How many amps can I bang into my leisure batteries without cooking them? (1 Viewer)

[cmcardle75]

Ive got a bank of 24 volt batteries (chassis) and the leisure batteries that are not connected to each other. My logic with a B2b has been to boost the charging by effectively using both alternators to charge the leisure batteries?

It is certainly another option to use a 24V to 12V B2B and put the 12V alternator on eBay. Not sure I'd want to add another alternator into that mix, although there could be advantages for winter wild camping. Get the bulk charge capacity up to 0.3C or 0.5C depending on chemistry and recharge your bank in not much more than an hour (from 50%) whilst driving.

 

[jongood]

It is certainly another option to use a 24V to 12V B2B and put the 12V alternator on eBay. Not sure I'd want to add another alternator into that mix, although there could be advantages for winter wild camping. Get the bulk charge capacity up to 0.3C or 0.5C depending on chemistry and recharge your bank in not much more than an hour (from 50%) whilst driving.

I'm not keen to ditch the 12 volt alternator, why couldnt I use both?

 

[jongood]

Am I right in thinking that if I go Lithium they will cope with as much current as I can throw at it?

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[cmcardle75]

I'm not keen to ditch the 12 volt alternator, why couldnt I use both?

You could. However, the different charging regimes could conflict.

 

[funflair]

Am I right in thinking that if I go Lithium they will cope with as much current as I can throw at it?

You would need to read the spec of your chosen battery but up to 1C so thats the total capacity in 1 hour, not good for longevity though so stick to 2 or 3 hours would be my choice, our LadeBooster is 90A into 320ah not sure what they fit if you just have the standard one battery.
.
.

 

[cmcardle75]

Am I right in thinking that if I go Lithium they will cope with as much current as I can throw at it?

No, but they can take a lot more. Subject to specific model details, around 1C is typical, rather than 0.3 - 0.5C for various types of lead acid. Also bear in mind, though, that the LifePO4 can be discharged almost all the way, rather than just down to 50%, so a battery of similar usable capacity will charge in a similar time from its typical max discharge regardless of being a flooded lead acid or lithium. (i.e. lead acid can only be 50% discharged, so the halved maximum charge rate will take the same amount of time to complete).

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[supervario]

Hi Jon our old clou had the same twin alternaters its a great system also had two 220 amp hr vartas we could last a week but if your fridge is on 12 volt and your not on hookup your lucky to get two days as they eat amps put a mulmeterr on and see what it says on the clou i had the solar putting out 24 volts whith an mppt the higher the input is it pushes better and the mppt regulates it to 12 volt on this slidy i have them at 96 volts with a top mppt when the suns out for a cupla hours we don t need hook up also check your 12 volt coming in from the alternater with the metermake sure it givin enough volts hope your enjoying the clou

 

[jongood]

Hi Jon our old clou had the same twin alternaters its a great system also had two 220 amp hr vartas we could last a week but if your fridge is on 12 volt and your not on hookup your lucky to get two days as they eat amps put a mulmeterr on and see what it says on the clou i had the solar putting out 24 volts whith an mppt the higher the input is it pushes better and the mppt regulates it to 12 volt on this slidy i have them at 96 volts with a top mppt when the suns out for a cupla hours we don t need hook up also check your 12 volt coming in from the alternater with the metermake sure it givin enough volts hope your enjoying the clou

Thanks Tony

Do you remember what output your 12v alternator was?

 

[supervario]

Jon should be about 14.2max 14.5

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[jongood]

Thanks Tony

Do you remember what output your 12v alternator was?

Amps or watts i'm after, just be good to get an idea of what its supposed to do.

Yes really really happy with it and so is Sue, happy days!

 

[supervario]

volts Jon

 

[funflair]

Amps or watts i'm after, just be good to get an idea of what its supposed to do.

Yes really really happy with it and so is Sue, happy days!

65A on the spec sheet, get your dad round with his clamp meter.

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[jongood]

65A on the spec sheet, get your dad round with his clamp meter.

I think the obvious and logical choice is go Lithium, its just up to you to persuade Sue!

 

[funflair]

I think the obvious and logical choice is go Lithium, its just up to you to persuade Sue!

Wish me luck everyone

 

[jongood]

Wish me luck everyone

So assuming Martin is successful - any recommendations for LiFePo4 suppliers?

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[andy63]

So assuming Martin is successful - any recommendations for LiFePo4 suppliers?

have you contacted battery megastore to see if they are still doing a discount for funsters...
Andy

 

[CazPaul]

Is the problem just because of the fridge situation, can you not just run fridge on gas then problem solved?

 

[jongood]

Is the problem just because of the fridge situation, can you not just run fridge on gas then problem solved?

