Dangerously low batteries Sergent EC325 won’t switch on

[Titchdog]

yesterday my husband put the heating on in our Moho, he checked and the leisure batteries (2] were showing 8.7 dangerously low, so he connected the EHU and charged them, everything was fine. He checked this morning and again they showed 8.7 dangerously low, so he connected the EHU and switched on the EC325 unit, but nothing happened. We have tried rebooting the control panel over the door, checked the EHU but it still won’t switch on, any idea why? We have a solar panel tied into the unit.

 

[Speve]

I would think your batteries are goosed and you need to replace them.

 

[hilldweller]

First it looks like you fit new batteries.

 

[PhilandMena]

Some more info required I think. The batteries showing 8.7 after switching on the heating may not be an indication of low batteries as it's very difficult to get a true reading when a large load is applied. Questions! What did the reading say after the hook up was done. Was the hook up left connected and was the battery charger switched on aftet being hooked up. What kind oh heater do you have. Was your batteries left on charge all night with the hook up connected? Has your heating been left on all night too? I'm at a bit of a loss as to why no power when hooked up this morning
Check your kill switch had not been activated and check the 240 V circuit breakers. How old are the batteries how many are there and is this the first time you have found them to be flat

 

[csd4t]

I had a similar problem, turned out to be one of the connectors to the EC325 was almost burnt out! This one if my memory serves me correctly

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[Titchdog]

My husband took the unit out and put it back and hey presto we have electric! Must have been a loose wire, however the batteries are still going flat, not retaining a charge. If the batteries are flat again tomorrow then we need to buy some more. Thanks everyone!

 

[PhilandMena]

My husband took the unit out and put it back and hey presto we have electric! Must have been a loose wire, however the batteries are still going flat, not retaining a charge. If the batteries are flat again tomorrow then we need to buy some more. Thanks everyone!

I advise you to get to the bottom of why your batteries are flat otherwise if nothing changes your going to have another set of flat batteries.

 

[denisejoe]

It would take a long time to get the batteries back with a really good charger ones in mh aren’t the right sort for that

 

[autorouter]

He checked this morning and again they showed 8.7 dangerously low

Did you get the 8.7 Volts reading from the Control Panel or from a direct measurement of the battery terminal voltage?

I ask this because the charger, batteries and 12 volt user circuits are all switched by some relays, and one of these may have failed or might work intermittently. The batteries might be fine but the bad connection might show a low voltage at the panel.

This EC325 unit does 'off-line battery charging' where the battery is disconnected from the user circuits during charging, and the user circuits are powered by an internal mains power supply.

 

[Jaws]

Hhh.. the 325 is what we have..
By the sounds of it the charger in it has died a death
During experiments with ours I even stuck a known sh^gged traction battery on it to test things..
It was so past it I got 3.5v showing!!
Stuck it on, and to be fair the 325 did TRY.. brought it up to about 11v and would proly have kept going but I had proved it had no lower limit and that was all the test was about..
From what you say, the charger is doing absolutely naff all

BUT !
Make sure the mains breaker for the charger is up, and check the two 20A fuses in the 325 that feed the battery circuits

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[GWAYGWAY]

Check the liquid levels you might have boiled them dry with the solar if they haven't been topped up regularly.
I must check mine tomorrow before leaving. damned difficult to take them ou the see down into them.

 

[thebriars]

Whilst probably not a lot of use for the OP in this instance, but if the battery voltage gets too low, the normal van charger will not recover it. You need a smart charger, these will usually recover an almost fully discharged battery. These days, smart chargers are quite cheap to buy. Another trick is to put a pair of jump leads across it for a few minutes, until the voltage rises enough for the normal charger to take over. If you use the engine battery, do keep the engine running whilst doing this.

 

[tonyidle]

It's also worth knowing that it takes a lot more than 24 hours to charge a flat battery. If your batteries are, for example, 100Ah each a full charge will need to put back 200Ah + another 20% due to inefficiencies. That is 240Ah or 10A for 24h, 5A for 48h, etc. A charger will at best average 5A so you need to charge for at least two complete days and nights. And that doesn't include recovery time for damaged, over-discharged, batteries. If recovery is possible using a charger with that facility it is likely to take another 24h.

