Comparing Hymer Smart Battery System to cheaper alternatives

[PDrill]

Even though the Hymer Smart Battery system is ridiculously priced, I will most likely choose it as factory fit lithium solution for our new van. I'm fully aware that one can get a lithium system for 1/3 of the price but most likely I'm gonna skip them, YET I would like to know what - if any - differences will this system offers over a diy build.

In case the Hymer system is unfamiliar, I'll start by a short description. The van will still have the original 95Ah AGM battery and a booster (I think you call it B2B charger) for it. Then there will be the lithium battery. The primary battery will be the lithium, and only when it's drained the AGM will be used. And when on EHU, the AGM will be charged first and the lithium only when the AGM is full. As a factory fit it will be plug & play & forget. No need to think about temperatures to be able to charge, EBL battery settings, balancing the cells (wtf..?) etc. Basically it should just work.

On youtube I've seen lithium setups done as simply as just removing the old AGM and replacing it with a lithium battery (made by a garage). Really that simple? On the contrary I've seen DIY installs that have had wires going all around the place from some battery pack to every kind of devices unknown to me.

So are they all just the same, me just paying 2800 eur for exactly the same capacity and usability as someone paying 700 eur for a battery swap, or is there something that doesn't meet the eye on the first look?

 

[Kannon Fodda]

Strikes me as being an unduly complex fudge to keep the AGM yet add lithium. Can’t see there is a real benefit unless the lithium is tiny. If agm is the poor longevity that many suggest it become a liability in the remaining upgraded system.

KISS springs to mind and they should instal lithium with decent B2B and EHU and that’s it. Would be a lot cheaper than the “workaround” they’ve created.

 

[Lenny HB]

The Hymer system is a pile of poo not a setup I would want to go anywhere near.
Why on earth would you want a crappy AGM battery in the system the whole thing appears to be a bodge.

Charging the lead battery first appears to be arse about face I would expect to charge the Lithium first to take advantage of their fast charge rates.

You can fit a much better system for less than half the cost.

 

[autorouter]

Many people don't use the full battery capacity all the time. Some rarely discharge below 50%, but like the idea of a reserve for occasional use. So half the battery is rarely used, and is kept fully charged as a reserve.

Lead-acid batteries are best kept 100% fully charged, and lithium batteries are fine with 50% average charge, being charged and discharged frequently. So why not have a system that takes small everyday discharges from the lithium, but has a big lead-acid reserve for occasional use. That would require a clever electronics box to control the switchover, plus all the charging and monitoring. That's the idea behind the smart battery system.

The economics of this system depends on lithium being much more expensive than lead-acid. Since lithium prices have come down so much, that is questionable. Look at the price of a lithium-only system of similar capacity.

 

[Jamesh]

I had thought of a similar system for running power tools using a inverter / lithium battery (probably a car battery) for safe discharge which is then topped up by the leasure battery on the van? A basic b2b would slow charge between the two.

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[paddymcc]

It does seem unduly complicated. The critical aspects for lithium are not to charge it below freezing and to have the correct charging system. It makes more sense to go all lithium but have a battery with built-in 12v heating to solve the first problem ( polinovel do them they are more expensive). Particularly as you live in Finland. Then have all the chargers ( solar EHU and B2B ) set to the lithium profile with battery temperature sensors as back up. I'm not sure how the charging profiles will work with a combined lithium and AGM system but it seems a bit odd.

 

[Googlebot]

For €2800 you could have a complete system with 2 100ah lithium and an inverter wired into your mains.

Then you could sell the new AGM to recoup some of that.

I wouldn’t touch the Hymer system with a barge pole.

