Understanding voltage in Van

Otter Spotter

Otter Spotter

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Hi, my set up is 1 190ah leisure battery, 160ah solar panel, Sterling power controller, solar pane” controller and Numax battery charger.
the voltage is indicated regularly at 14.5 without any real draw, once lights(leds) and other kit is switched on then the voltage drops to around 12.7. All without being hooked up to site.
if I wild camp, what should I expect the voltage to do, will the solar panel keep the battery topped up subject to suns strength? is it possible to drain the battery What should not let the system do?
up to now I have always used EHU, should I consider not hooking up and drain the battery down to any voltage level?
you can tell I do not understand electricity and I did not fit the kit only told convertor what I wanted, which was be able to wild camp in Scotland in winter.
 
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160W is marginal for Scotland in winter, although doable if you has a gas fridge and heating. If you drive about (and if you're driving in northern Scotland, you'll have to do a lot of it!) you can get lots of charge in, but need a proper B2B charger to make the most of the engine running, not a split charge relay which will only give a slow lazy charge. More battery will give you more time before any charge issues become a problem.
 
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Otter Spotter said:
the voltage is indicated regularly at 14.5 without any real draw, once lights(leds) and other kit is switched on then the voltage drops to around 12.7
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14.5v will be the solar float charge voltage.
12.7v is the fully charged battery voltage and will of course drop lower with use at night.
 
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I live in Scotland and have a 100w panel. From November through to February it's not enough to keep the battery charged even with the van just parked on the drive with no current draw. I suggest you need more solar especially as your heater will be in use a lot during the winter.
 
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pappajohn said:
14.5v will be the solar float charge voltage.
12.7v is the fully charged battery voltage and will of course drop lower with use at night.
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But will recover somewhat after the circuits in use are turned off, but not immediately, so check again in the morning before the solar clicks in.

Geoff

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A rule of thumb I follow is under a gentle load, a couple of lights and say the TV on, not to let the battery voltage fall below 12. In reality I start to fidgit at around 12.2 and start turning things off.

The reason for the phrase "gentle load" is if you are using an inverter for a brief spell to make coffee or whatever the voltage might drop for a short period below 12 but this may not be something to fret about if it subsequently recovers when the inverter is turned off.

All I can suggest is give it a try and don't let the steady state voltage under a normal light load fall below 12. :)
 
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WillH said:
I live in Scotland and have a 100w panel. From November through to February it's not enough to keep the battery charged even with the van just parked on the drive with no current draw. I suggest you need more solar especially as your heater will be in use a lot during the winter.
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Heater is Wallas Diesel with very low electric draw not like Webasto.
 
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DBK said:
A rule of thumb I follow is under a gentle load, a couple of lights and say the TV on, not to let the battery voltage fall below 12. In reality I start to fidgit at around 12.2 and start turning things off.

The reason for the phrase "gentle load" is if you are using an inverter for a brief spell to make coffee or whatever the voltage might drop for a short period below 12 but this may not be something to fret about if it subsequently recovers when the inverter is turned off.

All I can suggest is give it a try and don't let the steady state voltage under a normal light load fall below 12. :)
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I should have said, no tv, sometimes will use laptop via soft start invertor (not pure sine wave) so apart from brewing up on invertor most power draw in the evenings will be lights as we both read a lot.
 
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cmcardle75 said:
160W is marginal for Scotland in winter, although doable if you has a gas fridge and heating. If you drive about (and if you're driving in northern Scotland, you'll have to do a lot of it!) you can get lots of charge in, but need a proper B2B charger to make the most of the engine running, not a split charge relay which will only give a slow lazy charge. More battery will give you more time before any charge issues become a problem.
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B2b charger, isn’t that what the Sterling or Numax is ?

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Otter Spotter said:
Ok I will need to read the labels 😆
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Not decrying other makes, which incl. Victron, but Sterling have a very good explanation on their website about how B2Bs work, worth reading.

We have one and they do hammer in good charge when MH is on the move - 30 min. running will often re-charge the batteries.

Can also be used if MH is stationary - ask the neighbours first.

Geoff
 
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Otter Spotter said:
Is 14.5 good ?
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Depends on the exact type of battery, and whether the charger is smart or not.

If you apply about 13.6V to a fully charged battery, the voltage from the battery just about cancels the voltage from the charger, and very little charge flows into the battery. This is called float charging. Ideally, just enough charge goes in to compensate for the internal loss within the battery. It's easy to do this when the battery is isolated on a bench, but when it's in a motorhome, with constant small loads like the alarm, tracker, frost protection valve etc. it's not so easy.

If you apply the float voltage to a discharged battery, it will eventually be fully charged, but it might take a fortnight. To speed up the charge, a smart charger will apply an overvoltage of about 14.4 to 14.8 volts, constantly checking the amps flowing in until it reduces below a fixed threshold. Sometimes the overvoltage is applied for a fixed time of several hours, for gel and AGM batteries for example.

So the answer to the question is, if the charger knows what it is doing, then it's fine, but randomly applying 14.5 volts continuously to a battery is not good.
 
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I have a single 110ah battery, no solar, Wallas XC Duo hob/heater, Waeco CRX-50 compressor fridge, small 12v tv, lights & waterpump

Can do 3 days (2 nights) without hookup - no problem.....
 
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Nasher said:
I have a single 110ah battery, no solar, Wallas XC Duo hob/heater, Waeco CRX-50 compressor fridge, small 12v tv, lights & waterpump

Can do 3 days (2 nights) without hookup - no problem.....
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Yes it's amazing how long a good battery will last. I got up for the toilet this morning at 5am and our battery was at 12.7v with 0.5 amp drain. The TV had been on until 3am 😳🤭

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Richard and Ann said:
Yes it's amazing how long a good battery will last. I got up for the toilet this morning at 5am and our battery was at 12.7v with 0.5 amp drain. The TV had been on until 3am 😳🤭
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Especially as my battery (fitted by the converter) is a cheap Lion (as in the animal rather than Lithium) battery and is 5 years old
 
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