Solar Trickle Charging for ATV Batteries

**mjp24coho** · September 1st, 2009, 7:01 PDT

Thanks, all - great advice. If I could summarize, it sounds like the best option would be to use a 5W panel, and have it feed into some sort of a box, where I had 3 separate blocking diodes to isolate each charging line, 3 separate fuses, and possible switches for 3 separate leads that would go into each battery. I think it would also be a good idea to have some type of a regulator from the panels to ensure no overvoltage. I assume a 1 Amp blocking diode would be sufficent. Have I summarized that correctly?

**Dave Sparks** · September 1st, 2009, 7:16 PDT

I stand by everything I posted and only would add that the OP should actually measure the voltage and get on with it. This is pretty basic stuff here. Just talking about a problem without data is not going to get a solution.

As for AGM's getting toasted off grid my experience is not to design with them until controllers have crowbar circuits that are doomsday proof. One of the failure modes is array voltage going to battery. It may be unlikely but NASA won't allow charging without a crowbar because of the obvious failure modes of AGM'a and the previous GEL's that went up there.

**mjp24coho** · September 1st, 2009, 7:17 PDT

Or another option would be to have 3 separate 5W panels ($66each) with a SunGuard 4.5 amp 12 Volt Charge Controller ($30 each). Would that be overkill, or could I get by with just 3 separate 1W panels? It seems like if I used 3 separate 1W panels (one for each battery), I wouldn't need a charge controller on each, right?

**mike95490** · September 1st, 2009, 8:19 PDT

Originally Posted by mjp24coho

Or another option would be to have 3 separate 5W panels ($66each) with a SunGuard 4.5 amp 12 Volt Charge Controller ($30 each). Would that be overkill, or could I get by with just 3 separate 1W panels? It seems like if I used 3 separate 1W panels (one for each battery), I wouldn't need a charge controller on each, right?

12, 18 & 28 A batteries. Maybe 4, 1W solar chargers, sometimes they have a LED in them used as a "alive & working" and blocking diode . Use 2 on the 28AH battery if needed. Buy 4 or 5 of them, they are cheap and one may be DOA. That's how I shop at Frys, 3 of everything, and return the duds at the next trip. I look for virgin boxes, and still get duds, I guess they fired the quality worker at the plants.

Get a good meter, and check the voltage when you arrive at camp, and then after a weekend running, enough start/stop cycles, the may be low when you depart.

**Dave Sparks** · September 1st, 2009, 10:44 PDT

Also check if the battery is a sealed AGM like Honda uses. These are great for the vibration. If you really have a liquid type battery consider the AGM with the diode as this will be a simple fix that will not harm your electrical system on board.

If you go solar how are you dealing with the alternator output?

I think if your problem is like all the other ATV battery problems I have seen and it is the AGM being slightly over charged and they last 2 or 3 years. AGM's are superior at staying charged all winter long even up here where it is cold. Your problem has nothing to do with staying charged it is lost capacity from being over volted. Once that happens you get the symtom of the battery not staying charged.

It will get worse and with a defective battery you'll get stuck somewhere unless you can pull start it. Then you start looking at buying an alternator from driving a defective battery. The real problem is the manufactures did not select and regulate the battery voltage set-point and the battery manufactures are very happy with this......