# Leisure Battery Voltage ......too high?



## wakk44 (Jun 15, 2006)

I have just had 2 new solar panels fitted each with a separate regulator.The leisure battery is a 270 A/H Elecsol sealed lead acid and the system is monitored by a BM1 battery monitor. 

When the leisure battery is fully charged and with no load applied the BM1 is reading 15 volts,this is confirmed with my multimeter.When I remove the solar panel fuses and just use the on board charger(EBL 99 set for lead acid)the BM1 is reading 13.9 volts with no load. 

Is this normal or could there be a problem with the 2 regulators charging at too high a voltage ?I know there will be an excess surface charge after charging and no load applied but 15 volts seems a bit high to me. Any comments from our mhf experts would be appreciated.


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## Techno100 (May 8, 2010)

Do your regulators have battery type settings? 15 is too high 14.3 or 14.4 is the most I'd expect on bulk charge only.

EDIT when fully charged my regulator holds mine at 13.4


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## Spiritofherald (May 18, 2012)

Around 13.5 volts is just right. 15V is too high and will damage the battery. The worst scenario is the battery could explode so disconnect your solar charger now!


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## aircool (Jul 13, 2009)

Regulator failing?


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## davesport (Nov 12, 2006)

Further investigation required. 15 V is too high. Lead acid batteries can be charged to higher voltages albeit at the expense of the electrolyte evaporating.

This is a potentially dangerous scenario as there will be an excess of hydrogen being produced into the battery locker.

I'd open & vent the battery compartment. Disconnect the solar regs & check the settings. Don't disconnect the solar regs whilst under load. Doing this may cause damage to the reg.

D.


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## helperman (Mar 1, 2013)

poor advice above.

The better regulators bulk charge at up to 14.8v in an ambient temperature of 25c and most have a temperature sensor to vary the voltage ambient temperature dependant. The figures are quoted in the technical data and its no suprise to do a quick calculation at todays 8c ambient and come up with a voltage around 15v. 

To suggest a regulator outputting 14.4v max can fully charge the batteries in winter conditions is preposterous and i d suggest a good google and a bit more professionality about what is posted.

(refer to your specific technical data on the regulator) and for those having fitted the talked about mppt from Taiwan, i d be checking to see if it had a temperature sensor to do a good full charging job or if it was just pretending to !


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## davesport (Nov 12, 2006)

> poor advice above.
> 
> The better regulators bulk charge at up to 14.8v in an ambient temperature of 25c and most have a temperature sensor to vary the voltage ambient temperature dependant. The figures are quoted in the technical data and its no suprise to do a quick calculation at todays 8c ambient and come up with a voltage around 15v.


There is no mention by the OP that either of his regs are compensated for temp. Valid comment but slightly harsh in delivery IMO.

D.


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## helperman (Mar 1, 2013)

You re probably right about the delivery but its frustrating to see this "old" technology being so little understood on a forum thats been discussing it for years and still giving bad advice.,


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## autostratus (May 9, 2005)

helperman said:


> You re probably right about the delivery but its frustrating to see this "old" technology being so little understood on a forum thats been discussing it for years and still giving bad advice.,


If the forum has been discussing it for years how come you've only just mentioned it and what's more only registered as a member today and yet have that knowledge.

Perhaps you've been here before.


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## DABurleigh (May 9, 2005)

If the batteries are fully charged then 15V at the terminals is too high for a floating voltage, irrespective of battery construction and temperature.

If the batteries are not fully charged and are wet, then 15V at a freezing temperature wouldn't bother me. I'd still be bothered if they were gel.

Dave


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## cabby (May 14, 2005)

Can I ask why you have a regulator on each panel.

cabby


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## helperman (Mar 1, 2013)

DABurleigh said:


> If the batteries are fully charged then 15V at the terminals is too high for a floating voltage, irrespective of battery construction and temperature.
> 
> Dave


With batteries fully charged, if he entered his motorhome putting the step down (20a momentary current surge) or using any power the regulator may have flipped out of float mode and will quickly make its way to max bulk voltage before dropping back slowly to float.


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## DABurleigh (May 9, 2005)

The OP stated no load applied.

