If that’s the standard of their work, I wouldn’t let them anywhere near my motorhome.
Sadly, too many “professional” installers charge a lot of money for doing bad work.
Inverter anomaly: Hair dryer causing overload
- Thread starter offagen
- Start date
Sadly, too many “professional” installers charge a lot of money for doing bad work.
headlight many thanks for your helpful comments.
At one stage, prior to having the work done, I had been looking at replacing the previous lead/acid batteries with a single 150Ah lithium battery but then that particular brand suffered a couple of battery fires that damaged motorhomes. That detered me and, on the advice of the company we have been using for some years, the decision was taken to use AGM batteries. Regrettably I wasn't advised by them that the two AGMs would be inadequate to take full advantage of the 1200w inverter.
Am I right in thinking that a change to lithium battery would require a B2B installation to replace the present split-charge relay? I was also told by the lithium battery company that the present Sargent battery charger could not be used, being unsuitable for lithium.
At one stage, prior to having the work done, I had been looking at replacing the previous lead/acid batteries with a single 150Ah lithium battery but then that particular brand suffered a couple of battery fires that damaged motorhomes. That detered me and, on the advice of the company we have been using for some years, the decision was taken to use AGM batteries. Regrettably I wasn't advised by them that the two AGMs would be inadequate to take full advantage of the 1200w inverter.
Am I right in thinking that a change to lithium battery would require a B2B installation to replace the present split-charge relay? I was also told by the lithium battery company that the present Sargent battery charger could not be used, being unsuitable for lithium.
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Ideally yes a B2B is a much better way to charge lithiums and also protects the alternator.
As to your onboard mains charger it depends how you use your van.
I have lithium, a B2B and solar MPPT with lithium profile but as I rarely go on hook up (a couple of nights a year) I have left my Sargent PX300 non lithium profile charger in place.
I run a 2,000 watt inverter from a 230AH lithium.
BTW your inverter isn't 1200 watts it's 1200va.
It's rated at 1,000 watts continuous iirc.
If those batteries were wired up correctly with suitable cables your inverter will probably work, how long your batteries will last will depend how much you use the inverter for but for short burst they would do…
However the “professionals” have have made a balls up on yours and I wouldn’t trust them to do anything on my van, I’m quite capable of mucking it up myself..
However the “professionals” have have made a balls up on yours and I wouldn’t trust them to do anything on my van, I’m quite capable of mucking it up myself..
Lenny HB
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LifeP04 Lithium batteries are about the safest type of battery you can get for a Motorhome far safer and less of a fire risk than a lead battery.
Your installer obviously didn't have a clue also AGM batteries are about the worst type of battery for leisure use.
Although a lot of suppliers say their Lithium's are drop in replacements although they will work you will never get the best out of them. It's marketing BS.
I would think for your use 200 ah of Lithium would be ideal for you.
Yes you would need to fit a B2B, maybe a new solar controller if your one doesn't have a Lithium profile. If you use EHU it's worth fitting a mains charger with a lithium profile.
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Thanks again for the info and for clarifying watts v va. 1000w continuous would be OK for our needs. Like you, we rarely have hook-up so we started off just wanting an inverter to charge e-bike batteries, electric toothbrushes, etc but then thought it would be good if it could also power a 850w kettle to save gas.
Our mppt solar controller has a lithium setting so all is good there. There are two 100w solar panels which is all that will fit in the available roof space. It would just be a matter of efficient charging of the lithium battery while on the move. I also have a NOCO Genius battery charger with a lithium setting that could be used for winter charging from the house 240v supply if necessary.
Having started this thread with just a query about a hair drier problem I have learned that I have considerably bigger issues to resolve. I'm really grateful to all who have contributed advice. What a great forum this is.
Edit: Lenny HB I just saw your post. Many thanks for the additional information
eddie
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Out of all possible battery scenarios, your set up is the worse. Distance between batteries, inverter incorrectly connected to one battery, and the cross connection wire to parallel the two batteries in inadequate
Resolve those issues and re-test before spending anymore money
Ultimately lithium is the best way to get the most out of a decent inverter and solar set up
I rarely bother plugging in and an a heavy AC user so it is achievable
Resolve those issues and re-test before spending anymore money
Ultimately lithium is the best way to get the most out of a decent inverter and solar set up
I rarely bother plugging in and an a heavy AC user so it is achievable
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I also have 200 watts solar.
With 230AH of lithium I can easily do 4 or 5 nights with no hook up in winter with minimal solar input and no engine charging.
Obviously however it depends on how much electric you use.
Then I have to add in the fact that we always seem to find things that use a little bit more than we intended when we specified the system!
eddie thanks. It's not the sort of work I can do myself due to limited knowledge and not having, for example, the correct tool to crimp heavy duty cables. I'll need to get it sorted by someone capable. I also need to decide whether to dump the two AGMs and switch to lithium with B2B, etc.
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Just an FYI I fitted a bigger inverter to my motorhome this week and a second leisure battery and inverter to my sisters motorhome 2 weeks ago.
I bought ready made cables, for £6.50 each, as my crimping tools are not really up to crimping 240 amp 35mm2 cables.
Do you have a link to the ready made cables please headlight?
BTW I should clarify that the 'scrawny' cables (good description RedFrame) connecting the two batteries weren't fitted by the company who installed the inverter. They were fitted by the original AutoTrail dealer when we requested an additional leisure battery at the time of MoHo purchase, back in 2017. An inverter wasn't envisaged at that time. However, the recent inverter installer should, of course, have replaced them with much more substantial cables.
