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

 

[t0mb0]

Pretty difficult to advise on 100ah vs 200ah without knowing the expected use case, loads, etc. I assume you have some requirement above and beyond the usual camper use case to actually need 200ah of lithium.

 

[BigDean]

Pretty difficult to advise on 100ah vs 200ah without knowing the expected use case, loads, etc. I assume you have some requirement above and beyond the usual camper use case to actually need 200ah of lithium.

Thanks for that.

Its a good point, and one that I don't really know the answer of. I have never run out of power, but why wouldn't you go for the max if upgrading the system anyway? We have stayed on campsites in the main, so by having 200ah, would give opportunity to be more offgrid.

Thanks for your input

 

[t0mb0]

Do you have solar? Adding Ah gives you potential added storage but, ultimately, your ability to stay off hookup depends on the net input keeping up with the net output.

As an example, we haven’t touched a hookup lead in years using a combination of factory 75Ah AGM, DC-DC charger and 250w solar. Depends on the kind of trips you do obviously, this wouldn’t work staying static for a week over winter (without firing the engine up).

 

[BigDean]

Do you have solar? Adding Ah gives you potential added storage but, ultimately, your ability to stay off hookup depends on the net input keeping up with the net output.

As an example, we haven’t touched a hookup lead in years using a combination of factory 75Ah AGM, DC-DC charger and 250w solar. Depends on the kind of trips you do obviously, this wouldn’t work staying static for a week over winter (without firing the engine up).

Yes, solar will be installed as well, so will size that according to the max battery capacity.

Great point. Probably want to be offgrid for up-to 5 days/long weekend.

 

[DXX]

Battery capacity requirement depends of what you want to do with the van.
I only have 110Ah of AGM with 140W solar, 99% of the time we are not using EHU and no issues apart from the depths of winter on very overcast mornings.
In my situation 100Ah of LiFePo would be more than adequate.
Remember the weight and space all adds up. If you are travelling you will almost certainly find the additional space more important than ‘what if’ power.

 

[BigDean]

Battery capacity requirement depends of what you want to do with the van.
I only have 110Ah of AGM with 140W solar, 99% of the time we are not using EHU and no issues apart from the depths of winter on very overcast mornings.
In my situation 100Ah of LiFePo would be more than adequate.
Remember the weight and space all adds up. If you are travelling you will almost certainly find the additional space more important than ‘what if’ power.

Thanks for that. Paper and pencil required to do some maths!

 

[t0mb0]

It sounds like your use case is reasonably typical. In this case, my plan would be:

1) Maximise solar. You can't have too much solar as the idea of bigger panels is to deliver some input in non-perfect conditions and, unlike a battery, upgrading a stuck-on solar panel is a massive PITA.
2) Ensure a decent DC-DC charger for charging whilst driving or in emergencies when you are static without sun and just need to run the engine.
3) Go for the 100Ah battery option (unless the expense just isn't a factor and you fancy 200Ah!).

 

[Long tall John]

We’ve got 100 AH lithium, no solar and no hook up so always off grid even on a campsite. We’ve got diesel heater, fridge, lights and chargers Draining the battery and we easily managed three days/ nights in October in The New Forest without driving to recharge it. Bear in mind with a good DCDC Charger the battery will go from empty to full in two hours driving so a daily trip to the shops will top it back up pretty easily. Buying again I’d probably buy 120ah just for the extra piece of mind and the battery will thank you for not going below 80% discharge

 

[BigDean]

It sounds like your use case is reasonably typical. In this case, my plan would be:

1) Maximise solar. You can't have too much solar as the idea of bigger panels is to deliver some input in non-perfect conditions and, unlike a battery, upgrading a stuck-on solar panel is a massive PITA.
2) Ensure a decent DC-DC charger for charging whilst driving or in emergencies when you are static without sun and just need to run the engine.
3) Go for the 100Ah battery option (unless the expense just isn't a factor and you fancy 200Ah!).

Thanks again,

If going for the 200ah, would you do 2 x 100ah or 1 x 200ah?

 

[Dellmassive]

I would say the only difference would be physical size...

If you can fit 1x200ah then go for it. (Say in a kitchen cabinet build)

But if you have smaller spaces . .. ie under seat, then you will need to drop to 2x100ah.

***

200ah is 200ah capacity wise, so that wont change.

***

To work out what you need:

add up all the Watts/Amps of the kit that you plan to use on a daily basis . . . then convert to Amps. (this gives you the Amps ie 5A,10A, 20A)

This Amps rate per hour would be 5Ah, 10Ah, 20Ah

Then work out roughly how many hours it will be used over your trip, then add a margin.

5Ah for 10hrs = 50ah, (plus 20% margin = 53Ah)
10Ah for 10hrs = 100ah, (plus 20% margin = 120Ah)
20Ah for 10hrs = 200ah, (plus 20% margin = 220Ah)

Now you have this value, you know what you can draw from the battery bank . . . . but also what you need to do to RECHARGE the battery bank.

ie

if you run this "10Ah for 10hrs = 100ah, (plus 20% margin = 120Ah)" for 5 hours you could depleate the battery bank by 50% or 50Ah . . . . which only leaves 50% or 5hours left.

so the recharge is just as imp[ortant.


Note these figures above relate to "Lifepo4 battery's" as you can use all the capacity of the battery.

doing this calculation for SLA batterys "ie AGM" then you need to calculate for ONLY 50% of the battery capacity . . . ie 50ah for a 100ah battery or 100ah for a 200ah battery bank.
***


as per @t0mb0 , look at adding DC-DC charger, and some extra mobile solar.

