# Battery state



## richard863 (May 1, 2005)

I read on the blurb from RW Motortech Advanced Battery Analyser the under neath para 6. 

6. Effects of Over Charging:
OVER CHARGING is the most destructive
element in battery service. During over
charging, excessive current causes the oxides
on the plates of the battery to "shed" and
precipitate to the bottom of the cell and also
heat the battery, thus removing water from the
electrolyte.
Once removed, this material (which represents
capacity) is no longer active in the battery. In
addition, the loss of water from the electrolyte

Ok so some of us do spend quite a lot of time on a site with a mains hookup. This can destroy your leisure batteries. How or what can one do to help counteract this? Is it just a case of switching off the charger if indeed it has a on/off switch, or disconnect the mains cable? Remember on a lot of continental sites you may have your socket pinched.

Sorry if this has been coughed up before, I couldn't find the post.


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## DABurleigh (May 9, 2005)

Ensure you have a multi-stage charger where the terminal float voltage is 13.5-13.8V. Then forget about it (apart from routine checks X times a year).

Dave


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## richard863 (May 1, 2005)

Hi Dave thank you for your prompt reply. My bus has a made in Italy electronic battery charger model A2018 it seems a very professional and robust bit of equipment looking at all the fuses and variable switching for setting Gel/Lead acid etc, it seems to be able to do most things except peel potatoes. How can you ensure this is working correctly, as I have had 2 sets of Exide Gel go duff on me in 3 years, although they have been replaced under warranty. I am wondering am I just unlucky.
Kind regards


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## DABurleigh (May 9, 2005)

You may be unlucky, you may not, largely depending on the why and how specifics behind your "gone duff" comment, and whether or not you followed the advice in your charger manual.

It's here, by the way:
http://www.cbe.it/english/component...ategory_id,23/option,com_virtuemart/Itemid,87

Dave


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## richard863 (May 1, 2005)

Good morning Dave
Thank you. Yes that link is to my charger. My reasons for the duff statement is based on. First, at Newbury last year it poured down with rain and on the first night we ended up with candle power for lighting. The Hymer guys came the next day with a battery analyser one leisure was zero charge and zero efficiency the other 100 percent charge and ten percent efficiency. They said that was a common fault with gels and changed them both. After a 8 hours run from a external generator charge we had light. 
A year later after a few trips to the EU and around the UK we ended up with the same senario. I then replaced the 2 leisure batteries with 2 x US31TMX see http://www.batterymegastore.co.uk/cgi-bin/megastore/commerce.cgi?product=Batteries_Caravan!Ultra_Deep_Cycle

The offending gels yet again on a different analyser showed a similar set of figures which once again Hymer replaced with new cells these had the the plastic anti tamper covers on. I have still got these unfitted and new, only had a charge.
While at the P'boro show last weekend the big cells went down to 12.1 volts and having run the 2Kw Honda for some 4 hours the display panel in the cabin only showed 12.5 volts. The initial charge was very high and made the Honda splutter before it settled down. When I started the van to come home the charge initially was some 40 odd Amps, hence the reason for my query.
With kind regards


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## DABurleigh (May 9, 2005)

How did you get 40 Amps out of an 18 Amp charger? And how can a 2kW genny be on its limit of output in so doing? There are all sort of things in your post I simply do not understand, sorry.

However, you could do worse than follow the advise given to everyone on MHF in similar circumstances. Charge the batteries on a good mains charger (yours is fine). Let them rest for 6 to 8 hours. Measure the terminal voltage with a multimeter. Report back.

(And if you have a solar panel, ensure it isn't charging in sunlight while the batteries are resting)

Dave


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## richard863 (May 1, 2005)

Hi Dave
The initial 40Amp was registered on the over the door control panel when the engine was running just after startup. On the Hymer/N&B panel when the engine is running there is a silhouette of 2 batteries and a star between them indicating so the manual says van & engine batteries plus alternator charging, if you then push the battery state button it also gives Amps in or out, I know this is only a guideline and most probably not accurate.
With regards to the Honda 2Kw after I started it it was running fine until I plugged in the mains lead then it coughed and spluttered under the initial load, so I took it as working under strain.
I am sorry this is a classic example of I known what I meant to say but didn't put it into words.
Thank you for the advice. Do I put a blanket or something over the solar panel to stop the charge?
With kind regards


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## camper69 (Aug 30, 2007)

richard863 said:


> Do I put a blanket or something over the solar panel to stop the charge?
> With kind regards


If it is like mine you could just pull the inline fuse out.

