Lithium Batteries - 100ah or 200ah?

[BigDean]

Morning all,

If you were to upgrade to lithium batteries, what config would you go for?

I can just do 1 x 100ah, but would really like 200ah. So, would you go for a single 100ah, 2 x 100ah or 1 x 200ah?

A 200ah is the same height and width as the 100ah, just 50% longer, so there is a size benefit over 2 x 100ah, but there is resilience in 2 x 100ah.

Over to you guys.....

Thanks
BigDean

 

[cmcardle75]

Morning all,

If you were to upgrade to lithium batteries, what config would you go for?

I can just do 1 x 100ah, but would really like 200ah. So, would you go for a single 100ah, 2 x 100ah or 1 x 200ah?

A 200ah is the same height and width as the 100ah, just 50% longer, so there is a size benefit over 2 x 100ah, but there is resilience in 2 x 100ah.

Over to you guys.....

Thanks
BigDean

Personally, I'd go with a single battery if it fits. You don't have to worry about wiring diagrams, voltage/current differentials and balancing.

 

[Lenny HB]

If very little difference in cost I would go for 2 x 100, if the 200 was a lot cheaper I would go for that.
Seems a bit strange the 200 amp is only 50% longer as the batteries are made from standard cells I would need some convincing that it was double the power.

 

[BigDean]

If very little difference in cost I would go for 2 x 100, if the 200 was a lot cheaper I would go for that.
Seems a bit strange the 200 amp is only 50% longer as the batteries are made from standard cells I would need some convincing that it was double the power.

Thanks for that,

The unit I am looking at has a BMS built in etc, so that could explain some of the size difference. Will check the spec sheets.

Out of interest, why 2 x 100 if price wasn't much difference, resilience/redundancy?

Thanks
BigDean

 

[BigDean]

Personally, I'd go with a single battery if it fits. You don't have to worry about wiring diagrams, voltage/current differentials and balancing.

Thanks for that. Good points.

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[dunnah01]

Come on - somebody has to recommend 2x200Ah

 

[Lenny HB]

Out of interest, why 2 x 100 if price wasn't much difference, resilience/redundancy?

Yep.

 

[BigDean]

Come on - somebody has to recommend 2x200Ah

Now theres a thought....

 

[BigDean]

Yep.

Thanks Lenny.

 

[eddie]

If you wish to run an inverter 1 x 200 amp will give you less issues

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[BigDean]

If you wish to run an inverter 1 x 200 amp will give you less issues

Thanks Eddie.

 

[Lenny HB]

If you wish to run an inverter 1 x 200 amp will give you less issues

Can you explain why please?

 

[eddie]

Can you explain why please?

If you had two 100amp lithium batteries in parallel , and connected the inverter, quite properly across the two batteries, when the inverter tries to draw a higher current that the individual BMS, but less that the total rated output of the ‘bank’ the BMS can momentarily shut down.

This we established was the timing, in that one BMS would be reading say a 80 amp load not knowing there was another BMS working on the same circuit.

We know that some motor home converters experienced a similar conundrum.

The solution is fairly simple, connect the inverter to a BUS bar, along with the two Lithium positives, do the same with the negative connections, and the problem doesn’t occur

Which of course you don’t need to do if you use 1 x 200 with a larger BMS

Again, this isn’t an issue say when we install Victron Lithium batteries as we use an external BMS

 

[autorouter]

The main reason a 100Ah lead-acid is the standard is its size and weight, it's as big and heavy as the average person can reasonably lift and move around, in a confined space. So I believe a lithium battery of a similar size and weight will eventually become the standard unit, and that's about 200Ah.

In general, a single battery is better than two smaller batteries. Unless you are duplicating them for redundancy reasons. In which case you should go for two batteries, two chargers and alternators, and two solar panels and controllers.

 

[BigDean]

The main reason a 100Ah lead-acid is the standard is its size and weight, it's as big and heavy as the average person can reasonably lift and move around, in a confined space. So I believe a lithium battery of a similar size and weight will eventually become the standard unit, and that's about 200Ah.

In general, a single battery is better than two smaller batteries. Unless you are duplicating them for redundancy reasons. In which case you should go for two batteries, two chargers and alternators, and two solar panels and controllers.

Very good point. Single battery seems the correct solution.
thanks.

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[Lenny HB]

In general, a single battery is better than two smaller batteries. Unless you are duplicating them for redundancy reasons. In which case you should go for two batteries, two chargers and alternators, and two solar panels and controllers.

But if one battery fails you still have another, not an option with a single battery.
If one of the charging devices fails you still have two others, so don't need to duplicate.

 

[BigDean]

But if one battery fails you still have another, not an option with a single battery.
If one of the charging devices fails you still have two others, so don't need to duplicate.

My brain hurts, but very fair point.

 

[Pausim]

I find a single 100Ah Li works fine for me, it depends on how much power you use and how you recharge it. If you only use 40Ah to 50Ah a day but have the means to top the battery up you don’t need a big bank.

 

[Steve and Denise]

I’ve been looking at the eco-tree 320 seems good value with bms built in and 6 year warranty but not wanting to waste money I’ll wait till my gels die, plus we’re not traveling anywhere just yet

 

[Howard H]

Oh I do love these threads , absolutely no idea what you are talking about but more to do with motorhomes than politics so that will do for me carry on

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[Lenny HB]

not wanting to waste money I’ll wait till my gels die,

Going to be a long wait, two of my Gels are nearly 5 years old & one nearly 4 years old all performing as new, should be good for another few years.

 

[Lenny HB]

I find a single 100Ah Li works fine for me, it depends on how much power you use and how you recharge it. If you only use 40Ah to 50Ah a day but have the means to top the battery up you don’t need a big bank.

At this time of year in the UK you would need a couple of thousand watts of solar to do that, if you don't want to drive for an hour or two each day.

 

[Steve and Denise]

Going to be a long wait, two of my Gels are nearly 5 years old & one nearly 4 years old all performing as new, should be good for another few years.

Well I think the price will have come down a bit by then happy days

 

[Pausim]

At this time of year in the UK you would need a couple of thousand watts of solar to do that, if you don't want to drive for an hour or two each day.

True.

I have spent some of the children’s inheritance on an Efoy so lack of sun is not an issue for me. The point I am really trying to make is that a big battery only delays the need to recharge but sooner or later you have to put something back into it. If someone moves on most days or has good solar and only goes out in summer then they might not need a big a battery. I think the starting point should be an energy assessment, what do I want to run and how much of that demand will get replaced in normal use. If there is a deficit then more battery power or more solar or perhaps a B2B might be the answer.