I don't run the fridge on batteries Paul just noticed that they were after me mucking about with it. Had to plug it in tonight. Its been sat on the drive since Sunday PM , been in it a few times and a bit of experimenting but no significant use. I'm getting more convinced that the previous owners EHU habit have killed the Gels. and the solar is doing not much even though we ve had a sunnyish day today.

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[CazPaul]

I don't run the fridge on batteries Paul just noticed that they were after me mucking about with it. Had to plug it in tonight. Its been sat on the drive since Sunday PM , been in it a few times and a bit of experimenting but no significant use. I'm getting more convinced that the previous owners EHU habit have killed the Gels. and the solar is doing not much even though we ve had a sunnyish day today.

Yes it does seem like the gels are on their way out Jon, 440amp gels you should be able to leave them tons longer than that, we can ours.

 

[cmcardle75]

Yes it does seem like the gels are on their way out Jon, 440amp gels you should be able to leave them tons longer than that, we can ours.

We'd be able to go around 3-4 days on those batteries and we DO run our fridge on electric.

 

[JockandRita]

Good luck sorting it all out Jon.

Having just replaced the PCB module on our AES FF, I was experimenting this morning. When I unplugged the EHU, with the FF on the auto setting, it switched over to 12v, (rather than on gas as I was expecting), pulling 15.7 amps from the 4 x 80A Gel batteries. The 380w of solar was only producing just over 3 x amps with no sun, which is similar to your findings.

I can't stretch to LifePo4, but I do have all the gear needed for installing a 60A B2B anytime soon.

Cheers,

Jock.

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[CazPaul]

Good luck sorting it all out Jon.

Having just replaced the PCB module on our AES FF, I was experimenting this morning. When I unplugged the EHU, with the FF on the auto setting, it switched over to 12v, (rather than on gas as I was expecting), pulling 15.7 amps from the 4 x 80A Gel batteries. The 380w of solar was only producing just over 3 x amps with no sun, which is similar to your findings.

I can't stretch to LifePo4, but I do have all the gear needed for installing a 60A B2B anytime soon.

Cheers,

Jock.

Post 11 Martin says its normal Jock for Niesmann to do that, I can't for the life of me think why though, to save a penny or 2 on gas?

 

[denisejoe]

Wouldn’t it be cheaper to change the fridge to run on gas when stopped even if it means changing the fridge

 

[JockandRita]

Post 11 Martin says its normal Jock for Niesmann to do that, I can't for the life of me think why though, to save a penny or 2 on gas?

Yes, I did see that thanks Paul, and TBH, I'd rather it didn't do that unless the alternator is running, or bags of sun for 12v solar power.
When I unplugged the EHU yesterday, it switched straight to gas..............as expected.

Cheers,

Jock.

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[funflair]

Post 11 Martin says its normal Jock for Niesmann to do that, I can't for the life of me think why though, to save a penny or 2 on gas?

No he didn’t quite say that, N+B run the fridge from the habitation batteries when you select 12v manually over AES, if you leave it on AES the priority should be 240volts, gas, then 12v as a last resort (not sure it ever uses 12v with D+) that is how yours was Jock.

 

[funflair]

Yes, I did see that thanks Paul, and TBH, I'd rather it didn't do that unless the alternator is running, or bags of sun for 12v solar power.
When I unplugged the EHU yesterday, it switched straight to gas..............as expected.

Cheers,

Jock.

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

 

[jongood]

so clamp meter should be arriving today from you know who

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?

If my assumption is correct and I end up going for Lithium then what would I need to change regarding chargers?
I have 2 CBE mains chargers at 35w each with a gel or Pb settings.
Are they Ok to charge directly from the Alternator reg or will this need changing?
I'm going to change the Solar reg to Mppt regardless ( my earlier comparison between Clou and Arto was in August)

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[funflair]

Morning Jon

If you are taking the batteries off just put a load on each one after fully charging, a headlight bulb at 55 watts for example will be pulling about 4.4A you can confirm this with your clamp meter, keep a check on the volts and time, take it down to about 12v and then how many hours it has run x the amperage of the load gives you ah, compare that to the 130ah ish that you should be getting and then buy some lithiums.

Martin

 

[funflair]

No he didn’t quite say that, N+B run the fridge from the habitation batteries when you select 12v manually over AES, if you leave it on AES the priority should be 240volts, gas, then 12v as a last resort (not sure it ever uses 12v with D+) that is how yours was Jock.

Just to clarify, this should have said "without" apologies for any confusion

 

[bigtwin]

a headlight bulb at 55 watts for example will be pulling about 4.4A you can confirm this with your clamp meter, keep a check on the volts and time, take it down to about 12v and then how many hours it has run x the amperage of the load gives you ah, compare that to the 130ah ish that you should be getting and then buy some lithiums.

Ian

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