Alternative to Solar Panels, extra set of batteries

[themountaintiger]

Ok, im going for it, this could be a stupid idea, but lets express it anyway to more experienced motorhomers...

I have 2 x 110amp batteries. When not on hook up, and on the third day of motorhoming my batteries tend to be 'dying'. I asked onece upon a time about adding a third battery, but was told that to put full charge back into all three may be difficult unless travelling a long distance....

Ive been looking into addition of solar panel, but other comments re "may not be worth it depending on how used".... and "in winter, perhaps when more power is needed, less light is available" for the solar panels etc etc...

Is it not a valid solution then, (subject to space) to simply add a couple more batteries in a seperate circuit, with which a flick of a switch, could be used instead of the 2 used up batteries??

This would then give me 5-6 days use if required. I appreciate that I would have to recharge both sets up again, but wouldnt this be a vaild alternative solution to solar panel??

Any thoughts appreciated.....









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[themountaintiger]

Do you understand the difference between on load battery voltage and off load battery voltage?
I often see 11.8 volts at bedtime after heavy use but that is on load. If I switch everything off it goes back beyond 12 volts

Well in so far as I know that when I run the tap, and the pump is on, it will give me a lower reading than pump being off. And yes Im also aware that if TV is on it might give me a reading of 12.2v and then I turn off and battery goes to 12.4v for instance. I suppose I am aware of the difference, and it tends to be the early morning reading I go for (taking into account temperature)...


My Control Panel says though it will alarm me/switch everything off if battery level gets to (and im guessing here exact v) 12.0v. Its never actually got to this level yet though (although it did when I had the one 85ah battery!!)








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[pappajohn]

12.32v is 70% of full charge with no load, so you should last a bit longer with what you have.
12.20v is 60% and should be considered as maximum usage before recharge.
12.06v is 50% and should be considered flat and in need of immediate recharge

 

[Techno]

Good that's fine
During the Summer I get up mid morning and the batteries are already up to strength. I put the TV on for the daily news over breakfast and the solars are feeding the satellite the tv and charging the batts all at once.

 

[jonandshell]

12.32v is 70% of full charge with no load, so you should last a bit longer with what you have.
12.20v is 60% and should be considered as maximum usage before recharge.
12.06v is 50% and should be considered flat and in need of immediate recharge

Very good advice here for 'leisure' batteries.

However, if you ditch the woefully inadequate 'leisure' batteries and replace them with proper industrial (traction) batteries, you can safely discharge by 80%. This equates to an open circuit voltage of 11.66V).
You will get much a much longer lifespan from them as well.

Traction batteries usually cost about twice that of leisure batteries.

You pays your money and takes your choice!

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[callumwa]

Excellent, informative and very interesting thread, thanks to all.....:thumb::thumb:

 

[themountaintiger]

Good that's fine
During the Summer I get up mid morning and the batteries are already up to strength. I put the TV on for the daily news over breakfast and the solars are feeding the satellite the tv and charging the batts all at once.

Now then Techno, thats just taking the p@ss, cos you know I have no solar panels. When I put the TV on for daily news over breakfast I have nothing feeding the batteries...in fact I dont even have the telly on for breakfast for that very reason!!!!!!!










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[themountaintiger]

Very good advice here for 'leisure' batteries.

However, if you ditch the woefully inadequate 'leisure' batteries and replace them with proper industrial (traction) batteries, you can safely discharge by 80%. This equates to an open circuit voltage of 11.66V).
You will get much a much longer lifespan from them as well.

Traction batteries usually cost about twice that of leisure batteries.

You pays your money and takes your choice!

I dont mind paying the money..to an extent!! On purchsing the 2 x 110ah batteries, I thought that this would suffice in comparrison to the one 85ah battery in the motorhome id just bought. Bear in mind I was a newbie and had no prior experience to go off. Ill look into the traction batteries, but first ill try and relax using the current batteries to 12.2v. Thanks for this info though.

Also glad other funsters are getting use out of my 'stupid post'.















