Author Topic: Caravan PSU / Battery Charger issue  (Read 13149 times)

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Offline Another DaveTopic starter

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Re: Caravan PSU / Battery Charger issue
« Reply #25 on: May 05, 2016, 09:54:03 pm »
No charging data on the battery, i think im fighting a loser here..  Comparing the charger to a 6amp and 8amp
chargers that are probably as old as the caravan charger.

I used a 100A watt meter and 14awg cable thats approx 18" long.  Dropped the battery down to 12.1 volts under
a 3.8 amp load.  Connected the caravan charger and its barely over 1amp and drops quite quickly, but the voltage is
only around 13.3v.

I connected the 8amp charger and the amperage went over 4amps on the watt meter but the chargers LEDs showed
a max 8amps charge. (but its probably 20 years old and a similar design to the caravan charger. Voltage held at
slightly over 14v with the 8A charger though.

Pride says i want to fix it, but my pocket says give up and buy a new charger.

Thanks to Dave and this site i have fixed several TV's and now the readout on my lathe   :)

That feeling of i fixed something is great.  No sob story but my health has suffered and i cannot do a lot
of stuff that i used to  (lorry driver / mechanic).   

Thanks  :)

 

Offline tautech

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Re: Caravan PSU / Battery Charger issue
« Reply #26 on: May 05, 2016, 10:05:30 pm »
Just wondering if the old charger was well matched BUT you have low voltage mains supply.  :-\

That might explain the low charging rates.

Do you have a light gauge supply to the caravan and/or have low mains voltages locally.
Do you feel comfortable checking the mains voltages?
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Offline jitter

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Re: Caravan PSU / Battery Charger issue
« Reply #27 on: May 05, 2016, 10:15:37 pm »
Maybe the caravan charger isn't faulty after all.

From SLAs (Sealed Lead Acid) batteries I know that there are two sorts of usage. One is standby usage in which a charger is always maintaining the charge level to keep the battery ready for action (think e.g. of a UPS). The other is cycle use in which a large chunk of the charge is used up before charging takes place.
The former uses a lower level, say 13.8 V than the latter, which may be 14.4 V.

It may just be that the caravan charger is the standby type which charges at a lower max voltage that won't harm the battery when it stays connected for long periods of time.

Perhaps you can charge it as far as possible with the caravan charger and then have it tested by a pro. They should have a device that can assess the condition of the battery.

I'm also thinking about the mains voltage. If this is an old caravan that was made in the time when the UK (officially) still had 240 V mains, then maybe if your mains has been harmonized to the rest of Europe (i.e. dropped to 230 V), its output might be a little too low now (about 0.5 V).
I know that the UK may not actually have dropped from 240 V to 230 V as 240 V is still within tolerances, but who knows. We really did go from 220 V to 230 V.
« Last Edit: May 05, 2016, 10:18:40 pm by jitter »
 

Offline Delta

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Re: Caravan PSU / Battery Charger issue
« Reply #28 on: May 05, 2016, 10:49:09 pm »

I'm also thinking about the mains voltage. If this is an old caravan that was made in the time when the UK (officially) still had 240 V mains, then maybe if your mains has been harmonized to the rest of Europe (i.e. dropped to 230 V), its output might be a little too low now (about 0.5 V).
I know that the UK may not actually have dropped from 240 V to 230 V as 240 V is still within tolerances, but who knows. We really did go from 220 V to 230 V.

We didn't change anything!  Not a single transformer tap or voltage regulator was changed, we are still 240V!  (It was a political masterstroke - yeah yeah, we'll go to 230, but we want asymmetric tolerances.  So instead of 240 +/- 6% we "changed" to 230 -6 / +10% Do the maths...  ;)  I think some 220 countries also "changed" to 230 -10 / +6% )

Dave, please can you be a bit clearer in your posts, where exactly are you measuring these currents and voltages you are mentioning? 
 

Offline Another DaveTopic starter

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Re: Caravan PSU / Battery Charger issue
« Reply #29 on: May 16, 2016, 12:31:13 am »
Battery is 100% fine. I can run it for over 4 hours with a 100w load and it still held 12.2 volts.