Dave


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## Techno100 (May 8, 2010)

I suggest Steve looks at the spec of the regulators he's had fitted. If they're any good they will at least have that information in the instructions/manual. My MPPT is an excellent piece of kit and bulk charge for all four battery types is 14.3 only the float voltage is different for each type.

EDIT
The only time a battery might get 15 volts or more would be with a three stage charger that performs an equalisation charge at the end of a cycle. I've never encountered a solar regulator that performs this function.


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## wakk44 (Jun 15, 2006)

helperman said:


> poor advice above.
> 
> The better regulators bulk charge at up to 14.8v in an ambient temperature of 25c and most have a temperature sensor to vary the voltage ambient temperature dependant. The figures are quoted in the technical data and its no suprise to do a quick calculation at todays 8c ambient and come up with a voltage around 15v.
> 
> ...


What a slightly rude response,you sound very knowledgeable,I see you have joined today and this is your first post criticising established members who are trying to help.Not a good start.

Perhaps a post in introductions outlining your qualifications to comment on technical matters would be more appropriate,then members may take you seriously.


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## wakk44 (Jun 15, 2006)

Thanks for all the constructive responses,after reading the replies I have identified the problem and a couple of your suggestions were spot on.

One of the regulators was set for the incorrect battery type,after changing it the float voltage went down to 13.9 volts.So Techno was right........


Techno100 said:


> Do your regulators have battery type settings? 15 is too high 14.3 or 14.4 is the most I'd expect on bulk charge only.


The other regulator is for lead acid batteries only so doesn't have any adjustment for different types of battery.When I put this one into the circuit on it's own the battery monitor still read 15 volts,this one must be faulty so Ben was right..........



aircool said:


> Regulator failing?





cabby said:


> Can I ask why you have a regulator on each panel.
> 
> cabby


For wiring convenience and space considerations,however now I have found a regulator is faulty I am having a rethink and intend to put both solar panels through the good regulator.It is rated at 20 A,so they should handle my 170 watts of solar panels ok.

Thanks to all the helpers.............well most of them.


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## Techno100 (May 8, 2010)

Thanks Steve 
Despite a shadow being cast over the very good MPPT regulator from Taiwan , there are more than enough satisfied users to address the balance in spades. I would appreciate a link to a price and specification of anything proven to be anywhere near as good for this price. Don't pay for names like Steca etc just for the name they're Chinese anyway, not that that is a bad thing of course but it just means a bigger mark up in the UK.
I've opened up every regulator I've used and none compete


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## bigtwin (May 24, 2008)

wakk44 said:


> Perhaps a post in introductions outlining your qualifications to comment on technical matters would be more appropriate,then members may take you seriously.


All fora provide a platform for any individual to offer their opinion on whatever topic may be being discussed.

The main problem with this opportunity is that a variety of opinions can be proffered and the OP, by definition, is not qualified to filter the 'wheat from the chaff'.

While I agree that were respondents to outline their 'qualifications' this would help provide credibility to a post, this is not the norm!

While regulars here are able to recognise a handful of individuals who appear to have expertise in certain topics, others are not.



wakk44 said:


> What a slightly rude response,you sound very knowledgeable,I see you have joined today and this is your first post criticising established members who are trying to help.Not a good start.


Yes, helperman's delivery may have been abrupt but he too was trying to help the OP.

I dont see any criticism of established members, only someone offering an alternative opinion.

Hopefully he'll continue to offer his opinion.


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## wakk44 (Jun 15, 2006)

bigtwin said:


> Yes, helperman's delivery may have been abrupt but he too was trying to help the OP.
> I dont see any criticism of established members, only someone offering an alternative opinion.
> 
> Hopefully he'll continue to offer his opinion.


I'm afraid we will have to agree to differ bigtwin



helperman said:


> poor advice above...............................
> 
> ..............is preposterous and i d suggest a good google and a bit more professionality about what is posted.


I read that as rude,abrupt and unnecessary.For a new member who only joined today and therefore has no posting reputation to then criticise established members is not on and I take little notice of this type of post.

A shame really as helperman sounds a well informed new member who could make a contribution although a few lessons in forum etiquette would not go amiss.

As I have already said our established members pinpointed the 2 faults that I had and I appreciate that.I hope helperman subscribes after his 5 free posts,builds up a posting reputation and continues to offer advice,but I somehow doubt it.


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