Using a AGM Deep Cycle Battery/LiFePo4 battery for dashcam

[ChampaRando]

Hello everyone.

I've currently hardwired my dashcams (Blackvue, Viofo, Thinkware) to my car battery but one car's battery has been essentially messed up (parking mode only works for like 2 minutes then voltage of battery drops below 11.9V lol). Lucky that car is a hybrid so the 12V battery doesnt start the engine, it's the big hybrid battery that does it so I haven't suffered from flat battery issues but I'm sure the dashcam has ruined the battery and parking mode now only lasts like 10 minutes, from hours it used to. It was only 1.5 years old only anyways.

So I looked into alternative ways and I like the Cellink Neo/other dashcam battery packs. But honestly, with all the features, protection and extra "safe Lifepo4" temperature those guys claim, they are 3x overpriced. Honestly a $349 AUD for a 6000mah LiFePo4 (some are even 400+), those guys are kidding. Yeah I get it its a LifePo4 and with all fancy features like bluetooth, temperature circuits etc, but no way its worth more than 200 at best. I can buy a 14AH Lifepo4 jump starter literally for $130AUD or even an AGM 100AH+ car battery for around 350. I'll make my own DIY. And if I want to go around just 10AH (still more than 6000mah cellink offers), options are even cheaper

So to start off testing, I have found these two batteries off ebay australia;

1. https://www.ebay.com.au/itm/203309096248 (LiFePo4 Deep Cycle)
2. https://www.ebay.com.au/itm/323230999429 (Deep Cycle AGM Battery).

I am no expert in electrical engineering but I have heard in the past members here said that use an AGM car battery to prevent damage as they can handle deep cycles/discharging and high tempertures better.

So which battery is better do you guys think? Lifepo4 or AGM deep cycle? In australia, temperatures can be high but I am in Sydney (not in the middle of central australia) so maybe 40 degrees at WORST days in summer and maybe in interior, higher but not too much I think? Which is the better choice out of the two? Next step for me is to somehow find some circuits and or microcontroller. Dunno will be researching for that next!

Gonna do a DIY just like I did a DIY for cloud uploading, bypassing expensive restrictions of thinkware/blackvue

Thanks.

*PS extra quick question: Last year I had a 40,000MAH powerbank Li-Po used to power a crappy dashcam I had in my car (before I replaced it with blackvue & stopped using this powerbank), it was a crappy one and had no parking mode/hardwiring, just 24/7 recording so I used a powerbank to do it. And tbh the powerbank was fine all year. Even with high temperatures. I never even had an idea of issues with temperature last year lol so lucky I escaped but I wish Li-Po was made for high tempertures haha. The user manual for the powerbank said temperatures of 80 degrees celcius was good so could it be that?

 

[SawMaster]

To cover a few things first. LiFePO4 and LiIon and LiPo are all different creatures. While my own testing and that of some others has shown that LiIon is safe with any kind of heats a car will see, it's nature is touchy and temperamental about usage parameters. It will work here but you have better choices as you don't need it's best characteristic which is handling high current draws, so I'd say avoid LiIon. LiPo is safer and will handle the current draw but it tends to degrade and swell quickly in high heats so again not an ideal choice. The reason you see these two used in dashcamming is their cheapness and nothing else. LiFePO4 is s newer derivative of this technology and in addition to being safer, it also handles use in temperature extremes better, giving longer life and allowing current draw but not charging past the parameters of the other two. Of the common Li batteries this is best here and prices are reasonable- I wouldn't consider anything else. All these take special charging circuitry and you need some knowledge of them to both be safe and to get your best value. Not tough but too much to discuss in a general response; we can cover this if needed.

