# Mixing batteries of different amp hours???



## 90112 (May 1, 2005)

Is it a bad idea to mix batteries of differing amp hours?
The reason I ask is that I have found a handy place to fit 3 110ah batteries (less than 305mm in length) as well as the usual hole for the battery, which is huge and would probably take a 220ah battery.
Also regardless of the size of the single battery it has got to be the width of the van (2+meters) away from the bank of three. Is there an a way of wiring this for optimum results, ie cable type and diameter and resistance.
Thanks Martin


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## johnsandywhite (May 9, 2005)

Hi . I am no expert but I would say if you were to seperate the banks of batteries with seperate charging relays. Everything should work out OK. Make sure the cable is as short as possible and of sufficeint gauge. Here is a 
>> LINK <<< to calculate Voltage drop. :wink:


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## 88966 (May 11, 2005)

Hi Martin,

In answer to your first question, the ideal is that a bank of batteries should be all of the same age, type and capacity. It would be better to add 2 x 110 AH (and possibly cheaper?).

To answer the second part, as best I can, try and envisage the heaviest current load the cable is likely to carry (possible charging?) and add a bit for luck and if the length is considerable add a bit more (resistance is a combination of length and cross-section area). There are tables that will give you the size to use.

Obviously the batteries must all be connected in parallel (+ to + and - to -). If possible it would be better if you could split some of the load off from the remote battery.

Don't forget that all these batteries have to be charged!!! 550 AH will take some charging if they get down and if they don't there is not much point in having them!.

I hope this gives you a start, if you aren't confident about what you are doing I would suggest talking to an electrician - quite large currents can be involved.

BillD


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## 88724 (May 9, 2005)

Hi 

If you must use the 2 different batteries keep them seperate, I would avoid the use of relay's as this will bring all the batteries togethor for charging and instead use a diode, but this inevitably causes a voltage drop and alternator charging is woefully inadequate to begin with, to make this up you would need to add a smart charging regulator.

Obviously the idea is that you want to carry extra AmpHours, if the 3 batteries are charged via split charge relay they will not get charged beyond 65-70% ergo a 100 battery would not get 70 AH from split charging, put three in a line and you have lost a potential 90 AH, so by the simple expedient of charging properly you gain 90 AH so getting rid of a split charger and replacing with a smart regulator and diode would giveyou more useable power than adding a 220 ah battery, but with a Diode in place you could add this 220Ah battery and use it as a switched reserve.
(used 100ah to make maths easier on 3 x 110 ah the increase in capacity would be 99 ah, or 114ah if the 65% max was nearer truth)


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## johnsandywhite (May 9, 2005)

Here is a link that will help to explain about batteries, installation, charging etc. Disregard the reference to 110 Volts. >>>>> HERE <<<<<


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## 88724 (May 9, 2005)

Hi 

That link is pretty damned good, but If I might add:

1. if connecting batteries in parralel take positve from battery one and negative from battery 2, this helps to ensure even charging and discharging.

2. The state of charge diagram is incorrect for UK, the top figure should be 12.8-12.9v each 10% lower is 0.1v

Many people have said that their battery is at 12.6 when fully charged (in UK) , but this is after being charged via alternator, and alternators dont get much more than around 70% of fully charged, add back the .3v for really fully charged and......

3. 50% is generally accepted as the lowest you should take your batteries if you want them to last.

4. the battery type and life part is pretty much totally wrong, Lead acid is the battery to choose unless you really have a serious need for the other technologies

All in all a very good primer, there are other minor errors there, but it will put most of the population way ahead of where they are now.


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## johnsandywhite (May 9, 2005)

8O I'm sure I am wrong again? But I forgot to mention this one >>> HERE <<<. :roll:

:roll: >>>>>>>>> HERE TOO <<<<<<<< and >>>> HERE <<<<<


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## 91929 (May 1, 2005)

No dont do it

You will kn....r. them all


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## 90112 (May 1, 2005)

*Thanks. UK Smart reg suppliers??*

Thanks all, some interesting links for me to study. If you had`nt already realised I am also known here as Bluenote, but my laptop went kaput and I`m on my old computer where it signs me in as the above. I`ll get all the same ah rated batteries.
I dont understand 'Split load from the remote battery'
Can anybody help me with a UK supplier of 'smart regulators'. The nearer Nottingham the better. 
We`re off on our first fultiming trip sometime next week (depends on when the laptop comes back from the manufacturers!!), and I have sorted so much out in preparation for it, but I know its going to be a bit like being chucked in at the deep end. Splaaadooosh!
Thanks again for your responses, Martin


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## 88724 (May 9, 2005)

Hi Martin

Sterling Power Products is the manufacturer and one supplier, another supplier same item advertises here in top bar Marcleleisure, both do the split charge diodes and the Smart alternator regulator.

