How to Make a Bomb

[K4309 358]

How to make a bomb, and other battery charging questions.

What equipment do you use to give lead acid batteries an equilisation charge? Specifically a charger you can accurately specify the voltage and current so you don't make a bomb?

We currently have flooded lead acid batteries for the house bank, and they appear to have shat themselves, due to various reasons. We have never equalized them, despite the recommendation being to do it monthly. The main reason being all the other recommendations on how to do it safely and properly.

I'm now looking at new house batts that require an equilisation charge at 14.1v, while the bulk charge is 14.7v - they are lead carbon, and I have a query in with the supplier on the specifics of those charging requirements.

I can't use the alternator, because the start batt is in the same circuit. The solar controller has equilisation settings, but the equilisation voltage must be equal to or higher than the bulk charge (not lower than). That and solar isn't that reliable for specific current and time duration. Oh, and if I plan to do a specific charge, I also need it to be sunny. Based on last summer, that could be problematic.

And we don't have a mains powered battery charger at home that can do it. Ideally I want a digitally controlled charger where I can set the voltage and current (or at least ensure the current is within a correct range) and equalise the batteries properly, when I want to.

I haven't been able to find a suitable mains powered charger via google yet. Any recommendations?

An extension of the question, if I could get a DC powered charger that does the above, then I could isolate the house batts on the boat and give them an equalisation charge off the start batt with the alternator running. This would be super easy as I wouldn't have to take the batts home.

And just to make things difficult, it'd be good if this fancy battery charger doesn't cost more than the batteries...

[Island Time 1,286]

The definition of an equalization charge is a period of charge at a higher voltage.

Insist on a product data sheet from the manufacturer.  If the supplier can't do that, move on to another supplier.

Lead Carbon does not normally need equalization. 

[K4309 358]

Attached is the product data sheet.

I think the terms here may have different meanings to what we are used to. The supplier is asking the manufacturer in China to confirm my questions. I'm expecting a response on Monday, or early next week.

Aside from that, what gear do you use for a normal equilisation charge IT?

JPC12-100-DS.pdf

[Island Time 1,286]

Hmm, seams to me they have some issues in translation. Charge voltage and equalization seem to be reversed.

Also the max Charge current of 30a is a problem for most charging systems. Normally battery internal resistance restricts Charge rate.

I'd be cautious of this battery. There are local suppliers of lead carbon, 120a/r for about $600, with local support and neither if these requirements. 

[K4309 358]

2 hours ago, Island Time said:

Hmm, seams to me they have some issues in translation. Charge voltage and equalization seem to be reversed.

Also the max Charge current of 30a is a problem for most charging systems. Normally battery internal resistance restricts Charge rate.

I'd be cautious of this battery. There are local suppliers of lead carbon, 120a/r for about $600, with local support and neither if these requirements. 

Thanks IT,

This one is available from 2 local suppliers. Both providing 'support'. But so far they have struggled with a convincing answer on the above question, hence one is contacting / confirming with the manufacturer. He says they have good / responsive communications and is confident he can explain / answer my question.

But that said, what are these other lead carbon's you speak of?

My current thinking is to install 3 of the 100A/hrs in parallel to give me a 300A/hr bank. That will give a maximum charge current of 90a, and a recommended of 30a to 60a. We have a 70A alternator with a Balmar MC612 regulator. That restricts charge current to 75%, which is about 51a, which falls nicely within the 30-60a recommended charge range. (another reason we think these batts are suitable for our application).

I would not be surprised if the translation has swapped the cycle voltage with the equilise voltage. All of the other lead carbon's I've looked at have bulk charge voltages around 13.8 or 14.1 ish. They claim the lower resistance means they can be charged at lower voltages, which causes less wear on the positive plate. But then these batts charge the same as any other lead acid / agm.  That does not make sense.

For any other lead carbon at 13.8v odd, I'd need a DC-DC charger. That adds a fair bit of cost, between $600 to $800. If I get a DC charger, then I may as well go whole hog and get lithiums. Hence why I am getting clarification of the charging regime (in writing, from the manufacturer) before I go ahead.

IT, another question: Lithium's need a DC-DC charger ran of the start batt. My understanding of the reasons is that the resistance is so low, if an alternator is un-regulated, it can pull too much current (no resistance from batt) and fry itself in minutes. Also, if the BMS trips out, you can blow a diode, as the alternator is putting out full amps, and then suddenly there is no-where for it to go. The other reason being the start battery has a completely different charging regime to lithium. If lead carbon batteries also have very low resistance, is there the same risk of pulling too much current out of an un-regulated alternator, and will the Balmar MC612 address that issue?

[CarpeDiem 510]

I have one of these for the anchor winch and a backup start battery. 

The equalization applies if you are using it as a standby battery.  It would sit on float for 6 months and then undertake a equalization charge.

You're using it as a cycle battery. 

They don't provide a termination current but it's safe to assume 1amp.

Charge to 14.7 volts at a max current of 20a when the current drops to 1amp switch to a float charge of 13.8v

I don't float charge mine, I just switch off and let the battery sit. It's usually 12.9v after 2 weeks in winter. During summer it's generally 13v after 1 week.

Good luck finding a decent charger. You don't want to be over charging it and the solar could have that effect. Ideally you want the charger to turn off until the voltage drops to 12.7 and then restart. The problem with leaving the charger on float is when the sun goes down the charger can reset it's cycle and start again at 14.7v.

What charger do you have?

[K4309 358]

7 minutes ago, CarpeDiem said:

I have one of these for the anchor winch and a backup start battery. 

The equalization applies if you are using it as a standby battery.  It would sit on float for 6 months and then undertake a equalization charge.

You're using it as a cycle battery. 

They don't provide a termination current but it's safe to assume 1amp.

Charge to 14.7 volts at a max current of 20a when the current drops to 1amp switch to a float charge of 13.8v

I don't float charge mine, I just switch off and let the battery sit. It's usually 12.9v after 2 weeks in winter. During summer it's generally 13v after 1 week.

Good luck finding a decent charger. You don't want to be over charging it and the solar could have that effect. Ideally you want the charger to turn off until the voltage drops to 12.7 and then restart. The problem with leaving the charger on float is when the sun goes down the charger can reset it's cycle and start again at 14.7v.

What charger do you have?

Thanks CD,

Is it the same Kijo lead carbon you have?

Your explanation is logical, although not clear on the data sheet.

We have an EPever 20amp solar controller. We have been investigating the exact issue you mention. Every day at sun up, the controller gives it 2 hrs of bulk charge, regardless of what the batt voltage was, then goes through to float. I had 180w solar onboard so it may have been getting 12 amps, but one panel shat itself (there is a theme here). After investigating a few things, I've just put a 20w panel on so I can float, but there is no risk of overcharging. I did that as I was concerned about the state of my batteries and a potentially high self discharge. Since then they have died.

I've investigating the Victron solar controller, which is sh*t loads better than the EPever. At sun-up, it checks the battery voltage and shortens the bulk phase appropriately. It also has the blutooth and app, so I can monitor everything from the phone, and programme or change settings on the controller. Only issue is a victron controller is $200 (15 amp), and a 20w panel was $40. I'm working through a bunch of other issues / questions with my electrical system so may still either ditch the solar float, or change controllers. I may get more solar panels to replace my dead ones, which may initiate upgrading the controller, or I may get better batteries and ditch the solar altogether. The old batts were flooded lead acid, hence the solar to top up, and the float charge.

If it turns out I need a DC-DC charger for my new batteries I'll probably get one that handles the solar directly as well. Get all charge sources through the one charger, and get one with blutooth so I can programme it easily and monitor it to ensure what I want to happen is actually happening.

[CarpeDiem 510]

15 minutes ago, K4309 said:

Thanks IT,

This one is available from 2 local suppliers. Both providing 'support'. But so far they have struggled with a convincing answer on the above question, hence one is contacting / confirming with the manufacturer. He says they have good / responsive communications and is confident he can explain / answer my question.

But that said, what are these other lead carbon's you speak of?

My current thinking is to install 3 of the 100A/hrs in parallel to give me a 300A/hr bank. That will give a maximum charge current of 90a, and a recommended of 30a to 60a. We have a 70A alternator with a Balmar MC612 regulator. That restricts charge current to 75%, which is about 51a, which falls nicely within the 30-60a recommended charge range. (another reason we think these batts are suitable for our application).

I would not be surprised if the translation has swapped the cycle voltage with the equilise voltage. All of the other lead carbon's I've looked at have bulk charge voltages around 13.8 or 14.1 ish. They claim the lower resistance means they can be charged at lower voltages, which causes less wear on the positive plate. But then these batts charge the same as any other lead acid / agm.  That does not make sense.

For any other lead carbon at 13.8v odd, I'd need a DC-DC charger. That adds a fair bit of cost, between $600 to $800. If I get a DC charger, then I may as well go whole hog and get lithiums. Hence why I am getting clarification of the charging regime (in writing, from the manufacturer) before I go ahead.

IT, another question: Lithium's need a DC-DC charger ran of the start batt. My understanding of the reasons is that the resistance is so low, if an alternator is un-regulated, it can pull too much current (no resistance from batt) and fry itself in minutes. Also, if the BMS trips out, you can blow a diode, as the alternator is putting out full amps, and then suddenly there is no-where for it to go. The other reason being the start battery has a completely different charging regime to lithium. If lead carbon batteries also have very low resistance, is there the same risk of pulling too much current out of an un-regulated alternator, and will the Balmar MC612 address that issue?i

Lithiums don't need dc/dc. But that is one of many options.