L/A type batteries aren't directly comparable, even the 'deep cycle' types don't like being constantly discharged to their full rating, but they offer a wider range of safe charging/discharging parameters and are relatively cheap to purchase. SLA (aka VRLA) can work here but do their best when kept fully charged and used lightly and occasionally. AGM is an offshoot of this technology but considerably different in use. Given the slight increase in cost, AGM usage parameters are much better in every way, again the best choice by far for powering dashcams. Size and weight are the main drawbacks with L/A, but in their favor is simplicity of charging and use; you can manage this with just one high-amperage DPDT relay, perhaps with a filtering cap to smooth the current spikes when switching. On the easy can be done by swapping your standard car battery for an AGM type if it doesn't have one already. For a given usable power capacity this will be cheapest to do, but in the long run LiFePO4 can now equal or slightly better the cost as they will last longer.

All the "plug-and-play" type dashcam powering solutions are overpriced; you're paying a lot for convenience of installation but many are happy to pay the extra for that. Most economical here is having two standard powerbanks, swapping them out to charge the unused one and switching the cam power lead from car source to powerbank when you're going to park for longer times. Once you develop the habit it is not an issue. Prices vary wildly for all this based on your location, taxes, and laws regarding shipping of Li cells and batteries so be sure to factor in all the costs when choosing.

Phil

 

[ChampaRando]

Hey.

Alright so what I understood was that, firstly LiPo is slightly better than LiIon in high temperatures, but still it suffers when discharged/used in high heat so not an ideal choice. LiIon again useless.

Next so LiFePO4 is the better choice. And does this require extra circuitry? I found out that the Lifepo4 battery I mentioned above has a built-in BMS (Battery Management System) which protects against temperature/over-charging etc. Is that enough to safely use it or do I need extra equipment? Finally, so I think you said that AGM batteries are the best (and a better choice than the Lifepo4)? And would I need extra equipment with this (as the AGM battery I saw above mentions nothing of any BMS or any other circuitry)?

And what are some of the best ways to charge these? I don't really want to keep taking these out and every night charge them (sure I can make a habit but my wife cannot I am sure lol). I would want to do something similar to hardwiring these batteries to the fuse/or somehow directly connect it to the alternator (my friend is a bit more 'electricy' you can say and I guess I can ask him for a hand for more info too).

 

[SawMaster]

If it's got a good BMS you need nothing more for charging. You can get LiFePO4 batteries bare (without BMS) or you can change that part for a better one; this is the only reason I mentioned it. If the BMS will accept 13.8VDC for charging purposes this can be hardwired into the car, but you'll still need a relay to isolate the cam battery when the engine is off, and the way some of these BMS's are made you may not be able to draw from the battery when it's charging as that added load may 'gool' the charge monitoring and lead to overcharging. A DPDT relay can switch the cam to car power when the engine is running so the battery charges correctly if the BMS doesn't have a "pass through" function.

AGM is not necessarily better or worse, but with either you need to design around the different qualities and characteristics involved. The nice part is that these are nominally 12VDC like your car battery, so you can tie into that and let the car alternator do the charging, nothing else needed for that, but you do need a relay or switching circuit to isolate the cam battery when the car is not running. Easiest here is a "Battery Isolator" such as RV's use. Initial cost will be lower with AGM but long-term you'll replace the AGM before good LiFePO4's go away so long term AGM is at a slight cost disadvantage. That can be far different if you can't source Li batteries cheaply where you are.

The hidden issue here is switching between parking and driving modes. Cams which do this without a HWK by sensing no movement via GPS will 'plug-and-play" but those which don't will still need a HWK. It's all pretty simple really, the hardest part is deciding on what type of battery you want to use then using the correct parts to tie it all in. Think about how much power capacity you want, then check what your total costs will be either way including taxes and shipping; that may sway your decision.

Phil

 

[Nigel]

With lithium batteries, you generally need to provide the a current limit during charging, the BMS does not normally provide this function so you need to use a lithium battery charger. With AGM batteries you can generally connect them straight to the alternator, they will limit the current themselves, and your linked one does say on the side that it can use a constant voltage charge which is what the alternator provides. Note that with that being a fairly small AGM battery, the charge current is also fairly low compared to the maximum charging current for the lithium, although you may have difficulty finding a charger that will charge the lithium faster than the AGM. If you want a really fast charging AGM battery because you only make short journeys then you may want to choose a bigger battery.

