Hymer smart battery system (2 Viewers)

[jonasw19]

Has anyone any experience of the Hymer smart battery system, either as a retrofit or as original fit.
I am considering upgrading my 2 off 95ah agm batteries to cope with ebike charging while off grid.
Jon

 

[Detnor]

I saw one of the Hymer dealers retro fitting to a van a few weeks ago (you have to be nosey), this was the first one they had done and it all looked impressive. The display unit was Votronic and the battery unit was BOS-AG (Balance of Storage), I just happened to notice, so I guess Hymer have packaged them.
I got the impression they had waited for quite a while to get it in from Germany.

 

[Wagoneer]

Has anyone any experience of the Hymer smart battery system, either as a retrofit or as original fit.
I am considering upgrading my 2 off 95ah agm batteries to cope with ebike charging while off grid.
Jon

Do you mean the Intelligent Alternator Boost chargers made by Schault?

WA 121525 is 25amp version & WA 121545 is 45amp version. Basically B2B devices.

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[jonasw19]

Wagoneer
My standard fit includes a votronic 45 amp b2b.
I think the smart battery upgrade adds a 130ah lifepo4 battery into the system.
What I can't find is how they integrate charging two different battery chemistries.
The b2b will be excellent for topping up the lifepo4 but Iess good for the agm side as they will be current limited whilt charging, more so than the lifepo4.
The current setup is b2b ,2x agm (190ah total) 270w solar with mppt.
This works well 3 seasons mostly off hookup.
I will need to charge 2 ebikes ca 500wh per day in addition to our normal consumption of ca 400wh.
Unless we drive for a couple of hours daily and the sun shines, we are going to have to think carefully.
Jon

 

[HandyAndy]

I'm guessing here but all you would do is branch off your lead acid and through a B2B charger into the Lifep04.
Standard alternator/ EHU / Solar would still act upon the lead acid as per normal and the B2B would take / deliver whatever you set it to to the essentially "isolated" Lifep04.
Even if there was no incoming charge to the Lead acid, the lead acid battery, as long as it was full, could still be used as a charge / supply to the B2B - Lifep04..
Sounds like a perfect world setup. I'm sure there is an achillies heel in it somewhere
The B2B may be able to disconnect the Lifep04 from the Lead acid if the Lead acid was low volts or over volts depending how smart it is.
You'd still need some sort of cut off on the output of the Lifep04 to prevent low volts on that side, perhaps they are relying on an internal BMS..

Never seen or heard of the system mind

 

[jonasw19]

Andy
The blurb says that the agm stays charged and is only used when the lifepo4 is insufficient, or as battery heaters before charging the lifepo4 if the temperature is too low
My doubts are around the correct charging for the two battery types.

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[Lenny HB]

Hymer Smart Battery System is just what they call their LifePO4 option, do it yourself and save over a qrand or two.

 

[jonasw19]

Hymer Smart Battery System is just what they call their LifePO4 option, do it yourself and save over a qrand or two.

Lenny
I wonder, to just install a lifepo4 battery would mean a new b2b , solar and mains battery and a battery monitor all with lifepo4 settings.
Straight forward enough, and maybe simpler than adding it to the existing agm setup which is anyway 3.5 years old.
The dilemma will then be whether to go for a simple lifepo4 without internal bms, and have an external bms set up slightly conservatively for vmax and vmin, or use an internal bms.

 

[HandyAndy]

Andy
The blurb says that the agm stays charged and is only used when the lifepo4 is insufficient, or as battery heaters before charging the lifepo4 if the temperature is too low
My doubts are around the correct charging for the two battery types.

The B2B charger i think just a buck booster (sort of) so it can take the lead acid volts and dial it up or down to suit the Lifep04, that is what I meant in my previous post, the B2B charger basically isolates the two battery types from one another so you can have entirely different charging regimes for both batteries.

