Help! Is my EHU actually charging my batteries?

[Pudsey Bear]

If I don't charge the VB it will go flat, I've already seen the voltage drop to less than 11v in less than 14 days so I got the Ctek a while ago and it seems to be charging it up so no point in messing about with other methods to my mind.

The LB seem to be getting enough charge from the solar panel, so no point in doing much more, the van does have to be ready to go at fairly short notice as Liz has the car most of the time so if I need to go out I use the van.

Hopefully, when the sun is more overhead this crap MPPT controller will start to do the job I bought it for and start charging the VB again.

I should really have started a new thread for my van but I commented on this one and it's sort of progressed from there.

Both the VB & the LB I think need to be replaced at some point but I'm trying to keep them going a bit longer until I can afford it, even when I get new ones they will need to be kept charged.

 

[wildebus]

If I don't charge the VB it will go flat, I've already seen the voltage drop to less than 11v in less than 14 days so I got the Ctek a while ago and it seems to be charging it up so no point in messing about with other methods to my mind.

Except you are obessing about the cost of running that charger and constantly messing with when to turn it on, how long to have it switched on, etc, etc.
Life is too short for that!

The LB seem to be getting enough charge from the solar panel, so no point in doing much more, the van does have to be ready to go at fairly short notice as Liz has the car most of the time so if I need to go out I use the van.

Hopefully, when the sun is more overhead this crap MPPT controller will start to do the job I bought it for and start charging the VB again.

I should really have started a new thread for my van but I commented on this one and it's sort of progressed from there.

Both the VB & the LB I think need to be replaced at some point but I'm trying to keep them going a bit longer until I can afford it, even when I get new ones they will need to be kept charged.

If I had your van as you describe it, I would NOT connect a Mains Charger to the Vehicle Battery. I would fit an Ablemail AMT12-2 Battery Maintainer, program it so the vehicle battery is maintained at a certain level when the Leisure Battery is being charged via solar (if you are getting 'enough' charge from the solar, chances are you have spare charge from the solar) and even if the Leisure Battery was not charging, the AMT12-2 will ensure the Vehicle Battery does not drop to a critical level (part of the design features to help save one battery by using spare power from the other).

There really is no point (and I mean NO point) in having a mains charger dedicated to the starter battery.

 

[Pudsey Bear]

I seem to be getting very conflicting advice as when I first mentioned getting a Ctek and when I bought it none of this was mentioned, but I have it now and it's getting used, I'm not obsessing about the cost of using it I am just trying to see how much it costs to use it which I think is a fair point with energy prices as they are, once I know the useage cost I can evaluate.

What is actually wrong with having a Ctek on the starter battery exactly, it is I thought what they were designed for and the advice was to NOT use the onboard charger.

 

[wildebus]

I seem to be getting very conflicting advice as when I first mentioned getting a Ctek and when I bought it none of this was mentioned, but I have it now and it's getting used, I'm not obsessing about the cost of using it I am just trying to see how much it costs to use it which I think is a fair point with energy prices as they are, once I know the useage cost I can evaluate.

What is actually wrong with having a Ctek on the starter battery exactly, it is I thought what they were designed for and the advice was to NOT use the onboard charger.

There is nothing wrong with it per se, it is just not an energy efficient way to charge the battery in a Motorhome and you seem to be particularly interested in how much it is costing to run.
As a way to charge a dead starter battery, or maybe putting on once a month to do a battery condition, yes. But as a primary way to keep the starter battery maintained, there are better more efficient and more convenient ways.

 

[Pudsey Bear]

I know what you mean, but is it efficient to spend more money on buying more stuff then have to pay someone to fit it too, I've already bought the Ctek, it's fitted and working and I didn't need to pay someone, I bought the MPPT controller and was told it wasa god one, but it turns out not good enough at this time of year hence the Ctek.

Obviously, I'm interested in the cost to run the Ctek, I also need to get my meter out and see again the actual voltage.

 

[merl]

The comment, slightly tongue in cheek (I hope!) that seemed to suggest it is cheaper to just replace the battery than spend the money on charging it over a period of time, was silly and for some reason this thread has started to go down a path of working out the equivalent costs to compare. That may be an interesting excercise possibly, but so flawed it is pointless.

