nano gel battery worry

[roadwarrior]

I am worrying mainly because i dont know the answer and constantant research is leading to conflicting information.
This is keeping me awake at night.
i have a 2016 merc based moho with a smart alternator, i previously had 2 lead acid which died, probably my fault as i thought it was plugged in over winter but it turns out it was switched off and the voltage got too low and died i expect. Anyway they were never much good and so i decied to replace them with latest tech nano gel batteries. i did a test with them installed with a shunt overnight and they were impressive.
NOW. I am now concerned my annoying smart alternator will kill my batteries when driving as its not supposed to like more than 14.4v and i expect the smart alternator will exceed that on overrun, but i dont know. I did think of just starting the engine on the drive and watch the voltage on the shunt
but am i right in thinking the shunt voltage is showing the battery voltage when being charged as opposed to the charge GOING into it ?? so how would i know whats being pumped into it ? and most importantly does it matter ?

 

[jezport]

If you have a smart alternator you should have a dc to dc charger, so should be able to set the charging profile.

 

[roadwarrior]

If you have a smart alternator you should have a dc to dc charger, so should be able to set the charging profile.

so are you saying the dumb old lead acid battery is the the only battery that can withstand the whims of the smart alternator ?

 

[herald_400rl]

Above 14.4v gas bubbles can form in the electrolyte gel in gel batteries killing them off permanently. Do not charge these from your van if you don't have a b2b, disable the VSR or whatever relay you are using.
Lead acid batteries can be killed from overvoltage, too.

 

[Pausim]

so are you saying the dumb old lead acid battery is the the only battery that can withstand the whims of the smart alternator ?

A smart alternator without a B2B (booster) may damage any type of battery and is unlikely to charge it properly. I had a 2015 Mercedes Hymer which came with a smart alternator but no B2B so I had to fit one. Most converters quickly realised that split charge relays were not going to work with smart alternators but a few were very slow to understand the issue.

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[jezport]

so are you saying the dumb old lead acid battery is the the only battery that can withstand the whims of the smart alternator ?

No didnt say that

 

[roadwarrior]

what ther bloody hell is a vsr ?

 

[herald_400rl]

what ther bloody hell is a vsr ?

Voltage sensitive relay

 

[autorouter]

A non-smart alternator gives out a more or less constant voltage of about 14.4V, designed to charge a starter battery. A leisure battery can usually be charged OK from this too. So the usual arrangement is for a relay to directly connect both starter and leisure batteries together, so that the alternator can charge both at the same time. When the engine stops, the relay disconnects them. The relay is called a split charge relay. If it is switched on by the alternator voltage rising to 14.4V, then it may also be called a Voltage Sensitive Relay (VSR).

A smart alternator is designed to not fully charge the starter battery. When the engine overruns or braking is applied, the alternator grabs the waste energy and uses it to charge the battery. The voltage spike may be quite a bit higher than 14.4V, which is OK for the average starter battery.

However this is not good for a leisure battery. First, it never gets charged until full. Secondly, the voltage surges affect some types of leisure battery. But the worst thing is, if a full leisure battery is connected to a partially full starter battery with a relay, the leisure battery starts charging the starter battery, and loses charge itself. So you can start a journey with a full leisure battery, and end up with a half-charged one as you arrive on site.

The solution to this is to disable any relay type of charging, and use a DC-DC charger (also called a Battery-to-Battery, or B2B, charger). This isolates the leisure battery from the starter battery, and provides a proper charging profile for whatever type of leisure battery you have. It prevents any back-feeding of charge to the starter battery too. Charging any type of leisure battery with a smart alternator needs a B2B.

You can get B2Bs with various amps outputs, from 20A to 200A, and some of them have variable output settings.

The B2B can be triggered on and off by the same wire that triggers the existing relay on and off. That signal is called the D+ signal, from the alternator. Most B2Bs can also operate like a VSR if you want. Any existing relay needs to be disabled.

