4 x trojan T105 6v 225amp connected for 12v

[PeterCarole29]

In the specifications it say 13% charge rate.

I have 250w solar panel with victron mppt 1 x 12v to 12v x 30amp b2b
If i am driving in the sun can some one help to calculate what the max amps i am creating and what is the idea max charge rate as well.
This is so if i want to uprate more i dont over do it.
I am slowly getting the hang of understanding the technical data . Very good at bolting and building thing just not so clever
any help is appreciated
Thanks in advance

 

[PeterCarole29]

I also have connected a sterling power pro combi 1600 pure signwave inverter/ charger it has 70amp charger

 

[funflair]

So what total battery capacity do you have at 12v is it 450ah ? your solar will give you a maximum of 20A so plus the B2B is total max possible 50A so that would be 11%.

EDIT solar plus your charger at 70A would be over 13%

 

[Stealaway]

This is so if i want to uprate more i dont over do it.

Those four Trojan batteries will weigh over 18 stones. That's a lot weight for a motorhome.

 

[Hoovie]

Those four Trojan batteries will weigh over 18 stones. That's a lot weight for a motorhome.

Not really. The batteries in my last camper added up to 33 Stone (or 210 Kg in modern terms). No bother.

The battery bank in my current motorhome is 110Kg (17.3St for those living in the past).

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[Raul]

In the specifications it say 13% charge rate.

I have 250w solar panel with victron mppt 1 x 12v to 12v x 30amp b2b
If i am driving in the sun can some one help to calculate what the max amps i am creating and what is the idea max charge rate as well.
This is so if i want to uprate more i dont over do it.
I am slowly getting the hang of understanding the technical data . Very good at bolting and building thing just not so clever
any help is appreciated
Thanks in advance

In simple terms the 13% it’s the optimal charge rate. For your bank that translates to 58-60 charging amps. If you go higher it will shorten their life a little. If you go lower it will shorten their life a bit more; but you can mitigate this by compensating with longer charging times. Ideally you want a minimum of 10% charge rate, to prevent stratification for flooded cells, sealed or not.

 

[Stealaway]

The battery bank in my current motorhome is 110Kg (17.3St for those living in the past).

Nice to have so much spare payload. My van is only 3.5 tonnes so there is non / zero spare payload

 

[PeterCarole29]

The weight hopefully wont be an issue, we took them out of our last camper (5250kg with plenty of allowance)
Now a panel van converting.

 

[PeterCarole29]

In simple terms the 13% it’s the optimal charge rate. For your bank that translates to 58-60 charging amps. If you go higher it will shorten their life a little. If you go lower it will shorten their life a bit more; but you can mitigate this by compensating with longer charging times. Ideally you want a minimum of 10% charge rate, to prevent stratification for flooded cells, sealed or not.

I have just looked on the internet and instructions for the charger state 50amp yet the box it came in says on it 70amp.
So i have phoned sterling and they said it should be 50amp. I asked about the box, was it a printing error and he said they had to down rate the charger. (i hope they have).

So in theory if i am parked in the sun and on mains electric i should swich of solar before i put the charger on if i have low batteries

 

[Raul]

I have just looked on the internet and instructions for the charger state 50amp yet the box it came in says on it 70amp.
So i have phoned sterling and they said it should be 50amp. I asked about the box, was it a printing error and he said they had to down rate the charger. (i hope they have).

So in theory if i am parked in the sun and on mains electric i should swich of solar before i put the charger on if i have low batteries

Don’t need to swich any solar off. You can have multiple charging sources with same settings. When you are on ehu, you barely make you charging requirement. Solar don’t even touch it, it’s just a top up helper. If you cycle those batteries 40-50%, rest assured you need few hrs on ehu stable supply. Solar it’s opportunistic and variable, you need overpaneling to achieve stable solar charging. One cloud, and the absorb is screwed, going to float prematurely.

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[PeterCarole29]

Don’t need to swich any solar off. You can have multiple charging sources with same settings. When you are on ehu, you barely make you charging requirement. Solar don’t even touch it, it’s just a top up helper. If you cycle those batteries 40-50%, rest assured you need few hrs on ehu stable supply. Solar it’s opportunistic and variable, you need overpaneling to achieve stable solar charging. One cloud, and the absorb is screwed, going to float prematurely.

Thanks it seems potentially i have a problem i do have a 70amp charger in the inverter charger. If i use it will it cause a problem

 

[Raul]

No it won’t, the batteries will absorb in relation to their discharge state. The 70amp will only be valid if batteries are really empty and only at the beginning. After that it’s a pretty healthy charge rate. I would have no worries charging with the 70amp. Just monitor water usage that’s all. Excessive water loss= to high absorb voltage; not using any = to low absorption voltage, and potential partial sulphation with time. You have to use some water, to de sulphate the plates each cycle. Invest in a hydrometer 10-15 quid, and monitor acid density after full charge. If density low, or differ from cel to cell, run a equalisation charge.
Flooded cells are robust, but require maintenance.

 

[pappajohn]

So what total battery capacity do you have at 12v is it 450ah

Nope.....
Two banks of 6v in series so 12v per bank......amps remain the same....225amps
Two banks of 12v connected in parallel....12v total and 4.......

Bugger just realised you're correct

 

[DavidCh]

What I don’t get is my 280ah lithium is the same capacity but a quarter the weight and size and I suspect less money. Why?

 

[pappajohn]

What I don’t get is my 280ah lithium is the same capacity but a quarter the weight and size and I suspect less money. Why?

No lead plates, no water.
Lithium needs anchoring to stop it floating away on a breeze.

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