member
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# Posted: 16 Nov 2025 03:11pm
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Thanks for replying FishHog.
Quoting: FishHog You should be able to get any LifePo4 battery in any size you want, not sure why you think you can only get Relion. Even amazon has a wide selection these days, but there are lots of options out there.
Simply, this is what is available locally. We're in a retail desert. I'd rather not order online for something this heavy with questionable return policies.
Quoting: FishHog The thing with lead is you really shouldn't drain them past 50% capacity, and not even that often, LifePo4 can easily run down to 20% capacity so you get more power out of them, but they come with issues that cold weather causes. Basically if you want to charge them, they need to be above freezing.
I'm not sure how they get drained, but even in the summer we will have the warning chime come on the controller saying the batteries are low. We charge most stuff when the panel is in full sun, so it's generally two 9 watt lights that run in the evening for an hour or two.
Quoting: FishHog You numbers look reasonable, batteries almost charged so amps being put into them is low, just topping them up. But since we don't know your parameters of your charge controller its hard to know. If your using the preset lead acid charge level on Epevers, its only going to charge to 13.8v, so your almost there.
We do regularly go up to at least 14.6 V when charging. I have no idea what the controllers parameters are. They were set when we purchased everything.
Quoting: FishHog Suggest you do some research before you make a change. I could type novels on the subject, but its already on the internet so do some research. DIY solar forum has very good beginner info.
I'll check out that forum. The main problem I have doing research is that I end up more confused than when I started as everyone has different opinions.
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Whiskey Jack
Member
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# Posted: 16 Nov 2025 03:41pm
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Thanks for the reply Steve.
Quoting: Steve_S I'm surprised your old batteries lasted given that what you have for solar likely never managed to do an Equalizing Charge as it is grossly under capacity to do so... It's unlikely they ever really hit a full charge & got equalized, which likely killed 1/2 their lifecycle right off the bat.
So maybe you can clear up some of my confusion here. I have a 330 watt panel, and a 300 watt inverter. Can't the inverter only handle power from about 300 watts of panel?
Quoting: Steve_S In order to make suggestions/recomendations, would need more details on the gear you have in place, what you are using now and plan on over the next few years. I'm up near Algonquin Park so I know what your dealing with pretty much with regards to our weather & sunhours.
What additional information do you require? I was hoping the panel, battery, inverter and controller would have everything covered.
Quoting: Steve_S Unfortunately, you picked a terrible time in the year to start furtling around with your solar system.
I'm not fiddling around at the moment. I have power again, so will be looking for info to improve once the spring rolls around.
I'm not looking for a massive overhaul, I just want to make sure that the limited power needs we have can be met without worrying. This summer wasn't great for that. We're going to start clearing for the main cabin this winter, so will have a whole new system to plan for when that gets up and running.
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Whiskey Jack
Member
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# Posted: 16 Nov 2025 03:49pm
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Thanks for chiming in travellerw!
Quoting: travellerw First, have you done an ampacity calculation on your wires. You say the panel is 100' away. I'm guessing that means 100' away from the solar controller? So you are pushing 47V with a max amps of about 8 over 100'. A quick calculation says you would need 8AWG with a 3% loss. 10AWG would have a 5% loss!
I have not, and you are correct about the distance. It's not exact, but pretty close. Moving it picked up about 4-6 hours of sun on the panels. AWG is the guage of wire? I can't remember what I used, but it is fairly heavy wire.
Quoting: travellerw For FLA, the secret is having enough capacity. More=better for longevity. As others have said, not pulling below 50% is crucial. However the higher you can keep the state of charge (SOC), the longer FLA will live. If you are going to keep FLA, then I suggest you double the batts (4 6 volt).
I could probably do that easily enough. Might even have access to two more of these. I would then need to wire 2 in series, then connect in parallel to make them 12volts?
Quoting: travellerw As to corrosion. Ensure you are using some sort of anti corrosion paste (some people just use vaseline). Second, you have to ensure things are super clean before you make the connections. Finally, ensure your connections are tight. You need to check them about once a month and re-tighten as necessary.