 

[Outbacknomad]

I have four 26AH Gel batteries tucked inside the car. They are mostly for our 28L fridge 15AH per 24hour, but use it for phones etc. Charged via Victron DC-DC charger or solar.

 

[kamkar]

For sure if i got a need for longer duration, anything that suck power in the car, i would go for insulated AGM or LIFEPO battery / batteries for sure.

 

[ChampaRando]

If it's got a good BMS you need nothing more for charging. You can get LiFePO4 batteries bare (without BMS) or you can change that part for a better one; this is the only reason I mentioned it. If the BMS will accept 13.8VDC for charging purposes this can be hardwired into the car, but you'll still need a relay to isolate the cam battery when the engine is off, and the way some of these BMS's are made you may not be able to draw from the battery when it's charging as that added load may 'gool' the charge monitoring and lead to overcharging. A DPDT relay can switch the cam to car power when the engine is running so the battery charges correctly if the BMS doesn't have a "pass through" function.

AGM is not necessarily better or worse, but with either you need to design around the different qualities and characteristics involved. The nice part is that these are nominally 12VDC like your car battery, so you can tie into that and let the car alternator do the charging, nothing else needed for that, but you do need a relay or switching circuit to isolate the cam battery when the car is not running. Easiest here is a "Battery Isolator" such as RV's use. Initial cost will be lower with AGM but long-term you'll replace the AGM before good LiFePO4's go away so long term AGM is at a slight cost disadvantage. That can be far different if you can't source Li batteries cheaply where you are.

The hidden issue here is switching between parking and driving modes. Cams which do this without a HWK by sensing no movement via GPS will 'plug-and-play" but those which don't will still need a HWK. It's all pretty simple really, the hardest part is deciding on what type of battery you want to use then using the correct parts to tie it all in. Think about how much power capacity you want, then check what your total costs will be either way including taxes and shipping; that may sway your decision.

Phil

Oh sounds good. I'll see what I can hook up. I'll research a bit and let you guys know which way I went with haha. And for the parking mode, yeah well I was thinking that if I wire the system somehow that, once the ACC is on/alternator is on, the extra battery will charge and the alternator will power my camera, so yeah I will need one of those VSR / isolator switches and also power the dashcam. This avoids the issue of pass-through charging as well.

So I probably will not connect the ACC in the battery, might somehow wire it directly to the fuse/car battery so that upon engine running, camera runs externally (so yeah I will need some form of a relay here). Then of course, when engine is off, the extra battery is going to stop charging and also start powering the dashcam. Basic idea, now will try to implement this with more research. \

Probably not bother with the DCDC chargers as a quick search shows a decent quality is over 500 itself, so not much an improvement over what im trying to save by doing a DIY.

With lithium batteries, you generally need to provide the a current limit during charging, the BMS does not normally provide this function so you need to use a lithium battery charger. With AGM batteries you can generally connect them straight to the alternator, they will limit the current themselves, and your linked one does say on the side that it can use a constant voltage charge which is what the alternator provides. Note that with that being a fairly small AGM battery, the charge current is also fairly low compared to the maximum charging current for the lithium, although you may have difficulty finding a charger that will charge the lithium faster than the AGM. If you want a really fast charging AGM battery because you only make short journeys then you may want to choose a bigger battery.

Oh right, yeah sounds fair. Probably will try an AGM battery but might research a bit and reply back and see how it went What is a decent size do you reckon? I looked at a 10AH/12AH AGM, but don't mind spending more to go around 20/30AH+ honestly.

Cheers.

