Battery Tender Solar: Temperature Compensation test

[hammick]

I bought a couple of these for cheap: BT Solar

Deltran told me on the phone they have the same temp comp as the BT Plus. I sent and email to the tech dept but they didn't respond. I don't think they have any temp comp. Tell me if my testing is sound.

I am testing it indoors with a power supply and it seems to charge nicely and goes to float and holds a constant float voltage.

I put the charger in the freezer which is set at 0 degrees Fahrenheit. My house was at 74 degrees Fahrenheit. Using the temp comp algorithm for the BT Plus it should put out .513 more volts with a 74 degree drop in temp.

At 74 degrees indoor temp the voltage at the terminals was 13.14v. After being in the freezer for a few hours the voltage at the terminals was also 13.14v.

Is this a sound test or should the battery also be put in the freezer?

I'm going to try the same thing with a BatteryMinder that has a temp comp lead.

I was hoping to use the BT Solar on two 6v GC2 batteries to maintain them over the winter in a Garage in Montana that has no power.

Looks like I'll have to spend some money for a solar CC that is adjustable and has a temp lead.

[westend]

I've forgotten which controller has temp comp, that is inexpensive, but others here on the Forum have used it. My Morningstar MPPT-15 does a brilliant job with temp comp but it may be out of your budget limits.

If you get a controller that doesn't have temp comp, it may be all that is necessary for a 6 month storage situation. If the batteries are in Montana at, say, Sept. and you wish to charge them until Apr., select a float voltage that is just a wee bit more than typical. Your batteries should manage fine.

[hammick]

I ran the same test on my Battery Minder with a temp probe and the voltages immediately went up. So the BT Solar Jr. definitely doesn't have temp comp.

I'm going to test out this one next: http://www.amazon.com/gp/product/B00ADKOMDI/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A3VAEX6T4LXLDZ

Looks identical to the WindyNation CC.

[MEXICOWANDERER]

This may well be a case where the Chinese told their customer the device has temperature compensation and the Amazon vendor never bothered to check it out before advertising it on eBay. Temperature compensation intergral to a regulation device is stoopid engineering. The regulation device heats up while controlling voltage and Marx Bros seizes control of the entire act. Integral temperature compensation -can- be done but no one on the face of the earth is going to build a device large enough to keep temp increase under <1c then do a compensatory adjustment to account for the +1c. Another GINZU knife marketing con.