 

[eddie]

It’s a pointless system, that only Hymer use, as frankly I don’t think they know what their doing, regarding Lithium

 

[Hoovie]

A combination Lithium/Lead Hybrid system works very well in fact, but the way Hymer have done it is rather strange and very expensive.
I've been running a Hybrid setup of my own design for coming up for a year now, comprising 300Ah of Lead Carbon and 100Ah of Lithium, and it does everything I expected of it

 

[WildBunch]

I agree with other contributors. The Hymer lithium system does not make sense. It is very expensive for what it is, which means you could afford a much better conventional lithium system fitted.
I would suggest you get a price from your new van supplier for a "proper lithium system"
Alternatively get prices from several specialist lithium installers. Talk to them about what suits your needs. Are you having solar & inverters etc fitted. If you are having solar get a MPPT solar regulator. Also fit a B2B as part of the system. Take your time to get the system right to suit your needs now if you can.
Important if you are short of payload now or in the future ditch the AGM for much lighter lithium system.
Unfortunately you will find everyone will have different ideas as to the " best " lithium system. I had to do a lot of research to decide what suited me best.
Just spotted you live in Finland, thus you may need a heater in the battery, Eco-tree do one with a heater option, it adds about £100 extra cost.

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[Hoovie]

Many people don't use the full battery capacity all the time. Some rarely discharge below 50%, but like the idea of a reserve for occasional use. So half the battery is rarely used, and is kept fully charged as a reserve.

Lead-acid batteries are best kept 100% fully charged, and lithium batteries are fine with 50% average charge, being charged and discharged frequently. So why not have a system that takes small everyday discharges from the lithium, but has a big lead-acid reserve for occasional use. That would require a clever electronics box to control the switchover, plus all the charging and monitoring. That's the idea behind the smart battery system.

The economics of this system depends on lithium being much more expensive than lead-acid. Since lithium prices have come down so much, that is questionable. Look at the price of a lithium-only system of similar capacity.

A Lithium-only setup with the same usable capacity as a Lead Acid system is still going to be much more expensive, even with the way LiFoPO4 has come down in price over the last couple of years.
Your first sentence is a great summary however of the general situation, and Hymers system I think generally addresses that but in a very expensive way (and if you want a bigger battery, you have to buy another module with all the accompanying control setup, so end up with unnecessary duplication).

My own Hybrid system, at standard Retail prices, would be just under £1,300 for 300Ah of Lead Carbon Battery (the best type of Lead Acid Battery Tech), 100Ah of LiFoPO4 Lithium (with Heaters and Bluetooth SOC Monitoring) and the 'clever electronics box'. You would be hard pushed to get close to that much usable capacity from a full quality Lithium system for close to that cost. Plus if you wanted to increase the size of the Lithium (or the Lead) part of the Bank, it is solely the the cost of the extra battery (I used to use 200Ah of Lithium in the setup but sold the 2nd battery to provide a similar setup for another Motorhomer).

This chart (Lead in White, Lithium in Green) shows how the two parts work together and how the Lithium does all the day-to-day stuff and the Lead is there for the 'backup' and heavy lifting (for example but not shown here, when I put a heavy load on the inverter such as a Microwave, the Lead comes in to assist the Lithium).

Hybrid Battery Bank State of Charge
(The graphing shown required extra hardware, but it is not necessary in order to use the system)

 

[AgeingAndrew]

My own Hybrid system, at standard Retail prices, would be just under £1,300 for 300Ah of Lead Carbon Battery (the best type of Lead Acid Battery Tech), 100Ah of LiFoPO4 Lithium (with Heaters and Bluetooth SOC Monitoring) and the 'clever electronics box'. You would be hard pushed to get close to that much usable capacity from a full quality Lithium system for close to that cost.

I'm interested in what the 'clever electronics box' does in your installation, presumably it cuts the lithium off from charging just before it's at 100% full?. I guess your installation doesn't need to prioritise lead over lithium as your lead carbon batteries can tolerate being left in a partial state of charge.
I like the Hymer system; it's extremely simple to implement as all the clever stuff is hidden inside the BMS.

 

[Pausim]

No need to think about temperatures to be able to charge,

You can buy LiFePO4 batteries with inbuilt heaters that divert the incoming power to the heaters until the cells are warm enough to charge. They are at the pricey end of the Li range but are still a fraction of the cost of Hymer’s vastly overpriced system and a more sensible solution. Frankly I can't see any advantage of hybridising an AGM/Li set up other than cold weather charging which probably isn’t an issue with a Hymer heated battery compartment anyway.