I haven't used paste, but can grab some from work. I did check the batteries this year and topped them up. Plates were just below the surface. All connections have remained tight.
Quoting: travellerw Another suggestion would be to ditch the Epever controller. While they work, they are not the best, especially in shady or cloudy environments. Victron are cheap enough now. With that being said, I would prioritize the batteries before replacing the controller.
I will likely stick with the Epever simply because it is the bunkie and we are hoping to start on the main cabin soon. I want money for that.
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Whiskey Jack
Member
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# Posted: 16 Nov 2025 03:52pm
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One thing I should also mention. The only reason I don't want to bring my batteries in is due to the weight of these buggers. From my understanding, the LI batteries run around 9lbs. I would have no issue at that weight to disconnecting the battery and bringing it home every time we come in during the winter. And if it can be stored inside, even better. I can build a box and keep in the toasty bunkie with us.
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paulz
Member
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# Posted: 16 Nov 2025 05:12pm
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20 for 100ah
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gcrank1
Member
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# Posted: 16 Nov 2025 07:49pm - Edited by: gcrank1
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You Need to use a large enough gauge AWG cable (not solid wire) in copper, not alum to avoid more than the prev mentioned 3% line loss to the solar charge controller.
The scc Needs to be close to the battery bank and the inverter close to the bats all connected with adequate awg cable for the max load.
The inverter has its own fuses so you dont have to run it into a fuse box (for a larger system you should). Once the dc has been inverted to ac you can run a pretty far distance to your devices within the cabin with no more than std 'house wiring' (though with a small place even extension cords can be ok).
ALL connections Need to be solid, clean and proper.
You lighting is LED bulbs, they, and usb chargers etc draw so little that you almost dont even need to add the draw up. The inverter also has a draw when on even if it isn't powering anything. A 300w is likely about 85% efficient and a pretty low draw but turn it off when you aren't using any power to save energy.
If this is basically all you are powering 100ah of bat-bank should be plenty, even with lead acid bats. Because you say you get a 'bat low chime' from the controller that doesnt sound right. Are you sure you have the scc wired correctly to to bat bank? IE, the big wires to +/- (not the 'load' tap on the scc).
I would expect the chime would maybe come from the inverter shutting down (Low Voltage) because you had a failing bat in the bank as the bad bat pulls the good one down and chokes your output.
That is just what happened to me a few years back as the old set of 4x100+ah bats were dying off one by one. We limped through that last season and I had to decide buy more LA bats like you or change to LFP; we went (unheated) LFP but are not in your far north zone and hardly use the cabin in the winter (my aio portable is power when we do).
Fwiw, if I were you, Id make sure things are set up as good as possible as you are but learn more about this 'solar/bat electric thing' and do it way better on the new build.
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travellerw
Member
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# Posted: 16 Nov 2025 09:28pm
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AWG = American Wire Gauge. Smaller number = bigger wire. 8 AWG is pretty big. Its over double as thick as standard Romex used in house wiring.
You are correct about wiring 4 batteries (series/parallel). However you should google it as there are proper ways to wire them. The goal is the shortest connecting wires to reduce inbalances between the batts.
As to watering. I usually add water until it touches the bottom of the fill hole. Many consider this overwatering, but I have never had an issue and its an easy visual.
Totally understand about saving money. Epever controllers do work, just not the most efficient. When you do build your main system I highly suggest you use a better controller (like Victron, Midnight, ect).
Based on your last post, it seems that you don't have enough solar and batteries. If you are getting alarms for low batteries, that is not good. However, something is henky here. Your 2 Trojan 6V batteries have 2700 Watt hours(WH), divide by half and that is 1350WH. There is no way those lights, phones, batteries should use that much power. As an example a Ryobi 4AH battery has a capacity of 72WH, with losses that about 100Wh. Even if you charged 4 with no solar that would only take 400 of the 1350! Phones are like 20WH MAX.
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