# Dual Fuel - Battery life?



## timrhoffmann

Hello all!

After much mucking around with trying to get an electric Fracino Classic to run off inverter & batteries, we've licked our wounds and committing to a dual fuel for our mobile coffee cart.

Very excited at the prospect of it, but I'm just curious to know if anyone knows anything about the expected battery life when running a dual fuel? In particular, we'll be running a Flojet pump, grinder & the 2 group machine off of one battery and I wondered given 'regular' service of a van (circa 100/150 coffees/day) how long a battery could be expected to last?

Recharging the battery is going to be an issue given our remote location, so any input at all much appreciated!

Thanks,

Tim


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## froggystyle

You need to work out how much power each item will use, very easy to do, just check on all the items for the watts, should be printed on a label somewhere.

Use the conversion below.

Total watts / voltage

So if everything adds up to 1000 watts divide by 12 volts = 83 amps.

Batteries are rated as Amps per hour so a battery rated at 80 amps per hour will last one hour based on the above.

The watts will be max or peak so you may not use that many all the time, but best to work out at this and maybe knock a % off.


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## timrhoffmann

Hi there, thanks for that!

I did a quick calc before posting the query, because I came out with a similar number and I just don't think it's posible that a battery would drain down in an hour (even the most expensive batteries are still only 250Ah which would give 4 hours service maximum) which surely Fracino wouldn't bother doing, because that option is hardly viable unless you have a stock of 3 or 4 batteries?

I imagine unless the machine/flojet/grinder are all 'on' ie working at the same time, they can't operate at the suggested wattages, but i can't seem to find what the 'resting' wattage values are so it's difficult to find a sensible answer!


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## froggystyle

Maybe you can get a 250ah one and see how long it lasts.... then add more if needed.

You could also install a split charging relay, so when your engine is running you are putting amps back into the battery bank!


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## centaursailing

Not sure if this will help at all, but it may act as a stimulus to a workable alternative.

When we had a sailing yacht it was equipped with a couple of car batteries (each rated 80 amp/hour), one for domestic electricty and one for engine starting. Both were charged by the alternator when the engine was running, our difficulty came when we found a port we wanted to stay in for a few days and running the engine to charge the batteries would be a nuisance to people on nearby boats. As you might imagine we became very energy conscious! Crossing the busy shipping lanes between England and France at night meant using the radar which used a lot of power and being sailing sailors (as opposed to motor sailors) we really hated putting on the engine when there was sufficient wind to sail.

Finding a very helpful marine electrics expert, we purchased 2 (very heavy) AGM batteries (not cheap and each rated 120 amp/hours) and installed 2 flexible solar panels, one on the roof of the main cabin and one on the fore cabin hatch. The batteries were still charged whenever the engine ran, but now we had top-up power during daylight when sailing or in port. There was a switching system which allowed both solar panels to charge one battery, or the other, or both at the same time. The most usual set-up was both panel charging the domestics battery the engine being used to charge the engine starting battery.

Our setup would probably not be sufficient for your needs, but we could have added a wind generator and extra solar panels and I'm sure the technology must have moved on by now, i.e. electric cars.

Best wishes with finding a workable solution!

Rod


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## froggystyle

I have seen lots and lots of discussions on another forum about wind/solar.

To be honest, the power that will be drawn from the batteries will be to much for these to be a viable option, just a very expensive trickle charger system!

You need enough batteries to cover all the power, you can get a split relay for peanuts, but this of course uses fuel with the engine running, i am not sure how many amps per hour an engine will put back into the battery bank either.

Your gonna have to bite the bullet and put your hand in your pocket, as mentioned test one battery and see how long it lasts before you shell out for 3 or 4.


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## El carajillo

I think the previous contributors have covered most details pros and cons.

1. The batteries would need to be "deep cycle type" with the ability to be heavily drained and recharged.

2. You cannot just take the capacity an divide by wattage drain as the do not work on 100% availability/ also affected by temperature.

3.Depending on the "split charge system" It will depend on if it senses the charge in the vehicle battery, if it does then when that battery is charged it will cease to charge your auxiliary battery.

4.You would probably need to change the alternator for one with a much higher output. (more expense)

5.You may need some form of governor to adapt the engine speed for charging.

6.On warm/hot days your engine /cooling system would be working overtime.

Does all this sound like a good idea???


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## timrhoffmann

Thanks so much for the feedback guys.