 

[bigtree]

So many helpful posts and no replies from the OP, this is happening more and more. Come on for help and then disappear, is this what the world is coming to ?

 

[thebriars]

It's also worth knowing that it takes a lot more than 24 hours to charge a flat battery. If your batteries are, for example, 100Ah each a full charge will need to put back 200Ah + another 20% due to inefficiencies.

You say it needs 200ah to charge a 100ah battery, yet you've already allowed extra for inefficiencies, so where does the other 100ah go?

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[ChrisL]

You say it needs 200ah to charge a 100ah battery, yet you've already allowed extra for inefficiencies, so where does the other 100ah go?

The OP has two batteries so 100ah each I believe.

 

[thebriars]

Ah! Yes.

 

[PhilandMena]

So many helpful posts and no replies from the OP, this is happening more and more. Come on for help and then disappear, is this what the world is coming to ?

Perhaps the OP is being overwhelmed with all the different advice that is being posted. Unfortunately, one of the down sides on this forum I.M.O. when members with best intent contradict each other and the person seeking help does not know which way to turn.

 

[PhilandMena]

My husband took the unit out and put it back and hey presto we have electric! Must have been a loose wire, however the batteries are still going flat, not retaining a charge. If the batteries are flat again tomorrow then we need to buy some more. Thanks everyone!

I think it may help you move forward with your problem by simply establishing if your batteries are receiving a charge from your charger when on hook up and the charger is switched on. Simply place a digital multi meter on one of the batteries and look at the reading. You should be seeing 14.4 V or very close to it. This will tell you your charger is working. The charger with the EC325 is a three stage intelligent charger and can handle a battery bank up to 220 AH and be left on hook up for very long periods (Months) without causing damage to your batteries. I would advise you ensure there is no drain being placed on the batteries and then charge them for a minimum charge of 24 Hrs and then disconnect the batteries and allow to settle for a couple of hours then measure the batteries again with a multi-meter anything below 12.7 V should be a concern and indicate the battery capacity is not what it should be and you may need to replace them. However, as I said previously you need to understand why your batteries are flat otherwise this cycle may continue and you will find your self in a similar position again. You don't say how the batteries are being used or how old they are and it is possible they have just used up all of their capacity by cycling up and down (being discharged and then charged up again). It's also possible that they have been too deeply discharged, too many times. Lead Acid batteries should not be discharged more than 50 % and ideally 20% and your solar panel will help to a degree to prevent this, depending on how your using your power ?
If you are going to replace your batteries try and follow this advice and you should get the maximum life out of your batteries.

 

[tonyidle]

You say it needs 200ah to charge a 100ah battery, yet you've already allowed extra for inefficiencies, so where does the other 100ah go?

I thought the OP mentioned two batteries. I assumed 100Ah each as an example.

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[tonyidle]

for a minimum charge of 24 Hrs

May I suggest a minimum of 48 hours?

 

[PhilandMena]

May I suggest a minimum of 48 hours?

Sure. Why Not!
I took this statement out of the following link which discusses the subject matter in depth. Still trying to understand why the O.P. batteries are flat and I think members need more information to make the correct diagnosis.

Lead acid charging uses a voltage-based algorithm. The charge time of a sealed lead acid battery is 12-16 hours, up to 36-48 hours for large stationary batteries. With higher charge currents and multi-stage charge methods, the charge time can be reduced to 10 hours or less; however, the topping charge may not be complete. Lead acid is sluggish and cannot be charged as quickly as other battery systems.

https://www.recovermybatteries.com/batterybasics2.html

 

[Speve]

My husband took the unit out and put it back and hey presto we have electric! Must have been a loose wire, however the batteries are still going flat, not retaining a charge. If the batteries are flat again tomorrow then we need to buy some more. Thanks everyone!

So many helpful posts and no replies from the OP, this is happening more and more. Come on for help and then disappear, is this what the world is coming to ?

