Is a B2B charger what we need? (1 Viewer)

[Gorse Hill]

After fitting a battery monitor I was surprised to find I was using 32a/h a day before my estimate was around 20a/h.

Any suggestions on a good battery monitor Lenny
TIA

 

[two]

I've had both Nasa and Vlctron (and others), and prefer the Victron. It is a smaller display, provides more detail, and can be accessed remotely if you're unable to put the display somewhere convenient.

 

[Lenny HB]

Any suggestions on a good battery monitor Lenny
TIA

I have the Victron BM700, found the display a bit small so ended up getting the Bluetooth dongle for it.
In the last van I fitted a cheap £20 eBay one it did the job but I do prefer the Victron dispite the vast extra cost.
With the Victron Bluetooth dongle you can bring up your history and see use since last full charge number of full charge cycles, fun if you are a techie.

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[gerry mcg]

I have the Victron BM700, found the display a bit small so ended up getting the Bluetooth dongle for it.
In the last van I fitted a cheap £20 eBay it did the job but I do prefer the Victron dispite the vast extra cost.
With the Victron Bluetooth dongle you can bring up your history and see use since last full charge number of full charge cycles, fun if you are a techie.

I'd second the Victron BMV-700 (with a BT dongle) https://www.victronenergy.com/battery-monitors/bmv-700
it is a super bit of kit.

 

[Infinity31]

Or the BMV-712 no need for a dongle plus less power consumption.

 

[68c]

With modern motorhomes often having little payload I wonder if B2B is a better bet than the weight of an extra battery. The B2B will fit in a much smaller space and weigh very little, of course it will be dearer than a second battery. Having lost my C licence due to Glaucoma I have had to down rate to 3500kg so am conscious of extra weight.

I suppose it depends on how many Ampere Hours you have stored. One battery charged at 14.4volts by the B2B or two batteries charged at 13.8volts directly from the alternater.

At the moment I just have a single 110Ah battery with a 40Watt portable solar, at least I can point that at the sun.

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[PhilandMena]

With modern motorhomes often having little payload I wonder if B2B is a better bet than the weight of an extra battery. The B2B will fit in a much smaller space and weigh very little, of course it will be dearer than a second battery. Having lost my C licence due to Glaucoma I have had to down rate to 3500kg so am conscious of extra weight.

I suppose it depends on how many Ampere Hours you have stored. One battery charged at 14.4volts by the B2B or two batteries charged at 13.8volts directly from the alternater.

At the moment I just have a single 110Ah battery with a 40Watt portable solar, at least I can point that at the sun.

I too have a 3.5 T motorhome. I laso have 250W of solar and 2 x 100 HA batteries. If I was in your position and had a lot of money I would put up a shed load of solar and a Gel battery. I would not worry about being a few kilos over weight. I suspect I and many others are over the limit.

 

[two]

I also need to be under 3.5t. I bought a van without solar (or many of the other 'essentials') but did get a battery monitor. I have found that I don't need solar or B2B but your needs will depend on usage and travel style (we move a lot).

 

[68c]

I do worry about weight, had to get a weighbridge report, van weighs 3000kg full fuel, no water, no bike rack, no awning, no possessions no driver. That leaves me with 500kg. Take my wife and I off (I am the heavy one at 14st), the bike rack and two electric bikes, 20 litres of water so the toilet will flush, the wind out awning- a surprising 27kg, does not leave a lot left over for chairs, clothes, food etc. Daft thing is we used to camp with a motorbike with no problem.

We do the odd weekend and a couple of ten day/two week touring holidays. We rarely stop more than two days, usually on basic CLs, otherwise it is a campsite with hook up. I thought the B2B would boost the battery better than direct charge from the alternator. Our last smaller van had 100W solar and two 110Ah batts, never ran out of power, also never gave a thought to weight at that time.

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[Don Quixote]

OGM - Quote "I do worry about weight" really!! that means NO insurance cover in the event of a accident your fault or not.....
Quote from Chelmsford Weekly News in 2017:

Police in Essex have been sending out an early warning to leisure vehicle drivers ahead of the Easter holidays (this was in 2017) to make the necessary weight and safety checks before starting their journeys during a recent caravan and trailer operation. According to the Chelmsford Weekly News, two drivers in overweight vehicles received £600 fines and 32 other drivers were stopped by police during the first vehicle towing operation of the season.

Working with the National Vehicle Crime Intelligence Service and Central Registration & Identification Scheme, officers ran the operation at Junction 19 of the A12 trunk road, Chelmsford, near Boreham Services Lorry Park.

During the day of action, 34 vehicles were stopped, 21 of which were towing trailers and 11 were towing caravans. Of the vehicles stopped towing caravans and trailers, only 12 were clear of any faults. Two overweight 3.5 tonnes vehicles were found to be 15 per cent over the maximum authorised mass when weighed and the drivers fined £600. A number of vehicles' tyres were also over the five year recommendation and a total of eight vehicles had breakaway cables that were incorrectly fitted, or none fitted at all. Some vehicles towing caravans had no extendable mirrors.

