Solar panel regulators

[Stuwsmith]

Does anyone have any experience/comment of either the Morningstar Sunsaver or the Sunware Fox solar panel regulators? I want to replace my present very simple regulator with a more effective one and think either of the above would be a big improvement. The Sunsaver and the Fox use different methods of charging and after reading up on the specs on the Net I am not sure if one is better than the other!

[Don Madge]

[QUOTE]Stuwsmith - 2006-10-28 5:25 PM Does anyone have any experience/comment of either the Morningstar Sunsaver or the Sunware Fox solar panel regulators? I want to replace my present very simple regulator with a more effective one and think either of the above would be a big improvement. The Sunsaver and the Fox use different methods of charging and after reading up on the specs on the Net I am not sure if one is better than the other! [/QUOTE] Stu, I've got the Fox 150, had it for about 8/9 years never had a problem with it. I don't know anything about them. I've got the instructions still. If you would like a copy I can scan them and mail them to you. Don

[Stuwsmith]

Don Thanks, at least it looks as though Fox are reliable. I have the details off the web for the Fox regs but thanks for the offer Stu

[Clive]

Do you by chance own a Bilbos Nektar camper, have recently bought a 45watt solar panel which you wish to use in conjunction with a freestanding 25watt panel and you have Waeco MDC50 fridge??? Small world isn,t it? Clive

[Stuwsmith]

Yes Clive, thats me! Thanks for your earlier reply that convinced me of the need to change the regulator. The reason for this, my first ever posting on a forum is to see if anyone has experience of these two specific regs. I was particularly interested to hear from anyone who used the Morningstar regulator that has a higher voltage of 14.4 depending on temperature and whether they experience the need to top up the battery frequently. The Fox seems to have a voltage set at 14.1v before it falls back to 13.8v float which presumably gives less risk of gassing but might not charge the battery as fully as the Morningstar. Never thought battery charging was so complicated! Stuart ps if I reverse my solar panel wiring in the evening will it charge all night?

[Terrytraveller]

Hi Stuart, I have the Sunsaver Solar regulator http://www.selectsolar.co.uk/pics/pic07001MS02.php coupled to 85 watt solar panel, charging a 110 amp Elecsol carbon fibre battery for nearly five years now. I find that the battery uses about a litre of water every twelve months, once fully charged, terminal voltage is around 14.4 - 14.8volts and 400mA trickle charge. There is some gassing, you see a bubble about every 60 secs, so I don't think its being overcharged, but doesn't it use alot of H2O ! Looking at the above web site it seems the unit pulse charges - didn't realise that to now, always thought it trickle charged. During the summer can have the sat receiver (1.5 amps) and a 5" TV (0.08 amps) for radio listening on all day, with 15" TV (3 amps) on for evening viewing, and never run out of power. Regards Terry

[Stuwsmith]

Thanks Terry, just what I wanted to know. I know there is the option of fitting a link to the Sunsaver to make it suitable for sealed batteries. This sets a slightly lower voltage and presumably minimises gassing and loss of water which isnt a good thing for sealed units; perhaps this option could be used for flooded batteries if water loss became too much of a problem? From what I can determine more sophisticated regulators like the Sunsaver use Pulse width modulation (PWM) which seems to offer more accurate voltage and current regulation. Supposed to be better for the battery as well by "knocking" off and preventing sulphation. That could be just sales talk of course.

[Terrytraveller]

Hi Stuart, Pleased it was of some help, I have the regulator set for flooded cells and also have bypassed the disconnect feature, so I can still use the battery when the voltage has gone below the 11.5 volts mark. I have the regualtor mounted high up in the camper (so I can see the pretty lights!), the battery is located under the floor, so whatever the temperature sensor is supposd to do to compensate for ambient temperature, it doesn't do it for my battery. They say the Elecsol carbon fibre battery is virtually indestructable, certainly I have drained it down almost flat and it has always recovered. Regarding the PWM mesurements I made on "trickle" charge, they were made with DVM and therefore only mean voltages will have been displayed (mind you - they were very steady). When the sun comes out again in some strength, I shall have to put a scope on it, just to see if the actual "trickle" charge voltage is alot higher, I suspect it will be. Not sure how I can check the current used with the scope though. Aren't sealed flood cell batteries mean't to condense the water back into the cells, I wonder if anyone out there can tell us if it works okay. I will try your suggestion of strapping it for Gel - thanks Regards Terry

[Stuwsmith]

Hi Terry Wow this is getting pretty technical now with talk of 'scopes! I may be wrong but here are my thoughts. Looking on the web the manufacturer states that the temperature compensator alters the 14.4v setpoint by -28mVolts per deg C outside a 25deg C reference. Not clear if this means at 24deg and 26deg the setpoint would be 14.372v or if it is just per deg above the reference temp. I have a CTEK charger that features a facility to raise the charging voltage if the battery is very cold which seems to imply that the regulators compensator reduces the voltage above 25 deg rather than below. If that's the case putting your regulator in the "correct" position near the battery and hence cooler would be likely to make water loss worse! The pulses must be high frequency so I doubt you would see any sign of them with an analogue meter either. I imagine if you used a 'scope then with a high charge you would see a large duration "on" pulse with a small "off" period in between and your 400mA trickle would show as a small "on" pulse with a large "off period in between. Not sure how you would measure current other than possibly using a shunt resistance. I think sealed batteries must have some mechanism to retain the water content but they must also have some form of vent to prevent the thing from blowing itself up. But if they gas too much, not sure how they could reconvert the oxygen and hydrogen back into water. Regards Stuart

[Terrytraveller]

Stuart, Just saw your advice about reversing the solar panel wiring to charge at night - I bet no one else has thought of that! It reminded me of parking at St Michael Chef Chef one night directly under their street light, the little green LED came on dimly, showing the battery was excepting a charge from the solar panel. The same thing happened at Honfleur when parked under the big lights in the centre of the camper aires. At Quiberon during a thunder storm, the little green LED came on so bright that it was lighting up the interior of the camper for several seconds at a time. Regards Terry

[Stuwsmith]

OK, now I think I have it cracked; new reglator, park up under bright lights and wait for a thunderstorm and then my fridge will never stop working! Seriously, thanks for your comments. These, together with some excellent advice from MMMs electrical expert, Clive, who also frequents these forums makes me inclined to go for the "intelligent" Fox regulator which although a wee bit more expensive has a lower setpoint voltage and would probably overcome the frequency of topping up. Clive reckoned 14.4v was the critical voltage, any more would cause a fair bit of gassing and therefore water loss. You mentioned in an earlier post 14.8v measured; perhaps this is a bit high and is the cause of having to put a litre of water in each year. Regards Stuart

[colin]

Terry the elecsol batteries are not sealed they have a vent at end, when you recieve battery you should get vent kit, and at work boss wreaked two elecsol betteries on an electric train.

[Mel E]

Back to CHARGE REGULATORS: Solar panels typically output at about 16.5 volts. That's really too much for a 12 volt battery, so the charge regulators to choose are those that first reduce the voltage to something in the region of 13 to 14 volts before applying it to the battery. This has a second benefit - you get more amps into your battery, so a better rate of charge. For example, a 75 watt panel puts 4.5 amps into the battery at 16.5 volts, but manages 5.5 amps at 13.5 volts. It also means that the battery is much less likely to gas when fully charged. These more sophisticated chargers also 'switch off' the charging cycle when the battery is fully charged.