 

[Outbacknomad]

With lithium you simply have to stop charging when they are full. There is no float charge like lead acid. You have to stop the charging or you will kill it.

Unless the lithium has proper battery management it is doomed to fail.

If the lithium battery cannot be charged at 1C forget it. Look at another manufacturer.

If the box the battery is packed in weights less than 1.5kg per litre volume, you need to question what batteries are inside. More than likely small batteries packed in foam.

 

[ChampaRando]

Yeah so I've done heaps of research over the past month. So I've moved away from in-car charging for my external battery idea. I am going to use a battery like 30Ah-50Ah, plus, not all my cars have long driving times nowadays so no way they will be charged properly.

I'll just charge them once a night/weekly depending on the level in my garage using an external charger, with all built in voltage checking and all that. DC-DC charger was the only way for my cars as they are new and probably have smart alternators. Despite I read that they are not optimal chargers, alternator isn't the best source of charging. Also, DC-DC chargers that were decent quality were over 350 dollars, so that's out of the picture. So cancelled in-car charging idea, gonna charge at home. That's why gonna use a big battery.

At the moment, I see AGM batteries are dirt cheap right now compared to Lifepo4. With some calculations, if I go with AGM battery, I will look to do max 50% of usage/depth of discharge, so a 50Ah battery leaves me with 25Ah usable power (to maximise life cycle). AGM battery should last me roughly 4 years if I go with roughly 3 days of camera power on time, and that equates to like 400-500 cycles for the AGM. (I used the battery supplier's DOD Cycle Charts for this).

Going with a LiFePo4, I read we can go around 80% of DOD, rather than the 50% of AGM. If I go with 30Ah LiFePo4 (largest available below $200 lol), I can make it last roughly 18 years (I am kind of surprised at this lol, but thats what math is giving). Of course these are just raw math theoretical numbers, real life might be slightly off but eh. And this is a little bit of an understatement. The Lifepo4 battery manfucturer says I should be over 3000 cycles with up to 100% usage even, but I am only looking at 80% DOD AT 2500 cycles (rather than 3000 cycles at 100% DOD), so idk.

So now the only decision I need to make is, whether I spend extra 80 dollars for a LifePo4 to make it last longer than AGM. Currently a 50Ah AGM I can grab for like 100 bucks, Lifepo4 30Ah is 180 bucks, so I save around 20-40 bucks in the long run XD by buying 1 Lifepo4 rather than like 2 AGMs by like 8-10 years.

What do you guys think? How's my knowledge, anything I got wrong at the moment?

Also will install a ESP32 next to the battery with a wifi remote switch module and extra things so I have more remote control. And obviously adding this microcontroller will mean more power usage so take more life out of the batteries above, but eh, shouldn't be too bad.

 

[Nigel]

I read we can go around 80% of DOD, rather than the 50% of AGM.

Ideally you should charge them to only 90% and discharge to only 20% for a 18 year life, then after the 18 years they will still have over 75% of the original capacity.

However you do need something to stop the charge and discharge at the right point, which is not straightforward, while with AGM it is easy.

 

[ChampaRando]

Ideally you should charge them to only 90% and discharge to only 20% for a 18 year life, then after the 18 years they will still have over 75% of the original capacity.

However you do need something to stop the charge and discharge at the right point, which is not straightforward, while with AGM it is easy.

Yeah that's right. I don't care if the battery lasts even 8 years, that's more than good enough for a 200 dollar battery.

Only thing was, I was looking at a charger like this for AGM (only a quick google search will do more searching on the charges): https://www.australiandirect.com.au/Battery-Systems/20Amp-Deep-Cycle-Battery-Charger/KACHG1220

Actually another quick question (I haven't reasearched this yet): It says it is a 20Amp charger. If my battery wants 10A for constant current charging, is this charger suitable/smart to realise that or not? Does a smart charger like that even exist or I need to match the charger currents and voltages to the battery spec? ALso would a wall charger like this that is suitable for Lifepo4, automatically manage turning off/the charging for the battery automatically or do I have to have some extra circuitry outside of battery and charging. Because the Lifepo4 I mentioned has a BMS.