Just had a week away with the van and the small CTEK 3600 charger (3.6 amps max) No issues at
all.  The charger was left switched off most of the time.  The charger was also using the solar connection
point which has a 20ft length of cable to that battery.  I have a twin battery setup when using panels.
This doesnt affect the issue with the original charger, unrelated.

The charger would get a bit warm with several lights on at the same time, but it didnt take long
for the full battery light to come on after switching the lights off.  So even with several lights on
for a few hours its probably pulling about 4 amps in the caravan. During the day nothing will
be drawn from the battery.


Delta, sorry if i confused matters. But i do seem to have had a good tinker.

At home i have the charger connected to a leisure battery. To drain the battery i connect a 240v 60w bulb
through a 600w inverter and measuring the voltage at the battery terminals and the current drawn by the inverter.
Inverter is actually pulling around 100w with the single bulb.  Inverter is only my home test setup to drain/put a load
on the battery Not used in the caravan.

I used a watt meter or clamp meter to test the power drawn by the inverter.

The original chargers voltage is tested right at the charger and at the battery terminal also. But i seem to have an issue
with the el.cheapo leads with croc clips. Either my old chargers are showing themselves as putting out 6 and 8 amps but
really only putting out 3 amps or my leads are total crap? 

I need to repeat the tests with decent and very short cables. I may have done that before we left but i  have forgotten.... |O

So the battery is fine and the caravan is fine. I have a meter that shows the mains voltage and current consumption of
a mains powered item also.







 

Offline GEuser

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Re: Caravan PSU / Battery Charger issue
« Reply #30 on: May 16, 2016, 03:26:19 am »
Sounds all good Another Dave , what is those (i assume a deep cycle) battery's worth over there , they can be expensive over here .

Those 12v Fluoro bar lights lights are good and put out a decent light and consume a miserable amount (like 150ma) , one can get 1 or 2 bar (tube) and from 6" to a foot long , very economical .

See when you mention a Leisure battery any battery can be that , it would be better to categorize the type ie> gel , deep cycle , calcium , acid excetera .

I ran a thick lead via a 100a relay from the alternator through a plug to the battery in the van for the Fridge , a switch and voltage meter on the Dash , in gas mode sitting on 120k or more for hours used to blow the pilot light on the fridge out so i rigged up so the Fridge for 12v when in motion (it was a 3 way fridge) , as 500k or more during the day out bush is quite normal out here .
Soon
 

Offline jitter

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Re: Caravan PSU / Battery Charger issue
« Reply #31 on: May 16, 2016, 08:30:38 am »
I ran a thick lead via a 100a relay from the alternator through a plug to the battery in the van for the Fridge , a switch and voltage meter on the Dash , in gas mode sitting on 120k or more for hours used to blow the pilot light on the fridge out

What looks like a pilot light in an absorption type cooler actually is the (whole) burner. It's all that's needed to get the circulation in the cooling system going.

Quote
so i rigged up so the Fridge for 12v when in motion (it was a 3 way fridge) , as 500k or more during the day out bush is quite normal out here .

What do you mean with "120k" and "500k"?
 

Offline GEuser

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Re: Caravan PSU / Battery Charger issue
« Reply #32 on: May 16, 2016, 06:30:58 pm »
Quote
What do you mean with "120k" and "500k"?

Look at the speedo and then look at the tripmeter .
Soon
 

Offline Delta

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Re: Caravan PSU / Battery Charger issue
« Reply #33 on: May 16, 2016, 06:40:35 pm »
Quote
What do you mean with "120k" and "500k"?

Look at the speedo and then look at the tripmeter .

So your first use of "k" mean km/h, and your second use of the exact same thing means km?  Of course!
 

Offline GEuser

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Re: Caravan PSU / Battery Charger issue
« Reply #34 on: May 16, 2016, 06:50:48 pm »
Quote
What do you mean with "120k" and "500k"?