PeterCarole29
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Can you put a link to the breaker you refer to please
Battery Lead Power Strap Earth Bond Leisure Cable Leads - 16mm2 - 35mm2 Custom | eBay
Copper conductor with P.V.C insulation, (resistant to oils, petrol, diesel, lubes and a range of diluted acids). All Leads are Crimped for a solid crimp and connection, then protected in the correct colour heat shrink to match the cable colour.
www.ebay.co.uk
This is the seller I bought from.
The cables are available in different lengths and mm2 and different lug sizes.
The quality seems good.
This site contains affiliate links for which MHF may be compensated.
This breaker is UL listed accredited and tested to 50 ka,
Outback Panel Mount Breaker 250A 150VDC
www.bimblesolar.com
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Unless everything else is connected to the other battery there doesn't seem enough cables. What is supplying the rest of the van? Where is the wire from the solar or b2b or split charge etc?
It is all connected to the other battery, Boldly, which was the original battery location below the locker floor (before the second leisure battery, shown in the photo, was fitted).
Yes I assume who ever fitted the second battery left the split charge, solar and onboard charger connections just on the original battery.
They should have connected all the positives to one battery and the negatives to the other battery.
It seems they didn't have a clue what they were doing.
That particular omission was on the part of the AutoTrail dealer's 'engineer' who installed a second lead/acid leisure battery back in 2017, not the company that recently installed the inverter and the AGM batteries.
I am clearly going to have to get someone specialising in MoHo electrics to sort the whole lot out - and probably fit a lithium battery that won't limit the performance of the 1200va inverter. Lenny suggested 200Ah lithium so I'll have a look to see what might fit.
I'm based in the south-east. Are there any recommended companies in this part of the country to do this work or should I be looking farther afield?
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FYI I recently replaced 2 x 100AH lead acid batteries with a 230AH Fogstar Drift LifePo4.
The Fogstar fitted in the same plastic battery box that 1 lead acid was in.
The 230AH Fogstar is rated to power a 2500 watt inverter so would be fine running your inverter at max.
Also the wiring is easier with a single battery set up.
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Isn't Just smiffy down there maybe he can help?
That's the same type of battery box that the present 2nd leisure battery is in and is close to the inverter. The downside is that the various cables running from the 1st battery to the Sargent panel would need to be replaced or extended. No big deal as the Sargent is right behind the inverter.
If the new battery could fit in the original below-floor battery box the yellow battery box could be removed to free up locker space, and also perhaps avoid having to replace/extend existing cables, but I'm doubtful that a 230Ah lithium would fit. Perhaps, also, a below-floor installation may not suit cold weather charging?
None of these issues seem insurmountable. It's probably best to take advice from whoever does the remedial work and can see where everything is.
Thanks again for your input.
Edit: The below-floor battery box measures 395x193x255h so the Fogstar 230Ah would not quite fit. However, a KS Energy 155Ah would fit, so maybe a possibility?? We'll see.....
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I would not do anyone else’s electrics, I’m not qualified and am a self confessed useless sparky, but I’ll have a go at my own…
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Hi Grommet
Your explanation might answer the anomaly that we have.
We have just had a 1200 inverter fitted with a 280a Fogstar Drift.
We have a 1000w hairdryer.
On the low setting (440w) the inverter switches off within 2 seconds.
On the high setting (880w) it copes with it!
If we run it on high for a few seconds and then switch quickly to low, the inverter stops. (Although this might be because it’s a rocker switch with ‘off’ in the middle, so it is off for a fraction of a second before being on low).
The hairdryer has two voltage settings; 240 & 120. It is currently set to 240v
It definitely sounds back to front to me as well!
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There are a few possible explanations, all depending on how the hairdryer manufacturer actually reduces the load to achieve the lower setting.
Option 1
There aren't different resistance coils inside the hair drier for each power setting (in your case just two). Just a single 880W element, and then a switching circuit that cuts the power in and out. 1/2 of the cycle for 440W, full cycle for 880W.
The way to measure this is with a high frequency oscilloscope. Multimeters and the built in measurement of the inverter are not fast enough to see high currents for a fraction of a second (they will show the average over a cycle, or even multiple cycles, which are happening 50 times per second).
The overload circuit is fast enough to react to a potential overload though, which is what you're probably seeing on the lower setting.
Option 2
Sometimes, in order to reduce power on first stage, the hair dryer may use a simple diode to power the resistive element only by one side of the sine wave.
This could be very tricky for many inverters, because it is a very unbalanced load.
There might be other explanations that I’m not aware of.
In a nutshell, it all depends on how your dryer implements the lower setting. If it truly has two heating circuits and the switch switches on only one or both of them then the results are surprising.
If your dryer implements it using some “clever” electronics then the above explanation would hold.
One thing is clear though, on the higher “simple” draw the inverter is coping. So the inverter is providing enough for a 1000w dryer.
Option 1
There aren't different resistance coils inside the hair drier for each power setting (in your case just two). Just a single 880W element, and then a switching circuit that cuts the power in and out. 1/2 of the cycle for 440W, full cycle for 880W.
The way to measure this is with a high frequency oscilloscope. Multimeters and the built in measurement of the inverter are not fast enough to see high currents for a fraction of a second (they will show the average over a cycle, or even multiple cycles, which are happening 50 times per second).
The overload circuit is fast enough to react to a potential overload though, which is what you're probably seeing on the lower setting.
Option 2
Sometimes, in order to reduce power on first stage, the hair dryer may use a simple diode to power the resistive element only by one side of the sine wave.
This could be very tricky for many inverters, because it is a very unbalanced load.
There might be other explanations that I’m not aware of.
In a nutshell, it all depends on how your dryer implements the lower setting. If it truly has two heating circuits and the switch switches on only one or both of them then the results are surprising.
If your dryer implements it using some “clever” electronics then the above explanation would hold.
One thing is clear though, on the higher “simple” draw the inverter is coping. So the inverter is providing enough for a 1000w dryer.
Thank you
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