The driver of a trailer with a seized braking system was given a £100 fine and 3 points on his licence for driving a vehicle in a dangerous condition. Of the vehicles that were stopped, four drivers were issued with fines and three licence points after it was discovered they did not have the correct category BE licence.

Gary Winfield, Roads Policing Constable from the Casualty Reduction Team, said: "This was a successful day and we can be satisfied that in all these cases, appropriate and robust action has been taken. There are a number of measures that people can take to ensure they are driving safely while towing caravans and trailers. If these measures are not taken, there can be serious and quite frankly tragic ramifications for all involved. We will be carrying out more of these checks, so please heed the warning and ensure you are being responsible on the road."
Quote finished....

Overweight motorhomes safety understand the limits of the motorhomes capability is important making sure not to overload the motorhome is a legal requirement. Overloading has a detrimental effect on how the motorhome handles this affects the performance and the braking including stopping distances, therefore, safety with stability is important overloading may affect the insurance of the motorhome especially if it is outside the legal limits.


Yes I know we all do it, sometimes by mistake. Insurance companies will ALWAYS find a way not to pay out.

 

[two]

Somehow I don't buy the insurance argument. If your vehicle is built to carry 3850Kg and you are, say, 3750Kg, what additional risk have you introduced?

 

[68c]

Well if you do not have a C licence you are effectively driving without a licence. That would interest the insurance company.

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[RogerIvy]

@Ingwe knowing this thread started in Feb '18, did you ever consider a LifePo4 battery?
Much lighter and more usable capacity.

 

[Pausim]

Well if you do not have a C licence you are effectively driving without a licence. That would interest the insurance company.

Not sure that is strictly true. I believe the driving license relates to the registered maximum weight of the vehicle, not it’s weight in use. You can not drive a vehicle with a registered maximum weight of 3700kg without a C license, even if the actual weight in use is less than 3500kg, so why should the converse be different. I am not suggesting anyone should drive an overloaded 3500kg vehicle but I believe the offence would be overloading not driving without a license.

I emailed the DVLA about this very point and of course got a convoluted reply to a question I had not asked. However they did avoid stating that driving an overladen 3500kg vehicle would be a license offence as well as an overloading one.

 

[autorouter]

deleted

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[WESTY66]

I haven’t started upgrading my system yet, I had grand ideas but will have to scale back for various reasons, I presently have 100w solar with the crappiest cheapest pwm you’ve ever seen and TWO 110ah Gels. For now I’m thinking of upgrading the controller to a MPPT victron or votronic and getting a B2B. Opinions welcome. How long can I stay off grid with that, with average use and would the gels support a 2000w inverter in case I’d like a coffee?

 

[Lenny HB]

I haven’t started upgrading my system yet, I had grand ideas but will have to scale back for various reasons, I presently have 100w solar with the crappiest cheapest pwm you’ve ever seen and TWO 110ah Gels. For now I’m thinking of upgrading the controller to a MPPT victron or votronic and getting a B2B. Opinions welcome. How long can I stay off grid with that, with average use and would the gels support a 2000w inverter in case I’d like a coffee?

How long off grid is totally dependant on your power usage and time of year. At a guess with a decent MPPT regulator you would probably be OK from May until September with reasonable sunshine you could manage around 10 days but a few rainy days would halve that.
Outside of those months you are going to need a lot more solar even 600 watts won't be enough mid winter.

A 2000 watt inverter running at full chat will your batteries quite quickly, if you need that much power double your battery bank, also 200 watts of solar will never recharge then them with that sort of power use.
But if you are just going to use it for a few minutes a day for a coffee machine it will only have a minor impact on battery life.

 

[WESTY66]

How long off grid is totally dependant on your power usage and time of year. At a guess with a decent MPPT regulator you would probably be OK from May until September with reasonable sunshine you could manage around 10 days but a few rainy days would halve that.
Outside of those months you are going to need a lot more solar even 600 watts won't be enough mid winter.

A 2000 watt inverter running at full chat will your batteries quite quickly, if you need that much power double your battery bank, also 200 watts of solar will never recharge then them with that sort of power use.
But if you are just going to use it for a few minutes a day for a coffee machine it will only have a minor impact on battery life.

Hi Lenny, the 2000w is a guesstimate, the machine is 1400w so I’m probably overthinking it, and like all things coffee related it’s a luxury not a necessity! I never worried about all this with my elddis with 100w solar a cheap pwm and two 110 wet batteries, maybe because the set up was all new? I just cracked on and never hooked up unless I had to, then again I didn’t have a coffee machine or inverter! I guess I just don’t understand how much better my gels are than wets. Perhaps I’m just overthinking the whole thing.

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[Pausim]

I haven’t started upgrading my system yet, I had grand ideas but will have to scale back for various reasons, I presently have 100w solar with the crappiest cheapest pwm you’ve ever seen and TWO 110ah Gels. For now I’m thinking of upgrading the controller to a MPPT victron or votronic and getting a B2B. Opinions welcome. How long can I stay off grid with that, with average use and would the gels support a 2000w inverter in case I’d like a coffee?

I have a Votronic MPP 350 with remote control/display that I am no longer using. I could be persuaded to part with it. PM me if you are interested.

