[Carl2009]

Hi guys,

I have a Pure Freedom RO/DI van mount with 2 x pumps and 2 x Flowmaster DigiFM controllers one wired split relay to trickle charge a 12v 110aH leisure battery. System has worked flawlessly since installation in 2009. The leisure battery get's charged nightly with a CTEK MXS7 smart charger as well: belt and braces.

Last night as I sometimes do I had a problem charging the battery (it's 3.5 years old). Once in a while the red Error light comes on. This indicates a short, reverse polarity or a problem in charging. The manual says:

"Has charging been interrupted in or ?
Restart the charger by pressing the MODE-button. If charging is
still being interrupted, the battery...
 ...is seriously sulphated and may need to be replaced.
 ...can not accept charge and may need to be replaced.
 ...can not keep charge and may need to be replaced. "

I assume that my occasional problem is an issue with interrupted charging so I just reset the charger and off we go. it's fine. Last night (as Im do when I have these errors) I checked twice over the next 4 hours and it was charging normally.

This morning on the 2nd property flow to the brush suddenly reduced. I though the controller needed re-calibrating as it does in winter and the symptom is similar as the pressure switch flips in and out. However that was not the problem.
The problem was that BAT was showing on the controller - I was down to 11.9v. I have a trolley so I switched the battery out of it and off we go - controller showing 12.5v.

I decided to buy a new battery - this one is over 3 years old and gets a lot of hammer and for the price it's a no brainer. So I get home and swap out the trolley battery back into the trolley and wire up the new battery. Switch on - controller showing 12.5v.

I decide to get my meter on all 3 batteries, the old, the trolley and the new batteries:

Old one I have a problem with - 12.9v
Trolley: 13v
New battery: 12.9v

So now i'm confused. Just to clarify I have a digital controller on the trolley and it's showing 12.5v with the trolley battery in (but meter says 12.9v) and both controllers in the van were showing the same with the trolley battery - 12.2/4v), and both show the same voltage around 12.5v on the new battery, so what's occurring? If the controller that was hooked up to the original "problem" battery had gone bandit surely the other one would read the correct voltage - both unlikely to fail at the same time -  but they both show the same voltage.

Any ideas?

[Don Kee]

When they're fully charged the voltage will still be the same as the dud battery will still charge up to max (in other words a dud battery will still take charge)

The problem is how long the dud battery holds its charge (i.e run all 3 batteries for an hour and then check the voltage. You'll see a difference then) as it will have less capacity

The voltage is more of a capacity indicator, so how much charge is in the battery, not how long the charge will last for

[Dave Willis]

What Donkey said.

This is why when you take your duff battery back to get a new one under warranty they charge it up, take a reading and tell you there's nothing wrong with it ............. except it only runs your pump for half a day.

[Carl2009]

Thanks Don Kee, but that doesn't  explain why the controllers show one voltage and a meter another.... Any ideas?

[CleanClear]

Thanks Don Kee, but that doesn't  explain why the controllers show one voltage and a meter another.... Any ideas?

The connections to your controller are duff. They may look fine, seem secure etc.. but they have not got a good electrical contact. If you've used crimps etc..... you'll probably find any exposed copper wire has corroded. (light blue on the copper).

I only use soldered joints now for that reason. Its definately your wiring.

[andyM]

Thanks Don Kee, but that doesn't  explain why the controllers show one voltage and a meter another.... Any ideas?

The connections to your controller are duff. They may look fine, seem secure etc.. but they have not got a good electrical contact. If you've used crimps etc..... you'll probably find any exposed copper wire has corroded. (light blue on the copper).

I only use soldered joints now for that reason. Its definately your wiring.

I suspect this is probably right as well.
If a new battery that's fully charged is only reading 12.5 volts at the controller there could be a wiring/connection problem between battery and controller.
I find that when I do occasionally get an electrical problem it tends to happen during the damp and colder part of the year (Autumn/Winter), not sure if this is coincidence or not but the damp seems to show up weaknesses in the electrical system.

[Carl2009]

Thanks Don Kee, but that doesn't  explain why the controllers show one voltage and a meter another.... Any ideas?

The connections to your controller are duff. They may look fine, seem secure etc.. but they have not got a good electrical contact. If you've used crimps etc..... you'll probably find any exposed copper wire has corroded. (light blue on the copper).

I only use soldered joints now for that reason. Its definately your wiring.

Lads - do you mean the crimps on the terminal connectors that go on the battery? Or inside the controllers themselves...? Sorry to seem thick.

[SeanK]

The reading you get from your system will always be lower as it will be drawing power as the reading is being taken
the battery wont be in a rested state.

[Carl2009]

Cheers SeanK

Is it good enough to get some fresh crimp connectors and solder them on. Is that what you do  CleanClear? If not can you post examples of what you use. Ta.