Think you’ll find they did reply with thanks

 

[tonyidle]

Sure. Why Not!
I took this statement out of the following link which discusses the subject matter in depth. Still trying to understand why the O.P. batteries are flat and I think members need more information to make the correct diagnosis.

Lead acid charging uses a voltage-based algorithm. The charge time of a sealed lead acid battery is 12-16 hours, up to 36-48 hours for large stationary batteries. With higher charge currents and multi-stage charge methods, the charge time can be reduced to 10 hours or less; however, the topping charge may not be complete. Lead acid is sluggish and cannot be charged as quickly as other battery systems.

https://www.recovermybatteries.com/batterybasics2.html

Did you notice their example of charge currents in the graph? I've only skimmed the article but it appears to refer to (in our terms) tiny batteries. Smart chargers as installed on motorhomes don't, to the best of my knowledge, 'force' charge the leisure battery. Bulk charging current is normally determined by the battery voltage rising to oppose that from the charger so to force it to charge at a higher rate requires a higher (than 13.8v or 14.2v) voltage from the charger. A van charger can often be designed to act as a PSU for the van if no leisure battery is fitted or if the main battery fuse fails so any voltage higher than 14.2 or so could be potentially damaging to the habitation electrics. Some more recent motorhomes appear not to allow this by turning off all electrics if no battery is installed. Without a facility within the van charger for a higher charging voltage (and therefore current) a 200Ah battery will take considerably more than 24h to fully charge.

 

[PhilandMena]

Did you notice their example of charge currents in the graph? I've only skimmed the article but it appears to refer to (in our terms) tiny batteries. Smart chargers as installed on motorhomes don't, to the best of my knowledge, 'force' charge the leisure battery. Bulk charging current is normally determined by the battery voltage rising to oppose that from the charger so to force it to charge at a higher rate requires a higher (than 13.8v or 14.2v) voltage from the charger. A van charger can often be designed to act as a PSU for the van if no leisure battery is fitted or if the main battery fuse fails so any voltage higher than 14.2 or so could be potentially damaging to the habitation electrics. Some more recent motorhomes appear not to allow this by turning off all electrics if no battery is installed. Without a facility within the van charger for a higher charging voltage (and therefore current) a 200Ah battery will take considerably more than 24h to fully charge.

If you read in more detail you will note it refers to the voltage for a 'cell' rather than a whole battery and this may be why you think it's for tiny batteries. It clearly states flooded Lead Acid batteries and these are made up of 6 x 2.1 V cells, so I assume this is applicable to a 12.6 V battery. ? As for the rest of your assertion, that is something I have never come across before and would welcome your source of information. I'm always up for improving my battery knowledge.

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[tonyidle]

If you read in more detail you will note it refers to the voltage for a 'cell' rather than a whole battery and this may be why you think it's for tiny batteries. It clearly states flooded Lead Acid batteries and these are made up of 6 x 2.1 V cells, so I assume this is applicable to a 12.6 V battery. ? As for the rest of your assertion, that is something I have never come across before and would welcome your source of information. I'm always up for improving my battery knowledge.

Current is the same no matter how many cells: the graph shows max current as less than 1A. Which part of the rest of my post are you referring to?

 

[autorouter]

Bulk charging current is normally determined by the battery voltage rising to oppose that from the charger so to force it to charge at a higher rate requires a higher (than 13.8v or 14.2v) voltage from the charger

The bulk charge phase is 'constant current'. The charger fires out its maximum current, and looks at the resulting voltage. For a flat battery this might be 12.5 or 13 volts. It will continue sending out its maximum current, looking at the voltage all the time, which will gradually rise. As soon as it reaches a predetermined value, maybe 14.4 volts, the bulk charge phase is completed, and it switches into the 'absorption' phase.

The absorption phase is 'constant voltage'. The charger applies the constant voltage of say 14.4 volts, while monitoring the current, which will gradually fall. When it reaches a predetermined current level, the charger decides the battery charging is complete, and it switches to 'trickle charge' (aka float) phase.