 

[herald_400rl]

Also worth noting with a B2B you need to know your alternator output to buy an appropriate one.
I have a 20a B2B and at idle if I have lights on, blowers on full, and the b2b connected then the belt slips and the alternator output drops, the b2b disengages and lights dim. It's only a 95ah alternator (when it was new!).

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[roadwarrior]

ok my situation is that i have 2 week before i go to france, i have not the slightest idea what any of that means or how to disconnect any back feeding or whatever and am aware i need help pronto. but im pretty sure 3000 miles of driving wont do them much good.

 

[roadwarrior]

anybody know anybody that can help me ?

 

[herald_400rl]

If you have a smart alternator and you have a standard split charge relay then yeah it'll kill the batteries and probably wouldn't even take that long. if you have some form of b2b then you're golden.

Shunt will show the voltage of the wiring (if you like) so your shunt will show the charging voltage if its receiving charge.

 

[roadwarrior]

ok i hav noooo idea what i have, what ever is standard on my winchcome, am i right in thinking thr gel will get killed even faster thqan my old wet batteries

 

[Raul]

Give Roger a call to fit a B2B, Off grid Power Solutions

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[roadwarrior]

ok

Give Roger a call to fit a B2B, Off grid Power Solutions

lefdt him an answerphone message

 

[roadwarrior]

so, from the factory of autosleeper back in 2016 there had to be an aux battery or two supplied - what were they ?

 

[Gaston aires]

Why have a smart alternator when it can cause such problems anyway ?

 

[Pausim]

so, from the factory of autosleeper back in 2016 there had to be an aux battery or two supplied - what were they ?

No idea but I don’t think this will help you. Whatever battery they supplied will have been just as vulnerable to damage if they didn’t fit a B2B, which seems very likely. Autosleepers in 2016 was probably caught out by the Mercedes smart alternator just like Hymer was in 2015. The simple truth is any motorhome with a smart alternator needs a B2B.

Why the motorhome manufacturers ignored the difference between smart alternators and standard ones is another story. Some manufacturers were still ignoring the need for a B2B in September 2019 when Fiat joined the smart alternator club.

 

[herald_400rl]

Why have a smart alternator when it can cause such problems anyway ?

They reduce parasitic load on the engine and therefore decrease emissions. They aim to charge your battery under engine braking, etc. to use recovered energy rather than relying solely on being powered by fuel.

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[Pausim]

Why have a smart alternator when it can cause such problems anyway ?

They improve fuel consumption and reduce pollution. Alternators also need somewhere between 2hp and 5hp to drive them so by removing this load when you have your foot down climbing a steep hill means there is more power available to get you up the hill.

Until September 2019 at the request of motorhome constructors Fiat used a loophole in the testing procedures to avoid putting smart alternators in vehicles for motorhome use. Why would constructors ask them to do this? Answer, because they knew full well that cheap split charge relays were not going to work properly. Mercedes declined and sent out vehicles that were not cheating the Euro 6 standards and the better manufacturers soon started using more expensive B2B (boosters) instead.

 

[ChrisL]

I would second a visit to RogerIvy at offgrid, he may even be able to fit you in on your way south for the ferry.

 

[roadwarrior]

calibre is trying to help me, and yes i agree, knowingly making motorhomes that eat batteries is very wrong, but then, selling a motorhome with 200kg payload is pretty low too and that will never change either.
i spoke to Roger i think and he said it would take 6-8 hours and cost more than 600 quid the line was bad and im not sure we understood each other, I only want a B2B it cant be that much can it ?

 

[roadwarrior]

as a matter of referance i spoke to sergant who "assured" me the panel would be fine and be ok with my gel batteries, sighs ... anyway as a result of me fitting a shunt the sergent panel now wont show me SOC, a shame as it was pretty accurate suprisingly. more problems. I was told here that sergent make a more upto date one that is configureable. but as the sales team are so on the ball there nobody thought to flog me one, I seem to recall Flanders and Swan sing about the gas man - " oh it all makes work for the working man to do....."

