RV Voltages too high while charging

grizzzman wrote:

Chandalen wrote:
I have a problem and have been wrapping my head around this for a few days.

I have four 100w Solar panels, and a Morningstar RJ-45 programmable charge controller wired to batteries. I have Four Interstate golf cart batteries in serial/parallel to make a 12v bank.

I have a Pure sine 2k inverter wired to batteries with two 1/0 wires per pole, and fused @150 amps per positive line.

My (major) problem is the Absorption phase of charging is at 15.3 volts.

This changes the RV wide battery powered voltage to 15.3 +- volts. This is really high for the LED lights I have, and I am afraid they are going to start burning out.

Because the absorption voltage is 15.3, the inverter turns off. Its voltage threshold is 10-15v.

For now, I dialed down the absorption voltage to 14.9 and everything is working. I am aware that my batteries will not fully charge with that voltage as its 0.50 less than needed. I was planning on equalizing once a month, when I'm not using the camper, as that voltage is 15.6

I can’t imagine I am the only one who has run across this issue, so is there an inexpensive fix, that won’t waste valuable battery power?

I have a small (1 amp) voltage stabilizer for a battery venting fan that can tolerate no more than 14v (which I found out the hard way) that works well for the fan.

I know that the DC items in campers can tolerate 11-15ish volts, I’m just wondering how well and for how long that fridge can run on 14.9v while the batteries are topping off, and the inverter is useless if I cant run it when the batteries are topping off either!!

I appreciate any feedback and insight!!

-James

Interstate battery customer service contact info 1-888-772-3600
SUBJECT charging profiles for GC-2 XHD,HD,RD and SRM 24.

Interstate admit's there error on the charging profile for there CG-2 batteries. They now recommend 14.4 bulk, absorption time 2 to 4 hours.
There CG-2 batteries are hybrid type. The positive plate is antimoney and the negative plate are calcium. I believe that there recommendation was over a fastest "safe" charging profile. Bulk at 14.4 then when amps get to 3 or 4 % of total amp hours amps are clamped (not allowed to rise) and voltage is allowed to rise to 15.3 volts. This gets the most into the battery at the end of the charge cycle when it is most resistant. As an example the SRM 24 12 volt calcium batteries recommended charging profile is 14.8 volts bulk then at 4% amps of C20 the amps are clamped then it is allowed to rise to as high as 16 volts.
When i said i dont think the RV would like that he replyed well 15.1 will work. Go figure:)

Remember this profile is for the "fastest" safe charging. Personally i would use a hydrometer to deside bulk voltage. 14.6 to 14.8 would "likely" do it.

Good luck!

Interstate would like you to not get "the hardest part of the charging done" because that's what is missing and wrecks your new batteries fastest, making you a customer for life with replacement batteries far too frequently. Your electronic devices, your batteries. I'd contact the manufacturers of each appliance or light bulb and see what maximum voltage is. Most LED bulb have a wide range of operating voltage. Pretty rare to see them pop or go poof.