Help Please - generators

Hi Scottmo,

My advice would be to seek more advice before going down the Genny route. Not that I'm saying it's wrong but by the sound of things you need to look at the whole picture first and that will help guide you down the right path.

First of all while a 85 AH battery is ok if you plan on doing lots of wild camping then it would be more cost effective to add in an extra battery.

On the same vein look at your lighting - in winter halogen lights can really drain a battery very quickly.

I guess a lot will depend on how deep your pockets are but here is a summary of my experiences:



Experience 1

Understanding Power. This is probably one of the most important lessons there is. Most Manufacturers fit lots of lights and most use the 10 or 15W halogen bulbs. Without a doubt the cheapest way to improve your off grid use of existing battery power is to change all your bulbs for LED’s. They are becoming cheaper and there are more and more LED’s to fit the wide variety of fittings. Replacing a 10W halogen for a LED will reduce your consumption to less than 1W. Where you have invested in inverters then using low wattage kettles, toasters and hair dryers etc. will greatly reduce your power consumption. I replaced all our halogen bulbs and that alone increased our wild camping time without having to recharge from 3 days to over 8 days.

Experience 2

Extra Batteries – a no brainer. One of the cheapest and easiest ways of increasing self sufficiency is to add one or more batteries to your leisure circuit. Many vehicle alternators will only charge up to 75% of a battery’s capacity, however the biggest problem is that it takes much longer to replenish and even driving a couple of hours may not recharge them fully. Adding sophisticated chargers is one way to improve matters but it still takes more time than you realise to fully charge batteries. We fitted 3 x 180AH batteries and a Sterling 80amp Pro Digital 4 stage charger to our system on the assumption that the original 18amp charger wouldn’t cope. The logic was that whacking in 110amps would cut the charging time down, typically to less than an hour. Not so. When we first connect up it pumps in over 100amps but as the batteries recharge the chargers start cutting back so it takes a good hour to get the last 20 to 30 amps into the batteries. This means our goal of only using the generator for an hour or so falls down.

Experience 3

Solar Panels – absolutely great in summer – provided you don’t park under trees or its raining heavily and cloudy. (cloudy days will still produce power – just no were near as much) I did a fair amount of research before fitting Solar Panels, both on size and fixed or rotating. At that time I came to the conclusion that in summer, large fixed panels were more beneficial that small rotating and I still stand by that. However in winter, fixed solar panels are really very poor if you need them to supply even minimal power. The problem is that in winter the daylight hours are minimised yet the power demand is highest with lighting, heating etc. making higher demands on the batteries. In winter rotating panels are far better than fixed panels OF THE SAME SIZE. You would need at least 2 or even 3 rotating panels to maintain batteries in winter. Most of us don’t have the roof space to fit these, even if we did have the money. A word of caution all the current range of rotating panels by Alden or Ten Haaft will not co-exist easily with existing fixed panels as their regulators are built in. EDIT: Further information from Kyocera is that you should never mix different sized solar panels as this will lower the overal efficiency. There are a number of solar panel installers that will tell you that you can mix panels however the Manufacturers say don't

Experience 4

Generators – Petrol. Built in or portable, you either love em or hate em, however they do fulfil a need. It’s all about convenience and cost really. On the downside you have to carry fuel and they are noisy (even the so called quiet ones ) They are certainly frowned upon by neighbours and many campsites now ban their use. The unwritten code says that using generators before 10am or after 9pm is anti social. Built in and portable generators provide 240 volt power and that is used to power your on board chargers. As a by product you also have spare capacity to use any 240 volt appliances, however having 240 volt appliances that can only be used when the generator is running is false economy so an inverter would be better if you intend to use 240 volt appliances on a regular basis.

Generators – Gas. Pretty much the same as petrol and some of the data sheets state that using gas is more noisy than petrol. Some of the newer generation such as the Self Energy EG20 only produce 12 volt power for charging batteries so cannot be used for 240 volt appliances. The same criteria applies though and it can take hours to recharge batteries.

Generators – Fuel Cell. Efoy or SFC produce several models that will put between 50amps and 130 amps over a 24 hour period into your batteries by burning methanol. This form of battery recharging is becoming more and more acceptable to manufacturers of motorhomes with many now offering Efoy on their option lists. Its virtually silent and trickle charges your batteries however you have to carry stocks of methanol and methanol as yet isn’t cheap. EDIT: Efoy say that you should NEVER fit an Efoy system where the total battery capacity exceeeds 250AH


Experience 5 – Planning for expansion. Many of us use various forms of calculations to assess our power requirements and adopt our systems to match. Not many months later we find that things have changed, a new hair curler, a laptop or DVD player all make additional demands on our limited reserves. I have learnt the hard way and now include a 50% margin on power requirements.

Just a few things to get the brain thinking

Hope it helps

Pete

Thanks Vennwood,

I have looked at Efoy. quite like them but quite expensive, though not prohibitive. The genny would ONLY be used off site so shouldn't be a noise problem for others! I do want to add another battery but don't know how or which one :?
LED's will be fitted as soon as I can.
We don't use hair dryers, kettles or toaster - using gas kettle as it is only me that drinks tea etc, and grill for toast as wife prefers this.
We don't need to wild camp for quite as long as you, 3 days, maybe 4 max would be fine at a time.
Don't fancy solar. They are too expensive for very little power and 'seasonal' so to speak.
An inverter is something I was looking at BUT, don't know what to get, as I said.
If you can advise on the inverter and/or the battery issue I would be grateful.

PlanetGen

thanks, will look at the genny you suggest!

Scott

Thanks,

was looking at these - Numax CXV27MF 12v 105Ah Sealed Battery.
and upgrading to two, though the battery I have is new, it came with the van, an 09 plate. So maybe I should just get another, though 2 105Ah would be more appealing.
Also was looking at - Sterling 1000W Modified Sine-Wave Inverter

Would this set up, with a honda (or Planet equivalent) Eu10i generator, be sufficient for my requirements? Or, even the EU20i if necessary? The cost is not a real issue, as long as it does what I want. I realise Generators can annoy others but I have no intention of using it near anyone else, if we were ever near anyone we would be on a site and an EHU.

Thanks for your prompt and helpful advice!

Scott

PS any advice on how to fit the two batteries togehter?

Well its a simple mathmatical sum really, well not quite as when you get into "float mode" the charge rate drops so it will take much longer to get the last few amps in than the first few if you see what I mean.

So if you have 170AH batteries (2 x 85) then the most you will reasonably get out of them is around 100 as you shouldn't drop below 50% (there are folks on here that can give you all the technical stuff) So 100AH for this excercise it would take approx 6 hrs to recharge using 18AH charger. If you added a Sterling 50A charger that time would drop to around 2 hours. If you were using a generator then you can see the saving in time (and fuel) if you were in a carpark or on site etc. If you had a 85W Solar panel then during a reasonable day in summer (Jun/July) then you might expect that panel to recharge the batteries by 30/40 amps - just less than half.

The 1000W genny would work fine its just that you wouldn't have much left over if you needed to use extra power. Remember as soon as you switch to EHU (inc genny) the fridge switches ovwer to 240v unless you manually switch to gas

hope this helps

Pete