BATTERY MASTER

[autorouter]

On EHU both batteries are charged. On Solar, just the leisure batteriy. Are you saying that thios would not work to charge both on Solar??

Yes a BatteryMaster would work fine to charge the starter battery from the leisure battery on Solar. I think he was saying that if you have access to EHU all the time, and it charges the starter battery too, then a BatteryMaster is not necessary. However some people have limited access to EHU, on site and during storage, so a BatteryMaster is useful to keep the starter battery topped up. And some people just want to stay off-grid, parked by the beach, and spend the holiday surfing. So a BatteryMaster has its uses.

 

[Langtoftlad]

On my PVC, the cheapest of the cheapest PWM controller was fitted by the converter... And that charges the leisure battery and trickle charges the vehicle battery.

 

[TobyQuest]

Good shout on the battery master however as i sometimes store it covered/partially covered, the leisure battery would get drained over longer time and I actually turn my leisure battery off to avoid any parasitic draws on it. Seems like the 10w or less panels dont need a charge controller, perhaps their current is so small it cant really kill a 100ah engine battery and some of them have a charge controller anyway, so thinking to go that route.

Now just deciding whether 5w will be too small especially in winter and when the angle might not be into the sun and limited daylight hours, or go for a 10w/20w thats much larger and more noticeable and some pike might break in just for a few quid panel.

 

[Jev88]

Good shout on the battery master however as i sometimes store it covered/partially covered, the leisure battery would get drained over longer time and I actually turn my leisure battery off to avoid any parasitic draws on it. Seems like the 10w or less panels dont need a charge controller, perhaps their current is so small it cant really kill a 100ah engine battery and some of them have a charge controller anyway, so thinking to go that route.

Now just deciding whether 5w will be too small especially in winter and when the angle might not be into the sun and limited daylight hours, or go for a 10w/20w thats much larger and more noticeable and some pike might break in just for a few quid panel.

I saw some calculations that said less than 50W in windscreen was useless.

 

[autorouter]

I saw some calculations that said less than 50W in windscreen was useless.

However I have used a 2.5W panel successfully to keep a starter battery topped up. OK, it was facing directly south, with no shade, and tilted to about the optimum angle, but it worked. And the alarm etc was switched off because it was in a 24-hr patrolled secure area. If I was doing it again I'd go for a 10W at least, maybe a 20W.

I had a second 2.5W panel for the leisure batteries, and that didn't keep up with the discharge. It made a difference, but the level went down slowly. I'm sure a 10W or 20W panel would have been OK.

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[TobyQuest]

I saw some calculations that said less than 50W in windscreen was useless.

Sounds like very wrong calculations

 

[Jev88]

Sounds like very wrong calculations

I wish I could find it again...... it did mention actual harvest from sun in British weather so 50watt in reality may only generate 5W in winter - I think you see the argument but its so hard to advise depending on parasitic drawer from immobilisers and alarms etc....

 

[TobyQuest]

5w x 4 hours average lets say (on the low side) would be 20w per day, at 12v thats 1.66Amps per day, which over the course of a month is 50AH. The battery really wouldnt go down as much as that, possible something like 5-10AH max I would have thought.