[Guide] Mobile Solar Panels ? . . . - How I Did It -

Mobile Solar Panels ? . . . - How I Did It - There is loads of background to this . . . . . but for now here is a vid for you all. =] Just remember W = V*A and as a general rule a good 100W panel will give you up to 6A charge with good sun. 25w = 1.5A 50W = 3A 100w = 6A 200w = 12A 300w = 18A...

www.t6forum.com

[Guide] DC-DC Charger (for leisure battery) -- How I Done It --

DC-DC Charger (for Leisure battery) -- How I Done It -- ************************************************** Dellmassive`s -- "how I Done It" -- Thread ************************************************** Kit List And Stuff -- How I Done It & What I Use --...

www.t6forum.com

Lithium LifePo4 12v Batteries - Time For An Upgrade?

Lithium Batteries are the future, (keep checking back for the latest news/edits) ************************************************** Dellmassive`s -- "how I Done It" -- Thread ************************************************** Kit List And Stuff -- How I Done It & What I Use --...

www.t6forum.com

maybe look at adding the second Lithium as a Mobile battery box . . .

12v Lithium Leisure Battery Box 138Ah 1766Wh -- How I Done It --

12v Lithium Leisure Battery Box 138Ah 1766Wh -- How I Done It -- It's about time that I got this long-overdue project sorted out. The missing parts are on order and completion is in sight . . . . . . . . ready for the Post Pandemic 2020 Camping Trips (Hopefully) This is where it started. p1...

www.t6forum.com

more info:

Dellmassive’s "How I Done It" blogs.

-- Dellmassive`s -- "How I Done It" -- thread -- ************************************************** Dellmassive`s -- "how I Done It" -- Thread ************************************************** Kit List And Stuff -- How I Done It & What I Use --...

www.t6forum.com

 

[BigDean]

I would say the only difference would be physical size...

If you can fit 1x200ah then go for it. (Say in a kitchen cabinet build)

But if you have smaller spaces . .. ie under seat, then you will need to drop to 2x100ah.

***

200ah is 200ah capacity wise, so that wont change.

***

To work out what you need:

add up all the Watts/Amps of the kit that you plan to use on a daily basis . . . then convert to Amps. (this gives you the Amps ie 5A,10A, 20A)

This Amps rate per hour would be 5Ah, 10Ah, 20Ah

Then work out roughly how many hours it will be used over your trip, then add a margin.

5Ah for 10hrs = 50ah, (plus 20% margin = 53Ah)
10Ah for 10hrs = 100ah, (plus 20% margin = 120Ah)
20Ah for 10hrs = 200ah, (plus 20% margin = 220Ah)

Now you have this value, you know what you can draw from the battery bank . . . . but also what you need to do to RECHARGE the battery bank.

ie

if you run this "10Ah for 10hrs = 100ah, (plus 20% margin = 120Ah)" for 5 hours you could depleate the battery bank by 50% or 50Ah . . . . which only leaves 50% or 5hours left.

so the recharge is just as imp[ortant.


Note these figures above relate to "Lifepo4 battery's" as you can use all the capacity of the battery.

doing this calculation for SLA batterys "ie AGM" then you need to calculate for ONLY 50% of the battery capacity . . . ie 50ah for a 100ah battery or 100ah for a 200ah battery bank.
***


as per @t0mb0 , look at adding DC-DC charger, and some extra mobile solar.

[Guide] Mobile Solar Panels ? . . . - How I Did It -

Mobile Solar Panels ? . . . - How I Did It - There is loads of background to this . . . . . but for now here is a vid for you all. =] Just remember W = V*A and as a general rule a good 100W panel will give you up to 6A charge with good sun. 25w = 1.5A 50W = 3A 100w = 6A 200w = 12A 300w = 18A...

www.t6forum.com

[Guide] DC-DC Charger (for leisure battery) -- How I Done It --

DC-DC Charger (for Leisure battery) -- How I Done It -- ************************************************** Dellmassive`s -- "how I Done It" -- Thread ************************************************** Kit List And Stuff -- How I Done It & What I Use --...

www.t6forum.com

Lithium LifePo4 12v Batteries - Time For An Upgrade?

Lithium Batteries are the future, (keep checking back for the latest news/edits) ************************************************** Dellmassive`s -- "how I Done It" -- Thread ************************************************** Kit List And Stuff -- How I Done It & What I Use --...

www.t6forum.com

maybe look at adding the second Lithium as a Mobile battery box . . .

12v Lithium Leisure Battery Box 138Ah 1766Wh -- How I Done It --

12v Lithium Leisure Battery Box 138Ah 1766Wh -- How I Done It -- It's about time that I got this long-overdue project sorted out. The missing parts are on order and completion is in sight . . . . . . . . ready for the Post Pandemic 2020 Camping Trips (Hopefully) This is where it started. p1...

www.t6forum.com

more info:

Dellmassive’s "How I Done It" blogs.

-- Dellmassive`s -- "How I Done It" -- thread -- ************************************************** Dellmassive`s -- "how I Done It" -- Thread ************************************************** Kit List And Stuff -- How I Done It & What I Use --...

www.t6forum.com

Thanks Dellmassive, you are a legend. I have read so many of your articles already to get to where I am now. Van not even delivered to me yet (next week hopefully).

I am going with all Victron kit for the charger/inverter etc.

More questions to come, I am sure, as I get further down the line

Thanks again.