Lithium Ion batteries v Gel and Lead Acid

[Margaux2]

Been thinking about losing my heavy 95AH lead Acid battery to make a weight saving in favour of Lithium. However come across some interesting but confusing elements.
Li battery needs 14.8 bolts to adequately charge to full. Due to there being manufactured in 3V banks which all need charging simultaneously. However Caravan’s normally only can recharge at 13.8v! Wonder if Motorhome’s have a similar restriction?
Prices vary immensely. Also there are differing variations of Lithium Ion eg phos4.
I thought it would be simple just swap them over save weight and sell a perfectly good Lead Acid battery on eBay etc?
Hymer have a smart system which uses existing LeadAcid and adds banks of Li yet don’t see where the weight saving comes from?
What a minefield!

 

[Jim]

The only real downside to Lithium is the price... Fact is, if Lithium and Lead Acid were the same price, not many, if any, would buy lead acid or gel.

If the depth of discharge, the rate of charge and the lightweight are important to you, then they are worth paying for. If not, a good LA or Gell will last you years at a ¼ of the price.

Unless you are sure you know what you are doing, you should consider professional fitting.

 

[Lenny HB]

Chargers that only charge to 13.8v are long gone unless you have a really old vehicle.
Modern chargers are multi stage with bulk/absorbtion & float stages. They will work with Lithium but they are not ideal most will not fully charge a lithium and ideally you do not want a float charge.

Only one type of Lithium suitable for Motorhome use LifePo4.

I really don't get what Hymer do either.

 

[Pausim]

Lithium Ion is the generic name for all types of lithium batteries, including those used in phones and e cars. The type you need for a motorhome leisure battery is LiFePO4. Most motorhome chargers now have a Gel setting which will charge at about 14.4V which is fine for most LiFePO4 batteries, just check what the battery manufacturer says. Undercharging LiFePO4 batteries does no harm at all.

13.8V is not even sufficient to charge lead acid batteries properly and undercharging lead acid batteries causes damage, particularly the AGM type.

 

[Margaux2]

The only real downside to Lithium is the price... Fact is, if Lithium and Lead Acid were the same price, not many, if any, would buy lead acid or gel.

If the depth of discharge, the rate of charge and the lightweight are important to you, then they are worth paying for. If not, a good LA or Gell will last you years at a ¼ of the price.

Unless you are entirley sure know what you are doing, you should consider professional fitting.

Yes its nlooki. V tee

Chargers that only charge to 13.8v are long gone unless you have a really old vehicle.
Modern chargers are multi stage with bulk/absorbtion & float stages. They will work with Lithium but they are not ideal most will not fully charge a lithium and ideally you do not want a float charge.

Only one type of Lithium suitable for Motorhome use LifePo4.

I really don't get what Hymer do either.

thanks yes LifePo4.by float is that the same as Trickle charge? My van was new in October2020.

 

[Richard n Ann]

Our Votronic duo solar regulator has got a LifePo4 setting

 

[Lenny HB]

Yes its nlooki. V tee

thanks yes LifePo4.by float is that the same as Trickle charge? My van was new in October2020.

Yes.

 

[autorouter]

Here's my take on the Hymer hybrid lead-acid/lithium system.

Often when off-grid camping, on a MH with plenty of solar, the batteries stay 70 to 80% full overnight, and the solar fills them up again by mid-morning. So only 30% of the battery capacity is being used day-to-day. The rest is a kind of reserve, for that unlucky spell of bad weather that happens to us all every so often.

Lithium performs well when it is continually discharged and recharged, and doesn't need to be 100% charged every few days like lead-acid.

Lead-acid (I'm including gel and AGM here) does well if kept at 100%, and occasionally discharged, then recharged to 100% at the first opportunity. So a big lead-acid is ideal for a reserve in this system.

The hybrid system has an electronic control module that implements this idea. The day-to-day power is taken from the lithium battery, and only if that is exhausted does the lead-acid section take over. When charging resumes, the lead-acid bit is filled up first, then the lithium bit.

So here's the question. Is the lead-acid battery plus the electronic module cheaper than a couple of big lithium batteries? It looks like Hymer thinks yes, for this system.

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[steveh57]

Any idea who manufactures this electronic module?

Although the idea of carrying round an extra 25Kg and not using it would worry me. But then again I carry a spare wheel as well

 

[Lenny HB]

Any idea who manufactures this electronic module?

Although the idea of carrying round an extra 25Kg and not using it would worry me. But then again I carry a spare wheel as well

What module?

 

[autorouter]

What module?

The electronic module that controls the Hymer lead/lithium hybrid charging system mentioned by the OP. I don't know, but I'd guess it's made by Schaudt, who make the EBLs and B2B boosters for Hymer MHs.

 

[Pausim]

The electronic module that controls the Hymer lead/lithium hybrid charging system mentioned by the OP. I don't know, but I'd guess it's made by Schaudt, who make the EBLs and B2B boosters for Hymer MHs.

I see from an old Hymer price list (2019) the Smart-Battery-System cost £2,700 as an option when ordering new. For this you got a 135Ah Li battery, the clever module and an extra 18A charger. It added 25kg to the weight. The Op is looking to save weight and a simple swap of 95Ah lead acid to LiFePO4 will save about 14kg and £2k.