12V 100AH RELION LOW TEMPERATURE LITHIUM ION BATTERY RB100LT - Alpha Batteries

12V 100AH RELION LOW TEMPERATURE LITHIUM ION BATTERY RB100LT What is the Low Temperature Series? The LT Series lithium iron […]

www.alpha-batteries.co.uk

If payload and weight are issues then instead of adding a significant chunk with the Hymer (Smart?) system you can save weight by replacing the AGM with Li.

 

[Hoovie]

I'm interested in what the 'clever electronics box' does in your installation, presumably it cuts the lithium off from charging just before it's at 100% full?. I guess your installation doesn't need to prioritise lead over lithium as your lead carbon batteries can tolerate being left in a partial state of charge.
I like the Hymer system; it's extremely simple to implement as all the clever stuff is hidden inside the BMS.

The "'clever electronics box'" was a quote from Autorouters post. What I have in mine is a fairly clever box in the form of a microprocessor-controlled programmable relay of my own specification (I call it the 'VSDR Lithium Controller') that does indeed control the charging of the Lithium. The advantage of this approach is that it means you don't need "Lithium Compatible" charging systems as the VSDR manages that and it is a standalone unit that needs no exterior control, although it is possible to connect a bluetooth module to both tweak and monitor it. So all my chargers (B2B, EHU and Solar) are all configured for Lead Profiles. The only reason I fitted them above what was factory was I wanted better quality and more powerful ones.

You could actually have standard Lead Acid batteries as part of the Hybrid system, but as you rightly point out, because Lead Carbon are happy being in a PSOC, they are the perfect partner to a system that is Lithium prioristised. The other Hybrid setups with my VSDR do have Lead Carbons for best results alongside the Heated LiFePO4 with advanced BMSes.
I don't like the Hymer approach of using the Lithium first and then recharging the Lead first - that makes little sense to me in terms of logic as Lithium has much more efficient charging, so it makes far more sense to first recharge - and with less wasted energy - the battery which you expect to be drawing from, especially if charging opportunities may be limited.
All I can imagine is that they prioritise the Lead Charging because of the perceived 'best practice' of getting that technology full as soon as possible. If they used Lead Carbon instead of Lead Acid they could have ignored that requirement.

 

[WildBunch]

Hoovie . I think you are confusing the point a bit here. It is unlikely that P drill will want to design or use a unique system like you are advising. We do know from his original post he has a preference for a factory fitted system. But he can do far better than the Hymer lithium system for the cost. I can see why he may be reluctant to do a DIY installation on a new van with the possible warranty liability issues. His original dealer may be able to undertake the lithium installation work as pert of the original deal.
I have a Hymer. It came with the usual ELB 30 which comes with 2 battery profile settings 1 for Led acid/Gel the other AGM. My Hymer came with a AGM Habitation battery thus was set to suit the AGM battery, which did not suit the led acid starter battery, which failed in under 2 years. From the price list the Hymer hybrid Lithium system has an additional charger fitted just to charge the Lithium battery. It would follow that the new Hymer hybrid Lithium system will still have the same problem where the starting battery is being incorrectly charged with at the incorrect voltage & profile.
The answer is ditch the AGM & fit a lithium battery. Fit B2B & a MPPT solar controller, solar panel. All with lithium charging profiles. If you set the EBL to the Gel setting this will suit the starter battery & whilst not prefect will charge the Lithium. Also a good blue tooth smart shunt will be worth every penny.

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[Hoovie]

Nah, not confusing the point at all. I am actually responding to the comments that say a Hybrid Lead/Lithium battery is a waste of time and also to say that it is possible to have a superior system to both the Hymer Hybrid or a "proper lithium system" at a achievable cost.
As far as what PDrill actually posted and wanted to know, he also asked "YET I would like to know what - if any - differences will this system offers over a diy build." and I also responded to that question the PO asked, describing how a different Hybrid Approach would work compared to the Hymer Hybrid.