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[Techno]

It's not expensive if you do a bit yourself. The kit is relatively cheap, the labour can be unreasonable.
I was out of work due to redundancy in construction and stuck out for 7 months hoping to go back with an "employer" I went self employed and started fitting solars at a GOOD price but since I have acquired work shopfitting for a good company fitting for WH Smiths and they keep me busy with 52 hrs Monday to Friday so I'm presently cushdy
2 80's with quality lcd regulator all inclusive was £700
I doubt any dealer would come anywhere near but consider buying your own kit and getting such as Rhino installs to fit for you?

 

[themountaintiger]

It's not expensive if you do a bit yourself. The kit is relatively cheap, the labour can be unreasonable.
I was out of work due to redundancy in construction and stuck out for 7 months hoping to go back with an "employer" I went self employed and started fitting solars at a GOOD price but since I have acquired work shopfitting for a good company fitting for WH Smiths and they keep me busy with 52 hrs Monday to Friday so I'm presently cushdy
2 80's with quality lcd regulator all inclusive was £700
I doubt any dealer would come anywhere near but consider buying your own kit and getting such as Rhino installs to fit for you?

Thanks, Im going to have a good think about this..and all your responses ill take into account... :thumb:





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[veevee]

It's not expensive if you do a bit yourself. The kit is relatively cheap, the labour can be unreasonable.
I was out of work due to redundancy in construction and stuck out for 7 months hoping to go back with an "employer" I went self employed and started fitting solars at a GOOD price but since I have acquired work shopfitting for a good company fitting for WH Smiths and they keep me busy with 52 hrs Monday to Friday so I'm presently cushdy
2 80's with quality lcd regulator all inclusive was £700
I doubt any dealer would come anywhere near but consider buying your own kit and getting such as Rhino installs to fit for you?

Hello Techno

Do you think there is a quality/output difference between different manufactureres of solar panels? and what would be 'a quality lcd regulator' ?

I'm asking you as I know you don't have an axe to grind, hope you don't mind.

Ta

 

[Techno]

No I don't believe there is a substantial difference between "BP solar" "Kyocera" and many other very much cheaper panels. I have bought some crap however so it's not plain sailing.
A decent 80 watt panel will produce 4.5 to 4.8 ish no matter who's name is on it.

I was fitting Juta cmp24 in my price. Under £50 delivered but occasionally as low as £35 its all about luck and profit margins.

I have bought from 2 German seller now and both good panels but one seriously let down by parcel force on 3 occasions

I've bought from tjns Newcastle and they were abysmal

AKT are good but a bit over price for me so I bid only, got lucky once.

These are excellent at today's price with 5 metres of mc4 and further reduced it seems were £148.70 when I bought for Mikkidee
Link Removed

This is one pre fitting

 

[haganap]

I fitted my own, if I can then anyone can.
Bit nervous with the drill in my hand but job done. :thumb:

 

[hilldweller]

A decent 80 watt panel will produce 4.5 to 4.8 ish no matter who's name is on it.

Let's try some sums on this, just for FUN.

5A 12V = 60W.

Guess ( hopefully ) 8 hours a day = 480Wh per day

What does 480Wh mean. Well a 110Ah battery has a usable ( 12.25 * 110 / 2 ) 637Wh. So if you make a battery last 2 days, then this 80W panel under excellent sunlight will keep you going indefinitely. BUT it all hinges on my total guess of 8 hours sun a day.

Marjal's extortionate ( Jim ! ) €0.35/kWh

So the solar, under best conditions, produces €0.17 of electricity a day ( 5p at UK domestic rates )

I think I've seen about £350 fitted so payback is 2333 days in Spain or 7000 days in the UK.

Does not stand up economically but does if you want to live without hook-up or without genny.

 

[Techno]

At winter prices you can comfortably fit a good 80 watt panel all inclusive for very close to £200 or less if you use a basic regulator DIY

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[hilldweller]

At winter prices you can comfortably fit a good 80 watt panel all inclusive for very close to £200 or less if you use a basic regulator DIY

Especially with the link you just posted.

But the majority of people reading this are past crawling on roofs and a blown fuse is a nightmare.

A common question is "If I buy a 2000W inverter it will run my microwave and the essential hair dryer". I get fed up of typing "Yes for 39 seconds".

 

[Techno]

yes that is one of the universal questions across all forums oh: