Solar Panel/Leisure Battery Charging

[davieboy1956]

I have had 2 x Trojan TMX 27 batteriies fitted plus a 150w Bosch cell solar panel. The fitter told me that I didnt have to do any initial hook up charge on the batteries - the solar panel would do that for me. I also have had a Morningstar 25amp Sunsaver Duo fitted with a Remote Meter.All of this was done in order to allow me to stay out on the road longer before having to hook up on a site.

 

Now for my questions ! I have just returned from a 4 day test trip up to the North West coast of Scotland and am left rather puzzled and convinced something aint right. Firstly, my use is pretty light - water pump, 12 fridge freezer whilst on the move, LED lighting. At the end of each night the battery reading was 12.6 - I expected it to be much higher. . When I got up in the morning it would read anything from 13.6 to 14.3 - again something which surprised me given the restricted amount of light in the interim.

 

So -

 

1. Should I have charged the batteries on hook up before departure ?

 

2. The Trojan TMX27 is listed as a maiintenance free non sealed flooded leisure battery. What does this mean for charging and good maintenance?

 

3. Am I right in assuming that the 12.6 reading should not be the norm ?

 

4. What are the expected acceptable readings?

 

As always any constructive advice would be much appreciated.

 

Dave

 

 

[tonyg3nwl]

Hi, I am a little confused..firstly, are you sure that the fridge is only connected when the engine is running?

 

Secondly, the battery voltage for a fully charged battery at the end of the day having had engine running during travelling, will be expected to be near 14 volts..with engine off but still daylight, the solar panel will be charging, so it will still be around 14 volts.

 

after dark and no engine, but a small load of lighting, pump intermittently, and maybe indicating lights on fridge,or habitation control panel, the battery will probably settle back to nearer 12 volts overnight.

 

that is what I would expect to happen.

 

so when you get up in morning, and it is daylight again, the solar panel will be charging again and bringing voltage back up to 14 again.

does this make sense?

 

tonyg3nwl.

 

[StuartO]

I disagree. With a pair of relatively new batteries, at bedtime after an evenings light use, 12.6 seems to me to be a reasonable voltage to expect from what are only slightly discharged batteries which are not receiving any charge. I would expect your batteries to show 12.6 volts until they are at least 50% discharged, which it sounds like it's unlikely to happen. Likewise 14 volts is what you might expect when these slightly discharged batteries are being charged by solar panels once there is some daylight. All perfectly normal, no indication of fault and you almost certainly don't really have a problem.

 

What you are not measuring is the current flow in and out of the batteries over time, which would give you a better picture of what's going on, but your current system doesn't provide for that.

 

I wouldn't worry. Use your system and only if you encounter battery voltages below 12 volts might further investigation be needed.

[colin]

IIRC this has all been discussed and a concensus reached on a duplicate post in 'motorhome matters'

[nige118]

Hiya the reading you have said I would say it's normal. I have two 110amp battery's and two 90watt solar panels and the metre reads about 14.6 volts during the morning , using a 12volt tv blow air heating and led lights, by the end of the day it reads 12.6 volts, and we have camped 10 days without hookup. I would say your system is working correctly. Happy Days . :-D