how do I know its a 24 volt panel.

[native pepper]

Terry, I don't have a hybrid system, except for the gel pack in the bus, which is totally independent of the lifepo4 and charged by the engine. I have 3 sets of lifepo4 working, one for over 8 years and the others 4-5 years. All my understanding comes from hands on experience, have watched my mates many testing of systems, with varying setups working along side each other and he got into lithium well over a decade ago when he came back from Canada with a pack of li-poly.

He was a Virgo so every thing had to be precise and at times it was annoying how he would re do tests over and over because there was a little discrepancy in the results. So have seen the comparisons from the many different charging and controls he used and he never put anything into practise, until he had proven it in the workshop and on his own house and business premises. That's why I have the systems I have and why he built his own charge controllers, BMS and finally cell equalisers. I personally know the half dozen people who have his lifepo4 systems running for over 8 years and they have received his updates and new controls as he developed them, just as I have. Off course most are his family, as he used everyone close to him for his test guinea pigs and the results is what i use.

I'm sure there will be better set ups down the track, as there will be better storage systems which will make lifepo4 look ancient. For now I believe every bit of info surrounding this technology is relevant, until there becomes an accepted standard working control system everyone uses. The ones I use have been built specifically for litepo4 and the controllers have been in use for quite a few years now, along with the equalisers they are easy to set up and virtually fool proof.

It wasn't until my mate left that I began looking for information on lifepo4, realising how much I relied upon him for my energy systems. Nor would I be telling those with their current working system to change anything, I'm just letting others that are looking for advice, the sort of set up I use. Couldn't care less what everyone else uses, as long as it works, but from the testing I've seen, using lead acid chargers with float etc, will reduce their lives and now have read that a few times in my desperation to find out more so can fix things myself if they go wrong.

So I am very interested in what you post, even if most of it is well over my head. Just find it hard to accept my mppt controllers won't work in parallel with lifepo4, when everything I've seen and know states the opposite, if you use dedicated lifepo4 controls and not converted or programmable lead acid controls. Which are basically designed with parameters that will well over charge and discharge lifepo4 if a relay or some other control fails. Using bulk chargers with preset safe voltages, seems to me to be the only safe way for novices and know nothings and I know how they feel when confronted by these new approaches to energy storage. Sadly it seems no one except for the Stones and our group, use controls which are just designed just for lifepo4 and no one makes bulk chargers other than the ones we now have built. Maybe we have it all wrong.

[T1 Terry]

A tad confusing which system you are talking about at the time so sorry if I get them a bit mixed up at times. You say you have 3 LiFeP04 systems working at the moment, are each of these a stand alone single 12v battery? Which of these have multiple MPPT controllers connected to the one 12v battery?

T1 Terry

[native pepper]

The 3 systems are all stand alone, the house has 6 x 40amp mppt controllers on its 4.5 kw solar and 675amp lifepo4, the bus will have 2 x 40amp mppt controllers when I put the 1000w of solar on it. Currently it has 460w and one 40amp mppt controller, 480amp lifepo4, the other is the portable 120amp pack, which uses either a 40 or 60amp mppt controller and all are 12v nominal.

Here's a photo of my 8 year old 120amp lifepo4 pack, you will note the fine engineering and precision case, along with the finely tuned handle and special design holding the cell equaliser on it. It's been dropped in the ocean, fallen of tractors and left own in the weather at times, but it still provides just the same amount of energy when I first put it together. Can still remember the many laughs i got when it was put beside my mates 120amp work packs, in their neat little boxes with controls in the bottom of them. He put his cells on their side, which is what I should have done, but it works.

[Kappy]

Only you can make that call Kappy, best to be armed with as much knowledge as you can get to make the decision on which way suits you best. It is better to make a well informed investment that you will be happy with and can live with than taking the easiest path and regretting it in the near future. Do it right and you will only need to do it once, but which way is the right way ?

The bus was set with 600 watt of solar and 200 ah of AGM, that look as though they had passed the Use by date so I don't know if they are actually the problem.

The bus was set up to run on 24 volt not by me but the guy I brought it off, the fridge and lights,pumps run ok off 24 volt the inverter was a modified Sine wave that wouldn't run an A/C and did I mention the AGM's are toast. So I thought I would replace with LifePo.

Advice seems to back that.

Then I thought I would change to 12 Volt and lithium, then I discover I need heavier wire, so do I have to rpelace all the wiring throughout the bus or is that around the panels/batteries haven't discovered where.

Thought I would stay with 24 seemed to work sorta before AGM's died and add more panels for power generation.

So am I confused you betcha, a lot of the advise I have sifted through seems at times contradictory, for a lay person like me and when I think I got my head around it someone throws something else in the mix.

I'm guessing you aren't the only one Kappy There are so many experts ready to share their beliefs yet have very little technical expertise and virtually no side by side testing to verify their beliefs, you are just expected to have faith that they know best.
I don't claim to know it all, still learning after 6 yrs hands on testing, but with a few hundred systems out there now all making their owners very happy they went with my advice I fell I must be getting close to getting it right

On another thread about increasing the output of a 20 amp PWM controller all the experts said it wouldn't work, then said it wasn't efficient, now they say someone else came up with the idea first, not that it doesn't work because that can't be claimed any more ..... so much for experts eh
The solar cabling will need to be up to carrying the current involved no matter if it's 12v or 24v so it will probably need to be upgraded, unlikely any other wiring will need to be upgraded besides the high draw stuff like inverters and fridges if they run 12v, but again that idea that wouldn't work of using a 240vac inverter fridge seems to be the way to go with many very happy people doing the impossible, so that just leaves the inverter and you already knew you would need to upgrade that cabling if you wanted to run the air con

T1 Terry

Still quite confused regarding upgrading wiring throughout the bus.

I've checked all the low voltage wiring going from, shall I call it the control room and it all appears to be marked 12 volt, even through the panels are 24 volt as is the solar controller. Although its marked 12/24 Volt as is all the house side appliances.

Barring the A/c which is 230VAC and TV, electric hot water etc.

I understand the need to select or upgrade all wiring to and from the batteries/ inverter etc.

I pretty well get that I need 2 solar controller's if I have 2 types of 24 volt panels.

If I stick with a 1000 watts of like panels will say a PL 80 run it?

[T1 Terry]

If the correct solid state relays (that will handle the 46v open circuit the grid connect panels) become available in the new yr then a Dingo 20/20N will run the solar side with all the panels in parallel. The down side is the grid connect higher Vmp panels (36.7v)will waste a bit compared to the other panels (30.4v and 30v Vmp) closer to 28.0v, but when the panels get hot the 30v Vmp will be a bit below 28v due to the heat lowering the Vmp yet the 36.7v panels will still able to pour in their max current (amps) all the way till fully charged.
To give you an idea of just how much the Vmp can drop when the panels get hot, this chart is from Kyocera, a well respected name in Rv solar panel circles

Kyocera 140w panel with single voltage increments.jpg

double the voltages for 24v and you can see the panels starts to drop the voltage point where max output occurs as the panel heats up, and yes they do reach 75*C in full sun, Kyocera wouldn't put that on a chart it is didn't occur The panel in the chart would have an advertised 17.?v Vmp, so 34.? @ 24v.
Hopefully the graph and the post read through a few times will help clear some of the fog away.

T1 Terry