I would recommend against dc/dc for lithium. One of the main benefits of lithium is the fast charge rate and you lose that with dc/dc.

You raise valid issues but there's other ways to skin the cat... 

The MC612 can't measure current. It limits the output and that's it. I run my stock alternator at max output for a couple of hours and have never had any problems.

The reality is you cannot charge two different chemistries (incl lead carbon) with one charging source. Their will always be a compromise.

[K4309 358]

3 minutes ago, CarpeDiem said:

Lithiums don't need dc/dc. But that is one of many options.

 

What are some of the other options? The charging current is a key element for me, specifically faster charging. I could get two victron DC chargers, 30A each, but $800. We only have a 70a alternator, but the current batts aren't supposed to charge faster than 23 amps, so I can easily double the charging rate (safely, if I get the right batteries).

The other way to go is to change the start battery to the same chemistry as the new house batts. That may be cheaper than using DC chargers. Our anchor winch runs via the start batt, so I need to make sure there are no issues there (engine always running of course).

[CarpeDiem 510]

31 minutes ago, K4309 said:

What are some of the other options? The charging current is a key element for me, specifically faster charging. I could get two victron DC chargers, 30A each, but $800.

The other way to go is to change the start battery to the same chemistry as the new house batts. That may be cheaper than using DC chargers. Our anchor winch runs via the start batt, so I need to make sure there are no issues there (engine always running of course).

Use a splitter to charge the lithium and have it connected to the start as well. And use a cheap dc/dc from the Li to top off your start battery.

You've already got the mc612, it's not what I would recommend for a greenfields installation but it's an investment you can leverage. Obs you need to set the right specs. 

Connect your current solar controller to your new Li and set it up for whatever Li charge specs you are happy with. 

[CarpeDiem 510]

57 minutes ago, K4309 said:

Thanks CD,

Is it the same Kijo lead carbon you have?

Your explanation is logical, although not clear on the data sheet.

We have an EPever 20amp solar controller. We have been investigating the exact issue you mention. Every day at sun up, the controller gives it 2 hrs of bulk charge, regardless of what the batt voltage was, then goes through to float. I had 180w solar onboard so it may have been getting 12 amps, but one panel shat itself (there is a theme here). After investigating a few things, I've just put a 20w panel on so I can float, but there is no risk of overcharging. I did that as I was concerned about the state of my batteries and a potentially high self discharge. Since then they have died.

I've investigating the Victron solar controller, which is sh*t loads better than the EPever. At sun-up, it checks the battery voltage and shortens the bulk phase appropriately. It also has the blutooth and app, so I can monitor everything from the phone, and programme or change settings on the controller. Only issue is a victron controller is $200 (15 amp), and a 20w panel was $40. I'm working through a bunch of other issues / questions with my electrical system so may still either ditch the solar float, or change controllers. I may get more solar panels to replace my dead ones, which may initiate upgrading the controller, or I may get better batteries and ditch the solar altogether. The old batts were flooded lead acid, hence the solar to top up, and the float charge.

If it turns out I need a DC-DC charger for my new batteries I'll probably get one that handles the solar directly as well. Get all charge sources through the one charger, and get one with blutooth so I can programme it easily and monitor it to ensure what I want to happen is actually happening.

Yes. Exactly that battery. Cost $275. The best value deep cycle around IMO. 

There's so many different ways to build a solution. You need to build based on the outcome you want to achieve. 

You'll only get as much current as the battery will accept. If it's fully charged it will be f.all and certainly not 12amps. 

[K4309 358]

1 minute ago, CarpeDiem said:

Yes. Exactly that battery. Cost $275. The best value deep cycle around IMO. 

There's so many different ways to build a solution. You need to build based on the outcome you want to achieve. 

 

Champion.

$275 you say? I've currently found the best price at $280 each, but that is with a 10% sale via the Motor Caravan Association magazine. That gives me a 300 Ah bank, 150Ah working capacity for $840, and currently no other mods to my charging system. To do the same with lithium would cost about $2,300 ish.

If the batteries perform as they say, I can charge as fast as lithiums, and wont have to worry about getting a full trickle charge on each use to combat sulphation. i.e. the partial state of charge will be fine, same as lithiums. If they don't live up to the hype, then they cost as much as standard AGM's and I'd hope they would perform the same.

For your above lithium charging example what is a name / brand of battery splitter that would work? I've seen a few about, but I have no other knowledge of them. Never looked into them.