 

[Kannon Fodda]

Chargers that only charge to 13.8v are long gone unless you have a really old vehicle.

Nope. Sargent systems fitted to many modern Autotrail vans still have flat rate 13.8V chargers that aren't even smart such as the EC176 in my V-Line.

 

[autorouter]

The Op is looking to save weight and a simple swap of 95Ah lead acid to LiFePO4 will save about 14kg and £2k.

Also he could probably save weight by swapping the fixed 13.8V charger, which probably has a heavy iron transformer in it, for a modern switch-mode intelligent multistage charger, which would do a better job of charging, especially if it can be set to a lithium profile.

 

[Westbarn1]

I see from an old Hymer price list (2019) the Smart-Battery-System cost £2,700 as an option when ordering new. For this you got a 135Ah Li battery, the clever module and an extra 18A charger. It added 25kg to the weight. The Op is looking to save weight and a simple swap of 95Ah lead acid to LiFePO4 will save about 14kg and £2k.

I have the Hymer Smart Battery system on my BMCi690 and it has 2 x 135 Ah Lithium and a 95 amp Varta Professional AGM battery fitted under the floor, it looks like all the controlling bits are Schaudt and with 2x 130w solar panels on the roof I have found that as long as its sunny, or I'm moving now and again I really don't need a hook up, and you should see the size of my Mrs hair dryer!

 

[Lenny HB]

Nope. Sargent systems fitted to many modern Autotrail vans still have flat rate 13.8V chargers that aren't even smart such as the EC176 in my V-Line.

That is unbelievable quickest way to knacker any type of battery, I thought those had died a death over 25 years ago.

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[Richard n Ann]

That is unbelievable quickest way to knacker any type of battery, I thought those had died a death over 25 years ago.

Our 2014 elddis had one. Just a 13.8v power supply. Battery lasted 5 years, probably because I used an optimate at home and Votronic solar when out mainly.

 

[Pausim]

Nope. Sargent systems fitted to many modern Autotrail vans still have flat rate 13.8V chargers that aren't even smart such as the EC176 in my V-Line.

I agree with Lenny HB “unbelievable.” Have they not noticed they have been left behind using 20th Century kit.

 

[Richard n Ann]

I agree with Lenny HB “unbelievable.” Have they not noticed they have been left behind using 20th Century kit.

As long as it lasts a year they don't care. It saves them a couple of quid per van probably

 

[Lenny HB]

I agree with Lenny HB “unbelievable.” Have they not noticed they have been left behind using 20th Century kit.

Probably got way undersized wiring as well. Brit manufacturers still living on their caravan heritage.

 

[Pausim]

As long as it lasts a year they don't care. It saves them a couple of quid per van probably

Sadly reminds me of BL and most of our ship building industry, destined to disappear through shortsighted refusal to move with the times.

 

[Kannon Fodda]

Electrics are the real Achillies Heel of my 2019 V-Line. PVC Current models don't seem to be any better. I've made my thoughts well known in a review I put up. All bling yet little substance with light fittings everywhere, yet only a single 12V cigarette lighter point for the entire habitation area, no USB, apart from the cab. I'm OK now as Vanbitz helped empty my wallet with a Lithium replacement for the 72Ah (yes that is all it was) Banner lead-acid, with B2B, MPPT onto the solar. Didn't actually replace the EHU charger system, if necessary I could add a smart charger, I just have the Sargent EHU charger turned off as solar plus B2B is sufficient or I'll manually switch on for a few hours if I had really used the Lithium.

Now that I know what I know, in present form the electrics on the v-line would be enough to stop me buying another one, despite the rest of the van being ideal for my needs. Also means I'd be asking pointed questions of any other brand.

 

[Margaux2]

Here's my take on the Hymer hybrid lead-acid/lithium system.

Often when off-grid camping, on a MH with plenty of solar, the batteries stay 70 to 80% full overnight, and the solar fills them up again by mid-morning. So only 30% of the battery capacity is being used day-to-day. The rest is a kind of reserve, for that unlucky spell of bad weather that happens to us all every so often.

Lithium performs well when it is continually discharged and recharged, and doesn't need to be 100% charged every few days like lead-acid.

Lead-acid (I'm including gel and AGM here) does well if kept at 100%, and occasionally discharged, then recharged to 100% at the first opportunity. So a big lead-acid is ideal for a reserve in this system.

The hybrid system has an electronic control module that implements this idea. The day-to-day power is taken from the lithium battery, and only if that is exhausted does the lead-acid section take over. When charging resumes, the lead-acid bit is filled up first, then the lithium bit.

So here's the question. Is the lead-acid battery plus the electronic module cheaper than a couple of big lithium batteries? It looks like Hymer thinks yes, for this system.

Thanks good info but for me it’s about weight first as my payload is limited, efficiency 2nd and cost 3rd.

 

[Lenny HB]

Thanks good info but for me it’s about weight first as my payload is limited, efficiency 2nd and cost 3rd.

Replacing a 95ah lead with a 100ah Lithium is only going to save about 12kg hardly worth the bother but would give you move avaliable power. The more lead you are going to replace the better the weight saving if I replaced my 3 leads with 2 Lithium I would save about 58kg.