 

[Nigel]

Actually another quick question (I haven't reasearched this yet): It says it is a 20Amp charger. If my battery wants 10A for constant current charging, is this charger suitable/smart to realise that or not? Does a smart charger like that even exist or I need to match the charger currents and voltages to the battery spec? ALso would a wall charger like this that is suitable for Lifepo4, automatically manage turning off/the charging for the battery automatically or do I have to have some extra circuitry outside of battery and charging. Because the Lifepo4 I mentioned has a BMS.

Normally, AGM and all other lead acid batteries use constant voltage charging, so in your case the charger will offer the battery 20Amps, the battery will take 10Amps, and then the voltage will rise up to around 14.6 Volts at which point the charger will limit the voltage, the Amps is thus limited by the amount the battery can take without the volts rising to the limit, so you should be fine. That is why it is also OK to connect the AGM or any other lead acid battery straight to the car alternator capable of producing 80Amps, it will take what it wants.

For lithium batteries it is very different, if the charger offers them 1000Amps then they will try to take it, and self destruct in the process! So it is necessary to use a charger with a current limit as well as a voltage limit, often called CC/CV for constant current + constant voltage. You must not connect them straight to an alternator. In most cases a BMS does not provide the current limit or voltage limit, only a safety cutoff for current and voltage, it keeps them safe but does not charge them, it also balances the cells to ensure the charge is correctly distributed between cells connected in series, which is necessary otherwise they will self destruct after a few charges. You need to use a charger with a current limit less than the maximum for the battery you are using, or a configurable limit that can be set lower than the maximum, and you probably want significantly less since slower = longer battery life.

Hope that helps...

 

[joe384]

Yeah so I've done heaps of research over the past month. So I've moved away from in-car charging for my external battery idea. I am going to use a battery like 30Ah-50Ah, plus, not all my cars have long driving times nowadays so no way they will be charged properly.

I'll just charge them once a night/weekly depending on the level in my garage using an external charger, with all built in voltage checking and all that. DC-DC charger was the only way for my cars as they are new and probably have smart alternators. Despite I read that they are not optimal chargers, alternator isn't the best source of charging. Also, DC-DC chargers that were decent quality were over 350 dollars, so that's out of the picture. So cancelled in-car charging idea, gonna charge at home. That's why gonna use a big battery.

This is what I am moving to. (charging at home instead of while driving) Originally before the pandemic I had a Cellink B I got off ebay cheap. An hours driving would charge it up fully. When the pandemic hit though I went back to usb power banks as the car was not being driven enough.

I looked at DC-DC chargers like you mentioned, too expensive. I eventually bought one of these:

https://www.amazon.co.uk/gp/B08SW8WRMM
I plan to connect to the cellink as an extension battery detailed here:

Insides of BlackVue B-124 (DIY 11,852 mAh @12.8v / 151.7 W/h + extension battery for under $50?)

Due to the corona crisis i didnt order any parts from aliexpress as those would be delayed. Some time ago i did order a 15a 220v to sigarette charger that can supply the 9a hardwire mode but its still stuck at customs in my country so have to wait it out and use the 5a i already have. Also here...

dashcamtalk.com

Another option that's been discussed on this forum is something like this:

https://www.amazon.co.uk/gp/B07MC7TV2G
These are a lot more expensive than they used to be though, although they are quite nice in that you can just carry them inside the house to charge up.

 

[HonestReview]

Battery Packs vs. Hardwiring to fuse box really a judgment call. Battery packs are about the same price as a car battery. The benefit of course is battery packs can be daisy chained to allow for extended record times.

On the flip side, a car battery might set you back 200-400 Euros on an AGM. My S60 requires a light be reset and so dealer swapout sucked and was around 350 including battery. Flip side, I got 6 years out of the battery. Even if the life is shorted by 20%, it really doesn't offset the cost of a battery pack.