Just a general comment .... when a motorhome is parked up, why have a battery charger on the starter battery anyway? the more important battery in terms of value is the Leisure battery. Does that have a battery charger in it as well? (if not it should do).
It makes much more sense to concentrate on keeping the leisure battery maintained, be it via EHU or Solar, and then using some kind of method to use that same power to maintain the starter battery at a good level. That method can be a manual one, such as a simple cable (fuses each end for safety) between the starter and leisure batteries, or an automated one, such as a Batter Master or similar, or ideally an Ablemail AMT12-2, which is programmable so you can configure to precisely your own requirements.

There are good reasons to keep a starter battery in a charged state, and it is not just financial. The comment, slightly tongue in cheek (I hope!) that seemed to suggest it is cheaper to just replace the battery than spend the money on charging it over a period of time, was silly and for some reason this thread has started to go down a path of working out the equivalent costs to compare. That may be an interesting excercise possibly, but so flawed it is pointless.

Reasons to maintain the Starter Battery
1) so you can use the vehicle when you want
2) to avoid a potential large repair bill if you let it decline and try and start the engine with a low voltage. This is a very real issue on some Ducatos (and likely other Sevel vans) which should not be ignored.
3) avoid buying a new starter battery prematurely as it has been left to discharge too low

Reasons not to maintain the Starter Battery
1) ?


Cost of maintaining the Starter Battery
1) If you use a Mains Charger, cost of charger, plus the electrical overhead of the power used
or:
2) cost of a piece of cable and two fuse holders (manual maintenance method) as you are (or should be) maintaining the Lesiure Battery anyway
or:
3) cost of a Battery Maintainer/DC-DC Trickle Charger (automated method) as you are (or should be) maintaining the Lesiure Battery anyway

Cost of additional power to maintain the Starter Battery
1) If it was maintained by excess power from Solar, that would be £zero.
2) If it was maintained via the Mains Charger to the Leisure Battery, then you can base the cost roughly on the extra power taken by the trickle charger to send to the Starter Battery. Each van will vary, but in my own case (I just looked now to check the last 12 hours), the Starter Battery is taking around 5Ah/Day to maintain it at around 12.5V. More than I expected, but that is the number.

5Ah/Day at a nominal 12.5V is 62Wh/Day. Over a year (so you have not used the vehicle for a full year), that works out to be 22.6kWh/Annum.
22.6kWh at 50p/kW (we will assume that rate) will mean maintaining the Starter Battery at a healthy state for a year has cost £11.30 for the year. This would be worse case scenario as if you have solar, the solar would be doing the work for a reasonable period and that maintanance has no additional energy cost. Assuming you are using the vehicle sometimes (!), there is no maintenance needed during that time.
A more likely cost for this starter battery maintenance might be around £6/Annum to include a Winter Layover period with no use and poor solar


Ok. For those who just want to jump to the TL: DR summary ....
DO NOT USE A CHARGER ON THE STARTER BATTERY OF A MOTORHOME. GET A DC-DC BATTERY MAINTAINER AND LET THE STARTER BATTERY CHARGE VIA THE LEISURE BATTERY CHARGING SYSTEM

and if the reply is "I am not charging the Leisure Battery", then the answer to that is "Why the hell not if you think you need to charge the Starter Battery?"

The comment, slightly tongue in cheek (I hope!) that seemed to suggest it is cheaper to just replace the battery than spend the money on charging it over a period of time, was silly and for some reason this thread has started to go down a path of working out the equivalent costs to compare. That may be an interesting excercise possibly, but so flawed it is pointless.

The comment certainly wasn't tongue in cheek.
The comment was directed at Kev (Pudsey bear) and anyone else who leaves their charger/chargers on full time without actually considering what they are trying to achieve, what they actually do achieve and at what cost. Period.
Electricity will be 51p a unit in three weeks time, and depending on circumstances (which I mentioned) continuing on with the same old ways might not be the best way anymore but in order to ascertain what is sensible we must know the cost and to know the cost we must do the maths and hence definitely not flawed and pointless and rather than being "a possibly interesting exercise" I'd say an essential exercise and an eye opener for many.
Only after the true costs are known and factored in can we make the most logical decisions going forward. That could involve sticking with what we've got or changing our setups/actions along the lines you suggest but we MUST know the true cost first.

