Help! What’s happening to our batteries?

BooBooKing

BooBooKing

Joined
Jan 20, 2021
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Northamptonshire, UK
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Vantage Sol
We are currently in Spain, we’ve been away 4 weeks, on hook up all the time until the last few days. It’s only our second ever try at off grid in our 2021 Vantage Sol. We have 2x 100A batteries and a 100w solar panel. We woke this morning after our second night and the battery was at 11.9V We were shaded by a tree so moved into bright sun and over a few hours it improved to 12.8V Over the afternoon it’s dropped gradually. We are now on 12.1 but it drops when the fridge cuts in to 11.6. Over the day we have generated 321 watt hours ( 20 amp hours) and the fridge is the only draw as far as we know. I dont understand why generating a good amount of solar over the day hasn’t left us with a decent battery level! At 11.6 with fridge on are the batteries going to be irreversibly damaged? Should I book campsites with EHU for the next 2 weeks until we get home?Our other trip last year was just to Wales, we had similar levels then by the 3 Rd day but presumed it was just poor solar in the UK. Any thoughts welcome!
 
Compressor fridges are much more efficient than 3-way, but they still take a lot of juice to keep going. I suspect it's eating a hell of a lot more than 20Ah per day.

With only 100w of panels, it would be tough to keep up with a fridge in the summer. You've not got much chance at this time of year. Every day will be draining your battery more than you're charging with that sun.

I'm assuming the 200Ah of batteries are lead acid, so you've only got about 100Ah before you're starting to damage them.

If your batteries were healthy, you should have got a few days before they started to die.
 
We find our compressor fridge very efficient and if battery capacity is a problem we turn it down a couple of notches. It still keeps things cold but does not stay on for as long, so saving battery AHs.
When I say turn it down I mean set it on a warmer temperature, which I suppose is actually turning it up?

Geoff

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Perhaps also worth remembering that lead acid batteries are not 100% efficient. This means you need to put more back in when charging than you took out in the first place. I think new they are about 95% efficient but I don’t know if that efficiency falls off as they get older.
 
I have a similar van a 2017 Vantage Med with a compressor fridge My experience is that I use between an average of 40 to 50 amps per day and get between max 4 amps per hour from the solar and an an average of less than 2 amps The daily deficit works out about 30 amps per day in summer in the UK. I can get 2/3 days with careful use before the batteries are really complaining. I try and keep the fridge full on a low setting, in itself it can eat up to 30 amps per day. I find that a 100 mile journey will enable the existing old style alternator to restore near full battery power. I have deliberately kept the above numbers “average” as it very much depends how you use the van; showers, laptop charging, trackers, alarms, tv etc will have an implication. I hope this helps.
 
Thanks that’s really helpful. Seems we’ve been somewhat over optimistic in thinking we could do longer periods off grid. It’s very helpful to see your figures. I think our alarm and tracker run from the can battery, and we have nothing else running, but it’s been extremely hot here in Spain so I guess that’s the issue. Thank you.
 
If the fridge is taking 50Ah per day, then you would be draining the battery by the middle of day 3, even with some late autumn sunshine.

If you had 200w of solar, you'd still be running it down, but you'd last quite a few days longer. However, if it becomes cloudy, you're back to a similar situation as now.

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In my opinion the batteries are already damaged.
The don't appear to have full capacity even with the voltage produced.
The actual capacity could be 60% or even less compared to 100% for a new battery.
 
pappajohn said:
In my opinion the batteries are already damaged.
The don't appear to have full capacity even with the voltage produced.
The actual capacity could be 60% or even less compared to 100% for a new battery.
Click to expand...
I agree. When I picked up my 2020 (nearly new) van last year, the hab battery was dead. I've put it on a recovery charger and it's OK, but it's definitely weak. I get large voltage drops when my shunt says I'm still at 70% charge. The van had been sitting on the forecourt for a few months with no solar and hadn't been plugged in. I've since measured and even when everything is off, it'll drain the battery in 2-3 weeks.
 
Even in Spain at this time of year the sun is quite low, in over ten years of Motorhoming we never turn the fridge on. :oops:
 
BooBooKing said:
Thank you for these replies. I wonder if lithium batteries are required before our next saunter abroad.
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Lithium would be a good move but to take maximum advantage you need to be able to take advantage of their quick charging so would need to fit another 300 Watts of solar.
 
BooBooKing said:
Thank you for these replies. I wonder if lithium batteries are required before our next saunter abroad.
Click to expand...
If you are mostly on sites with hookup it's not worth the expense.
A couple of new lead acids would be a better option.
If you plan on spending a lot more time off grid then yes, go lithium.
 
Are your batteries under the drivers seat? I ask because I cannot fit 2 100ah batteries under mine (Vantage Neo) due to size constraints, mine are 85ah these are now almost kaput and will only just last 1 night. Lithium would mean changing the whole set up as I have the sargent EC325 system.
 
Hmm. I wonder if RoadPro are still overwhelmed with work, I think we could do with some cost comparisons- we have been mostly on hookups until now but wanted to start using aires more in Europe.
 
