solar panel output query

[Neil S]

I have a 120 watt PV Logik solar panel on the roof of my motorhome and on checking the incoming voltage before the regulator its reading 18.93 volts and the output is 13.1 volts and never go's any higher even in very bright overhead sunlight .
I have 2 x 110amp Banner leisure batterys which were new 14 months ago and i have had to top them up several times with distilled water .
we were on a MCC rally over the weekend with no EHU and had the Satellite and Avtex TV on for 4/5 hours on Friday Night and minimal lighting , went to bed and the battery's were down to 12.2 volts next morning they had recovered a bit up to 12.6 volts and after switching on the Alde heating for warm water and the TV on for an hour watching the morning news the low battery alarm went of even though the sun was beaming down although not directly overhead .
I'm wondering if the battery's are knackered or perhaps I've topped them up to often or am I expecting to much .
Would it be worth investing in another solar panel .

 

[DBK]

Sounds like bad batteries. Do you know how old they are? They have a finite life based on charge and discharge cycles.
Do you know the model of the solar charger? Although if it is holding the panel at around 18 volts it sounds like it is doing what it should.

 

[Neil S]

Thanks for replying , the battery’s are about 18 months old and the solar controller is just the supplied 10amp with the PV Logic 120 watt solar panel kit supplied by
Solar Technologies International
Tewkesbury

 

[Neil S]

Forgot to add I have 2x110amp battery’s wired up this way
(Battery’s changed to Banners since this photo but still wired the same

 

[pappajohn]

Looking at the bottom pic I don't see any solar wires connected to the batteries, only the linking wires.... Are they connected elsewhere.?

13.1v isn't high enough to boil the battery fluid so I suspect your mains charger rather than solar.

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[Neil S]

Looking at the bottom pic I don't see any solar wires connected to the batteries, only the linking wires.... Are they connected elsewhere.?

13.1v isn't high enough to boil the battery fluid so I suspect your mains charger rather than solar.

good question ? I'll have to check but they must be connected somewhere because the panel is charging
I checked the voltage at the output on the charge regulator and at the batterys and they were the same

 

[funflair]

If your battery voltage is 12.2 when you go to bed that is a pretty reliable figure as the batteries have had a rest from any solar charging and also pretty low really, if you are seeing 12.6v in the morning that is not the state of charge as much as a voltage between the actual battery voltage and the output from the solar regulator, 120watts is going to take a long time to bring two batteries back up from 12.2v.

Martin

 

[Neil S]

just been and traced the wiring back and the output from the panel is spliced into the feed between the charger and batterys with a fuse in line

 

[Lenny HB]

Well either your solar regulator has had it or the batteries have had it.
18 months is a pretty long life for Banners
I would be inclined to replace the regulator with a decent one like Votronic or Victron, get some decent batteries also the solar wiring looks well undersize so replace that why you are at it.

 

[Neil S]

Well either your solar regulator has had it or the batteries have had it.
18 months is a pretty long life for Banners
I would be inclined to replace the regulator with a decent one like Votronic or Victron, get some decent batteries also the solar wiring looks well undersize so replace that why you are at it.

ok can recommend me a reasonably priced pair of leisure battery's for about £220 max

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[DBK]

ok can recommend me a reasonably priced pair of leisure battery's for about £220 max

I'm sure you will get lots of views on this but I've been very happy with Varta LDF 90s. The first set lasted five years of fairly heavy use including an inverter for their last year.

But your Banners should have lasted a bit longer. Do you remember ever running them down flat, say sub 10 volts?

 

[Wissel]

Was just going to recommend these:
https://www.tayna.co.uk/leisure-batteries/varta/lfd90/

But I see @DBK has beaten me to it

Great rep for the price.

 

[Spanner]

ok can recommend me a reasonably priced pair of leisure battery's for about £220 max

I recently bought a pair of 115ah Yuasa batteries for about £180 inc vat
Guaranteed 4years, bought from TPS (Trade Parts Supply) they have branches all over the country

 

[Lenny HB]

ok can recommend me a reasonably priced pair of leisure battery's for about £220 max

That price will only get you flooded cells as others have said Varta Ldf 90 have a good rep you will get a pair for under £200, they also do 120 & 140 a/h.

The Banners in my last van only lasted 18 months and Banner don't honour their warranties.

 

[Neil S]

I'm sure you will get lots of views on this but I've been very happy with Varta LDF 90s. The first set lasted five years of fairly heavy use including an inverter for their last year.

But your Banners should have lasted a bit longer. Do you remember ever running them down flat, say sub 10 volts?

Not below 10 volts but I did leave the tank heaters on one night and the battery's were down to 12.1 which is near dead flat , also the van sat idle all winter but the battery's appeared to be well enough charged after 2 months of inactivity and gave a reading of 12.7 volts .

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[Lenny HB]

I would give the batteries a full test as below.

You really need to seperate the batteries and test each one separately as one duff one will drag the other one down.

Before starting the test you need to cover or disconnect your solar panel or do the tests in the dark. Although you won't get much solar at the moment it will effect the voltage readings.


Best way of testing a leisure battery is to fully charge it, let it rest for an hour then & check the voltage:-
1) Place a load on it of say 5 amps (can do this in the van by turning on lights etc.).
2) Leave it with the load for a time that equates to 25% of battery capacity (100A/H battery it would be 5 amps for 5 hours).
3) Turn the load off let the battery settle for ½-1 hour measure the voltage, the battery will now be @ 75% state of charge.
4) Repeat 3, battery will now be @ 50% state of charge.
6) Repeat 3, battery will now be @ 25% state of charge. - not recommended to take a wet cell (standard battery) below 50% too often.