 

[ChampaRando]

This is what I am moving to. (charging at home instead of while driving) Originally before the pandemic I had a Cellink B I got off ebay cheap. An hours driving would charge it up fully. When the pandemic hit though I went back to usb power banks as the car was not being driven enough.

I looked at DC-DC chargers like you mentioned, too expensive. I eventually bought one of these:

https://www.amazon.co.uk/gp/B08SW8WRMM
I plan to connect to the cellink as an extension battery detailed here:

Insides of BlackVue B-124 (DIY 11,852 mAh @12.8v / 151.7 W/h + extension battery for under $50?)

Due to the corona crisis i didnt order any parts from aliexpress as those would be delayed. Some time ago i did order a 15a 220v to sigarette charger that can supply the 9a hardwire mode but its still stuck at customs in my country so have to wait it out and use the 5a i already have. Also here...

dashcamtalk.com

Another option that's been discussed on this forum is something like this:

https://www.amazon.co.uk/gp/B07MC7TV2G
These are a lot more expensive than they used to be though, although they are quite nice in that you can just carry them inside the house to charge up.

Damn that's pretty cheap compared to the prices I'd be getting for that in Australia haha. I tried finding power stations and all, but they're all Li-ion/Li-po here. Something like this doesn't exist here no idea why. Tried searching a lot.

And just a general question (to anyone), I've read that LiFePo4 is the safest of all, mostly because it is less/not flammable due to the different materials it houses. But I see Toyota RAV4 Prime housing an Li-Ion for their main electric car, Tesla as well. How come those batteries are considered 'safe'? Just out of curiosity, I know they might have some extra and expensive protection and all but it does make sense that Li-Ion are fine too? Assuming they're well designed and protected. I'll still probably go with a Lifepo4 but that Li-Ion just came to mind.

 

[ChampaRando]

Battery Packs vs. Hardwiring to fuse box really a judgment call. Battery packs are about the same price as a car battery. The benefit of course is battery packs can be daisy chained to allow for extended record times.

On the flip side, a car battery might set you back 200-400 Euros on an AGM. My S60 requires a light be reset and so dealer swapout sucked and was around 350 including battery. Flip side, I got 6 years out of the battery. Even if the life is shorted by 20%, it really doesn't offset the cost of a battery pack.

Exactly why never buying those ready to go battery packs. Lol a cellink neo is the biggest rip off I've seen in terms of my eyes. All that crap for 350-400AUD. No way! Haha.

 

[ChampaRando]

Normally, AGM and all other lead acid batteries use constant voltage charging, so in your case the charger will offer the battery 20Amps, the battery will take 10Amps, and then the voltage will rise up to around 14.6 Volts at which point the charger will limit the voltage, the Amps is thus limited by the amount the battery can take without the volts rising to the limit, so you should be fine. That is why it is also OK to connect the AGM or any other lead acid battery straight to the car alternator capable of producing 80Amps, it will take what it wants.

For lithium batteries it is very different, if the charger offers them 1000Amps then they will try to take it, and self destruct in the process! So it is necessary to use a charger with a current limit as well as a voltage limit, often called CC/CV for constant current + constant voltage. You must not connect them straight to an alternator. In most cases a BMS does not provide the current limit or voltage limit, only a safety cutoff for current and voltage, it keeps them safe but does not charge them, it also balances the cells to ensure the charge is correctly distributed between cells connected in series, which is necessary otherwise they will self destruct after a few charges. You need to use a charger with a current limit less than the maximum for the battery you are using, or a configurable limit that can be set lower than the maximum, and you probably want significantly less since slower = longer battery life.

Hope that helps...

Yep makes pretty good sense. Thanks mate.