As mentioned you need more solar panels, a better battery, also a B2B for the darker months.
If you cannot or don't want to DIY, then Vanbitz would be my 1st port of call.
Just like a premium beer.....They touch the parts others cannot reach!
(y):giggle:
LES

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A fridge takes 25-30ah or about 300-400wh per day. You did very well to harvest 321wh in a day with 100w solar. It harvested just enough to keep the fridge going, but without replenishing the empty battery and sustaining other loads. If you would had at least 300w of solar, you stand a good chance to succeed in your energy needs. Also if those batteries have never seen a good long absorb, followed by few hrs of float in a long while, rest assured they have reduced capacity, despite recovering to good voltage. A 10ah battery when full, archives a good top voltage, same as a worn out 100ah. The difference is the Ah left to play with.
If you switch to even one 100ah lfp, you will be in a better position compared to new Pb of your existing capacity.
 
I looked in depth at converting over to 230 AH lithium, B2B, mains charger, additional solar panel, inverter to charge electric bike battery, upgrading the wiring, professional installation etc. and your looking well in excess of £3000 and could be significantly more. That buys a lot of EHU!
With my van even that would only give me about 5/6 days off grid because I can’t get enough solar on the roof, or resort to a lot of driving using a hefty B2B. You need to do all the sums and address how you intend to use the van and choose the equipment as appropriate. I decided that using Camping Car Parks or similar was a much simpler/cheaper option for my usage.
 
csd4t said:
Are your batteries under the drivers seat? I ask because I cannot fit 2 100ah batteries under mine (Vantage Neo) due to size constraints, mine are 85ah these are now almost kaput and will only just last 1 night. Lithium would mean changing the whole set up as I have the sargent EC325 system.
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For clarity, my 2017 Vantage Med does not have the EC325 system and I think a Roamer 230ah lithium will fit below the drivers seat. Don’t forget that lithium batteries can be put on their side and you could possibly still fit in the space of the existing 2x100ah lead acids
 
Consider tilting your solar panels south. This time of year it makes a massive difference, I fitted removable pin hinges on both sides of our panel so it can hinge up forward or rearward facing. The output goes to almost full power when the sun is on them directly. iirc it's about 3x the flat output.
 
Guigsy said:
If the fridge is taking 50Ah per day, then you would be draining the battery by the middle of day 3, even with some late autumn sunshine.

If you had 200w of solar, you'd still be running it down, but you'd last quite a few days longer. However, if it becomes cloudy, you're back to a similar situation as now.
Click to expand...
We had a similar situation when we had our Globecar Campscout with a compressor fridge, 2 x 85ah gel batteries and 200w of solar, even in southern Spain we were always watching the power draw and it often got lower than we were happy with, as a comparison we did similar in our Carthago with 2 x 80ah gels and 200w solar but a 3-way fridge and never had any issues whatsoever despite using more power during that trip and it wasn't as sunny.

Doesn't help the OP but personally I'd never have another compressor fridge without a lot more solar and as big a bank of batteries as I could fit/afford.

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We have a compressor fridge and it draws maybe 2A when the compressor is running.
, so if the compressor ran 24hrs, that would be approx. 48A. draw in 24h.
In truth, at a proper operating temperature, the compressor runs maybe 50% of the time, so daily current draw of say 24A, of which 12A is during daylight (and therefore usual directly offset by solar) and 12A at night, which leaves a small deficit in the morning that solar recovers in the daytime.

We could going for may 4 days off grid in poor weather ( I.e no solar) with 190Ah of AGM Batteries without needing hookup
Now with 205Ah lithium leisure battery and a 50A B2B, we are pretty much independent of grid.

No issues with the compressor fridge and the benefit of it is it can be positioned anywhere in the van, as it does not require external ventilation holes cut into the van walls / skin
 
Richard n Ann said:
Consider tilting your solar panels south. This time of year it makes a massive difference, I fitted removable pin hinges on both sides of our panel so it can hinge up forward or rearward facing. The output goes to almost full power when the sun is on them directly. iirc it's about 3x the flat output.
Click to expand...
According to this calculator you would be better off having your panel hanging vertically on the side of the van for half the year (UK). In Spain it would be bit less only 5 months.
www.solarelectricityhandbook.com

Solar Angle Calculator

The solar angle calculator tells you by location the optimum angle to get the best out of your system.
www.solarelectricityhandbook.com www.solarelectricityhandbook.com
 
Thank you for all your replies. We’ve now moved to a site with hook up. We can use campsites all the way back to Santander in 2 weeks although it’s a shame as there are some lovely aires in Spain that we had intended trying. When we went to bed last night the battery was on 12.4v, fridge off, nothing drawing. It was 9.7 on waking so clearly damaged beyond repair. If it’s not a daft question I presume we can just use campsites all the way home without any problems likely to occur, I must admit that speaking no Spanish and being far away from big towns or cities, we don’t really want to go off and try and get new leisure batteries while we are away.
 
BooBooKing said:
If it’s not a daft question I presume we can just use campsites all the way home without any problems likely to occur
Click to expand...

Yes sounds like you'll be ok. Just check neither of the batteries are getting warm while on ehu and charging. 👍

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