How many amps can I bang into my leisure batteries without cooking them?

[JockandRita]

Hi Jock

On AES it should only go to 12v with a D+ signal, if it is still doing it have a look and see if the AES light is on on the regulator, if it is it should only stay on 12v for 30 minutes and then go to and stay on gas unless as you say there is loads of sun,

Martin

I did Martin, and yes, the AES light was illuminated on the solar regulator. I stayed with it for 5 x minutes pulling almost 16A. I had to go out, so shut everything down to prevent an unnecessary discharge, but I will check it out again. One theory is that it is sensing over voltage, (as the batteries were on charge prior to EHU disconnection), and should switch to gas one the voltage drops a little.
30 x minutes pulling 16A seems a long time.

Sorry to go off subject Jon.

On the advice of Lenny, I purchased a clamp meter, which certainly makes easier, the job of knowing the amount of charge/discharge, and appears to be more accurate than the CBE display.

Some of the Sterling Power Product videos on YouTube, by the man himself, are very interesting and informative, eg, B2B vs Alternator, Lithium vs AGM, Pb Acid/Pb Crystal, etc.

Cheers,

Jock.

 

[funflair]

I did Martin, and yes, the AES light was illuminated on the solar regulator. I stayed with it for 5 x minutes pulling almost 16A. I had to go out, so shut everything down to prevent an unnecessary discharge, but I will check it out again. One theory is that it is sensing over voltage, (as the batteries were on charge prior to EHU disconnection), and should switch to gas one the voltage drops a little.
30 x minutes pulling 16A seems a long time.

Sorry to go off subject Jon.

On the advice of Lenny, I purchased a clamp meter, which certainly makes easier, the job of knowing the amount of charge/discharge, and appears to be more accurate than the CBE display.

Some of the Sterling Power Product videos on YouTube, by the man himself, are very interesting and informative, eg, B2B vs Alternator, Lithium vs AGM, Pb Acid/Pb Crystal, etc.

Cheers,

Jock.

So the run signal is from the Regulator and the fridge priority sequence will be correct, 30 minutes at 16A is only 8ah so not a lot lost, it should shut off in 30 minutes and then most likely stay on gas unless you have a lot more sun than us DC clamp meter is great I treated myself to one.

Martin

 

[jongood]

I did Martin, and yes, the AES light was illuminated on the solar regulator. I stayed with it for 5 x minutes pulling almost 16A. I had to go out, so shut everything down to prevent an unnecessary discharge, but I will check it out again. One theory is that it is sensing over voltage, (as the batteries were on charge prior to EHU disconnection), and should switch to gas one the voltage drops a little.
30 x minutes pulling 16A seems a long time.

Sorry to go off subject Jon.

On the advice of Lenny, I purchased a clamp meter, which certainly makes easier, the job of knowing the amount of charge/discharge, and appears to be more accurate than the CBE display.

Some of the Sterling Power Product videos on YouTube, by the man himself, are very interesting and informative, eg, B2B vs Alternator, Lithium vs AGM, Pb Acid/Pb Crystal, etc.

Cheers,

Jock.

No problem Jock, all part of the picture for me.
Will check out the sterling stuff. Thanks. Jon

 

[Lenny HB]

I'm wondering how I test the Gels? There's quite a big battery supplier in town but they re not doing testing because of the virus???? The garage I use for MOTs etc have a battery tester but I'm assuming this is for lead Acid, does anyone know if it will do the gels?

They will only do a CCA test which is for starter batteries useless for a leisure battery.
You need to do a controlled discharge, not perfect but gives you a good idea. You need to test each battery separately.

First charge the battery fully and leave it to settle for an hour then:-

For example if it's a 100a/h battery load it with a 5 amp load and run for 5 hours, this will represent a 25% discharge. (adjust load/time to suit the size of the battery)
Disconnect the load and leave to stand for at least 30 min then measure the voltage.
Repeat the test and you will have discharged the battery to 50%.
You can repeat again then it will be 75% discharged.

 

[funflair]

They will only do a CCA test which is for starter batteries useless for a leisure battery.
You need to do a controlled discharge, not perfect but gives you a good idea. You need to test each battery separately.

First charge the battery fully and leave it to settle for an hour then:-

For example if it's a 100a/h battery load it with a 5 amp load and run for 5 hours, this will represent a 25% discharge. (adjust load/time to suit the size of the battery)
Disconnect the load and leave to stand for at least 30 min then measure the voltage.
Repeat the test and you will have discharged the battery to 50%.
You can repeat again then it will be 75% discharged.

