Lithium and lead on a solar system

[wildebus]

So with most of all avenues now explored member wildebus has the answer and that seems the only route to go down.

Lots of paths and options, some suit better than others depending on situations.

The multiple arrays and controllers option can be a valid one, but for most having ALL the solar focused on your main use battery (e.g. Leisure) and then diverting some of that to a secondary battery as you choose is usually the most efficient.

There are reasons to have multiples. One example we did on a small camper was to have just two panels on the roof, but with a controller for each, so fully independent. Reason being it was a setup for a vehicle which was going to go on an overland expedition to Mongolia. Who knows what support and backup facilities will be available on that trip in the middle of the Gobi? So having two arrays allowed solar to still work, albeit reduced, if a panel smashed or a controller broke. (For a similar reason, went for dumb Lead-Carbon batteries. No BMS electronics to fail making the battery useless, and also one thing you can always find everywhere is a replacement Lead-Acid battery if it is needed).

 

[Sonar]

Lots of paths and options, some suit better than others depending on situations.

The multiple arrays and controllers option can be a valid one, but for most having ALL the solar focused on your main use battery (e.g. Leisure) and then diverting some of that to a secondary battery as you choose is usually the most efficient.

There are reasons to have multiples. One example we did on a small camper was to have just two panels on the roof, but with a controller for each, so fully independent. Reason being it was a setup for a vehicle which was going to go on an overland expedition to Mongolia. Who knows what support and backup facilities will be available on that trip in the middle of the Gobi? So having two arrays allowed solar to still work, albeit reduced, if a panel smashed or a controller broke. (For a similar reason, went for dumb Lead-Carbon batteries. No BMS electronics to fail making the battery useless, and also one thing you can always find everywhere is a replacement Lead-Acid battery if it is needed).

Again I think it is system that needs a design However I would like all the systems with minimal watching . And not to complicated .if possible
Think I may have found the split relay charger


See below images .

 

[wildebus]

Yup, that will be it ... pair of 40A relays, one for Split Charge and one for Fridge. Disabling the Split charge will be as easy as pulling the relay .
It looks like the fuses for that Relay block is on the left, but not 100% as the colours are not quite right for it. Typically 3 fuses ... two higher rated ones for relays and one small one for D+ signal. You have two Yellows = 20A, and what looks like a Blue which is 15A, but that Blue could possibly be a faded purple, which would be 3A. It will say on the end, and of course there is no guarentee they are correct anyway as could have been replaced at some time.

But of course .... maybe something else! could be headlight relays? have to get a meter on the leisure battery and check the voltages as you start the engine and have the relay in and out to check.

When you run the new cables for the B2B from Engine Bay to Rear Garage, you would also want to add the D+ cable as well for extra flexibility (may as well have it available if you're running cable anyway. Super-easy to add that).

 

[Sonar]

Fuses May have been changed. I take that the right hand one of the two is the split charge relay ..

Easy to install is ok for me.

 

[wildebus]

those cables to the fuse box there are Sargent cables and use the Sargent colour standards, so you will be able to look at that in conjunction with the wiring diagram you have to see which is which.
Brown/Green and Brown/Blue are the +ve Battery Cables. Not looked it up but the cable with the red colour (not sure it it is red or red striped?) might be the Fridge? Going by the fuse labels, the left hand 20A looks like it is newer? I wonder if that should be smaller? Just thinking - you can check by looking at the wiring diagram and also get a clue from the size of the wiring of course.

 

[Sonar]

those cables to the fuse box there are Sargent cables and use the Sargent colour standards, so you will be able to look at that in conjunction with the wiring diagram you have to see which is which.
Brown/Green and Brown/Blue are the +ve Battery Cables. Not looked it up but the cable with the red colour (not sure it it is red or red striped?) might be the Fridge? Going by the fuse labels, the left hand 20A looks like it is newer? I wonder if that should be smaller? Just thinking - you can check by looking at the wiring diagram and also get a clue from the size of the wiring of course.

Attached

 

[wildebus]

So that Red Cable is likely Red/Yellow then?
And the Brown/Green is fused, but always live.

 

[Sonar]

When I rewired the new fridge I found at the fridge end that the red/ yellow cable was live only when the engine was running I think …

 

[wildebus]

When I rewired the new fridge I found at the fridge end that the red/ yellow cable was live only when the engine was running I think …

That is how it should be. It is the 12V supply to a 3-Way Fridge.

A newer 3-Way fridge could well want the D+ signal appearing at the Fridge as well.

 

[Chasn]

Even if you use you MH out of season it is easy to allow the starter battery to lose enough charge to make starting difficult particularly on a cold day in winter. Last December was extremely poor for solar production and as my MH is stored indoors I don't rely on solar to keep the SB topped up. Where I store my MH I have EHU care of an off-grid system so I have wired in an extra mains charger for the SB. As an aside I have wired it so that if necessary it can be powered by the inverter. That way if my SB is low on energy when parked off-grid I have a means to charge it from the habitation battery.

 

[Sonar]

Seldom were on electric hookup and we use our moho all throughout the year.
The solar system we have is a dual system so charges the habitation batteries and also the starter battery.

I dont know how much sola wattage i would need in order to trickle charge the starter battery when i have changed to only lithium batteries.
Member wildebus has a solution …

 

[wildebus]

Seldom were on electric hookup and we use our moho all throughout the year.
The solar system we have is a dual system so charges the habitation batteries and also the starter battery.

I dont know how much sola wattage i would need in order to trickle charge the starter battery when i have changed to only lithium batteries.
Member wildebus has a solution …

I can monitor how much power the AMT12-2 Battery Maintainer sends to the Starter Battery via a Victron BMV I have on that circuit.
I'll reset the monitor so have a known position and check over a 24 hour period. The actual answer for a given Motorhome will be dependant on what parasitic loads are on the Starter Battery (have you an Alarm, a Tracker, is the Radio wired to the Starter Battery or Leisure Battery, and is it wired correctly (many are not!), etc) but you can get a feeling for it maybe.

 

[Sonar]

I can monitor how much power the AMT12-2 Battery Maintainer sends to the Starter Battery via a Victron BMV I have on that circuit.
I'll reset the monitor so have a known position and check over a 24 hour period. The actual answer for a given Motorhome will be dependant on what parasitic loads are on the Starter Battery (have you an Alarm, a Tracker, is the Radio wired to the Starter Battery or Leisure Battery, and is it wired correctly (many are not!), etc) but you can get a feeling for it maybe.

Just an alarm that has a flashing light. The radio will not come on until the ignition is on if it is not started within 10 mins it turns its self off .

 

[trevskoda]

Even if you use you MH out of season it is easy to allow the starter battery to lose enough charge to make starting difficult particularly on a cold day in winter. Last December was extremely poor for solar production and as my MH is stored indoors I don't rely on solar to keep the SB topped up. Where I store my MH I have EHU care of an off-grid system so I have wired in an extra mains charger for the SB. As an aside I have wired it so that if necessary it can be powered by the inverter. That way if my SB is low on energy when parked off-grid I have a means to charge it from the habitation battery.

Would have been much easyer to just run a batery cable through a 200ah relay and switch like mine, so you can use all the juice to crank here over, ne requirement for a inverter.