Thanks for your concern though

 

[Pausim]

I have a Hymer. It came with the usual ELB 30 which comes with 2 battery profile settings 1 for Led acid/Gel the other AGM. My Hymer came with a AGM Habitation battery thus was set to suit the AGM battery

It is good to see that Hymer have changed to an EBL30 that has an AGM setting. My 2015 Hymer came with an AGM battery and an EBL29 which had Gel and Lead Acid settings but did not have a charge profile to suit the very fussy requirements of AGM.

I bought a LiFePO4 battery for my Hymer and it has subsequently been moved to my Carthago. I don’t feel the need for a hybrid system and if I did it would not include an AGM battery.

 

[The Wino]

Hoovie . I think you are confusing the point a bit here. It is unlikely that P drill will want to design or use a unique system like you are advising. We do know from his original post he has a preference for a factory fitted system. But he can do far better than the Hymer lithium system for the cost. I can see why he may be reluctant to do a DIY installation on a new van with the possible warranty liability issues. His original dealer may be able to undertake the lithium installation work as pert of the original deal.
I have a Hymer. It came with the usual ELB 30 which comes with 2 battery profile settings 1 for Led acid/Gel the other AGM. My Hymer came with a AGM Habitation battery thus was set to suit the AGM battery, which did not suit the led acid starter battery, which failed in under 2 years. From the price list the Hymer hybrid Lithium system has an additional charger fitted just to charge the Lithium battery. It would follow that the new Hymer hybrid Lithium system will still have the same problem where the starting battery is being incorrectly charged with at the incorrect voltage & profile.
The answer is ditch the AGM & fit a lithium battery. Fit B2B & a MPPT solar controller, solar panel. All with lithium charging profiles. If you set the EBL to the Gel setting this will suit the starter battery & whilst not prefect will charge the Lithium. Also a good blue tooth smart shunt will be worth every penny.

Is there any point going to a lot of expense wouldn't it just be easier to disconnect the battery charger from the vehicle battery and use a battery master or the one mentioned on here recently designed specially for lithium battery with lead vehicle battery.

 

[Hoovie]

Dup.

 

[Lenny HB]

I like the Hymer system; it's extremely simple to implement as all the clever stuff is hidden inside the BMS.

The BMS is a safety device to limit any problems when things go wrong it shouldn't be used to control everyday charging.
If its being use for that it is very bad desgin.

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[AgeingAndrew]

If its being use for that it is very bad desgin.

Why???
The LE300 BMS was designed to protect the lithium part of the hybrid system and to control its charging/discharging. It was designed for the very purpose for which it is being used - how can that be bad design? It's designed to work as an extension to lead acid. All BMS's control charging, usually by disconnecting on over voltage, over current, over temperature etc.

There is a good write up at https://www.bos-ag.com/products/le300/battery-management-system/ where the BMS is described.

If these cells were half the current price I’d be at the front of the queue to buy, however, £2k plus VAT for 150Ah is excessive in my opinion so I'll look into a diy hybrid build.

 

[Pausim]

Why???
The LE300 BMS was designed to protect the lithium part of the hybrid system and to control its charging/discharging. It was designed for the very purpose for which it is being used - how can that be bad design? It's designed to work as an extension to lead acid. All BMS's control charging, usually by disconnecting on over voltage, over current, over temperature etc.

There is a good write up at https://www.bos-ag.com/products/le300/battery-management-system/ where the BMS is described.

If these cells were half the current price I’d be at the front of the queue to buy, however, £2k plus VAT for 150Ah is excessive in my opinion so I'll look into a diy hybrid build.

I don’t doubt the system is very clever but I just don’t see the need for a system that combines lead acid and lithium batteries. Particularly when a comparable lithium only system would be cheaper and lighter. In that sense it might be considered bad design because it is providing an expensive solution to a problem that does not exist.