Where did you see split load from remote battery? in itself I cannot make sense of it,maybe if I saw the context.


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## 88966 (May 11, 2005)

Hi George and Martin, 

I suspect it was my comment in an earlier post on this topic. It was suggested as Martin was thinking about putting his second battery set some distance from the first, by splitting the load (what you use the batteries to feed) what I meant was that it could help to reduce wiring voltage losses and help with the balance of battery charge/discharge. I didn't want to get too technical as I felt that if Martin needed to ask his first questions he was obviously not well versed in electrickery. 

I endorse George's comments about Sterling Power's products. I have been using their Battery to Battery charger for a while now and although it is a bit on the expensive side (c£250) it certainly does what it says on the tin. 

BillD


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## Don_Madge (May 1, 2005)

*Re: Thanks. UK Smart reg suppliers??*



MartinS said:


> Thanks all, some interesting links for me to study. If you had`nt already realised I am also known here as Bluenote, but my laptop went kaput and I`m on my old computer where it signs me in as the above. I`ll get all the same ah rated batteries.
> I dont understand 'Split load from the remote battery'
> Can anybody help me with a UK supplier of 'smart regulators'. The nearer Nottingham the better.
> We`re off on our first fultiming trip sometime next week (depends on when the laptop comes back from the manufacturers!!), and I have sorted so much out in preparation for it, but I know its going to be a bit like being chucked in at the deep end. Splaaadooosh!
> Thanks again for your responses, Martin


Martin,
Try A B Butt at Frog Island Leicester I've used them in the past and they do an excellent job http://www.abbutt.co.uk/

Don


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## 88724 (May 9, 2005)

Hi BillD

I didnt spot that in your answer from before.

Anyway the standard smart regulator is around £110 pounds depending on discounts at the time you buy.

The one that BillD as works the same but is easier to fit, the normal smart reg does require you to solder 2 wires into the alternator, which is all explained in the docs and Sterling will help via phone too if needed.


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## 88724 (May 9, 2005)

Hi Don

Do they do Alternator smart regulators? They only appear to do solar regulators on their website.


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## johnsandywhite (May 9, 2005)

GeorgeTelford said:


> Hi Don
> 
> Do they do Alternator smart regulators? They only appear to do solar regulators on their website.


So Solar regulators are no good?


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## 90112 (May 1, 2005)

*Thanks, UK smart reg supplier?*

Thanks all, useful info and links for me to study. In case you had`nt realised, I`m also known here as bluenote, but my laptop has gone kaput and my old computer signs me in as the above.
I will go with all the same ah rated batteries.
I dont understand the words :- split the load from the remote battery.
Can anyone let me know of a UK supplier for smart regulators, the nearer to Nottingham the better. I only seem to be able to come up with american firms on the net.
We leave for our first fultiming trip some time next week and despite sorting out so much stuff for it I know its gonna be like being chucked in at the deep-end. Still cant wait though.
Cheers for now, Martin


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## 88724 (May 9, 2005)

johnsandywhite said:


> So Solar regulators are no good?


Hi John

They are different, in this case no use for what Martin wants.

An alternator smart regulator turns an alternator into a 4 stage charger, it actually controls and sets the output from the alternator, a solar regulator takes the high (voltage) input from a panel and then regulates it, it does not and cannot set the panel to produce more power.

Hope this helps


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## johnsandywhite (May 9, 2005)

8O Well fancy that. It really is a shame because the one below only cost's £69.98 and seems pretty good for the money. It even does 3 different types of battery. It would certaionly do for me anyway. Then again. What do I know? :roll:


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## 90112 (May 1, 2005)

*OOoooooops!*

Oops, it looks like my old computer does`nt find recent posts, or is it just the state of my brain. . . . . .I`m a bit frazzled to be honest, trying to do everything at once and feeling a bit like a headless chicken. My hoarding ways have caught up with me, it had been an occupational hazard for many years when I was buying, selling and restoring antiques. I`m about 1/2 way through clearing my house out and I still reckon I`ve more stuff than an average family of four, and I`ve been living here alone for 5 years!! Very good storage boxes, houses! I`ll be glad to see the back of the bulk of my possessions and lighten my load in life. 
So please ignore my repeating myself. 
Thanks for the info regards the Sterling regs, I`ll invest there. I`m sure I`d come across them somewhere here before but had managed to lose track of it. 
BillD, did you fit your (easier to fit) version yourself, and was it easy? Your right I`m not much good when it comes to electrickery, but I`m capable and am going to have to get to grips with it if I want to have the level of independence I`d like. I have a Hymer 654 and its not easy to get at things such as alternators. 
George, you`ve been a great help as always, I was getting very confused as I was coming across a lot of solar regulators when searching for smart regs. 
Thanks for your efforts regards links John, this will hopefully get me a little further down the road of understanding. 
Cheers for now, Martin

Ps. Now I`ve gone and posted this as a new post, doh!