Look at the speedo and then look at the tripmeter .

So your first use of "k" mean km/h, and your second use of the exact same thing means km?  Of course!

What are you getting picky about?

Its all in the reading , can't you be careful how you read , as if i was sitting on 120k does that mean i'm sitting there on a 120k strip of bitumen , and 500k during the day means 500k hours in 1 day , come on now bored at home with nothing better too do 100000000000000000000009k .
Soon
 

Offline Delta

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Re: Caravan PSU / Battery Charger issue
« Reply #35 on: May 16, 2016, 06:56:18 pm »
Because this is an engineering forum, and correct use of units is important.
 

Offline jitter

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Re: Caravan PSU / Battery Charger issue
« Reply #36 on: May 16, 2016, 09:06:56 pm »
Agreed.

I kinda understood the meaning of 120k because the blowing out of the flame of the cooler hinted at motion. And then 500k per day hinted at distance travelled.
But the usage of just a multiplier (k = kilo = 103) is confusing because over here, in daily speech, the word "kilo" used on its own exclusively means kilogram (kg). A speed of 120 km/h is either "120" or "120 kilometres per hour". Distance is "kilometres" only (well actually, "kilometre" as we tend to keep (monetary) units single).
And then the accountants like to say "500k" when they mean 500,000... So in non engineering circles it would have been all the more confusing.

On a more general note, often small and capital letters in the SI are used incorrectly. I often see (e.g.) 200 v when it should be 200 V. In that case it doesn't really lead to confusion, but wait until you mix up m (milli = 10-3) and M (mega = 106)...

And as an aside, all standard SI units are without multiplier with the exception of the kg.
« Last Edit: May 16, 2016, 09:23:14 pm by jitter »
 

Offline Another DaveTopic starter

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Re: Caravan PSU / Battery Charger issue
« Reply #37 on: May 17, 2016, 12:46:25 am »
Yeah a deep cycle battery, probably a car battery really with a label saying leisure. I have my
doubts as to whether the internals are any different.

2005 ish i paid about £40 for a 110Ah battery, prices increased quite a bit over the next few years
until the same budget battery was approx £110.  Prices have dropped again over the last year
or two. You can pickup a budget 110Ah battery for around £60.

What can this charger teach me, and nope i dont want to plug it in and lick my fingers and
have a poke around it  :)

What tests can i do and what silly mistakes can i make where the results do not match the theory?

Thanks.

 

Offline GEuser

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Re: Caravan PSU / Battery Charger issue
« Reply #38 on: May 17, 2016, 03:25:38 am »
Us mechanics/lorry bods can talk in our own language aye! Another Dave .

Those prices mentioned are going back a bit , when lead went up worldwide a few years ago battery's went up the next day practically and "Shot" up .

Also that's the trouble with buy on budget items sometimes at least when i have too i look for specifications or stickers on items and then also go by practicability , like for instance the weight of a battery .

I just looked about for a real 200A DCB and are they "Up" there still , a real arm and a leg job btw .

Personally i'd go with whats working atm , and find something else to learn from as the variables are too great (like the type/real size/ fake or not battery , i't be far more of a concern if the battery was a £200 or more real one , one could spend some time and money fitting up low consumption lights? or a vibrating bed? or chook band radio's? see you ha ha ha ...

Happy Vanning .
Soon
 

Offline Another DaveTopic starter

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Re: Caravan PSU / Battery Charger issue
« Reply #39 on: May 17, 2016, 06:06:10 pm »
Low consumption lights already done,  vibrating bed is self powered from my snoring or worse :)

Radio is mains powered.  I never did get around to installing a 12v unit.

Thats why i had a feeling the charger was at fault initially, battery good and no excessive loads
so it left nothing else really.

My last trip confirmed that a ikkle 3.6A charger had no issues with keeping the battery topped up
and it was switched off at night and during the day. Only on whilst the lights were on at night
4- 5 hours or so. and a short burst in the morning after using the waterpump for washing etc.

What to replace it with though?  "proper" caravan chargers are silly money.