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[jonasw19]

Maybe I have used the wrong term for the Votronic box that sits between the engine alternator and the hab. battery and can deliver up to 45A charging current.
Whilst this setup does work with 2x 95Ah agm batteries, I feel that the Agm will not accept the max rate of charge, before reducing it.
Lifepo4 will accept this sort of rate so making short drives more likely to put adequate charge back in.
The addition of ebike charging ca 500wh per day, and short journeys will strain the electrical system.

 

[HandyAndy]

Maybe I have used the wrong term for the Votronic box that sits between the engine alternator and the hab. battery and can deliver up to 45A charging current.
Whilst this setup does work with 2x 95Ah agm batteries, I feel that the Agm will not accept the max rate of charge, before reducing it.
Lifepo4 will accept this sort of rate so making short drives more likely to put adequate charge back in.
The addition of ebike charging ca 500wh per day, and short journeys will strain the electrical system.

Jono did some testing on this on his narrow boat and at tickover with a high amp alternator he could charge his Victron 300 ah batteries in 88 minutes....(from 50% to 100%)

 

[HugoBNB]

Hello. I just found this thread on a search, as scouring the Hymer manual yielded nothing. My question is - is it okay to leave the smart battery system in EHU whilst in storage? There is a significant, and fairly rapid (vehicle battery getting critical), deterioration of the battery condition if l leave it off the EHU after about 4 weeks. There is150w of solar on top, but we are under cover with no dire t such light. Any help would be greatly appreciated.
Thanks.

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[StillGoing]

Lenny
I wonder, to just install a lifepo4 battery would mean a new b2b , solar and mains battery and a battery monitor all with lifepo4 settings.
Straight forward enough, and maybe simpler than adding it to the existing agm setup which is anyway 3.5 years old.
The dilemma will then be whether to go for a simple lifepo4 without internal bms, and have an external bms set up slightly conservatively for vmax and vmin, or use an internal bms.

Your B2B is fine. The Votronic has a lithium option. If it doesn’t have a temperature probe you’ll need to fit one - simple to do and not expensive (it’s in the manual how to do it).

What solar controller do you have?

My advice would be not to over complicate it. You can easily spend a lot of money unnecessarily. An internal BMS is more than adequate.

 

[jonasw19]

My original query was in 2019.
I settled on replacing the AGM battery pack, which was 3.5yrs old and unwilling to run the ebike chargers, with 2 off sterling 100ah LiFePo batteries. This has now done 4 years and is excellent. We have just returned from 60 days in France cycling 1200 miles on our ebikes, no hook up and driving 30 ish miles a day.
The solar controller remained the Schaudt mppt, no lithium profile. Sometime will replace with a Victron Unit.
jon

 

[LithiumConvert]

I settled on replacing the AGM battery pack, which was 3.5yrs old and unwilling to run the ebike chargers, with 2 off sterling 100ah LiFePo batteries.

My action plan is to do the same thing. I did the same thing in our last Hymer. I see no point in keeping any heavy AGM batteries. The Sterling LiFePo4 batteries and B2B work very well and are so much lighter.

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[HugoBNB]

Hello. I just found this thread on a search, as scouring the Hymer manual yielded nothing. My question is - is it okay to leave the smart battery system in EHU whilst in storage? There is a significant, and fairly rapid (vehicle battery getting critical), deterioration of the battery condition if l leave it off the EHU after about 4 weeks. There is150w of solar on top, but we are under cover with no dire t such light. Any help would be greatly appreciated.
Thanks.

Just by way of an update for anyone else with the same query as I, here is the response from Hymer technical support.
Safe and happy travels.
*****
Thank you for your inquiry to Hymer. When storing your motorhome for the winter, you can leave the 230 volt power supply connected to the vehicle the entire time. You can also do what would be good for the battery: just recharge it every 2 weeks, both of which are correct. Recharging is certainly good for consumers and their alarm system. With the Alde hot water heating system, the clycol content means that this system is designed to be suitable for temperatures down to -30 degrees. When refilling, please make sure that the exact center specified by ALDE is inserted, and if you often only fill with water, have the minus degree measured again. We hope to have helped you here and wish you a lot of fun with your Hymer motorhome.
*****