 

[Westbarn1]

I had the Hymer Smart battery system fitted in my last Hymer BMC690 and it worked as I wanted it too, so have specified it for my factory order replacement, due later this year, together with factory fit solar panels, expensive options, I agree, but at least, when it does eventually arrive, will need nothing extra and no modifications.

 

[Hoovie]

I don’t doubt the system is very clever but I just don’t see the need for a system that combines lead acid and lithium batteries. Particularly when a comparable lithium only system would be cheaper and lighter. In that sense it might be considered bad design because it is providing an expensive solution to a problem that does not exist.

How much is a Lithium Setup with 280Ah of usuable power?

 

[Pausim]

How much is a Lithium Setup with 280Ah of usuable power?

You can get a 320Ah LiFePO4 battery for £1,700. A good quality B2B would add £400 to £500 to that.

Can you please explain where your 280Ah of useable power comes from. How much is Li and how much AGM, just so I can understand the comparison you are asking me to make.

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[Jamesh]

You can get a 320Ah LiFePO4 battery for £1,700. A good quality B2B would add £400 to £500 to that.

Can you please explain where your 280Ah of useable power comes from. How much is Li and how much AGM, just so I can understand the comparison you are asking me to make.

6x 95ah LA batteries £300.... Payload nil..!

Sorry I'll get me coat!!!

 

[Lenny HB]

6x 95ah LA batteries £300.... Payload nil..!

Sorry I'll get me coat!!!

Only about 150kg what's the problem, I've got 3 batteries another 6 would still leave me with 150kg spare payload fully loaded with full tanks.
Whats the problem?

 

[Hoovie]

You can get a 320Ah LiFePO4 battery for £1,700. A good quality B2B would add £400 to £500 to that.

Can you please explain where your 280Ah of useable power comes from. How much is Li and how much AGM, just so I can understand the comparison you are asking me to make.

100Ah of Lithium. 80Ah Safely Usable
300AH of Lead Carbon. 200Ah Safely Usable. (don't get sucked into the "can't go below 50%" rubbish)
Does your 320Ah LiFePO4 battery include heaters so it can be charged at low temp? does your 320Ah LiFePO4 include an Integral State of Charge Monitor?

 

[paddymcc]

Does your 320Ah LiFePO4 battery include heaters so it can be charged at low temp? does your 320Ah LiFePO4 include an Integral State of Charge Monitor?

I have a 230Ah lithium with an integral SOC monitor. I'm not convinced that a heater is required for lithium batteries used in motorhomes. They can after all be discharged when cold so it would still be possible to put the gas heating on to warm them up if they did for some reason get cold. I have temp sensors connected to both my chargers to prevent charging when too cold. That seems to solve the problem.
Prices are coming down - I only paid ,£950 for my battery, and about £400 for chargers (B2B and solar) temperature sensors, cabling etc. It was then just my time to fit it all together and that was free.

 

[Hoovie]

I have a 230Ah lithium with an integral SOC monitor. I'm not convinced that a heater is required for lithium batteries used in motorhomes. They can after all be discharged when cold so it would still be possible to put the gas heating on to warm them up if they did for some reason get cold. I have temp sensors connected to both my chargers to prevent charging when too cold. That seems to solve the problem.
Prices are coming down - I only paid ,£950 for my battery, and about £400 for chargers (B2B and solar) temperature sensors, cabling etc. It was then just my time to fit it all together and that was free.

You don't live in the North or Scotland. I monitor and log all the data on a minute-by-minute basis and over the winter for a period of 90 days, my batteries were below 5C for 88 or 89 of those 90 days. Maybe some, or maybe most, folk don't need heaters in order to have a USABLE lithium setup, but I would, and most in this area and above would.
PREVENTING charging from cold is not the best solution. It just means all you can do is stop it charging and you just deplete the battery. With a heater you use that charging energy that in your setup you are throwing away to warm the battery to allow charging. A much better solution.
Does your battery not have an integral low-temp charge cutoff in the BMS anyway to prevent charging at low temps? Why do you have to add extra external circuitry to do that? I would avoid Lithium batteries that used a BMS that was missing such a fundamental function.

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