View attachment 438673

And then buy some lithium’s Jon has already decided the outcome of the test before he starts, he just needs some evidence for Sue.
.

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[JockandRita]

So the run signal is from the Regulator and the fridge priority sequence will be correct, 30 minutes at 16A is only 8ah so not a lot lost, it should shut off in 30 minutes and then most likely stay on gas unless you have a lot more sun than us DC clamp meter is great I treated myself to one.

Martin

As usual, you are bang on Martin. Thanks.
I waited until the AES light was showing on the regulator, unplugged the EHU, and after 120 seconds, the FF went to 12v. That was at 10.52 and banging in 5.8A from the solars. (We have blue skies and sunshine here today. )
At 11.08, it dropped out of 12v, and took 15 x minutes to kick in on gas...........just as I would expect, had I just turned the engine off for example.

Hopefully, the B2B will be installed in the next week or so, with the help of someone more savvy to it all than myself, and who has fitted a couple (boat and MH) recently.
He wanted to know what kit I already have, so here it all is.

Cheers,

Jock.

 

[jongood]

So in the ahem unlikely event that the Gels are knackered, whats the panels view on this

12V 300Ah LiFePO4 HD Series

Need Low Carbon Batteries For Your RV or Caravan? Our LiFePO4 Lithium Ion Batteries Are High Performing & 60% Weight Saving. Discover More Today!

www.qualitysource.co.uk

 

[Lenny HB]

As usual, you are bang on Martin. Thanks.
I waited until the AES light was showing on the regulator, unplugged the EHU, and after 120 seconds, the FF went to 12v. That was at 10.52 and banging in 5.8A from the solars. (We have blue skies and sunshine here today. )
At 11.08, it dropped out of 12v, and took 15 x minutes to kick in on gas...........just as I would expect, had I just turned the engine off for example.

Hopefully, the B2B will be installed in the next week or so, with the help of someone more savvy to it all than myself, and who has fitted a couple (boat and MH) recently.
He wanted to know what kit I already have, so here it all is.

View attachment 438688View attachment 438689

Cheers,

Jock.

Thats what I like to see a man with proper crimp tools.

 

[JockandRita]

Thats what I like to see a man with proper crimp tools.

On loan Lenny. I though better of the lump hammer and concrete post method.

So in the ahem unlikely event that the Gels are knackered, whats the panels view on this

12V 300Ah LiFePO4 HD Series

Need Low Carbon Batteries For Your RV or Caravan? Our LiFePO4 Lithium Ion Batteries Are High Performing & 60% Weight Saving. Discover More Today!

www.qualitysource.co.uk

I'm not in that market myself Jon, but if I was, I think I'd prefer the 300A battery which is only 20A less than my current bank, but a more useful range than gels.
If trying to get Sue on your side, the cost of it is equivalent to 62 x nights on a site with EHU, at a site fee of £30 pupn............so it'll pay for itself in no time at all.
Obviously, the cost of changing the charging regime, has to be taken in to account too though.

Cheers,

Jock.

 

[jongood]

On loan Lenny. I though better of the lump hammer and concrete post method.


I'm not in that market myself Jon, but if I was, I think I'd prefer the 300A battery which is only 20A less than my current bank, but a more useful range than gels.
If trying to get Sue on your side, the cost of it is equivalent to 62 x nights on a site with EHU, at a site fee of £30 pupn............so it'll pay for itself in no time at all.
Obviously, the cost of changing the charging regime, has to be taken in to account too though.

Cheers,

Jock.

Yes I must admit to being tempted. A part of me thinks I shouldnt rely on only one battery but then Ive read on other threads about issues matching them.

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[JockandRita]

Yes I must admit to being tempted. A part of me thinks I shouldn't rely on only one battery but then Ive read on other threads about issues matching them.

With a battery monitor installed, you would know of a deterioration long before it became crucial. I get the impression that sudden failure isn't an issue, but the biggest killer appears to be heat.

Some interesting reading here Jon.

Cheers,

Jock.

 

[andy63]

Yes I must admit to being tempted. A part of me thinks I shouldnt rely on only one battery but then Ive read on other threads about issues matching them.

I think id be the same with just one battery... if you buy from a reputable source there shouldn't be an issue with balancing and having more than one battery..
the problem with lithium drop in batteries they all have a a monitoring system installed so its not just cell failure ..if the bms goes faulty then the battery is useless.. if you had two batteries at least it would cover that unlikely option...
more food for thought
Andy

 

[funflair]

Morning Jon

Have you thought about going 24v for your batteries
.

