Charging Lithium Batteries Vs Charging AGM Batteries

As I said in the other thread I would test and time the Charging abilities of these Two Battery technologies.

First Off I Discharged a 40Ah Lithium Battery down to 46% having used 54% of it's power which means I used a total of 21.6Ah

At the same time I discharged a brand New 80Ah/800cca Exide AGM fast charging Stop Start battery down to 81% which equals 15.5Ah just to give it a fighting chance,

I hooked the PLB 40 up to it's 8/10A Charger and I hooked the AGM up to the 26A Noco Smart Charger which is meant to be very fast at charging

The PLB Charger has to replace 27.9% "More" than what the Noco had to replace even though the Noco is 2.6X more powerful than the Stock Dometic PLB Charger,

I timed them with a Stopwatch and the PLB charger had replaced 54% / 21.6 Ah in 3 hours 10 minutes and shut Off reading 100% Full.
The Noco finish it's bulk Charging phase in 3 hours 20 minute and then switched to it's final mode and I am still sitting here at 11 hours 22 minutes and Counting and it has still not finished Charging, And even though The PLB 40 Charger had an extra 27.9% more work to complete compaired to the AGM The Lithium was/is Fully Charged in a quarter of the time which means the Lithium Batteries Charge at leased 4 X Faster than their AGM Counterparts,

If I had only used 15.5Ah from the Lithium Pack as I did with the AGM the Lithium Pack would of been fully Charged in 2 hours 16 minutes, That actually means that the Lithium Pack charges over 5X Faster than the AGM Batteries.

It's now been 11 hours 50 minutes and the AGM is still in it's final charging phase,

So what does all this mean to you Guys/Gals, Well for start One 80 to 100Ah Lithium Battery with do the job of 2 100Ah AGMs but when you compare the Charge times being 5X faster that equates to having 8 X 100Ah AGMs,

But in real world Use 1 X 100Ah Lithium is going to charge faster than you can use the power which means and with 2 of them and a couple of 150w panels I doubt if you would ever use more than 5% of the stored power.

Food for thought Ay :Y:

I have a 10A 7 stage charger. Would that be enough to keep my 130A AGM batt charged? Too damn heavy for me to lift now.......

Jaros said:

I have a 10A 7 stage charger. Would that be enough to keep my 130A AGM batt charged? Too damn heavy for me to lift now.......

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As a rule an AGM battery can be charged at a maximum of 30% So for your 130Ah the max Charging Amperage is 39A which means your 10A is fine for maintaining a couple of batteries of that size whilst not in use or as an emergancy Charger but on a battery of that size a 20 to 25A would be a nice balance.

Yeah thats what I am finding too, I don't know why they put the thinnest Handles on the Heaviest batteries,

Thats another reason why I am enjoying the Lithium packs @ 7.6/7.8 kgs and the fact I can charge them from the cigar socket without no extra DC to DC chargers or wiring makes everything so easy and is as simple as plugging in your phone and I am serious it's that simple.

Jaros said:

I have a 10A 7 stage charger. Would that be enough to keep my 130A AGM batt charged? Too damn heavy for me to lift now.......

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I was just thinking what you said about the weight issue and remembered these I found a while back,

Two of these would be close to your 130Ah and each one only weighs 7kg so they are easy to move around and a pair would give you 96Ah to play with Vs 65Ah from your 130Ah AGM and both would be half the weight of the AGM +/-.

Hopefully they sell em in Australia, because the price is good. I just prefer the self contained units, So all I have to do is plug in to them.

https://www.amazon.co.uk/Ultramax-L...&pd_rd_wg=5pxPQ&ref_=pd_gw_ci_mcx_mr_hp_atf_m

I disagree to an extent re charge rates for an AGM. If you Google "Maximum" it will give 30%. However if you Google "Recommended" most battery manufacturers state between 10 and 20 % and some 15% to 25% as a recommended charge rate. However maximum does not mean it is best re life span. It's all in the wording, lol.

Like Jaros I have a 130 AH AGM so the recommended rate is 13 to 26 amps at 10-20%. My charger is a variable (switched) charger in 10% increments from 3 to 30 amps.
It is set to 21 amps as I have always used the 10-20% rate.

All that happens with being a little lower than recommended, like Jaros, is it will take a bit longer to charge. Bottom line, charging an AGM at a too higher rate, will likely overheat the battery, especially in an Ozi Summer and shorten it's life. so why take the risk.

I only have 200 W of solar and the highest charge rate I've monitored is a bit under 14 amps, so when off grid I'm right at the lower end of the 10-20% range.

I'll add, Lithium is a whole different ball game.

condor22 said:

I disagree to an extent re charge rates for an AGM. If you Google "Maximum" it will give 30%. However if you Google "Recommended" most battery manufacturers state between 10 and 20 % and some 15% to 25% as a recommended charge rate. However maximum does not mean it is best re life span. It's all in the wording, lol.

Like Jaros I have a 130 AH AGM so the recommended rate is 13 to 26 amps at 10-20%. My charger is a variable (switched) charger in 10% increments from 3 to 30 amps.
It is set to 21 amps as I have always used the 10-20% rate.

All that happens with being a little lower than recommended, like Jaros, is it will take a bit longer to charge. Bottom line, charging an AGM at a too higher rate, will likely overheat the battery, especially in an Ozi Summer and shorten it's life. so why take the risk.

I only have 200 W of solar and the highest charge rate I've monitored is a bit under 14 amps, so when off grid I'm right at the lower end of the 10-20% range.

I'll add, Lithium is a whole different ball game.

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MasterVolt State that the Maximum Rate of Charge for AGM Batteries being 30%, I said a nice balance would be 20 to 25A, Again MasterVolt Say Between 15% = 19.5A to 25% = 32A, So like you I also said up to 20% which = 26A,

Jaros's 10A Charger is "Only" 7.6% of 130Ah which is why I quoted him a Charger between 15 to 20% which is around the same numbers you just Quoted. IF an AGM loses around 5% +/- of its charge per month then his charger is not big enough.

A Classic Example of Lead Acid Vs Lithium Note that AGM's are also Lead Acid Tech be it better than standard lead acid.

The Minelab GP 3500 uses a 12Ah Lead Acid Battery And on Page 10 of the Manual it states that it takes up to 24 hour to charge a depleted Battery,

The GPX 4800/5000 uses a 9.2Ah Lithium Battery and on Page 18 it States it takes up to 5 hours to when Depleted/Flat.

If the GPX battery had 12Ah capacity like the GP Lead Acid battery then it would still only take 6.52 hours to charge OR 6hrs 32 minutes Vs 24 Hours.

A 130Ah AGM has 67.5Ah of useable power before it hits the safe level @ 50%

An 84Ah Lithium Battery will give you 67.2Ah at a DOD of 80% and it only weighs 10.2kgs. My 80AGM = 22.9kgs

OR 2 X 60Ah Lithium Batteries will give you 96Ah and only weigh 7kgs each = ( 14kgs )

I advocate leaving an AGM on charge when not used. However, you need a good quality charger to do that. In my current situation, I have mains power to the van, the charger floats the battery at 13.2 V and once a month puts it into a brief full charge cycle to condition it.

However, I'm moving home in a few months and the van will be in an area without power access, so I'll leave the solar panels on. The Victron has been reprogrammed to float at the same 13.2 V.

If Jaros's battery lost 5% a month = 6.5 AH, the charger will recharge it. If he left it 6 months it might lose 39 AH, his charger will still charge it, but just take longer to bring it back to full, compared to say my charger. I agree, his charger could be bigger and would be better if it were, but, what he has will work.

I do not dispute the available power in a comparable Lithium battery, or the weight saving. It all boils down to what you have, what you need and how deep your pockets are.


I am looking to put a 100AH Lithium into my caravan before I next use it. However, my mains charger will be ok as it a. has a lithium profile, but I will use power supply mode. and b. my mate will reprogram the Victron solar controller to suit. I don't use DC-DC in the van.

condor22 said:

I advocate leaving an AGM on charge when not used. However, you need a good quality charger to do that. In my current situation, I have mains power to the van, the charger floats the battery at 13.2 V and once a month puts it into a brief full charge cycle to condition it.