Thanks


 

Offline Delta

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Re: Caravan PSU / Battery Charger issue
« Reply #40 on: May 17, 2016, 08:06:33 pm »
12v smart chargers can be had cheaply - I got mine for £13 from Aldi (or was it Lidl...?).  Essentially the same as this one.

Benefits; they will charge at their max rate (probably only about 5A on mine) until the battery is full, then switch to a nice gentle float charge, so you can leave it connected.

Not sure how they will react to the loads being connected as it tries to charge, but it sounds like you could just charge overnight.
 

Offline Another DaveTopic starter

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Re: Caravan PSU / Battery Charger issue
« Reply #41 on: May 17, 2016, 10:47:07 pm »
Thats what worried me with the CTEK charger it only gave out 3.6Amps max.

With the lights on at night the charger got quite warm. Fighting a losing battle but only just
i think.  It didnt take long after switching the lights off for the charger to show the green
battery full light.

I thought the ALDI/LIDL one was 3.6Amp also?   The voltage also goes a little high and over time
i think it may cause the battery to gas.

Budget option for a charger and to keep the voltage down to 13.8 max?

Thanks

 

Offline Delta

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Re: Caravan PSU / Battery Charger issue
« Reply #42 on: May 17, 2016, 11:25:42 pm »
What about a generic 15V SMPS, with a solar charge controller to look after the battery and power the loads?

Solar dudes - would this work?  Would the controller just stop drawing current from the PSU when the battery is full?
 

Offline Another DaveTopic starter

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Re: Caravan PSU / Battery Charger issue
« Reply #43 on: May 18, 2016, 07:45:12 pm »
I was just about to type i have charge controllers for the solar, but do not use the solar and mains
charger at the same time. Solar packed when we are off grid.

But i re-read your post and i think you mean use that as a charge controller?  Instead of the solar
panel connected, connect a 13v supply to that side and then onto the battery as normal?

Even though it states 20A i have read reviews where they are identical to the 10A ones with no additional
features to handle 20A. Most reviews state they are dountful whether it will handle 10A.

I think i have that one, but its only used with a 25w panel.

 

Offline Delta

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Re: Caravan PSU / Battery Charger issue
« Reply #44 on: May 18, 2016, 10:09:35 pm »

But i re-read your post and i think you mean use that as a charge controller?  Instead of the solar
panel connected, connect a 13v supply to that side and then onto the battery as normal?


Yeah, that's what I was getting it, should have been clearer!

You may need more that 13v to give it enough headroom to float the battery at 13.8v.

Maybe start a new thread in the renewables section to see if any of the solar experts can advise....  :-//
 

Offline Another DaveTopic starter

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Re: Caravan PSU / Battery Charger issue
« Reply #45 on: May 19, 2016, 08:28:29 pm »
They say 13.8v floating, but does it really need to be that high?  I think 12.8v - 13v would suffice in
my situation.   The battery doesnt really get run down and a 6amp charger should keep it
close to fully charged anyway.

As long as it can keep the 13v under load.

Or am i missing something?
 

Offline tautech

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Re: Caravan PSU / Battery Charger issue
« Reply #46 on: May 19, 2016, 08:50:47 pm »
They say 13.8v floating, but does it really need to be that high?  I think 12.8v - 13v would suffice in
my situation.   The battery doesnt really get run down and a 6amp charger should keep it
close to fully charged anyway.

As long as it can keep the 13v under load.

Or am i missing something?
You are.

https://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery
<snipped>
Open-circuit (quiescent) at full charge: 2.10 V
Open-circuit at full discharge: 1.95 V
Loaded at full discharge: 1.75 V
Continuous-preservation (float) charging: 2.23 V for gelled electrolyte; 2.25 V for absorbed glass mat (AGM) and 2.32 V for flooded cells. Float voltage recommendations vary among manufacturers due to different lead acid concentration and positive plate grid alloy. Precise float voltage (±0.05 V) is critical to longevity; insufficient voltage (causes sulfation) is almost as detrimental as excessive voltage (causes positive plate corrosion, expansion and electrolyte loss.)
Typical (daily) charging: 2.37–2.4 V (depending on temperature and manufacturer's recommendation)