 

[Pudsey Bear]

I went down to the van and thought I'd check the vans habitation panel for both batteries, no idea how accurate they are as I'm not about to attack the batteries with my meter until my back is a bit better.

Hab is being fed by the panel, Engine is fed by the Ctek.

 

[wildebus]

The comment, slightly tongue in cheek (I hope!) that seemed to suggest it is cheaper to just replace the battery than spend the money on charging it over a period of time, was silly and for some reason this thread has started to go down a path of working out the equivalent costs to compare. That may be an interesting excercise possibly, but so flawed it is pointless.

The comment certainly wasn't tongue in cheek.
The comment was directed at Kev (Pudsey bear) and anyone else who leaves their charger/chargers on full time without actually considering what they are trying to achieve, what they actually do achieve and at what cost. Period.
Electricity will be 51p a unit in three weeks time, and depending on circumstances (which I mentioned) continuing on with the same old ways might not be the best way anymore but in order to ascertain what is sensible we must know the cost and to know the cost we must do the maths and hence definitely not flawed and pointless and rather than being "a possibly interesting exercise" I'd say an essential exercise and an eye opener for many.
Only after the true costs are known and factored in can we make the most logical decisions going forward. That could involve sticking with what we've got or changing our setups/actions along the lines you suggest but we MUST know the true cost first.

The true cost? I told you the costs in my post of using a battery maintainer via LB (probably under a fiver/year) and the much greater convenience vs using a battery charger which will ALWAYS be greater. The cost of buying each item will be comparable. it is a no-brainer to which is easier to run and the cost per kW is actually not relevant in fact. This is why you and kev are going down a rabbithole of maths which will tell you nothing regarding best practice. it is as essential an excercise as watering your plants in the rain.

The comment was available for all to comment on. you don't get to choose who replies.

 

[wildebus]

I went down to the van and thought I'd check the vans habitation panel for both batteries, no idea how accurate they are as I'm not about to attack the batteries with my meter until my back is a bit better.

Hab is being fed by the panel, Engine is fed by the Ctek.

View attachment 118170

Kev, I know you don't want to hear it, but you are wasting ALL the power the CTEK is using. The solar can do the VB as well. It is that straightforward.
Ok, you bought the CTEK so may as well use it. But just remember every penny it is using is a penny you don't need to have spent if you did even such a simple thing as putting a piece of wire between the two batteries.

 

[merl]

The true cost? and the much greater convenience vs using a battery charger which will ALWAYS be greater. The cost of buying each item will be comparable. it is a no-brainer to which is easier to run and the cost per kW is actually not relevant in fact. This is why you and kev are going down a rabbithole of maths which will tell you nothing regarding best practice. it is as essential an excercise as watering your plants in the rain.

The comment was available for all to comment on. you don't get to choose who replies.

The comment was available for all to comment on. you don't get to choose who replies.
Sorry, but I don't understand what you're trying to get at? I don't want to choose who replies David. Can you explain please?

 

[Pudsey Bear]

David can you cast your mind back to when I bought the Controller, you said it was a good make (this is after I bought it I think so not blaming you at all in any way) it is supposed to charge the VB as well, but a few weeks ago, maybe January you took a look at the manual or the website for it and you said in words I struggled to understand that it actually couldn't do that at this time of year I think because it just wasn't getting enough sun or something. I recall being well pissed off as I had bought the thing in Jan 22 so a bit late to complain to them

High efficiency 10A dual battery MPPT solar charge controller with LCD display for solar panels up to 130W (12V battery system) / 260W (24V battery system) from Photonic universe

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

 

[Pudsey Bear]

I'm wanting a bit more info actually on another charger for my Chromebook at home.

Pushing my luck ??

I can either charge it via a USB plug or I can use the supplied charger but I'm not sure which is the most efficient, the USB charger is mega slow and won't keep up with watching Netflix or YouTube, I assume the supplied charger will cope better, but I always for get to turn them off after things are charged, do they still use much juice when not connected to the devices?

The Chromebook charger

 

[merl]

David can you cast your mind back to when I bought the Controller, you said it was a good make (this is after I bought it I think so not blaming you at all in any way) it is supposed to charge the VB as well, but a few weeks ago, maybe January you took a look at the manual or the website for it and you said in words I struggled to understand that it actually couldn't do that at this time of year I think because it just wasn't getting enough sun or something. I recall being well pissed off as I had bought the thing in Jan 22 so a bit late to complain to them

High efficiency 10A dual battery MPPT solar charge controller with LCD display for solar panels up to 130W (12V battery system) / 260W (24V battery system) from Photonic universe

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

No Sun=no charge kev, it's not the controller's fault

 

[Pudsey Bear]

But it was charging the LB.

