Overcharging

[Mags52]

Hi Folks, We have 120 w solar and 2 x 100 batteries (new last year)
Our alarm is flashing on the battery to say it is overcharging and in the sun this afternoon the reading was 14.7 on the leisure batteries. I understand that over charging the batteries is probably as bad as running them down too low. What could be causing this?I'm wondering if it's the solar controller but really I'm just talking out of ignorance. Any thoughts?
BTW we're leaving tomorrow south in the direction of the tunnel but not crossing until next week.
Thanks as always
Mags

 

[Figaro]

I think 14.7 volts is normal in full sun and solar working.
I'm sure others will confirm.
What alarm was sounding, it might need calibrating ?

 

[Phill D]

it may help if you say what type of batteries are they , lead acid/ gel/ agm etc. also what type of solar controller do you have.
do you have a battery monitor that shows the charge and the voltage?

i assume the alarm is battery temperature sensor, but i am guessing there.

my gel battery when under charge on solar can be 14.8v which drops to 13.8v when on 3rd phase of charge.

does you battery voltage drop from 14.7v when it is fully charged and resting?

 

[DBK]

Something doesn't sound right. If the batteries were a bit discharged you might see a voltage of 14.4 if the sun was shining and you have normal lead acid batteries. Once the batteries are charged the voltage should drop to say around 13.4. This is the float voltage where the system is just keeping the batteries topped up.

But the unknown variables are what type of batteries you have and the charging profile set in the charger. This can alter the expected voltages. However, 14.7 volts and more importantly a flashing warning needs investigating. My guess is the controller has failed and needs replacing.

 

[the1andonly]

Might be a good idea to measure the temperature of the battery and actual voltages at terminals with a DVM. Add type of battery controller etc

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[Lenny HB]

Unless they are AGM's 14.7 v is too high sounds like regulator may be playing up.

my gel battery when under charge on solar can be 14.8v which drops to 13.8v when on 3rd phase of charge.

Too high, should be 14.2 to 14.4v.

 

[WESTY66]

I know NOTHING about electrics but the most I’ve seen on the carthago gels is 14.4 but normally they settle on 14.2 then mysteriously go down to 13.8 for a while then next day back up at 14.2

 

[Lenny HB]

I know NOTHING about electrics but the most I’ve seen on the carthago gels is 14.4 but normally they settle on 14.2 then mysteriously go down to 13.8 for a while then next day back up at 14.2

That's what supposed to happen.

 

[WESTY66]

That's what supposed to happen.

Thank god for that

 

[Old Gibber]

Is there an adjustment on the solar regulator, or battery charger if you are on mains? Depending on the chargers, it could be a small switch, or a Bluetooth setup on your phone for some of the better chargers. It sounds like it is set for an AGM battery which should have a maximum charging voltage of 14.7v.

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[Phill D]

Unless they are AGM's 14.7 v is too high sounds like regulator may be playing up.

Too high, should be 14.2 to 14.4v.

I will check the settings on my votronic mppt in the morning to make sure it's on gell and not agm...

 

[Mags52]

So, here's the thing. We got the Hymer last year from a dealer having traded in a van with a lot of solar and victronic controller etc. I know it's pointless having regrets. This panel was put on the van by the dealer at my request but I don't know what type of controller it is. I'll stick my head in the cupboard it to try to find out. The alarm is on the Hymer control panel above the door (bear in mind she's an oldish lady) and the leisure battery image flashes when the voltage is going up when in full sun. There is also an exclamation mark flashing with the word Alarm above it. From there I am clueless. However, last night, after dark the battery reading fell back to 12.6 and everything worked as it should overnight. Perhaps Heidi the Hymer is confused because she's never had solar before??

 

[Lenny HB]

You need to establish what type of batteries you have, and solar regulator. Then take some voltage measurements with a meter.
Put photos of your solar regulator and panel on here it will help us.

 

[Phill D]

Unless they are AGM's 14.7 v is too high sounds like regulator may be playing up.

Too high, should be 14.2 to 14.4v.

Well I check mine out this morning and I must have had crap In my eyes when I looked a my panel the last time.

Liesure battery on charge this morning 14.3v at panel, 14.32v on the meter at terminals and definitely set on gell.
Phew!!

 

[Barti Ddu]

If ambient temperatures are low, and your solar controller has temperature compensation built-in, then 14.7v during bulk charging is not unusual.

I've got a Victron Smart Solar MPPT controller connected via Bluetooth to a Smart Battery Sense (reads battery voltage and temperature) monitor attached to a standard flooded lead battery. At UK winter temperature it will often bulk charge up to 14.75v before an absorption phase, and then floating back to around 13.85v.

The following give the full lowdown -

Lead acid battery charging in cold weather - Victron Energy

This blog covers lead acid battery charging at low temperatures. A later blog will deal with lithium batteries. Charging lead acid batteries in cold (and indeed hot) weather needs special consideration, primarily due to the fact a higher charge voltage is required at low temperatures and a lower...

www.victronenergy.com

Battery Temperature Compensation - SunWize | Power Independence

The following is a discussion on battery temperature and the effects of warm and cold weather on battery charging setpoints.

www.sunwize.com

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[Lenny HB]

Although your info above is good, It's not winter at the moment it's 17° also very few people fit the temperature sensor so I don't think that is applicable in this case.