[CarpeDiem 510]

You definitely cannot charge any LA as fast as Li.

You may be thinking that you can only charge so fast because of your alternator capacity, therefore it makes no difference - that's not correct either, because LA will push back on the current far far sooner than the Li will.  Eg, the Li will continue to accept 100amps up to 95% capacity.  While the LA will probably be down to 15amps at 95% capacity so your charge time is considerably longer to reach the same capacity.

If you have a 100ah alternator and a 100ah LFP battery, you can pretty much gaurantee that after 1hour the battery will be fully charged.  (NB:edit assuming you have a 1C LFP - which is unlikely - most LFPs are C2 - but it is still going to be faster). 

Another consideration is the efficiency in PbC. Pbc is about 90% efficient.  So you can expect to put in 110% - 115% to get back 100% - the Li is exceptionally efficient - obvs not 100% but really close to it - this might not be an issue.

I know that these batteries claim 1000 cycles at 100% DoD, but I truly struggle to believe that, they don't advertise the capacity loss at this discharge rate either.  The recommendation in most places for PbC is a MAXIMUM 20%DoD, that gives you 240AH, other manufacturers claim 30% (210Ah) - where as if you have 300Ah of LFP, then you have 300Ah of usable battery.

If you run your engine for long periods of time then PbC might be a better choice financially, for me, I rarely run the engine even when crusing, I rarely use it to drop or weigh anchor either - 6 years into a new engine and we have just topped 225 hours - so being able to fast charge is the number one benefit for me.

Yes Li is more expensive but it is horses for courses and again depends on what you want your outcome to be.

[CarpeDiem 510]

I got mine a year ago +/-  from here:  https://www.ivent.co.nz/product/category/951/12v 100ah deep cycle lead carbon battery/38317 I am pretty sure I paid $275 incl.. I note that site now says $275 and I suspect that that is excl GST, so maybe I got that wrong... although prices may have also gone up....

[K4309 358]

9 minutes ago, CarpeDiem said:

I got mine a year ago +/-  from here:  https://www.ivent.co.nz/product/category/951/12v 100ah deep cycle lead carbon battery/38317 I am pretty sure I paid $275 incl.. I note that site now says $275 and I suspect that that is excl GST, so maybe I got that wrong... although prices may have also gone up....

Yes, I'm talking to ivent. Their prices on line are ex GST. Currently $280 incl (pick up).

[CarpeDiem 510]

Also, 

Victron ArgoFET is the best splitter I have come across: https://www.victronenergy.com/battery-isolators-and-combiners/argo-fet-battery-isolators

But in hindsight and thinking about it right now, I am not actually sure how these would cope with an alternator load dump/voltage spike which is your use case - maybe that is something @Island Time could comment on?!?  Maybe a traditional diode splitter would be better just cranking up the voltage at the alternator to compensate for the voltage drop.

[K4309 358]

1 hour ago, CarpeDiem said:

Use a splitter to charge the lithium and have it connected to the start as well. And use a cheap dc/dc from the Li to top off your start battery.

You've already got the mc612, it's not what I would recommend for a greenfields installation but it's an investment you can leverage. Obs you need to set the right specs. 

Connect your current solar controller to your new Li and set it up for whatever Li charge specs you are happy with. 

Hay CD, in this example, how do you cater for the different charging voltages required for the lithium and the AGM start? the battery isolator outputs the same voltage doesn't it?

[CarpeDiem 510]

42 minutes ago, K4309 said:

Hay CD, in this example, how do you cater for the different charging voltages required for the lithium and the AGM start? the battery isolator outputs the same voltage doesn't it?

You set up your alternator/regulator pair for the Li and use the dc/dc to top up your start.  So you can take your start battery to 14.7 while your Li is charging at 13.2... Or if your Li has topped out at 13.8 then your dc/dc will continue at 14.7.

All numbers are made up and will depend on your setup but are realistic. 

Now you have 2 chargers. Your alternator, that is smart because of your mc612, and the dc/dc charger.  The voltage from the alternator while charging your Li should be too low to charge a agm start fully. 

 

[Island Time 1,286]

Please read this guys. 

https://marinehowto.com/drop-in-lifepo4-be-an-educated-consumer/

It will show you a good basic lifepo4 system using an argo fet splitter, and lots of other great info.

[CarpeDiem 510]

Thanks IT, I was curious if you had an opinion?

If we take MHT as the single source of truth, ArgoFET isolator splitters aren't the be all and end all for load dump protection. Quote "and yes we have seen FET isolators fail".

Blowing up an ArgoFET isolator vs blowing up alternator diodes appears to be a similar proposition  

If you wanted to be more risk adverse then going for a diode to your start battery could provide that, at the expense of voltage drop. 

Personally I think I would risk it.