 

[merl]

I'm wanting a bit more info actually on another charger for my Chromebook at home.

Pushing my luck ??

I can either charge it via a USB plug or I can use the supplied charger but I'm not sure which is the most efficient, the USB charger is mega slow and won't keep up with watching Netflix or YouTube, I assume the supplied charger will cope better, but I always for get to turn them off after things are charged, do they still use much juice when not connected to the devices?

The Chromebook charger
View attachment 118171

Measure it, you've got the kit!
Shouldn't be very much and considerably less than running a Ctek to your cab battery!!! (arf, arf)

 

[merl]

The true cost? I told you the costs in my post of using a battery maintainer via LB (probably under a fiver/year) and the much greater convenience vs using a battery charger which will ALWAYS be greater. The cost of buying each item will be comparable. it is a no-brainer to which is easier to run and the cost per kW is actually not relevant in fact. This is why you and kev are going down a rabbithole of maths which will tell you nothing regarding best practice. it is as essential an excercise as watering your plants in the rain.

The comment was available for all to comment on. you don't get to choose who replies.

after 23:50 minutes

But the online calculator is way off
View attachment 118145

£1.86 must be wrong but I set it to 0.228 Kwh (as per the display) @ 34p for 24 hours. so it must be only 0.22 Watts which makes more sense
View attachment 118146

View attachment 118147

The display shows 0.228 Kwh and that was used over 24 hours.
Over a year that equates to 365 X 0.228 Kwh = 83 Kwh / year.
85 Kwh at 51p = £42 per year to run your Ctek.

 

[wildebus]

It is a decent controller. But solar in the winter is a waste of time.
Solar is starting to work now we are in March.
Today I got 700Wh of Solar. Doesn't sound too bad until you remember that in the summertime you can get over 1kWh from a 100W panel, and I have 590W of panels connected. still only getting a 1/10th of what I would expect/hope to get in about 4 months time.
You are getting a reasonable result from it right now considering the time of year.

You have the dual output controller? in that case get that second output wired up to the starter battery! it won't do the vehicle/starter without it being connected.

 

[trevskoda]

I know what you mean, but is it efficient to spend more money on buying more stuff then have to pay someone to fit it too, I've already bought the Ctek, it's fitted and working and I didn't need to pay someone, I bought the MPPT controller and was told it wasa god one, but it turns out not good enough at this time of year hence the Ctek.

Obviously, I'm interested in the cost to run the Ctek, I also need to get my meter out and see again the actual voltage.

Why did you not fit a votronic mppt solar control unit, 1 ah goes to the starter batt, the rest for the hab batt.
Maybe your solar is too small, im running 200w and could go another 50w portable in the front cab windshield, just remembered I have one in the loft, next job sorted.

 

[Pudsey Bear]

You are getting a reasonable result from it right now considering the time of year.

You have the dual output controller? in that case get that second output wired up to the starter battery! it won't do the vehicle/starter without it being connected.

Yes, it does seem good but this is where I get a bit (a lot) lost the van is facing south and is tilting forwards towards the sun and perhaps why it's a bit better than expected.

Yes, it is dual output and I paid to have it all connected up last year so it should be putting something into the VB as well as the LB but not measurable at the moment hence the Ctek, which will hopefully not be needed much longer.

I do have a simple 4a charger, but if I left that on I reckon it'd turn the VB into a kettle.

 

[Pudsey Bear]

Why did you not fit a votronic mppt solar control unit, 1 ah goes to the starter batt, the rest for the hab batt.
Maybe your solar is too small, im running 200w and could go another 50w portable in the front cab windshield, just remembered I have one in the loft, next job sorted.

I don't have that kind of money Trev, I already have a controller that does the same, if I bought a Votronic I'd have two, then someone else would come along and suggest some other method, in fact, they have but I have to work with what I have.

What irks me most is not being able to get to grips with testing or fitting things myself, and conflicting advice and suggestions is most confusing, and often not as helpful as intended as I'm not a sparky or understand most of it.