[Don Kee]

Everyones answered your questions really

As SeanK says, once your controller is on, its putting light load on the battery (as its pulsing your pump to test the 'DE') so a reading of 12.5-12.7 is about right
When you're using your voltmetre is showing a reading of your battery in a rested state

Soldered wiring and proper battery terminals will be a good idea. Crimps work as well (i crimp to be honest but use proper battery terminals with a bit of grease on too) but they'll probably want changing every so often due to light corrosion (moisture in the air will oxidise the copper after a while)

[Carl2009]

Good advice from all. Thanks. I'll let you know how I get on. Appreciate your time.

Carl

[Ian Sheppard]

Very good advise above.  In particular regard Battery capacity and the ability of a battery to hold a Charge as it ages..

These are links to some general information regarding Volt drop and battery basics that  find useful.
https://www.linkedin.com/pulse/volt-drop-its-effects-wfp-system-ian-sheppard?trk=mp-author-card

https://www.linkedin.com/pulse/12v-deep-cycle-batteries-ian-sheppard?trk=mp-author-card

With the system being 3 1/2 years old the controllers will be V9 models. The V9 measures the battery voltage at the controller rather than at the battery terminals. So allowing for volt drop along the cable and the pump coming under load. A difference 0f up to 0.4 of a volt is about right. The current V11 model controller measures voltage across the terminals so is less effected by volt drop along the cable.

It sounds like you have a good battery maintenance system and a well balanced system.

[Carl2009]

Very good advise above.  In particular regard Battery capacity and the ability of a battery to hold a Charge as it ages..

These are links to some general information regarding Volt drop and battery basics that  find useful.
https://www.linkedin.com/pulse/volt-drop-its-effects-wfp-system-ian-sheppard?trk=mp-author-card

https://www.linkedin.com/pulse/12v-deep-cycle-batteries-ian-sheppard?trk=mp-author-card

With the system being 3 1/2 years old the controllers will be V9 models. The V9 measures the battery voltage at the controller rather than at the battery terminals. So allowing for volt drop along the cable and the pump coming under load. A difference 0f up to 0.4 of a volt is about right. The current V11 model controller measures voltage across the terminals so is less effected by volt drop along the cable.

It sounds like you have a good battery maintenance system and a well balanced system.

Thanks Ian. I only had a couple of new crimp-on ring terminals in the toolbox. I put these on (can I solder them on as well?) on Sunday morning and the battery was fully charged. No issues since. I bought new ones last night - first opportunity to buy - and will replace all existing old ones this weekend.

Note that the controllers date from 2009, not 3.5 years ago.

Thanks for the links - interesting reads.

I might need to replace all the wire between the battery and the controllers - if I replace crimp bullet connectors as well I won't have enough wire to reach the battery terminals. Can anyone give me a link to what I need - i'm no electrician and don't want to get the wrong "gauge"

[Ian Sheppard]

Hi Carl

If you need to replace the cable I would suggest either 1mm or 2mm,Tri rated, with a maximum rating of 18amps. The 2mm gives a thicker copper core and reduces the effect of volt drop along the cable. Good tight crimped connectors are OK, ensure sufficient cable outer is stripped to give a good connection to the copper core. The usual DIY stores will sell this in meter lengths.

Cheers

Ian

[Carl2009]

Hi Carl

If you need to replace the cable I would suggest either 1mm or 2mm,Tri rated, with a maximum rating of 18amps. The 2mm gives a thicker copper core and reduces the effect of volt drop along the cable. Good tight crimped connectors are OK, ensure sufficient cable outer is stripped to give a good connection to the copper core. The usual DIY stores will sell this in meter lengths.

Cheers

Ian

Thanks Ian. Appreciate the time taken by all to reply.

[Carl2009]

1.5mm (can't find 2mm) seems to be rated max 21A. Is this OK?

[CleanClear]

I trim off any cable to be joined, twist it together, solder it, then its finished of with shrink tube. Get no problems.




I attatch the end to an eye, which is a crimp, but i just crimp in loosely and solder it. It makes for a much better connection than relying on just a crimp.



And i'm not sure what others use ? Most i've seen use crocodile clips or similar. I use these, get them from Halfords or Ebay.

[Carl2009]

I trim off any cable to be joined, twist it together, solder it, then its finished of with shrink tube. Get no problems.




I attatch the end to an eye, which is a crimp, but i just crimp in loosely and solder it. It makes for a much better connection than relying on just a crimp.



And i'm not sure what others use ? Most i've seen use crocodile clips or similar. I use these, get them from Halfords or Ebay.

Thanks for the pics. More things to consider.

[Ian Sheppard]

1.5mm (can't find 2mm) seems to be rated max 21A. Is this OK?

Hi Carl yes the 1.5mm max to 21 amps should be ok. As long as you have the 7.5a,p fuse in line the fuse will always blow well before any issue with the cable.

Cheers

Ian

[Carl2009]

Cheers Ian