 

[jongood]

Morning Jon

Have you thought about going 24v for your batteries
.

I have been having a think about that Martin but it then makes my 2nd alternator redundant and gives my main alternator a lot more to do and i then have to run most of the hab stuff through a dropper. It would also make battery monitoring a lot more difficult.

The clamp meter arrived yesterday so going to check the batteries out. being an impatient sort I'm thinking about wiring 2 headlamps bulbs up so that I'm getting a 9 amp drain, even if they re half Ok that could still take 7 hours each.

 

[funflair]

Hi Jon

You could change your second alternator to 24v of course but it’s where do you stop, I think the gains from going all 24v would be relatively small.
.

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[jongood]

Hi Jon

You could change your second alternator to 24v of course but it’s where do you stop, I think the gains from going all 24v would be relatively small.
.

I'm going to test the Gels today but unless they re 80% I'm going for Lithiums, now thinking 2 x 150ahs might be the best option. Any thoughts?

Do you think I need to change my 2 x mains chargers? currently 2 of these

35 AMP A2000 CHARGER

CBE CHARGERS are specifically designed for the motorhome caravan and boating sectors they are able to charge 12V gel or lead-acid batteries

leisurelines.net

 

[Lenny HB]

I'm going to test the Gels today but unless they re 80% I'm going for Lithiums, now thinking 2 x 150ahs might be the best option. Any thoughts?

Do you think I need to change my 2 x mains chargers? currently 2 of these

35 AMP A2000 CHARGER

CBE CHARGERS are specifically designed for the motorhome caravan and boating sectors they are able to charge 12V gel or lead-acid batteries

leisurelines.net

Idealy yes as they have absobtion & float charging which lithium doesn't need.

 

[andy63]

Jon..unless you fit a dedicated lifepo4 mains charger...you are going to have to settle for a lead acid type charger..
The dedicated lithium chargers ive seen are not suitable for use as power packs as well.. you will most probably end up using a charger with absorption and float cycles...its the voltages they employ in each cycle which is key..
That aspect concerned me as well but from the reading I've done it appears that some of the lead acid chargers are suitable along with their various charging cycles..the important points is that the voltages they use in each cycle are acceptable and they don't do a desulphation cycle..
Did jock not post a link in an earlier post on this thread..its a good article and puts things in perspective..if you haven't read through it have a look ..
Andy

 

[funflair]

SuperB, "other batteries are available but I have their charging manual" say,

One thing you would be missing with the CBE charger would be the temperature monitoring for low temperature charging but this may well be taken care of in the BMS, in situations like this I would tend to ask the manufacturer/supplier of your chosen battery.
.

 

[andy63]

One thing you would be missing with the CBE charger would be the temperature monitoring

I think that on most of the chargers ..including solar controllers ive seen would recommend not to fit the temperature sensor as a means of compensating the voltage, if you have lithium fitted..
The point about low temp charging cut off im assuming is taken care of by the bms
Andy
Andy

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[funflair]

On loan Lenny. I though better of the lump hammer and concrete post method.

Jock.

Is this one better than the lump hammer and post Jock?

The little finger is for scale only and it will take bigger fingers or even crimps,

You will need your own lump hammer jongood but you can borrow it if you need it
.

 

[funflair]

I think that on most of the chargers ..including solar controllers ive seen would recommend not to fit the temperature sensor as a means of compensating the voltage, if you have lithium fitted..
The point about low temp charging cut off im assuming is taken care of by the bms
Andy
Andy

Hi Andy

I was reading something a few days ago and the charger wouldn't function in the LiFePO4 cycle unless it had the temperature sensor fitted, might even have been Victron EDIT I might have dreamt this please ignore.

This is from Votronic solar instructions,

 Connection for Battery Temperature Sensor (Order No. 2001): Lead batteries: In case of low outside temperatures, full charging of the weak battery is improved by automatic adaptation of the charging voltage to the battery temperature, and in case of summery temperatures unnecessary battery gassing and battery load will be avoided.
LiFePO4 Batteries: Battery protection in case of high temperatures and particularly in case of low temperatures. Highly recommended, if the battery temperature might drop below 0 °C during operation.
.

 

[andy63]

Hi Andy

I was reading something a few days ago and the charger wouldn't function in the LiFePO4 cycle unless it had the temperature sensor fitted, might even have been Victron.