 

[Neil S]

That price will only get you flooded cells as others have said Varta Ldf 90 have a good rep you will get a pair for under £200, they also do 120 & 140 a/h.

The Banners in my last van only lasted 18 months and Banner don't honour their warranties.

Ok I've ordered a Victron Energy Blue Solar PWM 30 amp solar charge controller and will look at adding an additional 100watt PV Logik solar panel putting me up to 220 watts .
Considering Platinum AGM Plus AGMLB6110L 110 amp sold at GO OUTDOORS for £159.99 less 10% with a discount card

 

[Neil S]

I would give the batteries a full test as below.

You really need to seperate the batteries and test each one separately as one duff one will drag the other one down.

Before starting the test you need to cover or disconnect your solar panel or do the tests in the dark. Although you won't get much solar at the moment it will effect the voltage readings.


Best way of testing a leisure battery is to fully charge it, let it rest for an hour then & check the voltage:-
1) Place a load on it of say 5 amps (can do this in the van by turning on lights etc.).
2) Leave it with the load for a time that equates to 25% of battery capacity (100A/H battery it would be 5 amps for 5 hours).
3) Turn the load off let the battery settle for ½-1 hour measure the voltage, the battery will now be @ 75% state of charge.
4) Repeat 3, battery will now be @ 50% state of charge.
6) Repeat 3, battery will now be @ 25% state of charge. - not recommended to take a wet cell (standard battery) below 50% too often.

ok Lenny I have already ordered a new regulator but I will follow your advice and test them tomorrow before ordering replacements ...... thanks

 

[Lenny HB]

ok Lenny I have already ordered a new regulator but I will follow your advice and test them tomorrow before ordering replacements ...... thanks

From your figures probably the regulator has had it.
What have you bought?

 

[peterc10]

Look in the classified section ads. @Robert Clark is selling some good batteries at £50 each

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[Neil S]

From your figures probably the regulator has had it.
What have you bought?

as above # 17 hopefully that will be ok

 

[Neil S]

update on my battery / solar issue - have now fitted a new Victron Energy Blue Solar PWM Light 12/24V 30 amp Solar charge Controller and the battery's are now charging as high as 14.0 volts in bright overhead sunlight which seems a bit high , will that boil the battery's and cause them to gas

 

[Lenny HB]

update on my battery / solar issue - have now fitted a new Victron Energy Blue Solar PWM Light 12/24V 30 amp Solar charge Controller and the battery's are now charging as high as 14.0 volts in bright overhead sunlight which seems a bit high , will that boil the battery's and cause them to gas

No, should rise to 14.2 - 14.4 volts when reaching full charge and then hold at that voltage for an hour or so (time depends on settings) at a reduced current and then drop to a 13.8v float charge.

 

[Neil S]

No, should rise to 14.2 - 14.4 volts when reaching full charge and then hold at that voltage for an hour or so (time depends on settings) at a reduced current and then drop to a 13.8v float charge.

thanks Lenny just been and checked the the voltage is now indicating 13.7 float charge which would appear to be as you say .
I also tested the battery's individually as you suggested and they appear to be ok at the moment , however I'll look to replace them in the not to distant future

 

[Neil S]

Further to my original query I have fitted a Victron 30 amp charge controller and currently have a 120 watt solar , I want to fit a an additional panel .
what would be the maximum wattage a 30 amp controller can safely handle

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[funflair]

Charging 12v it would be 440w according to Victron data.

Martin

 

[Neil S]

Charging 12v it would be 440w according to Victron data.

Martin

Thanks , don't think I'll need as much as 440 watts but another 120 watt PV Logik panel married up to the existing 120 should allow me to be of grid a bit more and shorten recharge time

 

[Allanm]

We have 2x LDF90 batteries, 120 watts of solar and a Victron MPPT controller. We hardly ever use EHU and the batteries stay pretty well topped up all the time. Even after 3-4 hours of tv, lights, water pump and heating when we need it, I’ve never seem the batteries go below 12.6v.
Of course, if you are stayng in one place for a couple of weeks, you would need more solar, or a generator.........

 

[Neil S]

We have 2x LDF90 batteries, 120 watts of solar and a Victron MPPT controller. We hardly ever use EHU and the batteries stay pretty well topped up all the time. Even after 3-4 hours of tv, lights, water pump and heating when we need it, I’ve never seem the batteries go below 12.6v.
Of course, if you are stayng in one place for a couple of weeks, you would need more solar, or a generator.........

I'm hoping that by increasing my solar capacity from 120 to 240 watt that should allow me to stay without EHU for up to 2/3 weeks without moving with the very occasional inverter use for a low wattage hair dryer during the summer months

 

[funflair]

I'm hoping that by increasing my solar capacity from 120 to 240 watt that should allow me to stay without EHU for up to 2/3 weeks without moving with the very occasional inverter use for a low wattage hair dryer during the summer months

Always sunshine willing of course but yes with the right weather and sympathetic use 240w should see you sat in a field indefinitely. We have 320w and can stay in a field as long as we wish, we use the inverter quite a lot for microwave and coffee machine and of course the usual hairdryer

Martin

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