# Battery question



## 96299 (Sep 15, 2005)

Hi all

Ok..I have two 90 amh batteries in my burstner but when fully charged I only get a reading of 104amh.Is that right?The way I see it is..2x90 amh batts = 180 amh,not 104.Please can some of you tech heads give me the run down on it all.  

steve

ps Someone else on the forum,EdsMH has the same m/h and exactly the same readings. :?


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## DABurleigh (May 9, 2005)

What instrument do you have that is reading ampere-hours? I was unaware of that being provided as standard in any van; they tend to be expensive. In any case, they are usually calibrated to the claimed capacity once the multi-stage charger goes to float mode.

It looks a new van; what does the manual say?

Dave


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## 96299 (Sep 15, 2005)

DABurleigh said:


> What instrument do you have that is reading ampere-hours? I was unaware of that being provided as standard in any van; they tend to be expensive. In any case, they are usually calibrated to the claimed capacity once the multi-stage charger goes to float mode.
> 
> It looks a new van; what does the manual say?
> 
> Dave


Dave the manual is out of date and is for the 2006 burstner argos model I beleive. :roll: Totally different control panel for this model but cant help anymore than that as I`m new to all things motorhomes.  It`s just the reading I get when batt says 100% charged and I press another button and it tells you amh,and thats 104 amh.Seems strange to me. :?

steve


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## sallytrafic (Jan 17, 2006)

Steve 

For a Ahr meter to work it needs to know what the full Ahr of the system is. 

This calibration can normally be carried out by the user but obviously with an up to date manual.

Be warned though that it then works on a voltage basis which is unreliable.

A true Ahr meter, which as Dave says are expensive, works by sampling the currents in and out of the battery every tenth of a second or so interpolating the results and accumulating the answer. Even these drift with time and also require calibrating.


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## davesport (Nov 12, 2006)

I've got a panel in me Hymer that "indicates" the batteries remaining capacity. It's joined at the hip to the Schaudt eletroblock. My two 90 ah/hr batteries provide a theoretical total of 180 ah/hrs & this is indicated on the panel. I fully suspect it's got nothing to do with remaining capacity & is more closely linked to the state of charge. 

The panel has to be programmed so it knows what the total capacity of the batteries is. It's got no way of sensing this. So if the panel has the wrong figures for the battery capacity you'll get an incorrect reading when your batteries are fully charged.

I suspect that you need to "tell" the display panel you have 180ah/hrs worth of batteries. There'll be an engineering menu hidden somewhere allowing you to change the settings. 

Dave.


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## 96299 (Sep 15, 2005)

Dave & Frank...Thanks very much for your views but might have to wait for the proper manual to understand fully the panel operation.I`ve just been playing around with it for now trying to suss things out on my own and I was just reciting the readings it was giving me.
It must be ok if someone with the same model m/h and setup is getting the same readings.  

steve


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## vicdicdoc (May 14, 2005)

davesport said:


> " . . I suspect that you need to "tell" the display panel you have 180ah/hrs worth of batteries. There'll be an engineering menu hidden somewhere allowing you to change the settings. . . Dave.


I'd be interested in knowing if & how to enter the 'engineering' mode too as I'm not sure mine reads 100% correct


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## 96299 (Sep 15, 2005)

davesport said:


> I've got a panel in me Hymer that "indicates" the batteries remaining capacity. It's joined at the hip to the Schaudt eletroblock. My two 90 ah/hr batteries provide a theoretical total of 180 ah/hrs & this is indicated on the panel. I fully suspect it's got nothing to do with remaining capacity & is more closely linked to the state of charge.
> 
> The panel has to be programmed so it knows what the total capacity of the batteries is. It's got no way of sensing this. So if the panel has the wrong figures for the battery capacity you'll get an incorrect reading when your batteries are fully charged.
> 
> ...


Ah.Dave that makes sense about programming the panel.The trouble is I dont have the manual for my model. :roll:


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## davesport (Nov 12, 2006)

For some reason on my 644 the panel forgets how big the batteries are if I trip the main breaker on the Elektroblok. I was new to MH'ing & had just purchased a new van from H UK so I gave them a call the first time this happened. The "technician" confirmed the existence of the engineering set-up on my panel but refused point blank to tell me how to access it :? He told me just to leave the van on hook-up & the 180 ah'hr figure would reapear, which it did.

It makes sense of Dave's remark about indicating the "claimed" capacity once the charger senses that the batteries are fully charged.

A quick e mail to Schaudt http://www.schaudt-gmbh.de./ might reveal something


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## RASSER (May 6, 2007)

*BATTERY PROBLEM-HYMER PANEL FAULT?*


Hi Davesport,
I have a similar problem with my 2006 Hymer B544.
The solar panel goes direct to the two 85Ah batteries via a 'controller/regulator' to stop it overcharging, but it isn't linked into the Hymer electrobloc or panel.
I checked the state of the batteries on the panel which read 140Ah which seemed incorrect as the solar panel was only trickle charging on a bright day so should be full.
I put it on hook up and the reading jumped to 170Ah? immediately.
A technician from HUk gave me the same story about leaving it on hook up for three days and the '?'dissapears.
He also stated that the false reading was because the solar panel wasn't linked through the Hymer 'bits'
I admit to not understanding electricity, but if the batteries have 170Ah in them shouldn't the Hymer panel see this?
On my panel I can set the max Ah by selecting the battery view and then pressing the menu button. Can't you?
Cheers
Bob


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## DABurleigh (May 9, 2005)

"I admit to not understanding electricity, but if the batteries have 170Ah in them shouldn't the Hymer panel see this?"

Not if the solar panel is wired independently of the battery metering as yours is, so it can hardly be blamed for being less than telepathic.

Dave


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## 91645 (May 1, 2005)

Hi Chigman:

Unfortunately AMh is not AMh ( or Ah) for each application. If you rundown a battery to 0 in 2 hours your AMh is lower than if you run it down in 20 hours. So the amp rate is important. Therefore sometimes a battery capacity is given using the rundown time as a parameter and sometimes two ratings are given for two different ratings in hours to zero rundown time. Maybe this explains the confusion as to the rating of a battery.


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## DABurleigh (May 9, 2005)

Probably explained as well as this, anyway 
http://en.wikipedia.org/wiki/Peukert's_law


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