Morning, I thought I would give my batteries a good "bashing" whilst in the UK for 3 weeks and would like to share with members on here my findings as I have read all the posts on here about "my battery is dead" or "why is my onboard charger not changing my battery" or "why does my engine not charge my batteries whilst running parked up" Firstly I have the following: (a) 3 x 110amp hour battery - These are in good condition and hold charge well. (b) Victron BMV 600S - This is by far the best thing for monitoring your 12 volt system. (c ) CBE charging system as fitted by MH manufacture - After many hours of searching the CBE system I have 2 x Safety relays EPC they are both in front of the CBE box. Photo: The inside of the case with the relay, fuse 50Amp (power circuit) and one 5 Amp. (Control circuit relay) (c) Solar panel 80watts - A 80 Watt solar panel will give you about 320 Watt-hours of energy on a summer day. For a 12 volt system, that corresponds to 26.7 Amp-hours put back into your battery bank each day. On sunny days, you will get more; on overcast days you will get less. So in Winter, your 80 Watt solar panel will only be giving you about 80 Watt-hours of energy per day in the worst case. For a 12 volt battery, that corresponds to 6.7 Amp-hours put back into your battery bank each day . (d) Ctek MXS 25 main charger - This runs off mains supply (EHU) or gene ( no problems with 10i ) It will start off charging at 14.6 and drop down over a period to 13.5 - start up can be 16/18amps then down to 0.1 amps depending on how long you run the gene for. I have found that after 2/3 hours the batteries are charged with NO load on the batteries. (e) Honda 10i Generator - This was bought after being recommended by many people as being the best out there. To date I have used it a handful of times, however over the past week it has been on most nights for this test. Findings: A typical night parked up we would have a few LED lights on the TV and Sat system with tuner box. At most about 4.5amps for 4/5 hours and as and when the water pump ( for cuppa etc ) so quick 3/4 amps. The batteries lasted first night no problem and the second, however by the third night voltage is around the 12.4 mark, that is without moving or charging. During the day here in the UK the solar panel is at best just taking up room on the roof. So happy enough I thought the batteries and charging system were doing what they should. Now as many on here think - no problem, I will start the engine and that will charge the batteries whilst I'm parked up....... NOT so as such because it takes hours of engine running just to add a few amps. A battery needs about 120% INPUT to get to full charge...so...your 110 leisure battery/batteries would need: 110 x 120% = 130Amps per hour. I have 3 x 100!!! Normal charging rate is at 10% for best life...SO.....13A for 10 hours and as most alternators will charge....14.2 - 14.4V at about 2000rpm it will drop the amps from 5/6/7/8 at start to 0.2 after 1 or 2 hours of running. So after that you are only trickle charging so that when you park up the batteries look good for about 1 or 2 hours and then the voltage drops very quickly. At this point many think that their batteries are destroyed because they wrongly or rightly think the run/drive should have charged/them............. So running a gene would resolve the problem....... well sort of.... the gene can only put in xxx amps so the same effect happens unless you're running it for hours on end ( not recommended in a busy location - at best you will annoy people off at worst it will get stolen! ) so I thought why not try a........ CTEK MXS 25 Mains charger which would work whilst on EHU and for use on the generator. Well it works great on EHU conditioning the batteries and can on the generator charge the batteries in 1/2 hours ( with NO LOAD ) pushing into the batteries 14/16/18 amps depending on state of charge, however again the generator has to be run. Please note I do not use the word "fully" as the following conditions apply: 2 hours at 10A = 20 - 5 hours at 5A = 25 - 10 hours at 3A = 30 and 20 hours at 1A = 20 (The last one is your engine running! ) So now what next.......... Well if you're never "off grid" you have nothing to worry about. If you are "off grid" once in a blue moon again you have nothing to worry about as in both cases your on board charger will sort things out for you as soon as you return to EHU. If however you plan to use your MH without paying for the privilege of EHU then I hope the above helps you understand that in the case of 12 volt you need more than the standard charging system fitted to most motorhomes. Keeping your batteries charged off grid is a bit of a black art and as many do not fully understand the charging system that they have fitted in the motorhome I thought my findings might be of use to others ( don't forget the like button ) I have ordered a sterling battery to battery charger and hope to fit it before leaving the UK to head back home to Spain, but I'm not too worried if I don't. My plan is to get rid of the gene as carrying it means carrying petrol too. I will update this post when I have had the sterling battery to battery charger fitted and tested. Any feedback on the sterling battery to battery charger from those who have fitted it would be great and even better if you have fitted it with a CBE system. Thanks for reading.