 

[WESTY66]

I have a Votronic MPP 350 with remote control/display that I am no longer using. I could be persuaded to part with it. PM me if you are interested.

Wow where do all those wires go? Shouldn’t there be a plug of some sorts on the display cable. I guess the votronic has the starter trickle charge option but is more tricky to install, where as the victron is simple but no starter facility, is this correct?

 

[Pausim]

Wow where do all those wires go? Shouldn’t there be a plug of some sorts on the display cable. I guess the votronic has the starter trickle charge option but is more tricky to install, where as the victron is simple but no starter facility, is this correct?

It is easier than it looks. There is a plug on the display cable but it is clear plastic and didn’t show up in the original picture. The chunky cable is a plug in connection for a schaudt EBL. The other one is a temperature sensor for the battery. I think the temperature sensor and second battery connections are optional.

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[Lenny HB]

I guess the votronic has the starter trickle charge option but is more tricky to install,

No it's easy you just need a single wire to the starter battery positive.

 

[WESTY66]

I have a Votronic MPP 350 with remote control/display that I am no longer using. I could be persuaded to part with it. PM me if you are interested.

Well that’s the controller sorted

 

[RogerIvy]

Have you considered changing from lead acid to LifePO4?
You’d still need to charge them but you can charge much quicker on Li

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[autorouter]

the 2000w is a guesstimate, the machine is 1400w so I’m probably overthinking it, and like all things coffee related it’s a luxury not a necessity! I never worried about all this with my elddis with 100w solar a cheap pwm and two 110 wet batteries, maybe because the set up was all new? I just cracked on and never hooked up unless I had to, then again I didn’t have a coffee machine or inverter! I guess I just don’t understand how much better my gels are than wets. Perhaps I’m just overthinking the whole thing

Sadly the main downside of gels is they are not so good at very high amps. It's best to stick to the limit of C/5, where C is the battery Ah capacity - so for you it's 220/5 = 44 amps. If you consider that 1200W requires 100 amps, you can see the problem. This is about the only situation where re-badged starter batteries are better than proper leisure batteries.

 

[WESTY66]

Sadly the main downside of gels is they are not so good at very high amps. It's best to stick to the limit of C/5, where C is the battery Ah capacity - so for you it's 220/5 = 44 amps. If you consider that 1200W requires 100 amps, you can see the problem. This is about the only situation where re-badged starter batteries are better than proper leisure batteries.

Thanks for that, and here’s me all smug cos I thought gels were the bees knees (apart from Lithium of course) autorouter I’ve read read quite a few of your posts as well as Lenny HB and Raul on various things electrical and I’m blown away with your knowledge. Unfortunately when I’m reading these posts all I see is

Anyhow my votronic and display from Pausim has arrived and I will trawl the internet for a Janet and John diagram and get it wired in But thanks for the calculation and I’ll put the coffee machine back in the house

 

[leggings]

First step is to boost your storage capacity by adding another one or two batteries, no pont in having better chagre rates if you have nothing to store the power in. First choice then would be more solar and fit a decent MPPT solar regulator.
You could significantly improve your engine charging by fitting the correct size cables, British built vans are notorious for fitting well undersized cables. Replace the cables to the split charge relay and battery with at least 16mm sq cables and you should a big improvement.
If you go down the B2B route have a look at the Votronic unit a bit dearer than the Sterling but a much better bit of kit.

My set up is 3 x 80a/h gel batteries, 300 watts of solar with a MPPT regulator and a Sterling B2B. I only fitted the B2B as I picked up an almost new one on eBay for £130 if I was buying one at full price I would have bought the Votronic one, the Sterling is a pig to set up.
Standard charge from the split charge in the Hymer is an intial 22 amps dropping to 10 amps as the batteries resistance rises, the B2B gives an initial 40-49 amps dropping to 20-35 amps depending on state of the battery.

Reckon that’s top advice.

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[pappajohn]

Well if you do not have a C licence you are effectively driving without a licence. That would interest the insurance company.

That should be a C1 licence....up to 7500kg.
A C licence is for vehicles over 7500kg gross weight.

 

[wfdTamar]

Another battery alternative I looked at is a ‘poor mans lithium’ - Leoch lead carbon.

12v 100AH Leoch Pure AGM Lead Carbon PLH+ C100 Deep Cycle Leisure Battery NCC Class A - Alpha Batteries

12V 100Ah Ultra Deep Cycle battery for multiple applications – from Leoch’s Pure Lead Carbon series. Features • Pure Lead […]

www.alpha-batteries.co.uk

 

[Jev88]

Another battery alternative I looked at is a ‘poor mans lithium’ - Leoch lead carbon.

12v 100AH Leoch Pure AGM Lead Carbon PLH+ C100 Deep Cycle Leisure Battery NCC Class A - Alpha Batteries

12V 100Ah Ultra Deep Cycle battery for multiple applications – from Leoch’s Pure Lead Carbon series. Features • Pure Lead […]

www.alpha-batteries.co.uk

Did you buy any of these Lead Carbon batteries? New technology to me too....

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