Derek


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## richard863 (May 1, 2005)

Good morning Derek

Thank you, all I have to do is now find it. I'll wait until the rain stops, just hope it isn't on the roof in the terminal box. Sods law says it will be  
Kind regards


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## richard863 (May 1, 2005)

Hi All
Found the fuse for the solar panel it is within the Solar Gain regulator in the electrical bay. Should have applied RTFM. :lol: :lol:


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## DABurleigh (May 9, 2005)

I should have read your post more carefully. As we were talking about chargers and gennies I missed the bit about starting the van.

I would guess when you fired the genny you had other big loads on it, rather than just a snall to moderate mains battery charger.

Dave


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## richard863 (May 1, 2005)

Hi Dave nd Derek
Traced my battery fault. One of the new batteries has a damaged cell and wont accept a full charge.
Contacted Battery Megastore yesterday afternoon, a new unit is being dispatched at 16:00 hrs and will be with me today.
Talk about rapid service. Great in this day and age. Well done Battery Megastore.
8) 8)


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## richard863 (May 1, 2005)

Good morning Dave

These are the figures you asked for after the battery change and a full charge.
I then let the solar panel work for one day then disconnected the panel also separated the 2 batteries also switched off all systems, left the batteries over night in this state. Today one battery measured 13.13V the other 13.12V. After connecting them back up and switching on the system prior to connecting the solar panel the combined measurement was 14.1V on the Hymer panel I take it this is due to panel error. Please comment.
With kind regards


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## DABurleigh (May 9, 2005)

Your batteries are fine; enjoy. Take care of them appropriately (depends whether sealed or not). Ensure charger is set to your battery type, don't deplete them regularly below ~50%, check levels and specific gravity using a hydrometer occasionally if wet.

14.1V - depends whether your mains charger was active at the time. Fine if so, if not (and you are sure) then panel error I guess, but a biggie.

Dave


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## richard863 (May 1, 2005)

Thank you Dave for the comment. I am sorry I gave you some duff gen the Hymer panel reads 13.4V. I will accept that error. ( mental pause?)
Now I think I have another possible electrical problem.
In conjunction with my 270Ah batteries I have a 3Kw Pure SW inverter switched on and in a quiescent state it draws .1mA. I use the A/C for small time charging. Occasionally I put a mains 750W rated electric kettle on, the actual amperage is 3.34A so its wattage is not far out. 
1) Switching the kettle on how long would you expect it to take for the panel voltage to drop from 13.4V to 12.5V with no battery charging taking place? 

2) I realise that in theory this would be about a 64A drawing rate, also most batteries should hold a discharge better at 12.5V, so is this a fair test or should I let the power draw on for longer?

3) What sort of hydrometer readings would you expect at 13.4, 12.5 & 12V?

With kind regards


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## DABurleigh (May 9, 2005)

"I have a 3Kw Pure SW inverter switched on and in a quiescent state it draws .1mA"
That's amazingly low......

"I use the A/C for small time charging"
3kW is some small time charging........

"1) Switching the kettle on how long would you expect it to take for the panel voltage to drop from 13.4V to 12.5V with no battery charging taking place?"
That depends on how/ where you are measuring the voltage. Really AT the battery terminals or in some distant meter with no remote sensing. But I wouldn't be too concerned. 

"2) I realise that in theory this would be about a 64A drawing rate, also most batteries should hold a discharge better at 12.5V, so is this a fair test or should I let the power draw on for longer? "
A fair test of what? What's the problem or are you inventing one? 

3) What sort of hydrometer readings would you expect at 13.4, 12.5 & 12V? 
There's a coloured table on MHF somewhere that shows this but I'm rather maxxed out and frazzled so will leave you to use MHF search. I've only ever used a hydrometer myself after a thorough charge and rest to check whether the battery is still good or on its way out. Granted I have a battery monitor. I'd be a little unsure of measuring % remaining capacity either by terminal voltage or specific gravity due to the temperature dependency.

Dave


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## richard863 (May 1, 2005)

Hi Dave 
Many thanks for your assistance, the way you put it, it appears I don't have a problem, or nothing that heavier duty batteries wouldn't solve. I will let it rest there.
Thanks again.


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