However, I'm moving home in a few months and the van will be in an area without power access, so I'll leave the solar panels on. The Victron has been reprogrammed to float at the same 13.2 V.

If Jaros's battery lost 5% a month = 6.5 AH, the charger will recharge it. If he left it 6 months it might lose 39 AH, his charger will still charge it, but just take longer to bring it back to full, compared to say my charger. I agree, his charger could be bigger and would be better if it were, but, what he has will work.

I do not dispute the available power in a comparable Lithium battery, or the weight saving. It all boils down to what you have, what you need and how deep your pockets are.


I am looking to put a 100AH Lithium into my caravan before I next use it. However, my mains charger will be ok as it a. has a lithium profile, but I will use power supply mode. and b. my mate will reprogram the Victron solar controller to suit. I don't use DC-DC in the van.

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Don't get me wrong I still love abilities of big Lead Acid Battery banks for stationary use and I will always keep mine,

I have never been a fan of lithium until I started to test them Vs Lead Acid and AGM, but when you compare the Charge times Vs the Weight Vs the Useable power Lithium win at every hurdle,

Based on equal useable power, Weight and Charge times

A Basic 130Ah AGM has 67.5Ah of useable power. A 84Ah Lithium has 67.2Ah of useable power

The differance in Charge times between the two are up to 5 X faster with the Lithium

The weight differance between Lithium and AGM is Huge, An average 130Ah AGM is around 30kgs, Vs 10.2kgs.
thats a weight saving of over 66% or 19.8kgs.

OR By using 2 X 60Ah Lithium batteries you gain 42.2% more power or an extra 28.5Ah and save 53.3% in weight meening a saving of 16kgs,

Most of these Lithium batteries have 1000 to 2500 cycles at 80% DOD but if you did fully cycle them Once a week then based on those claims then a 2500 cycle battery would take 48 years before it would lose the top 20% of it's capacity and even then it would still work giving 80% of its full capacity, Those are just claims by the companies and has not been proven due to the Age of Lithium Tech but in essence a person could buy a battery at the age of 20 and still be using it when they retire., But if you only discharge them down to 50% you can/could get over 8000 cycles

My Cell/Mobile Phone battery after being Dropped, left and used in Sub Zero Weather and Abuse for over 10 years Still works, Not as good as the new one but it's still kicking So one of these Lithium should at leased double that life span.

Oh and you won't believe the speed they charge at.

I've yet to use the AGM as I bought it just before my back problems began 5 yrs ago-just keeping it charged and trickled.

Jaros said:

I've yet to use the AGM as I bought it just before my back problems began 5 yrs ago-just keeping it charged and trickled.

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They are a great Battery but humping those big lumps around is a young mans game, and Life is so easy with these ready made power stations and I can swing it in one hand, The worries of getting enough sunlight like I did with my Deep cycle batteries is over.

Have you ever found that perfect tool or Item that works just like you imagined it should ?? well thats how these packs work, Everything that you would normally get fitted to your car or camper is built in and combined add a 120w folding panel is all you need, If a person has a camper trailer then just swapping out the batteries might be a better option, but for in the car/ Boat/Tinny or a Tent or even a Van like mine it just makes life a pushover.

My Brother has a serious illness and walks with a Cane and he went and bought one 2 months ago too and he loves it.

I have to install it into the camper trailer body to take the weight off the hitch. The box in front will have 1 40ltr fridge, empty for the trip and in the Pathy there will be the freezer and and the Engel 45L for food and veggies and drinks. The front will also have main solar panel controller for the fridges in parallel with the AGM. I have a 60W solar panel laying flat on the roof rack to trickle charge the car battery hard wired/fused.
When the batteries I have are rooted i'll consider the lithium alternative.

Jaros said:

I have to install it into the camper trailer body to take the weight off the hitch. The box in front will have 1 40ltr fridge, empty for the trip and in the Pathy there will be the freezer and and the Engel 45L for food and veggies and drinks. The front will also have main solar panel controller for the fridges in parallel with the AGM. I have a 60W solar panel laying flat on the roof rack to trickle charge the car battery hard wired/fused.
When the batteries I have are rooted i'll consider the lithium alternative.