 

[Cal54]

I’ve read this thread and am as confused as ever but also worried.. I think I might need a B2B fitting to my little Leisuredrive but not sure - any advice appreciated!
My van came with a small Banner stop start battery as a leisure battery and I changed this for a 110 amp gel battery as I didn’t think the compressor fridge would last long off grid. Never thought about the implications for the split charger! My new battery has been in for 12 months now and all seems well with the solar panel keeping it well topped up. Given that my camper is my only vehicle and used nearly every day should I be worried?
Please keep any advice simple as I don’t understand all the technical stuff and don’t know if I have a smart alternator (2020 Renault traffic base vehicle).
Sorry to hijack your thread roadwarrior .

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[ChrisL]

I only want a B2B it cant be that much can it ?

From offgrid the Victron 50 amp DC/DC charger is £269 the 30 amp one is £182, labour is £60/hour I think, plus the cost of cables and ferrules etc. When they quote (without seeing your vehicle) they are likely to err on the expensive side so the customer doesn't get any unexpected surprises on the invoice.
When they supplied and fitted a Fogstar battery for me they also fitted a positive bus bar and a Bluetooth dongle for the shunt and still only charged me for one hours labour although it took longer.
They are very good at what they do and I think the labour charges are reasonable in comparison to some.

 

[Derbyshire wanderer]

I’ve read this thread and am as confused as ever but also worried.. I think I might need a B2B fitting to my little Leisuredrive but not sure - any advise appreciated!
My van came with a small Banner stop start battery as a leisure battery and I changed this for a 110 amp gel battery as I didn’t think the compressor fridge would last long off grid. Never thought about the implications for the split charger! My new battery has been in for 12 months now and all seems well with the solar panel keeping it well topped up. Given that my camper is my only vehicle and used nearly every day should I be worried?
Please keep any advice simple as I don’t understand all the technical stuff and don’t know if I have a smart alternator (2020 Renault traffic base vehicle).
Sorry to hijack your thread roadwarrior .

Although it is almost certainly fitted with a smart alternator, your fridge load will in most instances mean that it isn’t 100% charged and conflicting with the vehicle battery charging.
As you are a year in, the battery is clearly not being destroyed by the setup and use.
Fitting a B2B though (assuming it definitely hasn’t already got one you are unaware of) would be a real benefit for lack of solar input and ensure that the battery is charged with a correct profile when driving.

 

[Pausim]

calibre is trying to help me, and yes i agree, knowingly making motorhomes that eat batteries is very wrong, but then, selling a motorhome with 200kg payload is pretty low too and that will never change either.
i spoke to Roger i think and he said it would take 6-8 hours and cost more than 600 quid the line was bad and im not sure we understood each other, I only want a B2B it cant be that much can it ?

The cost is one possible reason why some manufacturers dodged fitting B2Bs for as long as they could. Another possible explanation is they never really understood battery technology, for years they happily fitted fixed voltage mains “chargers” in the 13V range despite the battery manufacturers telling them they were destroying the batteries and shouldn’t call them battery chargers because they didn’t charge them properly.

 

[roadwarrior]

Due to our government lemming drive for zero whatsit, all vehicles are fitted with smart alternator now. I would go and get your battery tested and prove its still fine. Interestingly you might not be far from.me and I have a battery tester, although to be honest halfords will test any battery for free so maybe go there. If it is indeed still in good shape then carry on. I know the charges from.my little solar and the EHU won't hurt them but I am sure the 3000 mile drive round france will.

 

[Pausim]

Due to our government lemming drive for zero whatsit, all vehicles are fitted with smart alternator now. I would go and get your battery tested and prove its still fine. Interestingly you might not be far from.me and I have a battery tester, although to be honest halfords will test any battery for free so maybe go there. If it is indeed still in good shape then carry on. I know the charges from.my little solar and the EHU won't hurt them but I am sure the 3000 mile drive round france will.

What type of battery tester do you have? The drop testers used by mechanics for engine battery testing are NOT suitable for use on leisure batteries and will probably damage them.

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