I've spoken to Fracino directly and they suggest a deep cycle Lucas gel battery (apparently you get 2 or 3 days service out of it before requiring recharge). NOt cheap at £250/pop but certainly a long-term option. Thanks again for your input.

As an aside - any mobile caterers out there using dual fuel who are willing to show their power set up? In terms of battery / LPG etc? Curious to know it will all fit neatly and snugly inside the Ape and how they recharge their batteries (power pack taken out, mains connection etc).

Thanks!

Tim


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## froggystyle

The one most important thing you need to remember is,

Take care of your battery, discharging + charging will take its toll on it, read up and look after it as they will become useless very fast if not looked after!


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## El carajillo

timrhoffmann said:


> Thanks so much for the feedback guys.
> 
> I've spoken to Fracino directly and they suggest a deep cycle Lucas gel battery (apparently you get 2 or 3 days service out of it before requiring recharge). NOt cheap at £250/pop but certainly a long-term option. Thanks again for your input.
> 
> As an aside - any mobile caterers out there using dual fuel who are willing to show their power set up? In terms of battery / LPG etc? Curious to know it will all fit neatly and snugly inside the Ape and how they recharge their batteries (power pack taken out, mains connection etc).
> 
> Thanks!
> 
> Tim


I think you will find that the GEL batteries require a particular type of dedicated charger (NOT your average car battery charger)


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## No big name!

With the boom in home solar power, there's a ready supply of the odd solar PV panel on ebay - stick a couple of these on your van roof.

Also, have you considered a dual fuel lever machine? They use even less power, make tasty coffee and look cool ;-)


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## froggystyle

Would need a very big van to run from solar!!


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## DavecUK

timrhoffmann said:


> Hello all!
> 
> After much mucking around with trying to get an electric Fracino Classic to run off inverter & batteries, we've licked our wounds and committing to a dual fuel for our mobile coffee cart.
> 
> Very excited at the prospect of it, but I'm just curious to know if anyone knows anything about the expected battery life when running a dual fuel? In particular, we'll be running a Flojet pump, grinder & the 2 group machine off of one battery and I wondered given 'regular' service of a van (circa 100/150 coffees/day) how long a battery could be expected to last?
> 
> Recharging the battery is going to be an issue given our remote location, so any input at all much appreciated!
> 
> Thanks,
> 
> Tim


It's not quite as simple as it seems, lead acid chemistry is fairly slow and something called "Peukerts Law" comes into play, in how internal resistance and chemistry recovery affects capacity. I would hazard a guess it's why when trying to get an electric Fracino Classic was unsuccessful. I would be surprised if you even got 30% of the run time you thought you would, as the continual heavy drain severely limits the capacity of a LA cell. With the Dual fuel you are somewhat better off, as the load will be more intermittent allowing the battery chemistry to recover between uses. I have to make an assumption here (because you have not said), that you have taken the sensible option to use a Lever with flojet to refill the boiler?

I would recommend a standard deep cycle leisure battery, with a good effecient sine wave inverter (grinders will run sweeter). Size the capacity of the batter by estimating around 70% of the stated batter capacity (max). If you cycle the battery much lower than that, it's life will be severely reduced as will it's ability to support heavy discharge and the overall useable capacity. Even AGM and Gell cells will be adversely affected. So if the capacity of the batter is stated as 240 amp (which is likely to be optimistic anyway, because they will measure this at the C20 discharge level, or about 2.5 amps!). Assume a 200 amp capacity of which you can use around 140 Ah. In an emergency, you can discharge more if required, but by sizing to only use 70% of the capacity, battery life/performance will be maximised.


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## espressotechno

Would you be better to use a small petrol generator with 230v output ? Amazon have a range starting from £200......They seem to be quite compact these days.....


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## No big name!

froggystyle said:


> Would need a very big van to run from solar!!


Correct! What I should have made clear, was that I meant as a supplementary 'top-up' for the batteries.

I.E. the high power draw for a minute whilst the pump/grinder is running..... then 5 minutes of solar top-up inbetween....

A couple of 100 watt panels should greatly extend the charge in the batteries


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## thesmartcoffeeco

can anyone help on this thread? i'm in a similar boat - we have a WEGA group 2 machine that is dual fuel and i'm trying to calculate my power requirements.

Does anyone know what power the group 2 machines typically use? If it is using gas for the bigger jobs like steam/hot water etc then surely the elec requirement is a lot lower, but i'm unsure as to how much? can anyone help with a correct ratio to calculate?


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