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Even a 60w panel will put a fair bit back in a Lithium battery because they normally accept around 80% + of the power provided where as lead acid type batteries only accept around 27 to 30% which why they are so slow at charging, It's a shame your not closer coz I have about 6 150w panels and a 100w panel all New never been used all going begging, If and when you get it sorted a 150w would give you a heap of power and a 84Ah Li 4 would equal your 130Ah, A 100Ah Li4 would give you even more in reserve,

Over here they mount all the heavy gear like batteries above the Axle, and the water tanks and waste water tank either side of the Axle, Only a few fit the batteries in the front box but mainly they only fit the Gas bottles in the front box to keep them out of harms way along with other light stuff like awnings and plastic leveling ramps etc, It makes it easy to manouver by hand if needed and easier to lift on and off the hitch too,

If you look on YT you will see that most EU/UK camper Trailers have the Kitchen and Gas Heating systems and the Fridge along with the battery/s mounted over the Axles.

Yep, I'm going to mount the batt over the axle in a batt box to suit which I already have. I also have a 1200A Peak jump starter with built in compressor and 400W inverter with 2 240V outlets as well as built in USB outlet.

Jaros said:

Yep, I'm going to mount the batt over the axle in a batt box to suit which I already have. I also have a 1200A Peak jump starter with built in compressor and 400W inverter with 2 240V outlets as well as built in USB outlet.

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If you can try and mount it on the Drivers side because then it won't cop a beating from all the pot holes, when ever I load the Fridge and batteries in the Van I load them on the drivers side between the front and rear axles that way it has a smoother ride, :Y:

Aaah, Weight n Balance, always a necessary thing to consider. Mind you 30 years working design on RAAF aircraft it was a bit more necessary when crap moves around in excess of Mach 1 and forward crash mitigation of up to 40G = "Smokin Hole in the Ground".

No less important when doing a 100kph, last thing in a car you need is something hitting you in the back of the neck if you come to a sudden stop.

I found this out last year going down the freeway, got the "death wobbles" at 100kph. Why, I put a slab of beer on the floor of the van ensuite at the back of the van. It was enough to unsettle the balance. Fortunately I managed to slow and pull over. I put the slab in the main van next to the bed and no prob after that.

condor22 said:

I found this out last year going down the freeway, got the "death wobbles" at 100kph. Why, I put a slab of beer on the floor of the van ensuite at the back of the van. It was enough to unsettle the balance. Fortunately I managed to slow and pull over. I put the slab in the main van next to the bed and no prob after that.

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If a slab of beer upsets the balance of your van I'd be looking closely at your whole rig. You're an accident waiting to happen.

Nightjar said:

condor22 said:

I found this out last year going down the freeway, got the "death wobbles" at 100kph. Why, I put a slab of beer on the floor of the van ensuite at the back of the van. It was enough to unsettle the balance. Fortunately I managed to slow and pull over. I put the slab in the main van next to the bed and no prob after that.

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If a slab of beer upsets the balance of your van I'd be looking closely at your whole rig. You're an accident waiting to happen.

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It was a Slab of Red Bull, It gave it Wings, :lol: :lol: :lol:

condor22 said:

Aaah, Weight n Balance, always a necessary thing to consider. Mind you 30 years working design on RAAF aircraft it was a bit more necessary when crap moves around in excess of Mach 1 and forward crash mitigation of up to 40G = "Smokin Hole in the Ground".

No less important when doing a 100kph, last thing in a car you need is something hitting you in the back of the neck if you come to a sudden stop.

I found this out last year going down the freeway, got the "death wobbles" at 100kph. Why, I put a slab of beer on the floor of the van ensuite at the back of the van. It was enough to unsettle the balance. Fortunately I managed to slow and pull over. I put the slab in the main van next to the bed and no prob after that.

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[video=480,360]https://www.youtube.com/watch?v=4jk9H5AB4lM[/video]
[video=480,360]https://www.youtube.com/watch?v=w9Dgxe584Ss[/video]

This one has a bit more info and it is from Bath University.

https://www.youtube.com/watch?v=zwlgZG55QWk

Thanks for those useful demonstrations fellas.