This is from Votronic solar instructions,

 Connection for Battery Temperature Sensor (Order No. 2001): Lead batteries: In case of low outside temperatures, full charging of the weak battery is improved by automatic adaptation of the charging voltage to the battery temperature, and in case of summery temperatures unnecessary battery gassing and battery load will be avoided.
LiFePO4 Batteries: Battery protection in case of high temperatures and particularly in case of low temperatures. Highly recommended, if the battery temperature might drop below 0 °C during operation.
.

Yes martin..that would be right..its referring to monitoring the temperature with regard to low temp and charging..etc..
Its not about the compensation of voltage of the charger during the charging cycle..
My mppt solar charger def said dont fit the temp sensor if you are installing lithium..
All the bms have temp sensing as far as I know but again I dont think its relative to altering charging voltages..
Andy

 

[andy63]

Is this one better than the lump hammer and post Jock?

View attachment 439197

The little finger is for scale only and it will take bigger fingers or even crimps,

You will need your own lump hammer jongood but you can borrow it if you need it
.

Be careful with that..I have one as well and look what happened..

 

[funflair]

Yes martin..that would be right..its referring to monitoring the temperature with regard to low temp and charging..etc..
Its not about the compensation of voltage of the charger during the charging cycle..
My mppt solar charger def said dont fit the temp sensor if you are installing lithium..
All the bms have temp sensing as far as I know but again I dont think its relative to altering charging voltages..
Andy

Yes it seems that the Votronic uses the temperature sensor differently in the LiFePO4 profile.

We have the temperature monitored by the Votronic solar and the Buttner charger and as you say by the battery BMS.
.

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[jongood]

Jon..unless you fit a dedicated lifepo4 mains charger...you are going to have to settle for a lead acid type charger..
The dedicated lithium chargers ive seen are not suitable for use as power packs as well.. you will most probably end up using a charger with absorption and float cycles...its the voltages they employ in each cycle which is key..
That aspect concerned me as well but from the reading I've done it appears that some of the lead acid chargers are suitable along with their various charging cycles..the important points is that the voltages they use in each cycle are acceptable and they don't do a desulphation cycle..
Did jock not post a link in an earlier post on this thread..its a good article and puts things in perspective..if you haven't read through it have a look ..
Andy

Hi Andy

Yes I looked at the article Jock posted but confess I might have started skimming a bit towards the end. having thought about it I'm not intending to be hooked up that much so as long as it won't damage them I guess its not a big deal, but would turning them off help if I'm on for a long time, winter heating for example

 

[jongood]

I think that on most of the chargers ..including solar controllers ive seen would recommend not to fit the temperature sensor as a means of compensating the voltage, if you have lithium fitted..
The point about low temp charging cut off im assuming is taken care of by the bms
Andy
Andy

I dont think temperature extremes are going to be a problem because the batteries are in the garage which is heated when its cold. and I think if I had in parked up in cold weather I would turn the chargers off.

 

[jongood]

Is this one better than the lump hammer and post Jock?

View attachment 439197

The little finger is for scale only and it will take bigger fingers or even crimps,

You will need your own lump hammer jongood but you can borrow it if you need it
.

Thats great Martin. I ve just found out the bloke whose helping me with it has got a crimper

 

[andy63]

Yes it seems that the Votronic uses the temperature sensor differently in the LiFePO4 profile.

We have the temperature monitored by the Votronic solar and the Buttner charger and as you say by the battery BMS.
.

So your system uses temperature sensing to alter the charging voltage???
I didnt know that was necessary or used with lithium..
Andy..

but would turning them off help if I'm on for a long time, winter heating for example

Truth is I dont know..its all new and no practical experience..but from reading I wouldnt leave myself hooked up for extended periods( as I did with lead acid )of time unless the charger was supporting a load on the system..
Andy.

 

[funflair]

I must admit I skimmed a bit as well,

Good advice at the end though, I guess the last two point can only be achieved with a programmable charger or at least a choice of profiles via dip switches.

To sum up, for long and happy LFP battery life, in order of importance, you should be mindful of the following:

1. Keep the battery temperature under 45 Centigrade (under 30C if possible) – This is by far the most important!!
2. Keep charge and discharge currents under 0.5C (0.2C preferred)
3. Keep battery temperature above 0 Centigrade when discharging if possible – This, and everything below, is nowhere near as important as the first two
4. Do not cycle below 10% – 15% SOC unless you really need to
5. Do not float the battery at 100% SOC if possible
6. Do not charge to 100% SOC if you do not need it

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