 

[Barti Ddu]

The standard reference temperature for batteries appears to be 25'C, so even at your 17'C there should be 8 degrees of temperature compensation added.

Also lead acid batteries are a massive heat-sink, so are still at a low temperature from last night's single figure even though now mid morning and glorious sun here in Pembrokeshire.

I've just taken screenshots of the current readings and the battery is currently at 9'C.

It's also finished it's bulk charge, (reaching 14.65v), had a 1 minute absorption phase, and is now floating back down to below 14v.

It's also worth noting that even without a separate Battery Sense temperature monitor, Victron solar controllers take a temperature reading from its own internal sensor at the start of the charge cycle each day and uses that for temperature compensation. I don't know if other makes of controller do too.

 

[Lenny HB]

But we don't know what controller or even what type of batteries he has, if dealer fitted very unlikely to be a Victron.

No point in jumping to conclusions until we have enough info to make an educated guess and no point in overcomplicating it for someone who is not that well up on electrics.

 

[karalal]

The standard reference temperature for batteries appears to be 25'C, so even at your 17'C there should be 8 degrees of temperature compensation added.

Also lead acid batteries are a massive heat-sink, so are still at a low temperature from last night's single figure even though now mid morning and glorious sun here in Pembrokeshire.

I've just taken screenshots of the current readings and the battery is currently at 9'C.

It's also finished it's bulk charge, (reaching 14.65v), had a 1 minute absorption phase, and is now floating back down to below 14v.

It's also worth noting that even without a separate Battery Sense temperature monitor, Victron solar controllers take a temperature reading from its own internal sensor at the start of the charge cycle each day and uses that for temperature compensation. I don't know if other makes of controller do too.

Could i ask How much solar have you got and which victron controller

 

[Barti Ddu]

But we don't know what controller or even what type of batteries he has, if dealer fitted very unlikely to be a Victron.

No point in jumping to conclusions until we have enough info to make an educated guess and no point in overcomplicating it for someone who is not that well up on electrics.

True enough. I was just wanting to point out to the OP, that contrary to some of the replies, 14.7v in March in the UK is not necessary excessive, and that his solar controller may not be kapput. But yes - more info from the OP required.

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[Barti Ddu]

Could i ask How much solar have you got and which victron controller

Only 100w (Perlight "All-black" panel) and a Victron 75/10 SmartSolar with built in Bluetooth. From memory the Smart Sense monitor was another £25.

We're not big power users - in addition to the LED lights and water pump, it's mainly daily charging of phones, plus a laptop and tablet a couple of times a week. However we had 16 days in the UK this January, all off grid, no hook up, and even with the blown air heating fan taking a fair wack out of the battery, we never ran out of juice, and didn't hammer the battery particularly hard, even when stationary in one spot for 3 nights (therefore without any input from the split charge when travelling).

 

[Mags52]

No idea what I'm doing but here is a picture of our controller. (Sorry it's huge!) As you can see only one battery is lit up. The warning Charge! has now gone off on the Hymer above door screen. Sorry to be slow to respond to all these comments but we're en route to the tunnel.

 

[golly]

On your regulator you can specify the type of battery you have, check it is set to the type you are using, here is the manual.

 

[Lenny HB]

No idea what I'm doing but here is a picture of our controller. (Sorry it's huge!) As you can see only one battery is lit up. The warning Charge! has now gone off on the Hymer above door screen. Sorry to be slow to respond to all these comments but we're en route to the tunnel.

Last year I was at a Fun rally two members were having problems with their solar both had that controller. One was over charging the other was drawing current fom the leisure battery taking 2 amp when there was no sun.

 

[jwells]

EPSolar are awful solar controllers, have had 2 of those, replaced with a Votronic unit and not had any further problems!
My Auto Sleeper with a Sargent electrical unit 8 years old now. Sargent even frigged the electronics so that the cheaper solar controller didn't set off the alarms!

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[jwells]

Further to my last entry, this website I have found extremely useful:- http://www.aandncaravanservices.co.uk/sargent.php
Very interesting general battery/charging/solar information as well!

 

[Mags52]

So we need a new solar controller. We're on the tunnel on Wednesday so it's probably too big an ask to get it fixed before we go. Anyone know of a good solar person in France (west side)? - We're heading slowly south towards North West Spain.

 

[Phill D]

So we need a new solar controller. We're on the tunnel on Wednesday so it's probably too big an ask to get it fixed before we go. Anyone know of a good solar person in France (west side)? - We're heading slowly south towards North West Spain.

the actual change over is likely to take less than 30 minutes... getting the part and someone with a screw driver may take longer..

 

[monzer]

So we need a new solar controller. We're on the tunnel on Wednesday so it's probably too big an ask to get it fixed before we go. Anyone know of a good solar person in France (west side)? - We're heading slowly south towards North West Spain.

You've got 2 batteries so I wouldn't say it's completely necessary to get it fixed straight away. On my solar controller I can simply turn it off to avoid putting any charge in. Do you (or anyone else) know if this model can do that?

How long are you away for?

 

[mitzimad]

why not try ringing round in the morning see if you can get it changed enroute, DMC perhaps as said its a half hour job at most
EDIT I meant DMS or theres others click the reviews tab in the blue banner above

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