In the 'trickle charge' phase, the charger applies a voltage just above the resting voltage of a charged battery, usually 13.6 to 13.8 volts. It is designed to just put in sufficient charge to compensate for the self-discharge loss of the battery, maybe 10 to 100 milliamps.

The voltages are set by the charger manufacturer; some chargers also have a switch setting for different battery types (Flooded, sealed, gel, agm etc). For some types of battery, some chargers have an absorption phase which is timed rather than determined by current.

The bulk charge current for the ECS325 is 25 amps, so is quite capable of charging two 100Ah batteries.

 

[tonyidle]

The bulk charge phase is 'constant current'. The charger fires out its maximum current, and looks at the resulting voltage. For a flat battery this might be 12.5 or 13 volts. It will continue sending out its maximum current, looking at the voltage all the time, which will gradually rise. As soon as it reaches a predetermined value, maybe 14.4 volts, the bulk charge phase is completed, and it switches into the 'absorption' phase.

The absorption phase is 'constant voltage'. The charger applies the constant voltage of say 14.4 volts, while monitoring the current, which will gradually fall. When it reaches a predetermined current level, the charger decides the battery charging is complete, and it switches to 'trickle charge' (aka float) phase.

In the 'trickle charge' phase, the charger applies a voltage just above the resting voltage of a charged battery, usually 13.6 to 13.8 volts. It is designed to just put in sufficient charge to compensate for the self-discharge loss of the battery, maybe 10 to 100 milliamps.

The voltages are set by the charger manufacturer; some chargers also have a switch setting for different battery types (Flooded, sealed, gel, agm etc). For some types of battery, some chargers have an absorption phase which is timed rather than determined by current.

The bulk charge current for the ECS325 is 25 amps, so is quite capable of charging two 100Ah batteries.

Agreed - some chargers are capable. To output a high constant current the charger has to be capable of considerably exceeding the battery voltage at that moment in time: it cannot monitor battery voltage in any meaningful way whilst applying a constant high voltage (= constant high current). It must drop the charge very briefly, look at the battery voltage, then resume (or not) charging. I understand the various charging 'phases' offered by sophisticated chargers. However it is possible to have an intelligent charger whose maximum voltage doesn't exceed 14.4v. It is this type of charger that will spend a very long time reaching the 'charging complete' state. For example charging a battery with terminal voltage on charge of 14v at 14.4v will result in a minimal charge current that would take a very long time to complete the bulk charge phase.

 

[PhilandMena]

Current is the same no matter how many cells: the graph shows max current as less than 1A. Which part of the rest of my post are you referring to?

This part : A van charger can often be designed to act as a PSU for the van if no leisure battery is fitted or if the main battery fuse fails so any voltage higher than 14.2 or so could be potentially damaging to the habitation electrics. Some more recent motorhomes appear not to allow this by turning off all electrics if no battery is installed. Without a facility within the van charger for a higher charging voltage (and therefore current) a 200Ah battery will take considerably more than 24h to fully charge.

 

[autorouter]

To output a high constant current the charger has to be capable of considerably exceeding the battery voltage at that moment in time: it cannot monitor battery voltage in any meaningful way whilst applying a constant high voltage (= constant high current). It must drop the charge very briefly, look at the battery voltage, then resume (or not) charging.

In constant current mode, charger does not use the battery 'open circuit rest voltage' as an indication of the state of charge of the battery. The manufacturer has determined from extensive measurements that there is another method to find out when the battery is 80% charged.

When a fixed current is put into a flat battery, the terminal voltage will be less than 14.4 volts. The measured terminal voltage will depend on the state of charge of the battery. For example, if that battery is 80% charged, the terminal voltage at the fixed current will be 14.4 volts. It is safe to push out the fixed maximum current into a flat battery, until the voltage rises to 14.4 volts. At that point, the battery is 80% charged.

Another way of looking at this is, the charger is trying to apply 14.4 volts to a flat battery, but the charger does not have the current capability to make the voltage up to 14.4 volts, so it struggles along, applying as much current as it can, until the voltage finally reaches 14.4 volts.

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