2.32 x 6 = 13.92V....close to the middle of the old and generally accepted 13.8 -14.2V


http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery


You've asked about chargers.....I say again, stick with your CTEK or get a larger CTEK, they're good stuff.
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Offline Another DaveTopic starter

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Re: Caravan PSU / Battery Charger issue
« Reply #47 on: May 20, 2016, 11:37:26 pm »
My CTEK got really warm though.  Although it is only rated at 3.6A. This was not far off keeping the battery
close to fully charged.

Would a larger one run cooler or would you recommend additional heatsinking?   The unit is fitted
directly beneath a bed so fans cannot be used unless 100% silent.

No issues with openeing one up and adding additional heat spreaders if that will help it last longer
and no risks of overheating.



 

Offline tautech

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Re: Caravan PSU / Battery Charger issue
« Reply #48 on: May 20, 2016, 11:51:28 pm »
My CTEK got really warm though.  Although it is only rated at 3.6A. This was not far off keeping the battery
close to fully charged.

Would a larger one run cooler or would you recommend additional heatsinking?   The unit is fitted
directly beneath a bed so fans cannot be used unless 100% silent.

No issues with opening one up and adding additional heat spreaders if that will help it last longer
and no risks of overheating.
If it's connected all the time it's not likely to run hot unless there's been a period of high draw off as the charger will supply some of the load too but then still needs to top the battery off.
Once the battery is close to fully charged and the draw on the charger low it should run quite cool....leave it connected for some time then check the draw which if more than a few hundy mA indicates the battery is tired.
Not saying it is  ;) but the more you play with these things the more feel you have for what's normal.

Trust the CTEK will not hurt your battery, just monitor it's behaviour for your own piece of mind.  :)
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Offline jitter

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Re: Caravan PSU / Battery Charger issue
« Reply #49 on: May 21, 2016, 06:59:29 am »
My CTEK got really warm though.  Although it is only rated at 3.6A. This was not far off keeping the battery
close to fully charged.

Really warm or downright hot? Warm is OK, blazingly hot isn't.

Quote
Would a larger one run cooler or would you recommend additional heatsinking?   The unit is fitted
directly beneath a bed so fans cannot be used unless 100% silent.

It looks like you keep the CTEK charger connected and switched on when you're using lights, etc. I don't think that you're supposed to use it that way because of its processor controlled nature.

I looked at the manual, and though it doesn't specifically state that it cannot be used to charge and supply power to a load at the same time, it does state that it should only be used what it's intended for, and that's as a charger. To me this implies that charging AND using stuff like lights must never be done simultaneously, not with this particular charger.

It doesn't look like it destroys the charger, but it will most likely be the reason why it's running hot despite having a fully charged battery. But that's to be expected. With two power sources in parallel, the one with the highest voltage (and that will always be the charger) will supply all the current up to the point that it's capable. Only then will the remaining current come from the battery. So while drawing 10 A, the charger will supply its full 3.6 A all the time with the battery supplying the rest. That's why the charger runs hot.

This is a processor controlled charger that goes through different charging phases to end up with a nicely charged battery. Once you start switching loads in and out, you will upset this programme. This might lead to the charger breaking off a phase and going back to the start, or jump right to the end when the load is switched off. So, the behaviour of the LED going green after switching off the load is not surprising at all IMHO.

Now, the original charger/power supply you started this topic with will basically not behave differently, but it is a non regulated device and it would have been designed with powering the caravan and charging the battery at the same time in mind. With this too, the current drawn will divide between PSU and battery depending on the voltages, but now there's no charging programme to be interrupted. In this setup, everything is determined by the currents drawn by the battery and the load.

Quote
No issues with openeing one up and adding additional heat spreaders if that will help it last longer
and no risks of overheating.

This won't be necessary when used as intended. Besides, that CTEK charger will most likely have protection against mishaps, among which should be overheating.
 


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