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## 88724 (May 9, 2005)

Hi John

For a solar panel excellent, but as I have explained its of no use as an alternator regulator, its does not have the facility to control and increase the power output of the alternator.

The Solar regulator you mention is available from Maplins for £10 less at £59.99 Regulator at Maplins

But even at this bargain price unfortantely no use for what Martin requires.


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## 90112 (May 1, 2005)

*Sterling choice?*

Hi George,
I`ve taken a look at Sterling`s site and I wonder if you can help me decide which of there products I need to go for.
They have the:- Sterling Advanced Alt Reg Digital 12volt £110.98
or
Sterling Advanced Alt Reg- Pro digital 12 or 24 volt £140.94
I could`nt find an easy fit version for £200+

Also I need a split charge diode and they have various ones of different amp ratings, and in either 2 or 3 outputs.

I`m not too bad with my hands and am contemplating having a go at fitting this myself, probably on the road at this rate, and wondered if there is any likelihood of damaging the vehicle, the unit or myself if things did`nt go well.
Thanks, Martin


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## 88724 (May 9, 2005)

Hi Martin

Their web presense is dire to be honest and I have heard they are slow answering emails.

I cannot remember the advantages of the Pro digital, but I didnt need them.

I would go for basic and fit it

here is Charlie Stewarts webpage showing how he fitted the smart reg

Diode sized over Alternator output and how many outputs do you need?


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## johnsandywhite (May 9, 2005)

8O It's a shame you didn't show us pictures of your installation *George*. . :wink:


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## 90112 (May 1, 2005)

Hi George.
Sorry if I seem really stupid, but is it the alternator spec that decides the diode amp rating required. Can the amp rating of the diode be greater with no ill affects.
Finally, if I`m using one bank of batteries for the domestic and one starting battery, does that equate to a 2 output diode?
Thanks for your help, Martin


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## 88724 (May 9, 2005)

Hi Martin

Yes you can use a much higher rated diode, its just its current handling capability.

Hi John

I am not going to get involved in your petty attempts to cause an argument. 

I did buy the version that I reccomended to Martin, however I have since purchased a 24v bus and as yet I have not decided whethor to get a pro version for or charge via the 24v Invertor.

I designed the set up for Charlies van, Batteries, invertor etc, somewehere I have the link where he was trying to find out what he needed and how the design unfolded.


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## bigfoot (May 16, 2005)

NICE ONE George! :lol:


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## 90112 (May 1, 2005)

Here, here! I`ve been there too :roll: 
Thanks George, I can get on with it from here I think, famous last words. We`re intending to have a couple of weeks just relaxing when we set off, so the plan is to use a site with hook-up for a spell initially where I can take time to fit the battery bank and the smart charger (if I can realistically get one sent through before we leave). 
I imagine these regulators are available (probably more so) on the continent, and this may be a consideration.
I`ll keep you posted whilst I do it at best, and fire few more questions about it at worst.
The last link you gave me was very interesting George, thanks.
Cheers for now, Martin :wink:


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## 88724 (May 9, 2005)

Hi 

Beware there are a few manufacturers, the sterling stuff seems to be far cheaper than the competition.

Are you going to be spending time on sites quite regularly? if so a decent sterling charger would be a good investment at around £50 these are ok as power supplies when on site and are good staged chargers too. 

If you can get to Worcs to the factory and are buying a few items a good cash discount can usually be obtained. I met Charles Sterling a few times fantastic bloke.


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## 90112 (May 1, 2005)

Hi George,
I`d like to become as independent of sites as I can be. We intend working our way around Europe playing our music, but I promised my partner a couple of weeks chilling out, she`s had a tough year at work followed by home dismantling. I`m pretty much ready for a spell relaxing myself too. We`ll stay on sites until I get the new 12volt system up and running.
As regards a charger, I think I have a good one already installed, you can see this here:-here. IUOU 2 stage charger.
I`m going to ring Sterling tomorrow, see if they can post the items I need straight away. Failing that we`ll make a detour when leaving next week and call in.
Thanks George, I`m confident about what to do regards a 12volt set-up.
Cheers, Martin


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