So in a nutshell to confirm it all, AGM I am able to use a charger with higher voltage ratings/amp ratings, it shouldn't be a big issue. Correct? Plus, I've read that many chargers do stages charging. Like once they're full, they go into float charging mode and all.

For a lithium, I need to match the requirements for the battery spec exactly to the charger right? I read this article that describes how a lower power charger will undercharge the battery so it isn't a good idea. Best idea for lifepo4 is to use the exact CC/CV specs correct?

 

[Outbacknomad]

People get too stressed over discharge % of lead acid. If you look at the data sheet of a lead acid battery. The total life AH of the battery is not a great difference whether it is discharged 30, 50 or 80%. (% x cycles = total life AH). The battery will not drop off a cliff at its total life AH limit. Just gradually lose capacity from the day it was manufactured.

So if you discharge once a month 80%, it's only 60 times over 5 years. A high % of the time one is probably discharging only 30%. Even 100% once or twice a year and then charge it up, don't stress.

The important thing with lead acid is to charge it up ASAP and top it up if not using it regularly.


P.S. Don't get sucked in by the "17" stage smart charger marketing BS.

It is Bulk, Absorption and Float, these are the 3 stages that are needed.

 

[Nigel]

So in a nutshell to confirm it all, AGM I am able to use a charger with higher voltage ratings/amp ratings, it shouldn't be a big issue. Correct?

Higher or lower Amp ratings is fine.

For voltage it should be a lead acid battery charger, they all use roughly the same voltages, although some do have AGM selections which use slightly different voltages, but only to achieve absolute maximum charge rate+maximum life, and your not really going to notice the difference that makes!

I've read that many chargers do stages charging. Like once they're full, they go into float charging mode and all.

Most lead acid batteries spend 99.9% of their time attached to a car alternator that has none of these clever stages, actually most do have a couple of minutes at higher voltage after startup these days, but that is it, staged charging is not necessary. The float charge is desirable if the battery is going to spend its life plugged into the charger except in a power cut, but otherwise it is a minor improvement that you will not notice. All modern chargers do what is necessary and more, so don't worry about the rest.

People get too stressed over discharge % of lead acid. If you look at the data sheet of a lead acid battery. The total life AH of the battery is not a great difference whether it is discharged 30, 50 or 80%. (% x cycles = total life AH). The battery will not drop off a cliff at its total life AH limit. Just gradually lose capacity from the day it was manufactured.

Yes, the main factor is the total number of Ah you take out of the battery, lower discharge levels only have a minor effect on wear until you get down to 10% charge. Best thing you can do to extend life is give it a 100.000% charge once a month to fully clean the plates.

Although some standard starter batteries are not built strong enough to cope with regular high discharge, thus using deep discharge batteries, or AGM for non-car starter purposes.

For a lithium, I need to match the requirements for the battery spec exactly to the charger right? I read this article that describes how a lower power charger will undercharge the battery so it isn't a good idea. Best idea for lifepo4 is to use the exact CC/CV specs correct?

Lower power chargers are fine, they just charge slower, in fact slower charging = longer life, so I always charge my phone on the 5W wireless charger, not the 18W fast charger, unless I want it charged fast. If I could charge it at 1W then I would, that would be fast enough for an overnight charge.

And just a general question (to anyone), I've read that LiFePo4 is the safest of all

It is possible to make dangerous batteries, and lead acid car batteries are very dangerous if mistreated, they can literally explode and do put people in hospital, a lithium can't, it just burns.

Modern lithium batteries of all types, if attached to a reasonable charger and not mistreated are all safe. LiFePo4 is only safer if you start mistreating it at which point it is somewhat more robust, but they can still catch fire if mistreated so I'm not sure that actually makes it any safer! The only big advantage of LiFePo4 is that you can charge it to full at full charge rate whereas most lithium batteries you have to slow down above 80%, however since LiFePo4 has 20% less capacity you can actually charge at full rate for the same amount of time so again it is of questionable advantage!